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Rogers EM, Banks NF, Trachta ER, Barone Gibbs B, Carr LJ, Jenkins NDM. Acceptability of Performing Resistance Exercise Breaks in the Workplace to Break Up Prolonged Sedentary Time: A Randomized Control Trial in U.S. Office Workers and Students. Workplace Health Saf 2024:21650799231215814. [PMID: 38314504 DOI: 10.1177/21650799231215814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2024]
Abstract
We investigated the acceptability of bodyweight resistance exercise breaks (REB) to disrupt prolonged sedentary behavior in the workplace. Twenty-nine individuals completed a REB, where they performed 3-min REB 4, 8, and 16 times on days 1-2, 3-4, and 5 of the workweek, respectively, and a control condition (i.e., SIT). Productivity was assessed on days 1 and 5 each week. The acceptability of each REB frequency was assessed. When asked to complete 4, 8, and 16 REB, participants completed (mean values) 3.2, 6.2, and 9.2 REB/day, respectively. Moreover, 88%, 40%, and 9% of participants expressed that the 4-, 8-, and 16-REB frequencies were acceptable, respectively. Decision-making ability and concentration levels increased from day 1-5 of the REB week (p=0.048) but were stable during SIT. REB (4/day) are highly acceptable and could be a promising intervention strategy for reducing occupational sitting, thus decreasing sedentary-behavior-induced risk.
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Affiliation(s)
- Emily M Rogers
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, The University of Iowa
- Department of Kinesiology, University of Wisconsin-Madison
| | - Nile F Banks
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, The University of Iowa
| | - Emma R Trachta
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, The University of Iowa
| | - Bethany Barone Gibbs
- Department of Epidemiology and Biostatistics, School of Public Health, West Virginia University
| | - Lucas J Carr
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, The University of Iowa
| | - Nathaniel D M Jenkins
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, The University of Iowa
- Abboud Cardiovascular Research Center, The University of Iowa
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Rogers EM, Banks NF, Jenkins NDM. The effects of sleep disruption on metabolism, hunger, and satiety, and the influence of psychosocial stress and exercise: A narrative review. Diabetes Metab Res Rev 2024; 40:e3667. [PMID: 37269143 DOI: 10.1002/dmrr.3667] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 04/27/2023] [Accepted: 05/18/2023] [Indexed: 06/04/2023]
Abstract
Sleep deficiency is a ubiquitous phenomenon among Americans. In fact, in the United States, ∼78% of teens and 35% of adults currently get less sleep than recommended for their age-group, and the quality of sleep appears to be getting worse for many. The consequences of sleep disruption manifest in a myriad of ways, including insulin resistance and disrupted nutrient metabolism, dysregulation of hunger and satiety, and potentially increased body weight and adiposity. Consequently, inadequate sleep is related to an increased risk of various cardiometabolic diseases, including obesity, diabetes, and heart disease. Exercise has the potential to be an effective therapeutic to counteract the deleterious effects of sleep disruption listed above, whereas chronic psychosocial stress may causally promote sleep disruption and cardiometabolic risk. Here, we provide a narrative review of the current evidence on the consequences of short sleep duration and poor sleep quality on substrate metabolism, circulating appetite hormones, hunger and satiety, and weight gain. Secondly, we provide a brief overview of chronic psychosocial stress and its impact on sleep and metabolic health. Finally, we summarise the current evidence regarding the ability of exercise to counteract the adverse metabolic health effects of sleep disruption. Throughout the review, we highlight areas where additional interrogation and future exploration are necessary.
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Affiliation(s)
- Emily M Rogers
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, The University of Iowa, Iowa City, Iowa, USA
| | - Nile F Banks
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, The University of Iowa, Iowa City, Iowa, USA
| | - Nathaniel D M Jenkins
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, The University of Iowa, Iowa City, Iowa, USA
- Abboud Cardiovascular Research Center, The University of Iowa, Iowa City, Iowa, USA
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West K, Spears K, Joyner B, Smith C, Jenkins NDM, Grosicki GJ, Siekirk NJ. The acute effect of passively assisted trunk stretching on central arterial stiffness and blood pressure in middle-aged to older adults. Eur J Appl Physiol 2024:10.1007/s00421-023-05389-9. [PMID: 38217670 DOI: 10.1007/s00421-023-05389-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 11/29/2023] [Indexed: 01/15/2024]
Abstract
PURPOSE We examined the effects of acute trunk stretching on central arterial stiffness and central and peripheral blood pressure in middle-aged to older adults. METHODS Twenty-eight middle-aged to older adults (14M/14F, 72 ± 7 years, 28.5 ± 5.3 kg/m2) completed this randomized, controlled, crossover design trial. We measured carotid-femoral pulse wave velocity (cf-PWV) and central and peripheral blood pressures (BP) before and after a single bout of passively assisted trunk stretching (i.e., five rounds of six 30-s stretches) and a time-matched seated control visit (i.e., 30-min). Changes (Δ; post - pre) in cf-PWV and central and peripheral BP were compared between visits and sexes using separate linear mixed-effects models controlling for baseline values. RESULTS Compared with seated control, central (systolic: - 3 ± 7 mmHg; diastolic: - 2 ± 5 mmHg) and peripheral (systolic: - 2 ± 8 mmHg; diastolic: - 1 ± 4 mmHg) BP were reduced following acute trunk stretching (ps ≤ 0.001). Between-visit differences for ∆cf-PWV (stretch: 0.09 ± 0.61 m/s; control: 0.37 ± 0.68 m/s, p = 0.038) were abolished when controlling for change in mean arterial pressure (∆MAP) (p = 0.687). The main effects of sex were detected for changes in systolic BPs (ps ≤ 0.029); more males (n = 13) saw BP reductions than females (n = 7). CONCLUSION These findings demonstrate the superiority of acute trunk stretching over passive sitting of equated duration for BP in middle-aged to older adults, with an appreciable effect in males compared to females.
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Affiliation(s)
- Kylee West
- Biomechanics Laboratory, Department of Health Sciences and Kinesiology, Georgia Southern University, P.O. Box 8076, Statesboro, GA, 30460, USA
- Biodynamics and Human Performance Center, Department of Health Sciences and Kinesiology, Georgia Southern University, Savannah, GA, USA
| | - Kaelyn Spears
- Biodynamics and Human Performance Center, Department of Health Sciences and Kinesiology, Georgia Southern University, Savannah, GA, USA
| | - Barry Joyner
- Center for Rehabilitation and Independent Living, Waters College of Health Professions, Georgia Southern University, Statesboro, GA, USA
| | - Collin Smith
- Internal Medicine, East Georgia Regional Medical Center, Statesboro, GA, USA
| | - Nathaniel D M Jenkins
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, Department of Health and Human Physiology, University of Iowa, Iowa City, IA, USA
- Francois M. Abboud Cardiovascular Research Center, University of Iowa, Iowa City, IA, USA
| | - Gregory J Grosicki
- Biodynamics and Human Performance Center, Department of Health Sciences and Kinesiology, Georgia Southern University, Savannah, GA, USA
| | - Nicholas J Siekirk
- Biomechanics Laboratory, Department of Health Sciences and Kinesiology, Georgia Southern University, P.O. Box 8076, Statesboro, GA, 30460, USA.
- Center for Rehabilitation and Independent Living, Waters College of Health Professions, Georgia Southern University, Statesboro, GA, USA.
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Banks NF, Rogers EM, Berry AC, Jenkins NDM. Progressive iso-inertial resistance exercise promotes more favorable cardiovascular adaptations than traditional resistance exercise in young adults. Am J Physiol Heart Circ Physiol 2024; 326:H32-H43. [PMID: 37889252 DOI: 10.1152/ajpheart.00402.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 10/23/2023] [Indexed: 10/28/2023]
Abstract
We compared the cardiovascular adaptations to resistance training (RT) using either traditional isotonic or iso-inertial resistance exercise in a randomized controlled study. Thirty-one healthy young adults (means ± SD, age = 24 ± 3 yr) completed 10 wk of traditional isotonic RT (TRT; n = 7 female/5 male), iso-inertial flywheel RT (FWRT; n = 7 female/4 male), or a habitual activity control (Con; n = 5 female/3 male). Before and following the intervention period, blood pressure, blood pressure reactivity, flow-mediated dilation (FMD), carotid-femoral pulse wave velocity (cfPWV), baroreflex sensitivity (BRS), and heart rate variability (RMSSD) were assessed. TRT and FWRT similarly improved isometric muscle strength. TRT significantly increased systolic blood pressure reactivity during isometric exercise compared with both FWRT (mean difference ± 95% CI, +10.8 ± 8.8 mmHg) and Con (+11.8 ± 9.1 mmHg). Cardiovagal BRS was significantly reduced in TRT versus FWRT (-6.82 ± 4.9 ms/mmHg; P = 0.006) but not between TRT versus Con (P = 0.12) or FWRT versus Con (P = 0.43). Resting heart rate (RHR) and RMSSD worsened in TRT compared with FWRT (RHR, +8 ± 5.8 beats/min, P = 0.006; RMSSD, -22.3 ± 15.6 ms, P = 0.004). Changes in BRS and RMSSD were associated with changes in blood pressure reactivity in the RT groups (r = -0.51 to -0.52). There were no significant changes in FMD or cfPWV in any group (P > 0.13). In conclusion, 10 wk of TRT and FWRT resulted in similar improvements in strength, but TRT caused impairments in blood pressure reactivity compared with FWRT and Con and parasympathetic nervous system activity compared with FWRT.NEW & NOTEWORTHY We characterized the cardiovascular effects of traditional, isotonic resistance training (TRT) versus flywheel-based iso-inertial resistance training (FWRT) in young healthy adults. Both TRT and FWRT improved strength, but TRT reduced cardiovagal baroreflex sensitivity and heart rate variability while increasing exercising blood pressure compared with FWRT. Our data indicate that TRT and FWRT result in different cardiovascular adaptations, where TRT, but not FWRT, may impair cardiovagal function and blood pressure reactivity in healthy, active young adults.
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Affiliation(s)
- Nile F Banks
- Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa, United States
- Department of Kinesiology, The University of Wisconsin, Madison, Wisconsin, United States
| | - Emily M Rogers
- Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa, United States
- Department of Kinesiology, The University of Wisconsin, Madison, Wisconsin, United States
| | - Alexander C Berry
- Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa, United States
| | - Nathaniel D M Jenkins
- Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa, United States
- Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa, United States
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, United States
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Keirns BH, Sciarrillo CM, Poindexter KL, Dixon MD, Medlin AR, Koemel NA, Hart SM, Geist CH, Jenkins NDM, Lucas EA, Emerson SR. Postprandial triglycerides across the aging spectrum: A secondary analysis utilizing an abbreviated fat tolerance test. Nutr Metab Cardiovasc Dis 2024; 34:121-125. [PMID: 37788958 DOI: 10.1016/j.numecd.2023.08.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 07/31/2023] [Accepted: 08/25/2023] [Indexed: 10/05/2023]
Abstract
BACKGROUND & AIMS Elevated postprandial triglycerides are an independent cardiovascular disease risk factor and observed in older adults. However, differences in postprandial triglycerides across the spectrum of adulthood remain unclear. METHODS AND RESULTS We performed a secondary analysis of six studies where adults (aged 18-84 years; N = 155) completed an abbreviated fat tolerance test (9 kcal/kg; 70% fat). Differences in postprandial triglycerides were compared in those ≥50 and <50 years and by decade of life, adjusting for sex and BMI. Compared to those <50 years, participants ≥50 years had higher fasting, 4 h, and Δ triglycerides from baseline (p's < 0.05). When examining triglyceride parameters by decade, no differences were observed for fasting triglycerides, but 50 s, 60 s, and 70s-80 s displayed greater 4 h and Δ triglycerides versus 20 s (p's ≤ 0.001). The frequency of adverse postprandial triglyceride responses (i.e., ≥220 mg/dL) was higher in participants ≥50 versus <50 years (p < 0.01), and in 60 s compared to all other decades (p = 0.01). CONCLUSION Older age was generally associated with higher postprandial triglycerides, with no divergence across the spectrum of older adulthood. In our sample, postprandial triglyceride differences in older and younger adults were driven by those >50 years relative to young adults in their 20 s. REGISTRATION N/A (secondary analysis).
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Affiliation(s)
- Bryant H Keirns
- Department of Nutrition and Health Science, Ball State University, Muncie, IN 47306, USA.
| | - Christina M Sciarrillo
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74075, USA
| | - Kara L Poindexter
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74075, USA
| | - Madison D Dixon
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74075, USA
| | - Austin R Medlin
- Department of Health & Wellness Design, Indiana University School of Public Health, 1025 E. Seventh St., Bloomington, IN 47405, USA
| | - Nicholas A Koemel
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, 2006, USA; Sydney Medical School, The University of Sydney, NSW, 2006, Australia
| | - Samantha M Hart
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74075, USA
| | - Caroline H Geist
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74075, USA
| | - Nathaniel D M Jenkins
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, 52242, USA; Abboud Cardiovascular Research Center, University of Iowa, Iowa City, IA, 52242, USA
| | - Edralin A Lucas
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74075, USA
| | - Sam R Emerson
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74075, USA
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Banks NF, Rogers EM, Stanhewicz AE, Whitaker KM, Jenkins NDM. Resistance exercise lowers blood pressure and improves vascular endothelial function in individuals with elevated blood pressure or stage-1 hypertension. Am J Physiol Heart Circ Physiol 2024; 326:H256-H269. [PMID: 37975709 DOI: 10.1152/ajpheart.00386.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 11/15/2023] [Accepted: 11/15/2023] [Indexed: 11/19/2023]
Abstract
Lifestyle modifications are the first-line treatment recommendation for elevated blood pressure (BP) or stage-1 hypertension (E/S1H) and include resistance exercise training (RET). The purpose of the current study was to examine the effect of a 9-wk RET intervention in line with the current exercise guidelines for individuals with E/S1H on resting peripheral and central BP, vascular endothelial function, central arterial stiffness, autonomic function, and inflammation in middle-aged and older adults (MA/O) with untreated E/S1H. Twenty-six MA/O adults (54 ± 6 yr; 16 females/10 males) with E/S1H engaged in either 9 wk of 3 days/wk RET (n = 13) or a nonexercise control (Con; n = 13). Pre- and postintervention measures included peripheral and central systolic (SBP and cSBP) and diastolic BP (DBP and cDBP), flow-mediated dilation (FMD), carotid-femoral pulse wave velocity (cfPWV), cardiovagal baroreflex sensitivity (BRS), cardiac output (CO), total peripheral resistance (TPR), heart rate variability (HRV), and C-reactive protein (CRP). RET caused significant reductions in SBP {mean change ± 95% CI = [-7.9 (-12.1, -3.6) mmHg; P < 0.001]}, cSBP [6.8 (-10.8, -2.7) mmHg; P < 0.001)], DBP [4.8 (-10.3, -1.2) mmHg; P < 0.001], and cDBP [-5.1 (-8.9, -1.3) mmHg; P < 0.001]; increases in FMD [+2.37 (0.61, 4.14)%; P = 0.004] and CO [+1.21 (0.26, 2.15) L/min; P = 0.006]; and a reduction in TPR [-398 (-778, -19) mmHg·s/L; P = 0.028]. RET had no effect on cfPWV, BRS, HRV, or CRP relative to Con (P ≥ 0.20). These data suggest that RET reduces BP in MA/O adults with E/S1H alongside increased peripheral vascular function and decreased TPR without affecting cardiovagal function or central arterial stiffness.NEW & NOTEWORTHY This is among the first studies to investigate the effects of chronic resistance exercise training on blood pressure (BP) and putative BP regulating mechanisms in middle-aged and older adults with untreated elevated BP or stage-1 hypertension in a randomized, nonexercise-controlled trial. Nine weeks of resistance exercise training elicits 4- to 8-mmHg improvements in systolic and diastolic BP alongside improvements in vascular endothelial function and total peripheral resistance without influencing central arterial stiffness or cardiovagal function.
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Affiliation(s)
- Nile F Banks
- Department of Health and Human Physiology, The University of Iowa, Iowa City, Iowa, United States
| | - Emily M Rogers
- Department of Health and Human Physiology, The University of Iowa, Iowa City, Iowa, United States
| | - Anna E Stanhewicz
- Department of Health and Human Physiology, The University of Iowa, Iowa City, Iowa, United States
| | - Kara M Whitaker
- Department of Health and Human Physiology, The University of Iowa, Iowa City, Iowa, United States
| | - Nathaniel D M Jenkins
- Department of Health and Human Physiology, The University of Iowa, Iowa City, Iowa, United States
- Abboud Cardiovascular Research Center, The University of Iowa, Iowa City, Iowa, United States
- Fraternal Order of Eagles Diabetes Research Center, The University of Iowa, Iowa City, Iowa, United States
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Schwager LE, Helwig NJ, Rogers EM, Banks NF, Alpers JP, Schulte SL, Lockwood CM, Jenkins NDM. Novel Energy Drink Improves Cognitive Function and Mood, without Influencing Myocardial Oxygen Demand or Ventricular Repolarization in Adult Gamers: A Randomized, Double-Blind, Placebo-Controlled, Crossover Trial. J Am Nutr Assoc 2024; 43:33-47. [PMID: 37186677 DOI: 10.1080/27697061.2023.2207096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 04/21/2023] [Indexed: 05/17/2023]
Abstract
OBJECTIVES To examine the efficacy of acute consumption of a novel energy drink (C4S) versus placebo for improving cognitive and gaming performance and mood. Secondarily, we examined the cardiovascular safety profile of acute C4S consumption. METHODS Forty-five healthy, young adult video gamers completed two experimental visits in randomized order where they consumed either C4S or a placebo and then completed a validated battery of neurocognitive tests, played five video games, and completed a mood state survey. Blood pressure (BP), heart rate (HR), oxygen saturation, and electrocardiogram measurements were taken at baseline and repeated throughout each visit. RESULTS Acute consumption of C4S improved cognitive flexibility (absolute mean or median difference [95% CI] = +4.3 [2.2-6.4]; p < 0.001; d = 0.63), executive function (+4.3 [2.3-6.3]; p < 0.001; d = 0.63), sustained attention (+2.1 [0.6-3.6]; p = 0.01; d = 0.44), motor speed (+2.9 [0.8-4.9]; p < 0.001; d = 0.44), psychomotor speed (+3.9 [0.1-7.7]; p = 0.04; d = 0.32) working memory (+1.0 [0.1-1.9]; p = 0.02; d = 0.35), and performance in the two-dimensional visuospatial game Tetris (+463 [-419-2,065] pts; p = 0.049; d = 0.30) compared to placebo. C4S also improved Fatigue-Inertia (-1 [-3-0]; p = 0.004; d = 0.45), Vigor-Activity (+2.4 [1.3-3.6]; p < 0.001; d = 0.64), Friendliness (+0 [0-1]; p = 0.04; d = 0.32), and Total Mood Disturbance (-3 [-6-0]; p = 0.002; d = 0.44). BP increased slightly in C4S versus placebo, while HR decreased from baseline to post-drink in the C4S condition. Rate-pressure-product was higher in C4S versus placebo independent of time but did not increase from baseline. There was no effect on corrected QT interval. CONCLUSION Acute consumption of C4S was efficacious for cognitive performance, visuospatial gaming performance, and mood enhancement, and had no effect on myocardial oxygen demand or ventricular repolarization, despite being associated with increases in BP.
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Affiliation(s)
- Laura E Schwager
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Nathaniel J Helwig
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Emily M Rogers
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Nile F Banks
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Justin P Alpers
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Sydni L Schulte
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, University of Iowa, Iowa City, Iowa, USA
| | | | - Nathaniel D M Jenkins
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, University of Iowa, Iowa City, Iowa, USA
- Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa, USA
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Gallagher J, Bayman EO, Cadmus-Bertram LA, Jenkins NDM, Pearlman A, Whitaker KM, Carr LJ. Physical Activity Among Rural Men: Barriers and Preferences. Prev Chronic Dis 2023; 20:E88. [PMID: 37797290 PMCID: PMC10557978 DOI: 10.5888/pcd20.230046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2023] Open
Abstract
INTRODUCTION Physical activity positively affects health. Although 94% of Americans know the health benefits of regular physical activity, more than 75% do not achieve recommended levels. The objective of our study was to identify and define the key components of a physical activity intervention tailored to rural American men. METHODS We recruited rural men (N = 447) via Amazon's Mechanical Turk online platform to complete a needs assessment survey focused on their interest in a physical activity intervention, preferred intervention features, and potential intervention objectives. Data were summarized by using descriptive statistics. A cumulative logistic regression model examined associations between the men's perceived importance of physical activity to health and their interest in a physical activity intervention. RESULTS Almost all participants (97.7%) rated physical activity as "at least somewhat important" to their health, and 83.9% indicated they would be "at least somewhat interested" in participating in a physical activity intervention. On a scale of 1 (not at all a barrier) to 5 (very much a barrier), motivation (mean 3.4; 95% CI, 3.3-3.5), cold weather (mean, 3.4; 95% CI, 3.3-3.5), and tiredness (mean, 3.3; 95% CI, 3.2-3.4) were rated the biggest barriers to physical activity. Becoming fitter (54.1%) was the top reason for joining a physical activity program. Preferred delivery channels for receiving an intervention were mobile application (ranked from 1 being the most preferred and 9 being the least preferred: mean, 2.8; 95% CI, 2.70-3.09) and e-mail (mean, 4.2; 95% CI, 3.92-4.36). Rural men preferred interventions that taught them how to exercise and that could be done from home. CONCLUSION Our findings suggest US men in rural areas are receptive to physical activity programs. A systematic approach and a clear model of development are needed to tailor future physical activity interventions to the special needs of rural men.
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Affiliation(s)
- Jacob Gallagher
- Department of Health and Human Physiology, University of Iowa, Iowa City
- 225 S Grand Ave, Iowa City, IA 52242
| | - Emine O Bayman
- Departments of Biostatistics and Anesthesia, University of Iowa, Iowa City
| | | | | | | | - Kara M Whitaker
- Department of Health and Human Physiology, University of Iowa, Iowa City
- Department of Epidemiology, University of Iowa, Iowa City
| | - Lucas J Carr
- Department of Health and Human Physiology, University of Iowa, Iowa City
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Tahsin CT, Michopoulos V, Powers A, Park J, Ahmed Z, Cullen K, Jenkins NDM, Keller-Ross M, Fonkoue IT. Sleep efficiency and PTSD symptom severity predict microvascular endothelial function and arterial stiffness in young, trauma-exposed women. Am J Physiol Heart Circ Physiol 2023; 325:H739-H750. [PMID: 37505472 PMCID: PMC10642999 DOI: 10.1152/ajpheart.00169.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 07/13/2023] [Accepted: 07/28/2023] [Indexed: 07/29/2023]
Abstract
Posttraumatic stress disorder (PTSD) is linked to sleep disturbances and significantly higher risk of developing cardiovascular disease (CVD). Furthermore, vascular dysfunction and sleep are independently associated with CVD. Uncovering the link between PTSD symptom severity, sleep disturbances, and vascular function could shine a light on mechanisms of CVD risk in trauma-exposed young women. The purpose of the present study was to investigate the individual and combined effects of sleep efficiency and PTSD symptom severity on vascular function. We recruited 60 otherwise healthy women [age, 26 ± 7 yr and body mass index (BMI), 27.7 ± 6.5 kg/m2] who had been exposed to trauma. We objectively quantified sleep efficiency (SE) using actigraphy, microvascular endothelial function via Framingham reactive hyperemia index (fRHI), and arterial stiffness via pulse-wave velocity (PWV). PTSD symptom severity was assessed using the PTSD checklist for fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) (PCL5). PWV was correlated with age (r = 0.490, P < 0.001) and BMI (r = 0.484, P < 0.001). In addition, fRHI was positively correlated with SE (r = 0.409, P = 0.001) and negatively correlated with PTSD symptoms (r = -0.382, P = 0.002). To explore the predictive value of SE and PTSD symptoms on PWV and fRHI, we conducted two multivariate linear regression models. The model predicting PWV was significant (R2 = 0.584, P < 0.001) with age, BMI, blood pressure, and SE emerging as predictors. Likewise, the model predicting fRHI was significant (R2 = 0.360, P < 0.001) with both PTSD symptoms and SE as significant predictors. Our results suggest that although PTSD symptoms mainly impact microvascular endothelial function, sleep efficiency is additionally associated with arterial stiffness in young trauma-exposed women, after controlling for age and BMI.NEW & NOTEWORTHY This is the first study to investigate the individual and combined impacts of objective sleep and PTSD symptoms severity on arterial stiffness and microvascular endothelial function in young premenopausal women. We report that in young trauma-exposed women, although low sleep efficiency is associated with overall vascular function (i.e., microvascular endothelial function and arterial stiffness), the severity of PTSD symptoms is specifically associated with microvascular endothelial function, after accounting for age and body mass index.
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Affiliation(s)
- Chowdhury Tasnova Tahsin
- Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States
| | - Vasiliki Michopoulos
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia, United States
| | - Abigail Powers
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia, United States
| | - Jeanie Park
- Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
- Department of Veterans Affairs, Research Service Line, Atlanta Veterans Affairs Healthcare Systems, Decatur, Georgia, United States
| | - Zynab Ahmed
- Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States
| | - Kathryn Cullen
- Department of Psychiatry, University of Minnesota Medical School, Minneapolis, Minnesota, United States
| | - Nathaniel D M Jenkins
- Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa, United States
- Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa, United States
| | - Manda Keller-Ross
- Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States
| | - Ida T Fonkoue
- Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States
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Rogers EM, Banks NF, Jenkins NDM. Acute effects of daily step count on postprandial metabolism and resting fat oxidation: a randomized controlled trial. J Appl Physiol (1985) 2023; 135:812-822. [PMID: 37560764 DOI: 10.1152/japplphysiol.00052.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 07/20/2023] [Accepted: 08/05/2023] [Indexed: 08/11/2023] Open
Abstract
To examine the effects of daily step count on same-day fat oxidation and postprandial metabolic responses to an evening high-fat mixed meal (HFMM). Ten healthy participants (5 females, 30 ± 7 yr) completed four different daily step counts-2,000 (2 K), 5,000 (5 K), 10,000 (10 K), and 15,000 (15 K) steps-on separate days in randomized order. On experimental days, participants ate the same meals and walked all steps on an indoor track at a pace of 100 steps/min in three roughly equal bouts throughout the day. After the final walking bout, participants' resting energy expenditure (REE), respiratory exchange ratio (RER), and fat oxidation rate (FATOX) were measured. Blood samples were obtained before (BL) and 30-, 60-, 90-, 120-, and 240-min following consumption of an HFMM (960 kcal; 48% fat) to measure triglycerides (i.e., postprandial lipemia; PPL), nonesterified fatty acids (NEFAs), insulin, and glucose. Two-way ANOVAs indicated condition effects where PPL was significantly higher after 2 K versus 10 K (+23 ± 8 mg/dL, P = 0.027), and NEFAs were significantly higher after 15 K versus 2 K (+86 ± 23 µmol/L; P = 0.006). No differences were found for insulin, glucose, or REE among conditions (all P > 0.124). Similarly, RER (P = 0.054; ηp2 = 0.24) and FATOX (P = 0.071; ηp2 = 0.23) were not significantly different among conditions. In young adults, 10 K steps elicited the greatest decrease in PPL, an established cardiovascular disease risk factor. NEFA levels were highest after the 15 K condition, likely due to alterations in adipose tissue lipolysis or lipoprotein lipase activity with increased activity.NEW & NOTEWORTHY This randomized controlled trial demonstrated that walking 10,000, compared with 2,000, steps/day significantly reduced postprandial lipemia (PPL), an independent predictor of cardiovascular disease (CVD) following same-day evening meal consumption. These experimental data support walking 10,000 steps/day to lower CVD risk.
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Affiliation(s)
- Emily M Rogers
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, The University of Iowa, Iowa City, Iowa, United States
| | - Nile F Banks
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, The University of Iowa, Iowa City, Iowa, United States
| | - Nathaniel D M Jenkins
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, The University of Iowa, Iowa City, Iowa, United States
- Abboud Cardiovascular Research Center, The University of Iowa, Iowa City, Iowa, United States
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Robinson AT, Jenkins NDM, Sanchez SO, Haack KKV, Lee DL, Mathis KW, Warrington JP. Supporting and promoting Black physiologists: How can the APS help? Am J Physiol Heart Circ Physiol 2023; 324:H782-H785. [PMID: 37000608 DOI: 10.1152/ajpheart.00082.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/01/2023]
Grants
- K01HL147998 HHS | NIH | National Heart, Lung, and Blood Institute (NHLBI)
- R15HL165325 HHS | NIH | National Heart, Lung, and Blood Institute (NHLBI)
- R49 CE003095 NCIPC CDC HHS
- K01HL139859 HHS | NIH | National Heart, Lung, and Blood Institute (NHLBI)
- R01HL153703 HHS | NIH | National Heart, Lung, and Blood Institute (NHLBI)
- R56HL159447 HHS | NIH | National Heart, Lung, and Blood Institute (NHLBI)
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Affiliation(s)
- Austin T Robinson
- Neurovascular Physiology Laboratory, School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Nathaniel D M Jenkins
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, Department of Health and Human Physiology, University of Iowa, Iowa City, IA, United States
- Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Sofia O Sanchez
- Neurovascular Physiology Laboratory, School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Karla K V Haack
- Global Clinical Trial Operations, U.S. Merck corporate headquarters, Rahway, NJ, United States
| | - Dexter L Lee
- Department of Physiology and Biophysics, Howard University College of Medicine, Washington, DC, United States
| | - Keisa W Mathis
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX, United States
| | - Junie P Warrington
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS, United States
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12
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Rogers EM, Banks NF, Tomko PM, Sciarrillo CM, Emerson SR, Thomas EBK, Taylor A, Teague TK, Jenkins NDM. Progressive exercise training improves cardiovascular psychophysiological outcomes in young adult women with a history of adverse childhood experiences. J Appl Physiol (1985) 2023; 134:742-752. [PMID: 36727632 PMCID: PMC10027078 DOI: 10.1152/japplphysiol.00524.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 12/14/2022] [Accepted: 01/30/2023] [Indexed: 02/03/2023] Open
Abstract
Adverse childhood experiences (ACEs) are early-life psychosocial stressors that are associated with poorer mental health and increased cardiovascular disease (CVD) risk in a dose-dependent manner. We examined the feasibility of an 8-wk combined aerobic and resistance exercise training program to improve systolic (SBP) and diastolic blood pressure (DBP), serum endothelin-1 (ET-1), resilience, hope agency, and hope pathways in young women with ACEs. Forty-two healthy women (21 ± 3 yr) with ≥4 (ACE+; n = 28) or 0 ACEs (ACE-; n = 14) participated in this study. Women with ACEs were randomly assigned to an exercise (ACE+EXT; n = 14) or nonexercise control (ACE+CON; n = 14) group, whereas all ACE- participants were assigned to a nonexercise control (n = 14) group. Hope agency and DBP did not change in any group (P ≥ 0.43), but hope pathways improved only in ACE+EXT (means ± SE change; +1.6 ± 0.74 au, P = 0.032, Hedges' g = 0.53). ET-1 decreased in ACE+EXT only (-0.31 ± 0.15 pg/mL, P = 0.043, g = 0.46). Although the interactions for resilience and SBP did not reach significance (P = 0.05-0.06), forced post hoc analyses indicated that resilience improved (+4.9 ± 1.9 au, P = 0.012, g = 0.64) and SBP tended to improve (-4.0 ± 2.0 mmHg, P = 0.053, g = 0.51) in ACE+EXT only. There were significant associations between changes in hope pathways and SBP (ρ = -0.43, P = 0.023) and ET-1 (ρ = -0.53, P = 0.005), and between changes in SBP and ET-1 (ρ = 0.49; P = 0.012) in the ACE+ group. In summary, structured exercise training reduces serum ET-1 levels, improves positive psychological coping, and may improve SBP in young women with ACEs. The relationships among the changes in hope pathways, SBP, and ET-1 suggest a cardiovascular psychophysiological relationship in young women with ACEs.NEW & NOTEWORTHY This randomized controlled pilot trial shows, for the first time, that 8 wk of structured, progressive exercise training lowers serum endothelin-1 (ET-1) and improves positive psychological coping in young women with significant early-life psychosocial stress. Furthermore, the observed associations among changes in psychological attributes, ET-1, and systolic blood pressure signify a potential interplay between positive psychology and cardiovascular disease risk among women with adverse childhood experiences.
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Affiliation(s)
- Emily M Rogers
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, University of Iowa, Iowa City, Iowa, United States
| | - Nile F Banks
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, University of Iowa, Iowa City, Iowa, United States
| | - Patrick M Tomko
- School of Health Sciences, Kent State University, Kent, Ohio, United States
| | | | - Sam R Emerson
- Laboratory of Applied Nutrition and Exercise Science, Oklahoma State University, Stillwater, Oklahoma, United States
| | - Emily B K Thomas
- Department of Psychology and Brain Sciences, University of Iowa, Iowa City, Iowa, United States
| | - Ashlee Taylor
- Integrative Immunology Center, University of Oklahoma School of Community Medicine, Tulsa, Oklahoma, United States
| | - T Kent Teague
- Integrative Immunology Center, University of Oklahoma School of Community Medicine, Tulsa, Oklahoma, United States
- Department of Surgery, University of Oklahoma School of Community Medicine, Tulsa, Oklahoma, United States
- Department of Psychiatry, University of Oklahoma School of Community Medicine, Tulsa, Oklahoma, United States
- Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Science, Tulsa, Oklahoma, United States
| | - Nathaniel D M Jenkins
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, University of Iowa, Iowa City, Iowa, United States
- Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa, United States
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13
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Rogers EM, Banks NF, Jenkins NDM. Metabolic and microvascular function assessed using near-infrared spectroscopy with vascular occlusion in women: age differences and reliability. Exp Physiol 2023; 108:123-134. [PMID: 36420592 PMCID: PMC10103776 DOI: 10.1113/ep090540] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 11/01/2022] [Indexed: 11/25/2022]
Abstract
NEW FINDINGS What is the central question of this study? Can the near-infrared spectroscopy with vascular occlusion test (NIRS-VOT) reliably measure skeletal muscle metabolic and microvascular function in women? What is the main finding and its importance? The NIRS-VOT can be used as a reliable technique for the assessment of skeletal muscle metabolism and microvascular function in women, with reliability being generally greater in younger women. These findings have important implications for the planning and development of future studies employing the NIRS-VOT in women, and provide insights into the effects of age on these parameters in women specifically. ABSTRACT We investigated the test-retest reliability of, and age-related differences in, markers of skeletal muscle metabolism and microvascular function derived from the near-infrared spectroscopy with vascular occlusion test (NIRS-VOT) in younger women (YW) and middle-aged and older women (MAOW). Seventeen YW (age 23 ± 4 years) and 17 MAOW (age 59 ± 8 years) completed this study. Participants completed identical experimental visits separated by ∼4 weeks during which the NIRS-VOT was used to quantify the occlusion slope, minimum and maximum tissue saturation, ischaemic index, reperfusion magnitude, the reperfusion and 10-s reperfusion slopes (slope 2 and slope 210-s ), time to max tissue saturation, and area under the reperfusion curve using the local tissue oxygen saturation signal. Except for slope 210-s (intraclass correlation coefficient (ICC) = 0.37; coefficient of variation (CV) = 31%), time to max tissue saturation (ICC = 0.21), and ischaemic index (ICC = 0.37) for MAOW, all of the NIRS variables demonstrated good to excellent relative reliability for the YW (ICCs = 0.74-0.86) and the MAOW (ICCs = 0.51-0.87), with CVs of 2-21% and 2-22%, respectively. The occlusion slope was significantly lower, indicating accelerated deoxygenation, while maximum tissue saturation, reperfusion magnitude, and ischaemic index were significantly higher in YW versus MAOW. No other group differences were found. In conclusion, our data support the use of the NIRS-VOT as a simple, reliable, non-invasive technique for the assessment of peripheral skeletal muscle metabolism and microvascular function in women, with the reliability being generally greater in YW versus MAOW. Further, our data suggest that ageing is associated with lower skeletal muscle metabolism and microvascular hyperaemic responsiveness in women.
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Affiliation(s)
- Emily M. Rogers
- Integrative Laboratory of Applied Physiology and Lifestyle MedicineUniversity of IowaIowa CityIAUSA
| | - Nile F. Banks
- Integrative Laboratory of Applied Physiology and Lifestyle MedicineUniversity of IowaIowa CityIAUSA
| | - Nathaniel D. M. Jenkins
- Integrative Laboratory of Applied Physiology and Lifestyle MedicineUniversity of IowaIowa CityIAUSA
- Abboud Cardiovascular Research CenterUniversity of IowaIowa CityIAUSA
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Jenkins NDM, Robinson AT. How do Adverse Childhood Experiences get Under the Skin to Promote Cardiovascular Disease? A Focus on Vascular Health. Function (Oxf) 2022; 3:zqac032. [PMID: 35859580 PMCID: PMC9279110 DOI: 10.1093/function/zqac032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 06/08/2022] [Accepted: 06/09/2022] [Indexed: 01/07/2023] Open
Affiliation(s)
- Nathaniel D M Jenkins
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, Department of Health and Human Physiology, University of Iowa, Iowa City, IA 52242, USA
- Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Austin T Robinson
- Neurovascular Physiology Laboratory, School of Kinesiology, Auburn University, Auburn, AL 36849, USA
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Jenkins NDM, Rogers EM, Banks NF, Tomko PM, Sciarrillo CM, Emerson SR, Taylor A, Teague TK. Structured, Progressive Exercise Training Improves Cardiovascular Psychophysiological Outcomes in Young Adult Women with a History of Adverse Childhood Experiences. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r6215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Nile F. Banks
- Health and Human PhysiologyUniversity of IowaIowa CityIA
| | | | | | - Sam R. Emerson
- Department of Nutritional SciencesOklahoma State UniversityStillwaterOK
| | - Ashlee Taylor
- University of Oklahoma School of Community MedicineTulsaOK
| | - T. K. Teague
- University of Oklahoma School of Community MedicineTulsaOK
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Banks NF, Rogers EM, Church DD, Ferrando AA, Jenkins NDM. The contributory role of vascular health in age-related anabolic resistance. J Cachexia Sarcopenia Muscle 2022; 13:114-127. [PMID: 34951146 PMCID: PMC8818606 DOI: 10.1002/jcsm.12898] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 10/18/2021] [Accepted: 11/22/2021] [Indexed: 12/25/2022] Open
Abstract
Sarcopenia, or the age-related loss of skeletal muscle mass and function, is an increasingly prevalent condition that contributes to reduced quality of life, morbidity, and mortality in older adults. Older adults display blunted anabolic responses to otherwise anabolic stimuli-a phenomenon that has been termed anabolic resistance (AR)-which is likely a casual factor in sarcopenia development. AR is multifaceted, but historically much of the mechanistic focus has been on signalling impairments, and less focus has been placed on the role of the vasculature in postprandial protein kinetics. The vascular endothelium plays an indispensable role in regulating vascular tone and blood flow, and age-related impairments in vascular health may impede nutrient-stimulated vasodilation and subsequently the ability to deliver nutrients (e.g. amino acids) to skeletal muscle. Although the majority of data has been obtained studying younger adults, the relatively limited data on the effect of blood flow on protein kinetics in older adults suggest that vasodilatory function, especially of the microvasculature, strongly influences the muscle protein synthetic response to amino acid feedings. In this narrative review, we examine evidence of AR in older adults following amino acid and mixed meal consumption, examine the evidence linking vascular dysfunction and insulin resistance to age-related AR, review the influence of nitric oxide and endothelin-1 on age-related vascular dysfunction as it relates to AR, briefly review the potential causal role of arterial stiffness in promoting skeletal muscle microvascular dysfunction and AR, and provide a brief overview and future considerations for research examining age-related AR.
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Affiliation(s)
- Nile F Banks
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, University of Iowa, Iowa City, IA, USA
| | - Emily M Rogers
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, University of Iowa, Iowa City, IA, USA
| | - David D Church
- Center for Translational Research in Aging and Longevity, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Arny A Ferrando
- Center for Translational Research in Aging and Longevity, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Nathaniel D M Jenkins
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, University of Iowa, Iowa City, IA, USA.,Abboud Cardiovascular Research Center, University of Iowa, Iowa City, IA, USA
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17
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Magrini MA, Colquhoun RJ, Ferrell MC, Fleming SR, Mota JA, Siedlik JA, Poidomani NM, Jenkins NDM, DeFreitas JM. The Influence of Motor Unit Number and Muscle Activation on Early Phase Rate of Torque Development in Younger and Older Men. J Mot Behav 2021; 54:422-428. [PMID: 34763617 DOI: 10.1080/00222895.2021.2001412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
This study examined the influence of muscle activation and motor unit number estimation (MUNE) on early phase voluntary rate of torque development (RTD) in younger (YM) and older (OM) men. Thirty-two YM (n = 17; Age = 22 yrs) and OM (n = 15; Age = 74 yrs) volunteered to participate in this study. Early phase RTD (first 50 ms of a rapid isometric contraction; RTD50) and normalized surface electromyography (first 50 ms of muscle excitation; nEMG50) were recorded from the right quadricep muscle group. MUNE was examined from the right vastus lateralis. Multiple linear regression analyses revealed that nEMG50 had a significant effect on RTD50 independent of age group (p ≤ 0.001). nEMG50 had a significant effect on RTD50 in the OM group (p = 0.037). MUNE had no effect on RTD50 independent of age. Older adults may depend more on muscle activation at contraction onset of early phase RTD compared to younger adults.
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Affiliation(s)
| | | | - Matt C Ferrell
- Oklahoma State University Center for Health Sciences, Tulsa, OK, USA
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18
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Jenkins NDM, Rogers EM, Banks NF, Tomko PM, Sciarrillo CM, Emerson SR, Taylor A, Teague TK. Childhood psychosocial stress is linked with impaired vascular endothelial function, lower SIRT1, and oxidative stress in young adulthood. Am J Physiol Heart Circ Physiol 2021; 321:H532-H541. [PMID: 34328346 DOI: 10.1152/ajpheart.00123.2021] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Adverse childhood experiences (ACEs) are psychosocial stressors that occur during sensitive developmental windows and are associated with increased lifetime cardiovascular disease (CVD) risk in a dose-dependent manner. Vascular endothelial dysfunction is a pathophysiological mechanism that promotes hypertension and CVD and may be a mechanism by which ACEs contribute to lifetime CVD risk. We examined whether exposure to ACEs is associated with reduced vascular endothelial function (VEF) in otherwise healthy, young adult women (20.7 ± 3 yr) with (ACE+) versus without (ACE-) ACEs, explored whether differences in circulating sirtuin 1 (SIRT1) or systemic oxidative stress could explain ACEs-related differences in VEF, and examined the ability of a pilot, 8-wk exercise intervention to augment VEF and SIRT1 or reduce oxidized LDL cholesterol (oxLDL) in ACE+ young adult women. Forty-two otherwise healthy young adults completed this study. Prior to the intervention, VEF (P = 0.002) and SIRT1 (P = 0.004) were lower in the ACE+ than ACE- group, but oxLDL concentrations were not different (P = 0.77). There were also significant relationships (P ≤ 0.04) among flow-mediated dilation (FMD), SIRT1, and oxLDL in the ACE+, but not ACE- group. Adjusting for circulating SIRT1 and oxLDL reduced the differences in FMD observed between groups (P = 0.10), but only SIRT1 was a significant adjuster of the means (P < 0.05). Finally, the exercise intervention employed was unable to enhance VEF or SIRT1 in the ACE+ exercise group. Our data suggest that ACEs likely increase susceptibility to hypertension and CVD by causing endothelial dysfunction, perhaps through a SIRT1 pathway-related mechanism.NEW & NOTEWORTHY Our study provides novel evidence that young adult women with moderate-to-severe adverse childhood experience (ACE) exposure present impaired endothelial function and lower circulating sirtuin 1 (SIRT1) concentrations than age-matched controls. However, an 8-wk exercise intervention was unable to augment endothelial function or SIRT1 concentrations in a subset of those with ACEs. Our data suggest that ACEs-related impairments in endothelial function may be secondary to decreased NO bioavailability via SIRT1 and/or oxidative stress-related mechanisms.
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Affiliation(s)
- Nathaniel D M Jenkins
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, University of Iowa, Iowa City, Iowa.,Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa
| | - Emily M Rogers
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, University of Iowa, Iowa City, Iowa
| | - Nile F Banks
- Integrative Laboratory of Applied Physiology and Lifestyle Medicine, University of Iowa, Iowa City, Iowa
| | - Patrick M Tomko
- School of Health Sciences, Kent State University, Kent, Ohio
| | - Christina M Sciarrillo
- Laboratory of Applied Nutrition and Exercise Science, Oklahoma State University, Tulsa, Oklahoma
| | - Sam R Emerson
- Laboratory of Applied Nutrition and Exercise Science, Oklahoma State University, Tulsa, Oklahoma
| | - Ashlee Taylor
- Integrative Immunology Center, University of Oklahoma School of Community Medicine, Tulsa, Oklahoma
| | - T Kent Teague
- Integrative Immunology Center, University of Oklahoma School of Community Medicine, Tulsa, Oklahoma.,Department of Surgery, University of Oklahoma School of Community Medicine, Tulsa, Oklahoma.,Department of Psychiatry, University of Oklahoma School of Community Medicine, Tulsa, Oklahoma.,Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma
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Moghaddam M, Estrada CA, Muddle TWD, Magrini MA, Jenkins NDM, Jacobson BH. Similar Anaerobic and Aerobic Adaptations After 2 High-Intensity Interval Training Configurations: 10:5 s vs. 20:10 s Work-to-Rest Ratio. J Strength Cond Res 2021; 35:1685-1692. [PMID: 30829982 DOI: 10.1519/jsc.0000000000002939] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
ABSTRACT Moghaddam, M, Estrada, CA, Muddle, TWD, Magrini, MA, Jenkins, NDM, and Jacobson, BH. Similar anaerobic and aerobic adaptations after 2 high-intensity interval training configurations: 10:5 s vs. 20:10 s work-to-rest ratio. J Strength Cond Res 35(6): 1685-1692, 2021-This study compares the effects of 2 high-intensity interval training (HIIT) configurations, a 10-5 vs. a 20-10 second work-to-rest ratio, on anaerobic and aerobic performance. Thirty-four individuals were randomly assigned to 10-5-HIIT (n = 17) and 20-10-HIIT (n = 17) groups to complete 6 cycles of 6 exercises, 3 days a week for 4 weeks. The 10-5-HIIT was performed with 10 s:5 s work-to-rest ratio with 1-minute recovery between cycles, while the 20-10-HIIT was performed with 20 s:10 s work-to-rest ratio followed by a 2-minute recovery. Anaerobic (i.e., peak power [PP], anaerobic capacity [AC], anaerobic power [AP], and total work [TW]) and aerobic fitness (i.e., time to exhaustion [TE], absolute V̇o2max [A-V̇o2max], relative V̇o2max [R-V̇o2max]) were measured with pre-training and post-training intervention. A significant main effect time was observed for both 10-5-HIIT and 20-10-HIIT (p < 0.05) in PP (9.2%, 5.7%); AC (14.9%, 8.6%); AP (9.0%, 6.2%); TW (15.1%, 8.5%); TE (4.3%, 5.5%); A-V̇o2max (9.4%, 8.9%); R-V̇o2max (8.5%, 8.2%), respectively. In conclusion, individuals may be able to achieve similar health benefits as 20-10-HIIT by performing 10-5-HIIT, despite exercising for 50% less total time. High-intensity interval training has been suggested as a "time-efficient" mode of exercise that can mitigate the most significant barrier to physical activity, "lack of time." Both 10-5-HIIT and 20-10-HIIT can induce performance adaptations to a similar extent. However, because of shorter time commitment, performing 10-5-HIIT at 10 s:5 s work-to-rest ratio may offer a shorter and equally efficient interval. Functional fitness training during HIIT protocols seems to be as beneficial as ergometer-based HIIT to improve anaerobic and aerobic performance.
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Affiliation(s)
- Masoud Moghaddam
- Department of Health and Human Performance, Oklahoma State University, Stillwater, Oklahoma
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20
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Sciarrillo CM, Koemel NA, Keirns BH, Banks NF, Rogers EM, Rosenkranz SK, Kurti SP, Jenkins NDM, Emerson SR. Who would benefit most from postprandial lipid screening? Clin Nutr 2021; 40:4762-4771. [PMID: 34242916 DOI: 10.1016/j.clnu.2021.04.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 03/22/2021] [Accepted: 04/10/2021] [Indexed: 01/22/2023]
Abstract
BACKGROUND & AIMS Individuals with fasting triglycerides (TG) <150 mg/dL can experience a deleterious postprandial TG response ≥220 mg/dL to a high-fat meal (HFM). The purpose of this study was to identify individuals based on fasting TG that would benefit most from additional postprandial screening. METHODS We conducted a secondary analysis of 7 studies from our laboratories featuring 156 disease-free participants (64 M, 92 F; age 18-70 years; BMI 18.5-30 kg/m2). Participants observed a 10-12 h overnight fast, after which they consumed an HFM (10-13 kcal/kg body mass; 61-64% kcal from fat). Two methods were used to identify lower and upper fasting TG cut points. Method 1 identified the lower limit as the TG concentration at which ≥90% of individuals presented peak postprandial TG (PPTG) <220 mg/dL and the upper limit as the concentration which ≥90% of individuals presented PPTG ≥220 mg/dL. Method 2 utilized receiver operating characteristic (ROC) curves and identified the lower limit as the fasting TG concentration where sensitivity was ≈95% and the upper limit as the concentration at which specificity was ≈95%. RESULTS In Method 1, 90% of individuals with fasting TG >130 mg/dL (>1.50 mmol/L) exhibited PPTG ≥220 mg/dL (≥2.50 mmol/L), while 100% of individuals with fasting TG <66 mg/dL (0.75 mmol/L) had PPTG that did not exceed 220 mg/dL (2.50 mmol/L). In Method 2, when sensitivity was ≈95%, the corresponding fasting TG concentration was 70 mg/dL (0.79 mmol/L). When specificity was ≈95%, the corresponding fasting TG concentration was 114 mg/dL (1.29 mmol/L). Based on methods 1 and 2, there was a moderate positive association (r = 0.37, p < 0.004) between fasting and PPTG for individuals with fasting TG between 70 and 130 mg/dL (0.79-1.50 mmol/L), in which 24% exhibited PPTG ≥220 mg/dL (≥2.50 mmol/L) while 76% did not. CONCLUSIONS Postprandial TG testing is likely most useful for individuals with fasting TG concentrations between 70 and 130 mg/dL (0.79-1.50 mmol/L). Outside of this range, postprandial TG responses are largely predictable. Establishing a specific patient group for which postprandial TG testing is most useful may lead to earlier risk detection in these individuals.
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Affiliation(s)
| | - Nicholas A Koemel
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, USA; Boden Collaboration for Obesity, Nutrition, Exercise, and Eating Disorders, University of Sydney, Sydney, Australia; Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - Bryant H Keirns
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, USA
| | - Nile F Banks
- Department of Health and Human Performance, Oklahoma State University, Stillwater, OK, USA; Department of Health and Human Physiology, University of Iowa, Iowa City, IA, USA
| | - Emily M Rogers
- Department of Health and Human Performance, Oklahoma State University, Stillwater, OK, USA; Department of Health and Human Physiology, University of Iowa, Iowa City, IA, USA
| | - Sara K Rosenkranz
- Department of Food, Nutrition, Dietetics and Health, Kansas State University, Manhattan, KS, USA
| | - Stephanie P Kurti
- Department of Food, Nutrition, Dietetics and Health, Kansas State University, Manhattan, KS, USA; Department of Kinesiology, James Madison University, Harrisonburg, VA, USA
| | - Nathaniel D M Jenkins
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, USA; Department of Health and Human Performance, Oklahoma State University, Stillwater, OK, USA; Department of Health and Human Physiology, University of Iowa, Iowa City, IA, USA
| | - Sam R Emerson
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, USA; Department of Food, Nutrition, Dietetics and Health, Kansas State University, Manhattan, KS, USA
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Dixon MD, Koemel NA, Sciarrillo CM, Lucas EA, Jenkins NDM, Emerson SR. The reliability of an abbreviated fat tolerance test: A comparison to the oral glucose tolerance test. Clin Nutr ESPEN 2021; 43:428-435. [PMID: 34024551 DOI: 10.1016/j.clnesp.2021.03.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 03/03/2021] [Accepted: 03/09/2021] [Indexed: 01/21/2023]
Abstract
BACKGROUND & AIMS Postprandial lipemia (PPL) is predictive of cardiovascular disease risk, but the current method for assessing PPL is a burdensome process. Recently, the validity of an abbreviated fat tolerance test (AFTT) has been demonstrated. As a continuation of this research, the purpose of this study was to determine the reliability of the AFTT and compare it to the reliability of the oral glucose tolerance test (OGTT). METHODS In this randomized crossover trial, 20 healthy adults (10 male and 10 female) completed 2 AFTTs and 2 OGTTs, each separated by a 1-week washout. For the AFTT, triglycerides (TG) were measured at baseline and 4 h post-consumption of a high-fat meal, during which time participants were able to leave the lab. For the OGTT, we measured blood glucose at baseline and 2 h post-consumption of a 75-g pure glucose solution, and participants remained in the lab. To determine reliability, we calculated within-subject coefficient of variation (WCV) and intraclass correlation coefficient (ICC). RESULTS The mean 4-h TG WCV for the AFTT was 12.6%, while the mean 2-h glucose WCV for the OGTT was 10.5%. ICC values for 4-h TG and TG change were 0.79 and 0.71, respectively, while ICC values for 2-h glucose and glucose change were 0.66 and 0.56, respectively. CONCLUSIONS Based on WCV and ICC, the TG response to an AFTT was similarly reliable to the glucose response to an OGTT in our sample of healthy adults, supporting the AFTT's potential as a standard clinical test for determining PPL. However, reliability of the AFTT needs to be further tested in individuals at greater risk for cardiometabolic disease.
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Affiliation(s)
- Madison D Dixon
- Department of Nutritional Sciences, Oklahoma State University, 301 Human Sciences, Oklahoma State University, Stillwater, OK 74078, Stillwater, OK, USA.
| | - Nicholas A Koemel
- Department of Nutritional Sciences, Oklahoma State University, 301 Human Sciences, Oklahoma State University, Stillwater, OK 74078, Stillwater, OK, USA.
| | - Christina M Sciarrillo
- Department of Nutritional Sciences, Oklahoma State University, 301 Human Sciences, Oklahoma State University, Stillwater, OK 74078, Stillwater, OK, USA.
| | - Edralin A Lucas
- Department of Nutritional Sciences, Oklahoma State University, 301 Human Sciences, Oklahoma State University, Stillwater, OK 74078, Stillwater, OK, USA.
| | - Nathaniel D M Jenkins
- Department of Health and Human Physiology, University of Iowa, E102 Field House, University of Iowa, Iowa City, Ioa 52242, Iowa City, IA, USA.
| | - Sam R Emerson
- Department of Nutritional Sciences, Oklahoma State University, 301 Human Sciences, Oklahoma State University, Stillwater, OK 74078, Stillwater, OK, USA.
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Guest NS, VanDusseldorp TA, Nelson MT, Grgic J, Schoenfeld BJ, Jenkins NDM, Arent SM, Antonio J, Stout JR, Trexler ET, Smith-Ryan AE, Goldstein ER, Kalman DS, Campbell BI. International society of sports nutrition position stand: caffeine and exercise performance. J Int Soc Sports Nutr 2021; 18:1. [PMID: 33388079 PMCID: PMC7777221 DOI: 10.1186/s12970-020-00383-4] [Citation(s) in RCA: 177] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 10/31/2020] [Indexed: 12/13/2022] Open
Abstract
Following critical evaluation of the available literature to date, The International Society of Sports Nutrition (ISSN) position regarding caffeine intake is as follows: 1. Supplementation with caffeine has been shown to acutely enhance various aspects of exercise performance in many but not all studies. Small to moderate benefits of caffeine use include, but are not limited to: muscular endurance, movement velocity and muscular strength, sprinting, jumping, and throwing performance, as well as a wide range of aerobic and anaerobic sport-specific actions. 2. Aerobic endurance appears to be the form of exercise with the most consistent moderate-to-large benefits from caffeine use, although the magnitude of its effects differs between individuals. 3. Caffeine has consistently been shown to improve exercise performance when consumed in doses of 3-6 mg/kg body mass. Minimal effective doses of caffeine currently remain unclear but they may be as low as 2 mg/kg body mass. Very high doses of caffeine (e.g. 9 mg/kg) are associated with a high incidence of side-effects and do not seem to be required to elicit an ergogenic effect. 4. The most commonly used timing of caffeine supplementation is 60 min pre-exercise. Optimal timing of caffeine ingestion likely depends on the source of caffeine. For example, as compared to caffeine capsules, caffeine chewing gums may require a shorter waiting time from consumption to the start of the exercise session. 5. Caffeine appears to improve physical performance in both trained and untrained individuals. 6. Inter-individual differences in sport and exercise performance as well as adverse effects on sleep or feelings of anxiety following caffeine ingestion may be attributed to genetic variation associated with caffeine metabolism, and physical and psychological response. Other factors such as habitual caffeine intake also may play a role in between-individual response variation. 7. Caffeine has been shown to be ergogenic for cognitive function, including attention and vigilance, in most individuals. 8. Caffeine may improve cognitive and physical performance in some individuals under conditions of sleep deprivation. 9. The use of caffeine in conjunction with endurance exercise in the heat and at altitude is well supported when dosages range from 3 to 6 mg/kg and 4-6 mg/kg, respectively. 10. Alternative sources of caffeine such as caffeinated chewing gum, mouth rinses, energy gels and chews have been shown to improve performance, primarily in aerobic exercise. 11. Energy drinks and pre-workout supplements containing caffeine have been demonstrated to enhance both anaerobic and aerobic performance.
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Affiliation(s)
- Nanci S Guest
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 1 King's College Circle, Room 5326A, Toronto, ON, M5S 1A8, Canada.
| | - Trisha A VanDusseldorp
- Department of Exercise Science and Sport Management, Kennesaw State University, Kennesaw, GA, 30144, USA
| | | | - Jozo Grgic
- Institute for Health and Sport (IHES), Victoria University, Melbourne, Australia
| | - Brad J Schoenfeld
- Department of Health Sciences, CUNY Lehman College, Bronx, NY, 10468, USA
| | - Nathaniel D M Jenkins
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, 52240, USA
| | - Shawn M Arent
- Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Colombia, SC, 29208, USA
- School of Social and Health Sciences, Leeds Trinity University, Leeds, UK
| | - Jose Antonio
- Exercise and Sport Science, Nova Southeastern University, Davie, FL, 33314, USA
| | - Jeffrey R Stout
- Institue of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, 32816, USA
| | | | - Abbie E Smith-Ryan
- Department of Exercise and Sport Science, Applied Physiology Laboratory, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Erica R Goldstein
- Institue of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, 32816, USA
| | - Douglas S Kalman
- Nutrion Department, College of Osteopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL, 33314, USA
- Scientific Affairs. Nutrasource, Guelph, ON, Canada
| | - Bill I Campbell
- Performance & Physique Enhancement Laboratory, University of South Florida, Tampa, FL, 33612, USA
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Jenkins NDM, Rogers EM, Banks NF, Muddle TWD, Colquhoun RJ. Increases in motor unit action potential amplitudes are related to muscle hypertrophy following eight weeks of high-intensity exercise training in females. Eur J Sport Sci 2020; 21:1403-1413. [DOI: 10.1080/17461391.2020.1836262] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Nathaniel D. M. Jenkins
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, OK, USA
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, USA
| | - Emily. M. Rogers
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, OK, USA
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, USA
| | - Nile F. Banks
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, OK, USA
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, USA
| | - Tyler W. D. Muddle
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, OK, USA
| | - Ryan J. Colquhoun
- Department of Health, Kinesiology and Sport, University of South Alabama, Mobile, AL, USA
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Koemel NA, Sciarrillo CM, Bode KB, Dixon MD, Lucas EA, Jenkins NDM, Emerson SR. Postprandial Metabolism and Vascular Function: Impact of Aging and Physical Activity Level. Int J Sport Nutr Exerc Metab 2020; 30:412-419. [PMID: 32908019 DOI: 10.1123/ijsnem.2020-0063] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 06/03/2020] [Accepted: 07/17/2020] [Indexed: 11/18/2022]
Abstract
The consumption of a high-fat meal can induce postprandial lipemia and endothelial dysfunction. The authors assessed the impact of age and physical activity on metabolic and vascular outcomes following meal consumption in healthy adults. The authors recruited four groups: younger active (age 22.1 ± 1.4 years; n = 9), younger inactive (age 22.6 ± 3.7 years; n = 8), older active (age 68.4 ± 7.7 years; n = 8), and older inactive (age 67.7 ± 7.2 years; n = 7). The metabolic outcomes were measured at the baseline and hourly for 6 hr post high-fat meal consumption (12 kcal/kg; 63% fat). Flow-mediated dilation was measured at the baseline, 2 hr, and 4 hr postmeal. The total area under the curve for triglycerides was significantly lower in the more active groups, but did not differ based on age (younger active = 6.5 ± 1.4 mmol/L × 6 hr, younger inactive = 11.7 ± 4.8, older active = 6.8 ± 2.7, older inactive = 12.1 ± 1.7; p = .0004). After adjusting for artery diameter, flow-mediated dilation differed between groups at the baseline (younger active = 4.8 ± 1.6%, younger inactive = 2.5 ± 0.5, older active = 3.4 ± 0.9, older inactive = 2.2 ± 0.4; p < .001) and decreased significantly across groups 4 hr postmeal (mean difference = 0.82; 95% CI [0.02, 1.6]; p = .04). These findings highlight the beneficial effect of regular physical activity on postprandial lipemia, independent of age.
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Banks NF, Rogers EM, Jenkins NDM. Electromyographic amplitude versus torque relationships are different in young versus postmenopausal females and are related to muscle mass after controlling for bodyweight. Eur J Appl Physiol 2020; 121:479-488. [PMID: 33123807 DOI: 10.1007/s00421-020-04532-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 10/12/2020] [Indexed: 11/29/2022]
Abstract
PURPOSE To examine differences in the electromyographic vs torque (EMG-T) relationship, as well as muscle strength and indicators of muscle mass and quality between young versus postmenopausal females, and explore whether the potential differences in the EMG-T relationships could be explained by differences in muscle mass. METHODS Thirty young (age = 20.7 ± 2.8 y) and 30 postmenopausal (age = 56.3 ± 4.7 y) females completed maximal isometric strength testing (MVIT) and isometric ramp contractions at 40% and 70% MVIT, during which electromyographic signals were collected to quantify the slopes (Slope40; Slope70) and intercepts (Intercept40; Intercept70) of the EMG-T relationships. Muscle mass and quality measurements were also completed. RESULTS Postmenopausal females exhibited lower skeletal muscle mass (- 2.3 ± 1.5 kg), fat-free mass index (- 1.1 ± 0.7 kg·m-2), MVIT (- 17.1 ± 16.3 Nm), phase angle (- 0.5 ± 0.0°), muscle cross-sectional area (- 5.5 ± 1.1 cm2), muscle quality (- 0.1 ± 0.0 a.u), Slope40 (- 0.0003 ± 0.0002 mV·%MVIT-1), Slope70 (- 0.0003 ± 0.0002 mV·%MVIT-1), and had a higher echo intensity (+ 9.8 ± 2.8 a.u), Intercept40 (+ 0.001 ± 0.001 mV), and Intercept70 (+ 0.004 ± 0.003 mV) (p ≤ 0.001-0.04) than the young females. The EMG-T relationship variables were correlated with both muscle mass and quality after controlling for bodyweight. When controlling for muscle mass and bodyweight, group differences in the slopes of the EMG-T relationship and muscle strength were eliminated. CONCLUSION Muscle mass and quality are primary contributors to the decrements in neuromuscular function observed in postmenopausal versus young females, and the preservation of muscle mass should be prioritized in the years leading up to, during, and immediately after menopause.
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Affiliation(s)
- Nile F Banks
- Kinesiology, Applied Health and Recreation, Department of Nutritional Sciences, Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, OK, 74078, USA.,Laboratory for Applied Nutrition and Exercise Science, Oklahoma State University, Stillwater, OK, USA
| | - Emily M Rogers
- Kinesiology, Applied Health and Recreation, Department of Nutritional Sciences, Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, OK, 74078, USA.,Laboratory for Applied Nutrition and Exercise Science, Oklahoma State University, Stillwater, OK, USA
| | - Nathaniel D M Jenkins
- Kinesiology, Applied Health and Recreation, Department of Nutritional Sciences, Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, OK, 74078, USA. .,Laboratory for Applied Nutrition and Exercise Science, Oklahoma State University, Stillwater, OK, USA.
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Luera MJ, Dowling B, Muddle TWD, Jenkins NDM. Differences in Rotational Kinetics and Kinematics for Professional Baseball Pitchers With Higher Versus Lower Pitch Velocities. J Appl Biomech 2020; 36:68-75. [PMID: 32143191 DOI: 10.1123/jab.2019-0235] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 12/07/2019] [Accepted: 01/03/2020] [Indexed: 10/27/2023]
Abstract
Pitch velocity (PV) is important for pitching success, and the pelvis and trunk likely influence pitch performance. The purposes of this study were to examine the differences in pelvis and trunk kinetics and kinematics in professional baseball pitchers who throw at lower versus higher velocities (HVPs) and to examine the relationships among pelvis and trunk kinetics and kinematics and PV during each phase of the pitch delivery. The pitch velocity, pelvis and trunk peak angular velocities, kinetic energies and torques, and elbow and shoulder loads were compared among HVPs (n = 71; PV ≥ 40.2 m/s) and lower velocities pitchers (n = 78; PV < 39.8 m/s), as were trunk and pelvis rotation, flexion, and obliquity among 7 phases of the pitching delivery. Relationships among the kinetic and kinematic variables and PVs were examined. Higher velocity pitchers achieved greater upper trunk rotation at hand separation (+7.2°, P < .001) and elbow extension (+5.81°, P = .002) and were able to generate greater upper trunk angular velocities (+36.6 m/s, P = .01) compared with lower velocity pitcher. Trunk angular velocity (r = .29) and upper trunk rotation at hand separation (r = .18) and foot contact (r = .17) were weakly related to PV. Therefore, HVPs rotate their upper trunk to a greater degree during the early phases of the pitching motion and subsequently generate greater trunk angular velocities and PV.
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27
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Tomko PM, Colquhoun RJ, Banks NF, Magrini MA, Muddle TWD, Jenkins NDM. Maximal contraction methods influence the magnitude and reliability of global electromyographic signal characteristics. J Electromyogr Kinesiol 2019; 48:121-127. [PMID: 31344640 DOI: 10.1016/j.jelekin.2019.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 06/11/2019] [Accepted: 07/06/2019] [Indexed: 10/26/2022] Open
Abstract
OBJECTIVE The purpose was two-fold: (1) to examine differences in maximal voluntary isometric torque (MVIT) production, and electromyographic signal amplitude (EMGAMP) and mean power frequency (EMGMPF) values obtained during traditional (MVICTRAD), rapid (MVICRAPID), and ramp (MVICRAMP) maximal voluntary isometric contractions, and (2) to determine if there were differences in the reliability of MVIT, EMGAMP and EMGMPF among the three MVIC types. APPROACH Twenty-two young males and females completed MVICTRAD, MVICRAPID, and MVICRAMP muscle actions on two separate visits separated by 48 h. During all MVICs, MVIT and EMGAMP and EMGMPF of the vastus lateralis (VL) and rectus femoris (RF) were quantified. MAIN RESULTS MVIT was greater during MVICTRAD and MVICRAPID than during MVITRAMP (both p < 0.001). VL and RF EMGAMP were greater during MVICRAMP than during MVICRAPID (p = 0.02 and 0.004). For EMGMPF, there were no significant differences among MVIC types. Although all MVIC types generally resulted in reliable measurements of MVIT and EMGAMP, reliability was stronger for EMGMPF quantified during the MVICRAMP. SIGNIFICANCE Investigators may choose MVIC type based on preference or equipment availability. However, investigators should note that MVICRAMP contractions will likely yield the greatest EMGAMP values and more reliable measurements of VL and RF EMGMPF.
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Affiliation(s)
- Patrick M Tomko
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, United States
| | - Ryan J Colquhoun
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, United States
| | - Nile F Banks
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, United States
| | - Mitchel A Magrini
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, United States
| | - Tyler W D Muddle
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, United States
| | - Nathaniel D M Jenkins
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, United States.
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McKay BD, Miramonti AA, Gillen ZM, Leutzinger TJ, Mendez AI, Jenkins NDM, Cramer JT. Normative Reference Values for High School-Aged American Football Players: Proagility Drill and 40-Yard Dash Split Times. J Strength Cond Res 2018; 34:1184-1187. [PMID: 30418328 DOI: 10.1519/jsc.0000000000002930] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
McKay, BD, Miramonti, AA, Gillen, ZM, Leutzinger, TJ, Mendez, AI, Jenkins, NDM, and Cramer, JT. Normative reference values for high school-aged American football players: Proagility drill and 40-yard dash split times. J Strength Cond Res 34(4): 1184-1187, 2020-The purpose of this short report was to provide test- and position-specific normative reference values for the 10- and 20-yd split times (10YD and 20YD) during the 40-yd dash (40YD) as well as 10-yd split times during the proagility drill (PA) based on a large, nationally representative sample of high school-aged American football players in their freshman, sophomore, and junior classes. Cross-sectional performance data were obtained from 12 different high school American football recruiting combines between March 7, 2015, and January 9, 2016, across the United States. The sample included (n = 7,478) high school-aged American football athletes in their freshman (n = 1,185), sophomore (n = 2,514), and junior (n = 3,779) classes. Each player self-classified their American football positions as defensive back, defensive end, defensive linemen, linebacker, offensive linemen (OL), quarterback (QB), running back, tight end, or wide receiver. The results of the freshman, sophomore, and junior class were aggregated to generate test- and position-specific normative values. Mean differences were found among classes for all positions and all measurements (p ≤ 0.05) except for OL and QB PA split time (p > 0.05). Greater percent differences for all 3 variables were observed between freshman and sophomore years than between sophomore and junior years. These normative reference values will be useful for athletes, parents, coaches, and high school strength and conditioning professionals to set realistic goals for young American football athletes.
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Affiliation(s)
- Brianna D McKay
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Amelia A Miramonti
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Zachary M Gillen
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Todd J Leutzinger
- Department of Biomechanics, Center for Research in Human Movement Variability, University of Nebraska Omaha, Omaha, Nebraska; and
| | - Alegra I Mendez
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Nathaniel D M Jenkins
- Department of Health and Human Performance, Oklahoma State University, Stillwater, Oklahoma
| | - Joel T Cramer
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
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Colquhoun RJ, Tomko PM, Magrini MA, Muddle TWD, Jenkins NDM. The influence of input excitation on the inter- and intra-day reliability of the motor unit firing rate versus recruitment threshold relationship. J Neurophysiol 2018; 120:3131-3139. [PMID: 30355024 DOI: 10.1152/jn.00490.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Decomposition of the surface electromyographic (sEMG) signal is commonly used to examine motor unit (MU) firing behavior. However, the intra- and inter-day reliability of these measurements has yet to be quantified or reported. This investigation 1) examined the effect of input excitation on the mean firing rate (MFR) vs. recruitment threshold (RT) relationship and 2) determined the inter- and intra-day reliability of the MFR vs. RT relationship at 30%, 50%, and 70% of maximum voluntary isometric strength (MVIC). Twenty-eight healthy males (23 ± 3 yr) completed two experimental visits, during which they performed MVIC testing and isometric ramp contractions at 30%, 50%, and 70% MVIC. sEMG signals were recorded from the vastus lateralis during the ramp contractions and decomposed to establish the MFR vs. RT relationship for the detected MUs. Intra- and inter-day reliability was then established for the slopes and y-intercepts of the MFR vs. RT relationship at each contraction intensity. All participants displayed significant MFR vs. RT relationships ( r range: -0.662 to -0.999; P ≤ 0.001-0.006). Intra- and inter-day intraclass correlation coefficients (ICCs) ranged from 0.766-0.824 and 0.867-0.919 for the slopes and from 0.780-0.915 and 0.804-0.927 for the y-intercepts, respectively. Furthermore, the slope coefficient was significantly greater at 70% than at 30% MVIC, and the y-intercepts increased with increasing contraction intensities. Changes in input excitation to the MU pool alter the magnitude, but not the reliability, of the slopes and y-intercepts of the MFR vs. RT relationship. NEW & NOTEWORTHY The firing behavior of the motor unit (MU) pool is often characterized using the mean firing rate vs. recruitment threshold relationship of the active MUs. Although this relationship has been widely used, this is the first study to report the effects of input excitation (contraction intensity) on the intra- and inter-day reliability of this relationship. The criteria used for MU analysis and the model utilized in this study allow for generalization to outside investigators and laboratories.
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Affiliation(s)
- Ryan J Colquhoun
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University , Stillwater, Oklahoma
| | - Patrick M Tomko
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University , Stillwater, Oklahoma
| | - Mitchel A Magrini
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University , Stillwater, Oklahoma
| | - Tyler W D Muddle
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University , Stillwater, Oklahoma
| | - Nathaniel D M Jenkins
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University , Stillwater, Oklahoma
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Jenkins NDM, Colquhoun RJ, Tomko PM, Gradnigo T, Magrini MA, Muddle TWD, Fleming S, Ferrell M, El-Sohemy A. Genetic variant in the β 2 -adrenergic receptor (Arg16Gly) influences fat-free mass, muscle strength and motor unit behaviour in young men. Exp Physiol 2018; 103:1645-1655. [PMID: 30267546 DOI: 10.1113/ep087145] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 09/28/2018] [Indexed: 12/25/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does a common genetic variant in the β2 -adrenergic receptor (β2 -AR) have effects on skeletal muscle function in young, healthy men? What is the main finding and its importance? This study provides preliminary evidence that β2 -AR Arg16Gly genotype has a significant effect on fat-free mass, muscle strength and motor unit behaviour in recreationally trained men. These data might have important clinical and exercise-related implications. For example, β2 -AR (rs1042713) genotype might influence the responsiveness of skeletal muscle to clinical or exercise-based interventions or β-AR agonist treatment. ABSTRACT This study explored whether the β2 -adrenergic receptor (β2 -AR) single nucleotide polymorphism at amino acid 16 (Arg16Gly) has functional effects on skeletal muscle mass, torque production and motor unit behaviour in young, healthy men. Twenty-eight recreationally active men (mean ± SD 23.1 ± 1.3 years of age) were genotyped for Arg16Gly polymorphisms of β2 -AR as arginine homozygous (ArgArg; n = 5), glycine homozygous (GlyGly; n = 11) or arginine-glycine heterozygous (ArgGly; n = 12). The participants then completed body composition testing, assessments of leg extensor size and echo intensity, and evoked and voluntary isometric leg-extension muscle actions. During the evoked muscle actions, peak twitch torque, peak rate of torque development and peak relaxation rate were assessed. During the voluntary muscle actions, maximal voluntary isometric (MVIC) strength was assessed, and surface EMG signals were obtained during submaximal isometric muscle actions and later decomposed to examine motor unit firing behaviour. Fat-free mass and MVIC strength were greater (P = 0.004, d = 1.74 and P = 0.026, d = 1.10, respectively) in those expressing the GlyGly versus ArgArg allele. The slope of the mean firing rate versus recruitment threshold relationship was more negative in the GlyGly than the ArgArg allele carriers (P = 0.012, d = 1.68) at 50% MVIC, but was less negative in GlyGly and ArgGly versus ArgArg allele carriers (P = 0.013 and 0.016, respectively; d = 1.34 and 1.20, respectively) at 70% MVIC. These data provide preliminary evidence that β2 -AR Arg16Gly genotype has a significant effect on fat-free mass, muscle strength and motor unit behaviour in humans.
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Affiliation(s)
- Nathaniel D M Jenkins
- Applied, Neuromuscular Physiology Laboratory, School of Kinesiology, Applied Health and Recreation, Oklahoma State University, Stillwater, OK, USA.,Laboratory for Applied Nutrition and Exercise Science, Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, USA
| | - Ryan J Colquhoun
- Applied, Neuromuscular Physiology Laboratory, School of Kinesiology, Applied Health and Recreation, Oklahoma State University, Stillwater, OK, USA
| | - Patrick M Tomko
- Applied, Neuromuscular Physiology Laboratory, School of Kinesiology, Applied Health and Recreation, Oklahoma State University, Stillwater, OK, USA
| | - Trey Gradnigo
- Applied, Neuromuscular Physiology Laboratory, School of Kinesiology, Applied Health and Recreation, Oklahoma State University, Stillwater, OK, USA
| | - Mitchel A Magrini
- Applied, Neuromuscular Physiology Laboratory, School of Kinesiology, Applied Health and Recreation, Oklahoma State University, Stillwater, OK, USA
| | - Tyler W D Muddle
- Applied, Neuromuscular Physiology Laboratory, School of Kinesiology, Applied Health and Recreation, Oklahoma State University, Stillwater, OK, USA
| | - Sydnie Fleming
- Applied, Neuromuscular Physiology Laboratory, School of Kinesiology, Applied Health and Recreation, Oklahoma State University, Stillwater, OK, USA
| | - Matthew Ferrell
- Applied, Neuromuscular Physiology Laboratory, School of Kinesiology, Applied Health and Recreation, Oklahoma State University, Stillwater, OK, USA
| | - Ahmed El-Sohemy
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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Barrera-Curiel A, Magrini MA, Thiele RM, Hernandez-Sarabia JA, Colquhoun RJ, Tomko PM, Jenkins NDM, DeFreitas JM. Antagonist Coactivation During A Reactive Leg Drop In Young And Older Adults. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000536922.37587.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Muddle TWD, Colquhoun RJ, Magrini MA, Luera MJ, DeFreitas JM, Jenkins NDM. Effects of fatiguing, submaximal high- versus low-torque isometric exercise on motor unit recruitment and firing behavior. Physiol Rep 2018; 6:e13675. [PMID: 29673119 PMCID: PMC5907942 DOI: 10.14814/phy2.13675] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 03/02/2018] [Indexed: 12/04/2022] Open
Abstract
The purpose of this investigation was to evaluate the effects of repeated, high- (HT: 70% MVIC) versus low-torque (LT: 30% MVIC) isometric exercise performed to failure on motor unit (MU) recruitment and firing behavior of the vastus lateralis. Eighteen resistance-trained males (23.1 ± 3.8 years) completed familiarization, followed by separate experimental sessions in which they completed either HT or LT exercise to failure in random order. LT exercise resulted in a greater time to task failure and a more dramatic decline in the muscle's force capacity, but the total work completed was similar for HT and LT exercise. An examination of the firing trains from 4670 MUs recorded during exercise revealed that firing rates generally increased during HT and LT exercise, but were higher during HT than LT exercise. Furthermore, recruitment thresholds (RT) did not significantly change during HT exercise, whereas the RT of the smallest MUs increased and the RT for the moderate to large MUs decreased during LT exercise. Both HT and LT exercise resulted in the recruitment of additional higher threshold MUs in order to maintain torque production. However, throughout exercise, HT required the recruitment of larger MUs than did LT exercise. In a few cases, however, MUs were recruited by individuals during LT exercise that were similar in size and original (pre) RT to those detected during HT exercise. Thus, the ability to achieve full MU recruitment during LT exercise may be dependent on the subject. Consequently, our data emphasize the task and subject dependency of muscle fatigue.
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Affiliation(s)
- Tyler W. D. Muddle
- Applied Neuromuscular Physiology LaboratoryOklahoma State UniversityStillwaterOklahoma
| | - Ryan J. Colquhoun
- Applied Neuromuscular Physiology LaboratoryOklahoma State UniversityStillwaterOklahoma
| | - Mitchel A. Magrini
- Applied Neuromuscular Physiology LaboratoryOklahoma State UniversityStillwaterOklahoma
| | - Micheal J. Luera
- Applied Neuromuscular Physiology LaboratoryOklahoma State UniversityStillwaterOklahoma
| | - Jason M. DeFreitas
- Applied Neuromuscular Physiology LaboratoryOklahoma State UniversityStillwaterOklahoma
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Luera MJ, Dowling B, Magrini MA, Muddle TWD, Colquhoun RJ, Jenkins NDM. Role of Rotational Kinematics in Minimizing Elbow Varus Torques for Professional Versus High School Pitchers. Orthop J Sports Med 2018; 6:2325967118760780. [PMID: 29581995 PMCID: PMC5863871 DOI: 10.1177/2325967118760780] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Background: Elbow injury rates among baseball pitchers are rapidly rising. However, this increase has been most dramatic among high school (HS) pitchers. Purpose: To examine pitch velocity and the kinetic and kinematic characteristics of HS versus professional (PRO) pitchers to identify potential differences that may play a role in the increased risk of ulnar collateral ligament injury in youth pitchers. Study Design: Controlled laboratory study. Methods: A total of 37 HS (mean ± SD: age, 16 ± 1 years) and 40 PRO (age, 21 ± 2 years) baseball pitchers completed maximal-effort baseball pitches during a single testing session, from which pitch velocity (PV), absolute and normalized elbow varus torque (EVTA and EVTN, respectively) during arm cocking and at maximum shoulder external rotation (MER), and 8 other elbow and shoulder torques or forces and rotational kinematics of the pelvis and trunk were analyzed, recorded, and compared. Results: PV was greater in PRO than HS athletes; EVTA was greater in PRO than HS athletes during arm cocking and at MER; but EVTN was similar during arm cocking and greater in HS than PRO athletes at MER. In PRO athletes, PV was not related to EVTA during arm cocking or MER (r = 0.01-0.05). Furthermore, in PRO athletes, EVTA during arm cocking and at MER were inversely related to upper trunk rotation at hand separation and foot contact and to pelvis rotation at elbow extension (r = –0.30 to –0.33). In contrast, in HS athletes, PV was strongly related to EVTA during arm cocking and MER (r = 0.76-0.77). Furthermore, in HS athletes, PV and EVTA during arm cocking and at MER were moderately or strongly related to the other elbow and shoulder torques and forces (r = 0.424-0.991), and EVTA was not related to upper trunk rotation or pelvis rotation throughout the throwing motion (r = –0.16 to 0.15). Conclusion: The kinetic and rotational kinematic differences observed between PRO and HS pitchers in this study may help explain the greater performance of PRO pitchers while allowing them to minimize EVT during pitching. HS pitchers, however, do not appear to be as capable of utilizing the forces generated by rotation of their trunk and pelvis to aid in pitching, and those who throw the hardest generate the greatest forces at the shoulder and elbow. As a result, they experience higher EVTs relative to their body size, which may place them at an increased risk of injury. Clinical Relevance: HS pitchers throw harder primarily by generating larger forces in the arm and shoulder. Thus, owing to the relative physical immaturity of HS versus PRO pitchers, these factors may place them at an increased risk of injury. Coaches may first wish to focus on improving the rotational kinematics of HS pitchers rather than first focusing on achieving greater pitch velocities.
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Affiliation(s)
- Micheal J Luera
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Brittany Dowling
- Motus Global, IMG Academy Campus, Rockville Centre, New York, USA
| | - Mitchel A Magrini
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Tyler W D Muddle
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Ryan J Colquhoun
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Nathaniel D M Jenkins
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, Oklahoma, USA
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Colquhoun RJ, Magrini MA, Haun CT, Muddle TWD, Tomko PM, Luera MJ, Mackey CS, Vann CG, Martin JS, Young KC, DeFreitas JM, Roberts MD, Jenkins NDM. Muscle phenotype is related to motor unit behavior of the vastus lateralis during maximal isometric contractions. Physiol Rep 2018. [PMID: 29527830 PMCID: PMC5845862 DOI: 10.14814/phy2.13636] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Previous investigations have reported a relationship between skeletal muscle phenotype and motor unit (MU) firing parameters during submaximal contractions. The purpose of the current investigation, however, was to examine the relationships between motor unit firing behavior during a maximal voluntary contraction, Myosin Heavy Chain (MHC) isoform content, and various molecular neuromuscular targets of the vastus lateralis (VL) muscle in resistance-trained men. Ten resistance-trained males completed a trapezoidal ramp contraction up to 100% of their maximal voluntary isometric strength (MVIC). Surface electromyography was recorded from the VL using a multichannel electrode array and decomposed to examine the firing characteristics of individual MUs. A skeletal muscle biopsy of the VL was also collected from each subject. Regression analyses were performed to identify relationships between type II fiber area and the slopes and/or intercepts of the mean firing rate (FRMEAN ) versus recruitment threshold (RT), max firing rate (FRMAX ) versus RT, and RT versus MU action potential amplitude (MUAPPP ) relationships. There were significant inverse relationships between type II fiber area and the y-intercept of the FR versus RT relationship (P < 0.05). Additionally, strong relationships (r > 0.5) were found between type II fiber area and FRMEAN versus RT slope and RT versus MUAPPP slope and intercept. These data further support the hypothesis that skeletal muscle phenotype is related to MU behavior during isometric contraction. However, our data, in concert with previous investigations, may suggest that these relationships are influenced by the intensity of the contraction.
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Affiliation(s)
- Ryan J Colquhoun
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, Oklahoma
| | - Mitchel A Magrini
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, Oklahoma
| | - Cody T Haun
- Molecular and Applied Sciences Laboratory, Auburn University, Auburn, Alabama
| | - Tyler W D Muddle
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, Oklahoma
| | - Patrick M Tomko
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, Oklahoma
| | - Micheal J Luera
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, Oklahoma
| | - Cameron S Mackey
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, Oklahoma
| | - Christopher G Vann
- Molecular and Applied Sciences Laboratory, Auburn University, Auburn, Alabama
| | - Jeffrey S Martin
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, Alabama
| | - Kaelin C Young
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, Alabama
| | - Jason M DeFreitas
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, Oklahoma
| | - Michael D Roberts
- Molecular and Applied Sciences Laboratory, Auburn University, Auburn, Alabama
| | - Nathaniel D M Jenkins
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, Oklahoma
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McKay BD, Miramonti AA, Gillen ZM, Leutzinger TJ, Mendez AI, Jenkins NDM, Cramer JT. Normative Reference Values for High School-Aged American Football Players. J Strength Cond Res 2018; 34:2849-2856. [PMID: 29489728 DOI: 10.1519/jsc.0000000000002532] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
McKay, BD, Miramonti, AA, Gillen, ZM, Leutzinger, TJ, Mendez, AI, Jenkins, NDM, and Cramer, JT. Normative reference values for high school-aged American football players. J Strength Cond Res 34(10): 2849-2856, 2020-The purpose of the present report was to provide test- and position-specific normative reference values for combine test results based on a large, nationally representative sample of high school-aged American football players in their freshman, sophomore, and junior classes. Cross-sectional anthropometric and performance data were obtained from 12 different high school American football recruiting combines between March 7, 2015, and January 9, 2016, across the United States. Subjects included a sample (n = 7,478) of high school-aged American football athletes in their junior (n = 3,779), sophomore (n = 2,514), and freshman (n = 1,185) classes. The database included combine date, school state, position, class, height, body mass (BM), 40-yard dash, pro-agility, 3-cone, vertical jump, broad jump, and power push-up. Each player self-classified their American football positions as defensive back, defensive end, defensive linemen, linebacker, offensive linemen, quarterback, running back, tight end (TE), or wide receiver. Test- and position-specific normative values were generated by aggregating data from freshman, sophomore, and junior classes. Mean differences were found among classes for all positions and all measurements (p ≤ 0.05), except for TE BM (p > 0.05). Greater differences for all variables were observed from freshman to sophomore classes than from sophomore to junior classes. These normative reference values may provide realistic comparisons and evaluations in performance for young American football players, parents, and coaches with collegiate football aspirations. High school strength and conditioning professionals should use these norms to set attainable goals and reward accomplishments for young football players.
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Affiliation(s)
- Brianna D McKay
- Department of Nutrition and Health Sciences, University of Nebraska, Lincoln, Lincoln, Nebraska; and
| | - Amelia A Miramonti
- Department of Nutrition and Health Sciences, University of Nebraska, Lincoln, Lincoln, Nebraska; and
| | - Zachary M Gillen
- Department of Nutrition and Health Sciences, University of Nebraska, Lincoln, Lincoln, Nebraska; and
| | - Todd J Leutzinger
- Department of Nutrition and Health Sciences, University of Nebraska, Lincoln, Lincoln, Nebraska; and
| | - Alegra I Mendez
- Department of Nutrition and Health Sciences, University of Nebraska, Lincoln, Lincoln, Nebraska; and
| | - Nathaniel D M Jenkins
- Department of Health and Human Performance, Oklahoma State University, Stillwater, Oklahoma
| | - Joel T Cramer
- Department of Nutrition and Health Sciences, University of Nebraska, Lincoln, Lincoln, Nebraska; and
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Gillen ZM, Miramonti AA, McKay BD, Jenkins NDM, Leutzinger TJ, Cramer JT. Reliability and Sensitivity of the Power Push-up Test for Upper-Body Strength and Power in 6-15-Year-Old Male Athletes. J Strength Cond Res 2017; 32:83-96. [PMID: 29084096 DOI: 10.1519/jsc.0000000000002313] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Gillen, ZM, Miramonti, AA, McKay, BD, Jenkins, NDM, Leutzinger, TJ, and Cramer, JT. Reliability and sensitivity of the power push-up test for upper-body strength and power in 6-15-year-old male athletes. J Strength Cond Res 32(1): 83-96, 2018-The power push-up (PPU) test is an explosive upper-body test performed on a force plate and is currently being used in high school football combines throughout the United States. The purpose of this study was to quantify the reliability of the PPU test based on age and starting position (knees vs. toes) in young athletes. Sixty-eight boys (mean ± SD; age = 10.8 ± 2.0 years) were tested twice over 5 days. Boys were separated by age as 6-9 years (n = 16), 10-11 years (n = 26), and 12-15 years (n = 26). The PPU test was performed on a force plate while rotating from the knees vs. the toes. Measurements were peak force (PF, N), peak rate of force development (pRFD, N·s), average power (AP, W), and peak power (PP, W). Intraclass correlation coefficients (ICC2,1), SEMs, coefficients of variation (CVs), and minimum detectable changes (MDCs) were calculated to quantify reliability and sensitivity. Peak force from the knees in 10-15-year-olds, PF from the toes in 12-15-year-olds, and pRFD from the knees and toes in 12-15-year-olds were comparably reliable (ICC ≥ 0.84). Neither power measurements (AP or PP) for any age group, nor any measurements (PF, pRFD, AP, or PP) for the 6-9-year-olds were comparably reliable (ICC ≤ 0.74). When considering the reliable variables, PF was greater in the 12-15-year-olds than in 10-11-year-olds (p ≤ 0.05). In addition, in 12-15-year-olds, PF and pRFD were greater from the knees than from the toes (p ≤ 0.05). For reasons largely attributable to growth and development, the PPU test may be a reliable (ICC ≥ 0.80) and sensitive (CV ≤ 19%) measure of upper-body strength (PF), whereas pRFD was also reliable (ICC ≥ 0.80), but less sensitive (CV = 30-38%) in 10-15-year-old male athletes.
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Affiliation(s)
- Zachary M Gillen
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Amelia A Miramonti
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Brianna D McKay
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Nathaniel D M Jenkins
- Department of Health and Human Performance, Oklahoma State University, Stillwater, Oklahoma
| | - Todd J Leutzinger
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Joel T Cramer
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
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Haun CT, Mumford PW, Roberson PA, Romero MA, Mobley CB, Kephart WC, Anderson RG, Colquhoun RJ, Muddle TWD, Luera MJ, Mackey CS, Pascoe DD, Young KC, Martin JS, DeFreitas JM, Jenkins NDM, Roberts MD. Molecular, neuromuscular, and recovery responses to light versus heavy resistance exercise in young men. Physiol Rep 2017; 5:5/18/e13457. [PMID: 28963127 PMCID: PMC5617935 DOI: 10.14814/phy2.13457] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 08/30/2017] [Accepted: 09/04/2017] [Indexed: 11/24/2022] Open
Abstract
Recent evidence suggests that resistance training with light or heavy loads to failure results in similar adaptations. Herein, we compared how both training modalities affect the molecular, neuromuscular, and recovery responses following exercise. Resistance‐trained males (mean ± SE: 22 ± 2 years, 84.8 ± 9.0 kg, 1.79 ± 0.06 m; n = 15) performed a crossover design of four sets of leg extensor exercise at 30% (light RE) or 80% (heavy RE) one repetition maximum (1RM) to repetition failure, and heavy RE or light RE 1 week later. Surface electromyography (EMG) was monitored during exercise, and vastus lateralis muscle biopsies were collected at baseline (PRE), 15 min (15mPOST), and 90 min following RE (90mPOST) for examination of molecular targets and fiber typing. Isokinetic dynamometry was also performed before (PRE), immediately after (POST), and 48 h after (48hPOST) exercise. Dependent variables were analyzed using repeated measures ANOVAs and significance was set at P ≤ 0.05. Repetitions completed were greater during light RE (P < 0.01), while EMG amplitude was greater during heavy RE (P ≤ 0.01). POST isokinetic torque was reduced following light versus heavy RE (P < 0.05). Postexercise expression of mRNAs and phosphoproteins associated with muscle hypertrophy were similar between load conditions. Additionally, p70s6k (Thr389) phosphorylation and fast‐twitch fiber proportion exhibited a strong relationship after both light and heavy RE (r > 0.5). While similar mRNA and phosphoprotein responses to both modalities occurred, we posit that heavy RE is a more time‐efficient training method given the differences in total repetitions completed, lower EMG amplitude during light RE, and impaired recovery response after light RE.
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Affiliation(s)
- Cody T Haun
- School of Kinesiology, Auburn University, Auburn, Alabama
| | | | | | | | | | | | | | - Ryan J Colquhoun
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater
| | - Tyler W D Muddle
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater
| | - Michael J Luera
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater
| | - Cameron S Mackey
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater
| | - David D Pascoe
- School of Kinesiology, Auburn University, Auburn, Alabama
| | - Kaelin C Young
- School of Kinesiology, Auburn University, Auburn, Alabama.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, Alabama
| | - Jeffrey S Martin
- School of Kinesiology, Auburn University, Auburn, Alabama.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, Alabama
| | - Jason M DeFreitas
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater
| | | | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, Alabama .,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, Alabama
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Martin JS, Mumford PW, Haun CT, Luera MJ, Muddle TWD, Colquhoun RJ, Feeney MP, Mackey CS, Roberson PA, Young KC, Pascoe DD, DeFreitas JM, Jenkins NDM, Roberts MD. Effects of a pre-workout supplement on hyperemia following leg extension resistance exercise to failure with different resistance loads. J Int Soc Sports Nutr 2017; 14:38. [PMID: 28959158 PMCID: PMC5615454 DOI: 10.1186/s12970-017-0195-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 09/20/2017] [Indexed: 01/24/2023] Open
Abstract
Background We sought to determine if a pre-workout supplement (PWS), containing multiple ingredients thought to enhance blood flow, increases hyperemia associated with resistance training compared to placebo (PBO). Given the potential interaction with training loads/time-under-tension, we evaluated the hyperemic response at two different loads to failure. Methods Thirty males participated in this double-blinded study. At visit 1, participants were randomly assigned to consume PWS (Reckless™) or PBO (maltodextrin and glycine) and performed four sets of leg extensions to failure at 30% or 80% of their 1-RM 45-min thereafter. 1-wk. later (visit 2), participants consumed the same supplement as before, but exercised at the alternate load. Heart rate (HR), blood pressure (BP), femoral artery blood flow, and plasma nitrate/nitrite (NOx) were assessed at baseline (BL), 45-min post-PWS/PBO consumption (PRE), and 5-min following the last set of leg extensions (POST). Vastus lateralis near infrared spectroscopy (NIRS) was employed during leg extension exercise. Repeated measures ANOVAs were performed with time, supplement, and load as independent variables and Bonferroni correction applied for multiple post-hoc comparisons. Data are reported as mean ± SD. Results With the 30% training load compared to 80%, significantly more repetitions were performed (p < 0.05), but there was no difference in total volume load (p > 0.05). NIRS derived minimum oxygenated hemoglobin (O2Hb) was lower in the 80% load condition compared to 30% for all rest intervals between sets of exercise (p < 0.0167). HR and BP did not vary as a function of supplement or load. Femoral artery blood flow at POST was higher independent of exercise load and treatment. However, a time*supplement*load interaction was observed revealing greater femoral artery blood flow with PWS compared to PBO at POST in the 80% (+56.8%; p = 0.006) but not 30% load condition (+12.7%; p = 0.476). Plasma NOx was ~3-fold higher with PWS compared to PBO at PRE and POST (p < 0.001). Conclusions Compared to PBO, the PWS consumed herein augmented hyperemia following multiple sets to failure at 80% of 1-RM, but not 30%. This specificity may be a product of interaction with local perturbations (e.g., reduced tissue oxygenation levels [minimum O2Hb] in the 80% load condition) and/or muscle fiber recruitment.
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Affiliation(s)
- Jeffrey S Martin
- School of Kinesiology, Auburn University, Auburn, AL 36849 USA.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, 910 S. Donahue Drive, Auburn, AL 36832 USA
| | - Petey W Mumford
- School of Kinesiology, Auburn University, Auburn, AL 36849 USA
| | - Cody T Haun
- School of Kinesiology, Auburn University, Auburn, AL 36849 USA
| | - Micheal J Luera
- School of Kinesiology, Applied Health and Recreation, Oklahoma State University, Stillwater, OK 74078 USA
| | - Tyler W D Muddle
- School of Kinesiology, Applied Health and Recreation, Oklahoma State University, Stillwater, OK 74078 USA
| | - Ryan J Colquhoun
- School of Kinesiology, Applied Health and Recreation, Oklahoma State University, Stillwater, OK 74078 USA
| | - Mary P Feeney
- School of Kinesiology, Auburn University, Auburn, AL 36849 USA
| | - Cameron S Mackey
- School of Kinesiology, Applied Health and Recreation, Oklahoma State University, Stillwater, OK 74078 USA
| | - Paul A Roberson
- School of Kinesiology, Auburn University, Auburn, AL 36849 USA
| | - Kaelin C Young
- School of Kinesiology, Auburn University, Auburn, AL 36849 USA.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, 910 S. Donahue Drive, Auburn, AL 36832 USA
| | - David D Pascoe
- School of Kinesiology, Auburn University, Auburn, AL 36849 USA
| | - Jason M DeFreitas
- School of Kinesiology, Applied Health and Recreation, Oklahoma State University, Stillwater, OK 74078 USA
| | - Nathaniel D M Jenkins
- School of Kinesiology, Applied Health and Recreation, Oklahoma State University, Stillwater, OK 74078 USA
| | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, AL 36849 USA.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, 910 S. Donahue Drive, Auburn, AL 36832 USA
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Palmer TB, Jenkins NDM, Thompson BJ, Cramer JT. Influence of stretching velocity on musculotendinous stiffness of the hamstrings during passive straight-leg raise assessments. Musculoskelet Sci Pract 2017; 30:80-85. [PMID: 28715304 DOI: 10.1016/j.msksp.2016.12.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 12/29/2016] [Accepted: 12/30/2016] [Indexed: 10/20/2022]
Abstract
BACKGROUND Recently, passive musculotendinous stiffness (MTS) has been assessed manually in the field; however, when conducting these types of assessments, the stretching velocity must be controlled to avoid eliciting the stretch reflex, which can be observed by increased electromyographic (EMG) amplitude of the stretched muscles and greater resistive torque (indicating the assessment is no longer passive). OBJECTIVE To examine the effects of slow, medium, and fast stretching velocities during manually-applied passive straight-leg raise (SLR) assessments on hamstrings MTS and EMG amplitude characteristics. STUDY DESIGN Crossover study. METHODS Twenty-three healthy, young adults underwent passive, manually-applied SLR assessments performed by the primary investigator at slow, medium, and fast stretching velocities. During each SLR, MTS and EMG amplitude were determined at 4 common joint angles (?) separated by 5° during the final common 15° of range of motion for each participant. RESULTS The average stretching velocities were 7, 11, and 18°·s?1 for the slow, medium, and fast SLRs. There were no velocity-related differences for MTS (P = 0.489) or EMG amplitude (P = 0.924). MTS increased (P < 0.001) with joint angle (?1<?2<?3<?4); however, EMG amplitude remained unchanged (P = 0.885) across the range of motion. CONCLUSIONS Although velocity discrepancies have been identified as a potential threat to the validity of passive MTS measurements obtained with manual SLR techniques, the present findings suggest that the SLR at any of the velocities tested in our study (7-18°·s?1) did not elicit a detectible stretch reflex, and thereby may be appropriate for examining MTS.
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Affiliation(s)
- Ty B Palmer
- Department of Kinesiology and Sport Management, Texas Tech University, Lubbock, TX, United States.
| | - Nathaniel D M Jenkins
- Department of Health and Human Performance, Oklahoma State University, Stillwater, OK, United States
| | - Brennan J Thompson
- Department of Kinesiology and Health Science, Utah State University, Logan, UT, United States
| | - Joel T Cramer
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
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Abstract
McKay, BD, Yeo, NM, Jenkins, NDM, Miramonti, AA, and Cramer, JT. Exertional rhabdomyolysis in a 21-year-old healthy woman: a case report. J Strength Cond Res 31(5): 1403-1410, 2017-The optimal resistance training program to elicit muscle hypertrophy has been recently debated and researched. Although 3 sets of 10 repetitions at 70-80% of the 1 repetition maximum (1RM) are widely recommended, recent studies have shown that low-load (∼30% 1RM) high-repetition (3 sets of 30-40 repetitions) resistance training can elicit similar muscular hypertrophy. Incidentally, this type of resistance training has gained popularity. In the process of testing this hypothesis in a research study in our laboratory, a subject was diagnosed with exertional rhabdomyolysis after completing a resistance training session that involved 3 sets to failure at 30% 1RM. Reviewed were the events leading up to and throughout the diagnosis of exertional rhabdomyolysis in a healthy recreationally-trained 21-year-old woman who was enrolled in a study that compared the acute effects of high-load low-repetition vs. low-load high-repetition resistance training. The subject completed a total of 143 repetitions of the bilateral dumbbell biceps curl exercise. Three days after exercise, she reported excessive muscle soreness and swelling and sought medical attention. She was briefly hospitalized and then discharged with instructions to take acetaminophen for soreness, drink plenty of water, rest, and monitor her creatine kinase (CK) concentrations. Changes in the subject's CK concentrations, ultrasound-determined muscle thickness, and echo intensity monitored over a 14-day period are reported. This case illustrates the potential risk of developing exertional rhabdomyolysis after a low-load high-repetition resistance training session in healthy, young, recreationally-trained women. The fact that exertional rhabdomyolysis is a possible outcome may warrant caution when prescribing this type of resistance exercise.
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Affiliation(s)
- Brianna D McKay
- 1Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska; and 2Department of Health and Human Performance, Oklahoma State University, Stillwater, Oklahoma
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Jenkins NDM, Miramonti AA, Hill EC, Smith CM, Cochrane-Snyman KC, Housh TJ, Cramer JT. Greater Neural Adaptations following High- vs. Low-Load Resistance Training. Front Physiol 2017; 8:331. [PMID: 28611677 PMCID: PMC5447067 DOI: 10.3389/fphys.2017.00331] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 05/08/2017] [Indexed: 11/15/2022] Open
Abstract
We examined the neuromuscular adaptations following 3 and 6 weeks of 80 vs. 30% one repetition maximum (1RM) resistance training to failure in the leg extensors. Twenty-six men (age = 23.1 ± 4.7 years) were randomly assigned to a high- (80% 1RM; n = 13) or low-load (30% 1RM; n = 13) resistance training group and completed leg extension resistance training to failure 3 times per week for 6 weeks. Testing was completed at baseline, 3, and 6 weeks of training. During each testing session, ultrasound muscle thickness and echo intensity, 1RM strength, maximal voluntary isometric contraction (MVIC) strength, and contractile properties of the quadriceps femoris were measured. Percent voluntary activation (VA) and electromyographic (EMG) amplitude were measured during MVIC, and during randomly ordered isometric step muscle actions at 10–100% of baseline MVIC. There were similar increases in muscle thickness from Baseline to Week 3 and 6 in the 80 and 30% 1RM groups. However, both 1RM and MVIC strength increased from Baseline to Week 3 and 6 to a greater degree in the 80% than 30% 1RM group. VA during MVIC was also greater in the 80 vs. 30% 1RM group at Week 6, and only training at 80% 1RM elicited a significant increase in EMG amplitude during MVIC. The peak twitch torque to MVIC ratio was also significantly reduced in the 80%, but not 30% 1RM group, at Week 3 and 6. Finally, VA and EMG amplitude were reduced during submaximal torque production as a result of training at 80% 1RM, but not 30% 1RM. Despite eliciting similar hypertrophy, 80% 1RM improved muscle strength more than 30% 1RM, and was accompanied by increases in VA and EMG amplitude during maximal force production. Furthermore, training at 80% 1RM resulted in a decreased neural cost to produce the same relative submaximal torques after training, whereas training at 30% 1RM did not. Therefore, our data suggest that high-load training results in greater neural adaptations that may explain the disparate increases in muscle strength despite similar hypertrophy following high- and low-load training programs.
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Affiliation(s)
- Nathaniel D M Jenkins
- Applied Neuromuscular Physiology Laboratory, Oklahoma State UniversityStillwater, OK, United States.,Department of Nutrition and Health Sciences, University of Nebraska-LincolnLincoln, NE, United States
| | - Amelia A Miramonti
- Department of Nutrition and Health Sciences, University of Nebraska-LincolnLincoln, NE, United States
| | - Ethan C Hill
- Department of Nutrition and Health Sciences, University of Nebraska-LincolnLincoln, NE, United States
| | - Cory M Smith
- Department of Nutrition and Health Sciences, University of Nebraska-LincolnLincoln, NE, United States
| | - Kristen C Cochrane-Snyman
- Department of Kinesiology and Health Promotion, California State Polytechnic University, PomonaPomona, CA, United States
| | - Terry J Housh
- Department of Nutrition and Health Sciences, University of Nebraska-LincolnLincoln, NE, United States
| | - Joel T Cramer
- Department of Nutrition and Health Sciences, University of Nebraska-LincolnLincoln, NE, United States
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Martin JS, Mumford PW, Haun CT, Roberson PA, Colquhoun RJ, Freeney MP, Luera MJ, Mackey CS, Muddle TWD, Riffe JJ, Young KC, Pascoe DD, Defreitas JM, Jenkins NDM, Roberts MD. Effects of a Pre-Workout Supplement on Hyperemia Following Leg Extension Resistance Exercise at Different Intensities. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000517053.94521.e0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Jenkins NDM, Cramer JT. Reliability and Minimum Detectable Change for Common Clinical Physical Function Tests in Sarcopenic Men and Women. J Am Geriatr Soc 2017; 65:839-846. [PMID: 28295148 DOI: 10.1111/jgs.14769] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVES To determine the test-retest reliability and minimum detectable change scores for seven common clinical measurements of muscle strength and physical function in a multiethnic sample of sarcopenic, malnourished men and women. DESIGN Each participant visited the laboratory seven times over 25 to 26 weeks. Reliability was assessed for each measurement from Familiarization 1 to Familiarization 2 (R1), Familiarization 2 to baseline testing (R2), Familiarization 3 to 12-week testing (R3), and Familiarization 4 to 24-week testing (R4). SETTING Data were collected during a clinical trial at 23 sites in the United States, Belgium, Italy, Mexico, Poland, Spain, Switzerland, and the United Kingdom. PARTICIPANTS Sarcopenic, malnourished, older adults (N = 257; n = 98 men aged 76.8 ± 6.3, n = 159 women aged 75.9 ± 6.6). MEASUREMENTS During each visit, participants completed the Short Physical Performance Battery (SPBB) and isometric handgrip and isokinetic leg extensor and flexor strength testing at a slow (1.05 rad/s) and fast (3.15 rad/s) velocity. RESULTS Handgrip strength, gait speed, SPPB score, and isokinetic leg extension and flexion peak torque (PT) had intraclass correlation coefficients (ICCs) that were significantly greater than 0 (all ≥0.59) at R1, R2, R3, and R4, although most of these variables demonstrated systematic increases at R1, and several exhibited systematic variability beyond the baseline testing session. CONCLUSION The ICCs and standard errors of the measurement (SEMs) generally improved with familiarization, which emphasizes the need for at least one familiarization trial for these measurements in sarcopenic, malnourished older adults. A three tier-approach to interpreting the clinical importance of statistically significant results that includes null hypothesis testing, examination and interpretation of the effect magnitude, and comparison of individual changes with the SEM and minimum detectable change of the measurements used is recommended.
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Affiliation(s)
- Nathaniel D M Jenkins
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, Oklahoma
| | - Joel T Cramer
- Neuromuscular Research and Imaging Laboratory, University of Nebraska-Lincoln, Nebraska, Oklahoma
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Miramonti AA, Jenkins NDM, Oza PD, Weir JP, Cramer JT. Mechanomyographic responses during recruitment curves in the soleus muscle. Muscle Nerve 2017; 56:107-116. [PMID: 27718510 DOI: 10.1002/mus.25432] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 10/03/2016] [Accepted: 10/06/2016] [Indexed: 11/07/2022]
Abstract
INTRODUCTION In this study we examined relationships among mechanomyographic (MMG), electromyographic (EMG), and peak twitch torque (PTT) responses as well as test-retest reliability when recorded during recruitment curves in the soleus muscle. METHODS PTT, EMG (M-wave, H-reflex), and MMG responses were recorded during recruitment curves in 16 subjects (age 24 ± 2 years) on 2 separate days. The sum of the M-wave and H-reflex (M+H) was calculated. Correlations among variables and test-retest reliability were determined. RESULTS MMG was correlated with PTT (mean r = 0.93, range r = 0.59-0.99), the M-wave (0.95, 0.04-0.98), and M+H (0.91, 0.42-0.97), but was unrelated to the H-reflex (-0.06, -0.56 to 0.47). Reliability was consistently high among most variables, but normalizing to the maximum value improved MMG reliability and the minimum detectable change. CONCLUSION MMG responses predicted 86%-90% of the variability in PTT, M-wave, and M+H; thus, MMG may be a useful alternative for estimating twitch torque and maximal activation. Muscle Nerve 56: 107-116, 2017.
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Affiliation(s)
- Amelia A Miramonti
- Department of Nutrition and Health Science, University of Nebraska, 211 Ruth Leverton Hall, Lincoln, Nebraska, 68583-0806, USA
| | - Nathaniel D M Jenkins
- Department of Health and Human Performance, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Preeti D Oza
- Department of Physical Therapy, University of the Pacific, Stockton, California, USA
| | - Joseph P Weir
- Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, Kansas, USA
| | - Joel T Cramer
- Department of Nutrition and Health Science, University of Nebraska, 211 Ruth Leverton Hall, Lincoln, Nebraska, 68583-0806, USA
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Jenkins NDM. Are Resistance Training-Mediated Decreases in Ultrasound Echo Intensity Caused by Changes in Muscle Composition, or Is There an Alternative Explanation? Ultrasound Med Biol 2016; 42:3050-3051. [PMID: 27590097 DOI: 10.1016/j.ultrasmedbio.2016.07.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 07/09/2016] [Indexed: 06/06/2023]
Affiliation(s)
- Nathaniel D M Jenkins
- Department of Health and Human Performance, Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, Oklahoma, USA.
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Smith CM, Housh TJ, Jenkins NDM, Hill EC, Cochrane KC, Miramonti AA, Schmidt RJ, Johnson GO. Combining regression and mean comparisons to identify the time course of changes in neuromuscular responses during the process of fatigue. Physiol Meas 2016; 37:1993-2002. [PMID: 27754975 DOI: 10.1088/0967-3334/37/11/1993] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The purposes of the present study were to apply a unique method for the identification of the time course of changes in neuromuscular responses and to infer the motor unit activation strategies used to maintain force during a fatiguing, intermittent isometric workbout. Eleven men performed 50, 6 s intermittent isometric muscle actions of the leg extensors, each separated by 2 s of rest at 60% maximal voluntary isometric contraction (MVIC). Electromyographic (EMG) and mechanomyographic (MMG) amplitude (root mean square; RMS) and frequency (mean power frequency; MPF) were obtained from the vastus lateralis (VL) every 5 of the 50 repetitions and normalized as a percent of the initial repetition. Polynomial regression analyses were used to determine the model of best fit for the normalized EMG RMS, EMG MPF, MMG RMS, and MMG MPF versus repetition relationships and one-way repeated measures ANOVAs with post-hoc Student Newman-Keuls were used to identify when these neuromuscular parameters changed from the initial repetition. The findings of the present study indicated two unique phases of neuromuscular responses (repetitions 1-20 and 20-50) during the fatiguing workbout. The time course of changes in these four neuromuscular responses suggested that the after-hyperpolarization theory could not explain the maintenance of force production, but Muscle Wisdom and the Onion Skin Scheme could. The findings of the current study suggested that the time course of changes in neuromuscular responses can provide insight in to the motor unit activation strategies used to maintain force production and allow for a greater understanding of the fatiguing process by identifying the time-points at which these neuromuscular parameters changed.
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Affiliation(s)
- Cory M Smith
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, NE 68505, USA
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Smith CM, Housh TJ, Herda TJ, Zuniga JM, Camic CL, Bergstrom HC, Smith DB, Weir JP, Hill EC, Cochrane KC, Jenkins NDM, Schmidt RJ, Johnson GO. Time Course of Changes in Neuromuscular Parameters During Sustained Isometric Muscle Actions. J Strength Cond Res 2016; 30:2697-2702. [PMID: 27658233 DOI: 10.1519/jsc.0000000000001547] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Smith, CM, Housh, TJ, Herda, TJ, Zuniga, JM, Camic, CL, Bergstrom, HC, Smith, DB, Weir, JP, Hill, EC, Cochrane, KC, Jenkins, NDM, Schmidt, RJ, and Johnson, GO. Time course of changes in neuromuscular parameters during sustained isometric muscle actions. J Strength Cond Res 30(10): 2697-2702, 2016-The objective of the present study was to identify the time course of changes in electromyographic (EMG) and mechanomyographic (MMG) time and frequency domain parameters during a sustained isometric muscle action of the leg extensors at 50% maximal voluntary isometric contraction. The EMG and MMG signals were measured from the vastus lateralis of 11 subjects to identify when motor unit activation strategies changed throughout the sustained isometric muscle action. The EMG amplitude (muscle activation) had a positive linear relationship (p = 0.018, r = 0.77) that began to increase at the initiation of the muscle action and continued until task failure. Electromyographic frequency (motor unit action potential conduction velocity) and MMG frequency (global motor unit firing rate) had negative quadratic relationships (p = 0.002, R = 0.99; p = 0.015, R = 0.94) that began to decrease at 30% of the time to exhaustion. The MMG amplitude (motor unit activation) had a cubic relationship (p = 0.001, R = 0.94) that increased from 10 to 30% of the time to exhaustion, then decreased from 40 to 70% of the time to exhaustion, and then markedly increased from 70% to task failure. The time course of changes in the neuromuscular parameters suggested that motor unit activation strategies changed at approximately 30 and 70% of the time to exhaustion during the sustained isometric muscle action. These findings indicate that the time course of changes in neuromuscular responses provide insight into the strategies used to delay the effects of fatigue and are valuable tools for quantifying changes in the fatiguing process during training programs or supplementation research.
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Affiliation(s)
- Cory M Smith
- 1Department of Nutrition and Health Science, University of Nebraska-Lincoln, Lincoln, Nebraska;2Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, Kansas;3Department of Exercise Science & Pre-Health Professions, Creighton University, Omaha, Nebraska;4Department of Exercise & Sport Science, University of Wisconsin-La Crosse, La Crosse, Wisconsin;5Department of Kinesiology & Health Promotion, University of Kentucky, Lexington, Kentucky; and6Department of Health and Human Performance, Oklahoma State University-Stillwater, Stillwater, Oklahoma
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Cochrane-Snyman KC, Housh TJ, Smith CM, Hill EC, Jenkins NDM, Schmidt RJ, Johnson GO. Inter-individual variability in the patterns of responses for electromyography and mechanomyography during cycle ergometry using an RPE-clamp model. Eur J Appl Physiol 2016; 116:1639-49. [PMID: 27325528 DOI: 10.1007/s00421-016-3394-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 05/06/2016] [Indexed: 11/24/2022]
Abstract
PURPOSE To examine inter-individual variability versus composite models for the patterns of responses for electromyography (EMG) and mechanomyography (MMG) versus time relationships during moderate and heavy cycle ergometry using a rating of perceived exertion (RPE) clamp model. METHODS EMG amplitude (amplitude root-mean-square, RMS), EMG mean power frequency (MPF), MMG-RMS, and MMG-MPF were collected during two, 60-min rides at a moderate (RPE at the gas exchange threshold; RPEGET) and heavy (RPE at 15 % above the GET; RPEGET+15 %) intensity when RPE was held constant (clamped). Composite (mean) and individual responses for EMG and MMG parameters were compared during each 60-min ride. RESULTS There was great inter-individual variability for each EMG and MMG parameters at RPEGET and RPEGET+15 %. Composite models showed decreases in EMG-RMS (r (2) = -0.92 and R (2) = 0.96), increases in EMG-MPF (R (2) = 0.90), increases in MMG-RMS (r (2) = 0.81 and 0.55), and either no change or a decrease (r (2) = 0.34) in MMG-MPF at RPEGET and RPEGET+15 %, respectively. CONCLUSIONS The results of the present study indicated that there were differences between composite and individual patterns of responses for EMG and MMG parameters during moderate and heavy cycle ergometry at a constant RPE. Thus, composite models did not represent the unique muscle activation strategies exhibited by individual responses when cycling in the moderate and heavy intensity domains when using an RPE-clamp model.
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Affiliation(s)
- Kristen C Cochrane-Snyman
- Department of Nutrition and Health Sciences, 110 Ruth Leverton Hall, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA.
| | - Terry J Housh
- Department of Nutrition and Health Sciences, 110 Ruth Leverton Hall, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Cory M Smith
- Department of Nutrition and Health Sciences, 110 Ruth Leverton Hall, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Ethan C Hill
- Department of Nutrition and Health Sciences, 110 Ruth Leverton Hall, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Nathaniel D M Jenkins
- Department of Nutrition and Health Sciences, 110 Ruth Leverton Hall, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Richard J Schmidt
- Department of Nutrition and Health Sciences, 110 Ruth Leverton Hall, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Glen O Johnson
- Department of Nutrition and Health Sciences, 110 Ruth Leverton Hall, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
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Smith CM, Housh TJ, Herda T, Zuniga JM, Camic CL, Bergstrom HC, Smith DB, Weir JP, Cramer JT, Hill EC, Cochrane KC, Jenkins NDM, Schmidt RJ, Johnson G. Electromyographic Responses from the Vastus Medialis during Isometric Muscle Actions. Int J Sports Med 2016; 37:647-52. [PMID: 27176892 DOI: 10.1055/s-0035-1564174] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
This study examined the electromyographic (EMG) responses from the vastus medialis (VM) for electrodes placed over and away from the innervation zone (IZ) during a maximal voluntary isometric contraction (MVIC) and sustained, submaximal isometric muscle action. A linear electrode array was placed on the VM to identify the IZ and muscle fiber pennation angle during an MVIC and sustained isometric muscle action at 50% MVIC. EMG amplitude and frequency parameters were determined from 7 bipolar channels of the electrode array, including over the IZ, as well as 10 mm, 20 mm and 30 mm proximal and distal to the IZ. There were no differences between the channels for the patterns of responses for EMG amplitude or mean power frequency during the sustained, submaximal isometric muscle action; however, there were differences between channels during the MVIC. The results of the present study supported the need to standardize the placement of electrodes on the VM for the assessment of EMG amplitude and mean power frequency. Based on the current findings, it is recommended that electrode placements be distal to the IZ and aligned with the muscle fiber pennation angle during MVICs, as well as sustained, submaximal isometric muscle actions.
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Affiliation(s)
- C M Smith
- Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, United States
| | - T J Housh
- Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, United States
| | - T Herda
- Health, Sport and Exercise Science, University of Kansas, Lawrence, United States
| | - J M Zuniga
- Exercise Science, Creighton University, Omaha, United States
| | - C L Camic
- Exercise & Sport Science, University of Wisconsin - La Crosse, La Crosse, United States
| | - H C Bergstrom
- Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, United States
| | - D B Smith
- Health and Human Performance, Oklahoma State University, Stillwater, United States
| | - J P Weir
- Health, Sport and Exercise Science, University of Kansas, Lawrence, United States
| | - J T Cramer
- Department of Nutrition & Health Sciences, University of Nebraska-Lincoln, Lincoln, United States
| | - E C Hill
- Nutrition and Health Sciences, Ethan Hill, Lincoln, United States
| | - K C Cochrane
- Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, United States
| | - N D M Jenkins
- Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, United States
| | - R J Schmidt
- Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, United States
| | - G Johnson
- Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, United States
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Cochrane KC, Housh TJ, Jenkins NDM, Bergstrom HC, Smith CM, Hill EC, Johnson GO, Schmidt RJ, Cramer JT. Electromyographic, mechanomyographic, and metabolic responses during cycle ergometry at a constant rating of perceived exertion. Appl Physiol Nutr Metab 2015; 40:1178-85. [PMID: 26481288 DOI: 10.1139/apnm-2015-0144] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ten subjects performed four 8-min rides (65%-80% peak oxygen consumption) to determine the physical working capacity at the OMNI rating of perceived exertion (RPE) threshold (PWCOMNI). Polynomial regression analyses were used to examine the patterns of responses for surface electromyographic (EMG) amplitude (EMG AMP), EMG mean power frequency (EMG MPF), mechanomyographic (MMG) AMP, and MMG MPF of the vastus lateralis as well as oxygen consumption rate, respiratory exchange ratio (RER), and power output (PO) were examined during a 1-h ride on a cycle ergometer at a constant RPE that corresponded to the PWCOMNI. EMG AMP and MMG MPF tracked the decreases in oxygen consumption rate, RER, and PO, while EMG MPF and MMG AMP tracked RPE. The decreases in EMG AMP and MMG MPF were likely attributable to decreases in motor unit (MU) recruitment and firing rate, while the lack of change in MMG AMP may have resulted from a balance between MU de-recruitment as PO decreased, and an increase in the ability of activated fibers to oscillate. The current findings suggested that during submaximal cycle ergometry at a constant RPE, MU de-recruitment and mechanical changes within the muscle may influence the perception of effort via feedback from group III and IV afferents.
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Affiliation(s)
- Kristen C Cochrane
- a Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
| | - Terry J Housh
- a Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
| | - Nathaniel D M Jenkins
- a Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
| | - Haley C Bergstrom
- b Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY, USA
| | - Cory M Smith
- a Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
| | - Ethan C Hill
- a Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
| | - Glen O Johnson
- a Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
| | - Richard J Schmidt
- a Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
| | - Joel T Cramer
- a Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
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