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Shoemaker ME, Smith CM, Gillen ZM, Cramer JT. Sex Differences in Test-Retest Reliability of Near-Infrared Spectroscopy During Postocclusive Reactive Hyperemia of the Vastus Lateralis. J Strength Cond Res 2024; 38:e40-e48. [PMID: 37815266 DOI: 10.1519/jsc.0000000000004619] [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: 10/11/2023]
Abstract
ABSTRACT Shoemaker, ME, Smith, CM, Gillen, ZM, and Cramer, JT. Sex differences in test-retest reliability of near-infrared spectroscopy during postocclusive reactive hyperemia of the vastus lateralis. J Strength Cond Res 38(2): e40-e48, 2024-The purpose of this study was to determine test-retest reliability for vascular reactivity measures and ranges for normalization of near-infrared spectroscopy (NIRS) variables from the vastus lateralis using postocclusive reactive hyperemia (PORH) procedure in male subjects, female subjects, and combined. Concentrations of oxygenated hemoglobin (Hb) + myoglobin (Mb) (O 2 Hb) and deoxygenated Hb + Mb (HHb) to derive total Hb + Mb (THb), difference in Hb + Mb signal (Hbdiff), and muscle tissue oxygen saturation (StO 2 ) from the vastus lateralis were measured during the PORH in 12 male subjects (age: 23.17 ± 1.77 years; stature: 180.88 ± 4.59 cm; and mass: 81.47 ± 9.68 kg) and 10 female subjects (age: 23.80 ± 2.07 years; stature: 165.95 ± 4.92 cm; and mass: 70.93 ± 10.55 kg) on 2 separate days. Adipose tissue thickness at the NIRS site was measured with ultrasonography. There were no significant differences between the mean values from visit 1 to visit 2 ( p > 0.076-0.985). In the composite sample, intraclass correlation coefficient (ICC) and coefficient of variation (CV) ranged from 0.35 to 0.91 and 4.74 to 39.18%, respectively. In male subjects, ICC and CV values ranged from 0.57 to 0.89 and 2.44 to 28.55%, respectively. In female subjects, ICC and CV values ranged from -0.05 to 0.75 and 7.83 to 61.19%, respectively. Although NIRS variables were overall reliable during PORH, when separated by sex, reliability in male subjects generally increased, whereas female subjects were not reliable, suggesting adipose tissue thickness may be a contributing factor. Understanding sex differences in reliability is important when using this technique for normalization or examining vascular reactivity during athletic performance. With greater utilization of NIRS monitoring in athletes to examine training adaptations, it is important for practitioners to understand the capabilities and potential limitations of the tool.
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Affiliation(s)
- Marni E Shoemaker
- College of Education and Human Sciences, South Dakota State University, Brookings, South Dakota
| | - Cory M Smith
- Robbins College of Health and Human Sciences, Baylor University, Waco, Texas
| | - Zachary M Gillen
- Department of Kinesiology, Mississippi State University, Mississippi State, Mississippi
| | - Joel T Cramer
- College of Health Professions and Sciences, University of Central Florida, Orlando, Florida
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Shoemaker ME, Gillen ZM, Fukuda DH, Cramer JT. Metabolic Flexibility and Inflexibility: Pathology Underlying Metabolism Dysfunction. J Clin Med 2023; 12:4453. [PMID: 37445488 DOI: 10.3390/jcm12134453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 06/29/2023] [Indexed: 07/15/2023] Open
Abstract
Metabolic flexibility can be defined as the ability of the skeletal muscle to adjust its utilization of substrate pathways [...].
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Affiliation(s)
- Marni E Shoemaker
- School of Health and Consumer Sciences, South Dakota State University, Brookings, SD 57007, USA
| | - Zachary M Gillen
- Department of Kinesiology, Mississippi State University, 180 Magruder Street, Mississippi State, MS 39762, USA
| | - David H Fukuda
- School of Kinesiology and Rehabilitation Sciences, University of Central Florida, Orlando, FL 32816, USA
| | - Joel T Cramer
- College of Health Professions and Sciences, University of Central Florida, Orlando, FL 32816, USA
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Shoemaker ME, Huynh LM, Smith CM, Mustad VA, Duarte MO, Cramer JT. Immunomodulatory Effects of Vitamin D and Prevention of Respiratory Tract Infections and COVID-19. TOP CLIN NUTR 2022; 37:203-217. [PMID: 35761885 PMCID: PMC9222791 DOI: 10.1097/tin.0000000000000284] [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] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Little is known about potential protective factors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), referred to as COVID-19. Suboptimal vitamin D status is a risk factor for immune dysfunction, respiratory tract infections (RTIs), and viral infections. Supplementation of vitamin D (2000-4000 IU) has decreased incidence and complications from RTIs, respiratory distress syndrome, and pneumonia and may be beneficial in high-risk populations. Given the possible link between low vitamin D status and RTIs, such as COVID-19, this review examined whether vitamin D supplementation can be supported as a nutritional strategy for reducing risk of infection, complications, and mortality from COVID-19 and found that the relationship between vitamin D and RTIs warrants further exploration.
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Affiliation(s)
- Marni E. Shoemaker
- College of Health Sciences, The University of Texas at El Paso, El Paso (Drs Shoemaker and Cramer); University of Nebraska Medical Center, Omaha (Ms Huynh); Departments of Kinesiology (Dr Smith) and Public Health Sciences (Dr Duarte), The University of Texas at El Paso, El Paso; and Nutrition Science Consulting, LLC, Galena, Ohio (Dr Mustad)
| | - Linda M. Huynh
- College of Health Sciences, The University of Texas at El Paso, El Paso (Drs Shoemaker and Cramer); University of Nebraska Medical Center, Omaha (Ms Huynh); Departments of Kinesiology (Dr Smith) and Public Health Sciences (Dr Duarte), The University of Texas at El Paso, El Paso; and Nutrition Science Consulting, LLC, Galena, Ohio (Dr Mustad)
| | - Cory M. Smith
- College of Health Sciences, The University of Texas at El Paso, El Paso (Drs Shoemaker and Cramer); University of Nebraska Medical Center, Omaha (Ms Huynh); Departments of Kinesiology (Dr Smith) and Public Health Sciences (Dr Duarte), The University of Texas at El Paso, El Paso; and Nutrition Science Consulting, LLC, Galena, Ohio (Dr Mustad)
| | - Vikkie A. Mustad
- College of Health Sciences, The University of Texas at El Paso, El Paso (Drs Shoemaker and Cramer); University of Nebraska Medical Center, Omaha (Ms Huynh); Departments of Kinesiology (Dr Smith) and Public Health Sciences (Dr Duarte), The University of Texas at El Paso, El Paso; and Nutrition Science Consulting, LLC, Galena, Ohio (Dr Mustad)
| | - Maria O. Duarte
- College of Health Sciences, The University of Texas at El Paso, El Paso (Drs Shoemaker and Cramer); University of Nebraska Medical Center, Omaha (Ms Huynh); Departments of Kinesiology (Dr Smith) and Public Health Sciences (Dr Duarte), The University of Texas at El Paso, El Paso; and Nutrition Science Consulting, LLC, Galena, Ohio (Dr Mustad)
| | - Joel T. Cramer
- College of Health Sciences, The University of Texas at El Paso, El Paso (Drs Shoemaker and Cramer); University of Nebraska Medical Center, Omaha (Ms Huynh); Departments of Kinesiology (Dr Smith) and Public Health Sciences (Dr Duarte), The University of Texas at El Paso, El Paso; and Nutrition Science Consulting, LLC, Galena, Ohio (Dr Mustad)
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Shoemaker ME, Pereira SL, Mustad VA, Gillen ZM, McKay BD, Lopez-Pedrosa JM, Rueda R, Cramer JT. Differences in muscle energy metabolism and metabolic flexibility between sarcopenic and nonsarcopenic older adults. J Cachexia Sarcopenia Muscle 2022; 13:1224-1237. [PMID: 35178889 PMCID: PMC8978004 DOI: 10.1002/jcsm.12932] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [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: 06/29/2021] [Revised: 12/17/2021] [Accepted: 01/10/2022] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Metabolic flexibility is the ability of skeletal muscle to adapt fuel utilization to the demand for fuel sources [carbohydrates (CHO) and fats (FAT)]. The purpose of this study was to explore muscle energy metabolism and metabolic flexibility under various conditions in sarcopenic (S) versus nonsarcopenic (NS) older adults. METHODS Twenty-two older adults aged 65 years or older were categorized as NS [n = 11; mean ± standard deviation (SD); age = 73.5 ± 6.0 years (males, n = 5; females, n = 6)] or S [n = 11; 81.2 ± 10.5 years (males, n = 6; females, n = 5) based on handgrip strength, body composition and physical performance. Indirect calorimetry was recorded before and after consumption of a high-CHO meal and during aerobic and anaerobic exercise. Respiratory quotient (RQ), CHO and FAT oxidation were assessed. Venous blood samples were collected for glucose and insulin concentrations. RESULTS At rest, compared with NS, S exhibited a 5-8% higher RQ at 0 (0.72 vs. 0.76) and 120 (0.77 vs. 0.82), 150 (0.76 vs. 0.80), and 180 min (0.74 vs. 0.80) (P = 0.002-0.025); 59-195% higher CHO oxidation at 0, 120, and 180 min (0.0004-0.002 vs. 0.001-0.002 g·min-1 ·kg-1) (P = 0.010-0.047); and 20-31% lower FAT oxidation at 0, 15, and 90-180 min (0.0009-0.0022 vs. 0.0011-0.002 g·min-1 ·kg-1 ) (P = 0.004-0.038). Glucose levels were significantly elevated in S versus NS at 0, 60 and 75 min (144.64-202.78 vs. 107.70-134.20 mg·dL-1 ) but not insulin. During aerobic exercise, RQ was 5% greater (0.90 vs. 0.86) (P = 0.039), and FAT oxidation was 35% lower at 6-8 min (0.003 vs. 0.005 g·min-1 ·kg-1 ) (P = 0.033) in S versus NS. During anaerobic exercise, CHO oxidation was 31% greater in NS versus S at 60-80% time to exhaustion (0.011 vs. 0.007 g·min-1 ·kg-1 ) (P = 0.015). Per cent contribution to energy expenditure was greater in S for CHO but lower for FAT at 0 (CHO: 22% vs. 10%; FAT: 78% vs. 91%) and 120-180 min (CHO: 35-42% vs. 17-25%; FAT: 58-65% vs. 75%-84%) (P = 0.003-0.046) at rest and 6-8 min during aerobic exercise (CHO: 70% vs. 57%; FAT: 30% vs. 45%) (P = 0.046). CONCLUSIONS The data show differences in skeletal muscle energy metabolism and substrate utilization between S and NS at rest, transitioning from fasted to fed state, and during exercise. Compared with NS, S displayed a diminished ability to adapt fuel utilization in response to feeding and exercise, reflecting metabolic inflexibility. Impaired metabolic flexibility could be a mechanism underlying the losses of strength and physical function accompanying sarcopenia.
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Affiliation(s)
- Marni E Shoemaker
- College of Health Sciences, The University of Texas at El Paso, El Paso, TX, USA
| | | | | | - Zachary M Gillen
- Department of Kinesiology, Mississippi State University, Mississippi State, MS, USA
| | - Brianna D McKay
- Department of Health Professions, Creighton University School of Medicine, Omaha, NE, USA
| | | | | | - Joel T Cramer
- College of Health Sciences, The University of Texas at El Paso, El Paso, TX, USA
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Dharamsi MS, Bastian DA, Balsiger HA, Cramer JT, Belmares R. Efficacy of Video-Based Forearm Anatomy Model Instruction for a Virtual Education Environment. J Med Educ Curric Dev 2022; 9:23821205211063287. [PMID: 35024450 PMCID: PMC8743927 DOI: 10.1177/23821205211063287] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
INTRODUCTION As virtual education becomes more widespread, particularly considering the recent COVID-19 pandemic, studies that assess the impact of online teaching strategies are vital. Current anatomy curriculum at Paul L. Foster School of Medicine consists of self-taught PowerPoint material, clinical vignette-centered team-based learning (dry lab), and prosection-based instruction (wet lab). This study examined the impact of video-based muscle model (VBMM) instruction using a student-designed forearm muscle model on anatomy quiz scores and student perceptions of its effectiveness with regards to learning outcomes. METHODS Students divided into Group 1 (54 students) and Group 2 (53 students) were assessed prior to and following a 3.5-minute video on anterior forearm compartment musculature using the muscle model. Group 1 began by completing a pretest, then received VBMM instruction, and then completed a posttest prior to participating in the standard dry lab and 1 hour wet lab. Group 2 completed the wet lab, then received the pretest, VBMM instruction, and posttest prior to participating in the dry lab. Both groups took an identical five-question quiz covering locations and functions of various anterior forearm muscles each time. RESULTS Mean scores were higher than no formal intervention with exposure to VBMM instruction alone (0.73 points, P = .01), wet lab alone (0.88 points, P = .002), and wet lab plus VBMM instruction (1.35 points, P= <.001). No significant difference in scores was found between instruction with VBMM versus wet lab alone (P = 1.00), or between either instruction method alone compared to a combination of the two methods (P = .34, .09). Student survey opinions on the VBMM instruction method were positive. CONCLUSION VBMM instruction is comparable to prosection-based lab with regards to score outcomes and was well received by students as both an independent learning tool and as a supplement to cadaveric lab. When compared to either instruction method alone, the supplementation of VBMM with cadaveric prosection instruction was best. VBMM instruction may be valuable for institutions without access to cadaveric specimens, or those looking to supplement their current anatomy curriculum.
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Affiliation(s)
- Miraal S. Dharamsi
- Paul L. Foster School of Medicine, Texas Tech University Health Science Center El Paso, El Paso, TX, USA
| | | | - Heather A. Balsiger
- Paul L. Foster School of Medicine, Texas Tech University Health Science Center El Paso, El Paso, TX, USA
| | | | - Ricardo Belmares
- Paul L. Foster School of Medicine, Texas Tech University Health Science Center El Paso, El Paso, TX, USA
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Jenkins ND, Miramonti AA, Hill EC, Smith CM, Cochrane-Snyman KC, Housh TJ, Cramer JT. Mechanomyographic Amplitude Is Sensitive to Load-Dependent Neuromuscular Adaptations in Response to Resistance Training. J Strength Cond Res 2021; 35:3265-3269. [DOI: 10.1519/jsc.0000000000003276] [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: 11/08/2022]
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Proppe CE, Rivera PM, Hill EC, Housh TJ, Keller JL, Smith CM, Anders JPV, Schmidt RJ, Johnson GO, Cramer JT. The effects of blood flow restriction resistance training on indices of delayed onset muscle soreness and peak power. ISOKINET EXERC SCI 2021. [DOI: 10.3233/ies-210158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND: Low-load resistance training with blood flow restriction (LL + BFR) attenuated delayed onset muscle soreness (DOMS) under some conditions. OBJECTIVE: The purpose of this study examined the effects of reciprocal concentric-only elbow flexion-extension muscle actions at 30% of peak torque on indices of DOMS. METHODS: Thirty untrained women (mean ± SD; 22 ± 2.4 years) were randomly assigned to 6 training days of LL + BFR (n= 10), low-load non-BFR (LL) (n= 10), or control (n= 10). Participants completed 4 sets (1 × 30, 3 × 15) of submaximal (30% of peak torque), unilateral, isokinetic (120∘s-1) muscle actions. Indices of DOMS including peak power, resting elbow joint angle (ROM), perceived muscle soreness (VAS), and pain pressure threshold (PPT) were assessed. RESULTS: There were no changes in peak power, ROM, or VAS. There was a significant interaction for PPT. Follow-up analyses indicated PPT increased for the LL + BFR condition (Day 5 > Day 2), but did not decrease below baseline. The results of the present study indicated LL + BFR and LL did not induce DOMS for the elbow extensors in previously untrained women. CONCLUSION: These findings suggested LL + BFR and LL concentric-only resistance training could be an effective training modality to elicit muscular adaptation without inducing DOMS.
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Affiliation(s)
| | | | - Ethan C. Hill
- University of Central Florida, Orlando, FL, USA
- Florida Space Institute, Orlando, FL, USA
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Proppe CE, Rivera PM, Hill EC, Housh TJ, Keller JL, Smith CM, Anders JPV, Schmidt RJ, Johnson GO, Cramer JT. The Effects Of Blood Flow Restriction Training On Indices Of Doms And Peak Torque. Med Sci Sports Exerc 2021. [DOI: 10.1249/01.mss.0000759264.76958.8c] [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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Affiliation(s)
- Zachary M. Gillen
- Department of Kinesiology Mississippi State University Mississippi State MS USA
| | - Malachy P. McHugh
- Nicholas Institute of Sports Medicine and Athletic TraumaLenox Hill Hospital New York NY USA
| | - Marni E. Shoemaker
- College of Health SciencesThe University of Texas at El Paso El Paso TX USA
| | - Joel T. Cramer
- College of Health SciencesThe University of Texas at El Paso El Paso TX USA
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Herda AA, Smith-Ryan AE, Kendall KL, Cramer JT, Stout JR. Evaluation of High-Intensity Interval Training and Beta-Alanine Supplementation on Efficiency of Electrical Activity and Electromyographic Fatigue Threshold. J Strength Cond Res 2021; 35:1535-1541. [PMID: 34027920 DOI: 10.1519/jsc.0000000000004038] [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: 11/08/2022]
Abstract
ABSTRACT Herda, AA, Smith-Ryan, AE, Kendall, KL, Cramer, JT, and Stout, JR. Evaluation of high-intensity interval training and beta-alanine supplementation on efficiency of electrical activity and electromyographic fatigue threshold. J Strength Cond Res 35(6): 1535-1541, 2021-The purpose of this study was to determine the effects of high-intensity interval training (HIIT) with or without β-alanine (BA) supplementation on the electromyographic fatigue threshold (EMGFT) and efficiency of electrical activity (EEA) in young women. Forty-four women (mean ± SD; age [yrs]: 21.7 ± 3.7; height [cm]: 166.3 ± 6.4; body mass [kg]: 66.1 ± 10.3) were randomly assigned to one of 3 treatment groups. The supplement groups performed HIIT on the cycle ergometer 3 times·wk-1 for 6 weeks. Electromyographic fatigue threshold and EEA were assessed at baseline (PRE), after 3 weeks of training (MID), and after 6 weeks of HIIT (POST). Two 2-way mixed factorial analyses of variance (time [PRE vs. MID vs. POST] × treatment (BA vs. PL vs. CON)] were used to analyze EMGFT and EEA with a predetermined level of significance α of 0.05. For EMGFT, there was no interaction (p = 0.26) and no main effect for time (p = 0.28) nor treatment (p = 0.86); thus, there were no changes in EMGFT regardless of training or supplementation status. For EEA, there was no interaction (p = 0.70) nor treatment (p = 0.79); however, there was a main effect for time (p < 0.01). Our findings indicated that neither training nor supplementation was effective in improving EMGFT in women. Efficiency of electrical activity was altered, potentially because of a learning effect. Coaches and practitioners may not use these tests to monitor training status; however, they may find EEA as a useful tool to track cycling efficiency.
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Affiliation(s)
- Ashley A Herda
- Department of Health, Sport, and Exercise Sciences, University of Kansas-Edwards Campus, Overland Park, Kansas
| | - Abbie E Smith-Ryan
- Department of Exercise and Sport Science, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina
| | - Kristina L Kendall
- Department of Exercise and Sport Sciences, Edith Cowan University, Joondalup WA, Australia
| | - Joel T Cramer
- Department of Kinesiology College of Health Sciences, University of Texas-El Paso, El Paso, Texas; and
| | - Jeffrey R Stout
- Exercise Physiology & Rehabilitation Science and Kinesiology Units School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, Florida
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Gillen ZM, Shoemaker ME, Bohannon NA, Gibson SM, Cramer JT. Comparing the torque- and power-velocity relationships between children and adolescents during isokinetic leg extension muscle actions. Hum Mov Sci 2020; 74:102678. [PMID: 33137582 DOI: 10.1016/j.humov.2020.102678] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 06/26/2020] [Accepted: 09/03/2020] [Indexed: 11/19/2022]
Abstract
The purpose of this study was to use polynomial regression analyses to examine the torque- and power-velocity relationships and calculate and compare the vertices of these nonlinear models, and how they relate to measurements of muscle size and maximal strength, between male and female children and adolescents during maximal isokinetic leg extension muscle actions. Sixteen children (n = 8 males, n = 8 females) and 22 adolescents (n = 11 males, n = 11 females) participated in this study. Measurements of growth included age, maturity offset, height, body mass, fat-free mass, and quadriceps femoris muscle cross-sectional area (CSA). Participants completed maximal voluntary isometric contractions (MVICs) of the leg extensors and maximal voluntary isokinetic leg extensions at 60, 120, 180, 240, and 300°·s-1. Variables calculated during all leg extension muscle actions included peak torque (PT, Nm) and mean power (MP, W). Polynomial regression analyses determined the model of best fit for the PT- and MP-velocity relationships. For each participant, the vertex from the PT- and MP-velocity quadratic models were quantified as the predicted maximum velocity of last measurable torque (VPT) and the predicted velocity of maximum mean power (VMP), respectively. Measurements of growth, PT and MP at all velocities, VPT, and VMP were greater in the adolescents than children. When normalized to CSA, VPT and VMP remained greater for adolescents than children, and exhibited low to very high relationships with measurements of growth. When normalized to MVIC strength, VPT and VMP were no longer different between children and adolescents and exhibited negligible to low relationships with measurements of growth. The results of the present study suggest that the ability to produce torque and power at high velocities may be more dependent on muscle strength than muscle size, which suggests that mechanisms other than muscular hypertrophy affect torque and power production at high velocities in young males and females.
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Affiliation(s)
- Zachary M Gillen
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Marni E Shoemaker
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Nicholas A Bohannon
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Sydney M Gibson
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Joel T Cramer
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, USA.
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Bohannon NA, Gillen ZM, Shoemaker ME, McKay BD, Gibson SM, Cramer JT. Test-Retest Reliability of Static and Countermovement Power Push-Up Tests in Young Male Athletes. J Strength Cond Res 2020; 34:2456-2464. [PMID: 32865943 DOI: 10.1519/jsc.0000000000003684] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Bohannon, NA, Gillen, ZM, Shoemaker, ME, McKay, BD, Gibson, SM, Cramer, JT. Test-Retest Reliability of Static and Counter-Movement Power Push-Up Tests in Young Male Athletes. J Strength Cond Res 34(9): 2456-2464, 2020-The primary purpose of this study was to evaluate test-retest reliability of the static (SP) and countermovement (CMP) power push-up test in young male athletes. The secondary purpose was to compare the reliability of vertical ground reaction forces versus torque measurements during the power push-up tests. Twenty boys (age = 11.60 ± 1.15 years) performed SPs and CMPs on force plates with the knees as the fulcrum on 2 laboratory visits separated by 2-7 days. Performance measurements included peak force (PF), peak rate of force development (pRFD), peak torque (PT), peak rate of torque development (pRTD), peak power (PP), average power (AP), eccentric impulse (ECC), and concentric impulse (CON) for both power push-up techniques. Age, maturity offset, height, body mass, fat-free mass, and estimated arm cross sectional area were obtained as measurements of growth. Intraclass correlation coefficients (ICC), SEM, coefficients of variation, and minimum detectable changes (MDC) were reported. Only PF (ICC = 0.87-0.88, SEM = 59-84 N) and PT (ICC = 0.89-0.90, SEM = 60-88 N·m) showed acceptable reliability. Neither pRFD, pRTD, PP, AP, ECC, or CON were reliable outcomes. There were no meaningful differences between force-time and torque-time curve measurements. The SP showed slightly lower CVs (33-34%) than the CMP (CVs = 39-40%). Coaches and practitioners would need to see 58-71% increases in upper-body strength measurements evaluated via power push-up on force plates to be 95% confident that the improvements exceeded the measurement variability.
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Affiliation(s)
- Nicholas A Bohannon
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
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Shoemaker ME, Gillen ZM, Mckay BD, Leutzinger TJ, Mustad VA, Cramer JT. Endogenous versus exogenous carbohydrate oxidation measured by stable isotopes in pre-pubescent children plus 13C abundances in foods consumed three days prior. Metabol Open 2020; 7:100041. [PMID: 32812942 PMCID: PMC7424810 DOI: 10.1016/j.metop.2020.100041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 05/21/2020] [Revised: 06/22/2020] [Accepted: 07/09/2020] [Indexed: 11/29/2022] Open
Abstract
PURPOSE The purposes of the present study were to (a) examine resting metabolism, substrate utilization, and endogenous versus exogenous carbohydrate (CHO) oxidation before and after 30-g rapidly-digesting carbohydrate (RDC) ingestion using indirect calorimetry and breath test analysis of stable isotope concentrations in pre-pubescent children and (b) report the 13C abundances in foods consumed for three days prior. METHODS Nineteen children (n = 10 boys, n = 9 girls) at Tanner stage I or II participated (mean age ± 95% CI = 9.84 ± 0.77 y) in this study. Food was administered to the children for three days preceding their scheduled breath tests. Breath tests and indirect calorimetry were performed after an 8-h fast before and 60 min following consumption of a 30-g simple RDC drink consisting of maltodextrin and sucrose. Open circuit spirometry and indirect calorimetry monitored resting metabolism and CHO oxidation. Separate breath samples were taken every 15 min. Samples of all foods and breath samples were analyzed for 13C and 12C abundances with a stable-isotope mass spectrometer. RESULTS 13C in expired breath samples were -23.81 ± 1.64‰ at baseline and increased every 15 min after consumption of the CHO drink (p < 0.001-0.009). Cumulative total, endogenous, and exogenous CHO utilization increased during the post-prandial period (p < 0.001). Endogenous CHO oxidation was consistently greater than exogenous CHO oxidation (p < 0.001-0.002).Blood glucose was elevated from baseline at 30- and 60-min post-prandial (p < 0.001). Insulin did not change over time (p = 0.184). CONCLUSIONS The foods provided during the 3-day controlled diet effectively minimized 13C variation prior to metabolic testing. The 13C abundances of foods reported herein should serve as practical recommendations to reduce 13C intake before breath tests. While endogenous CHO oxidation remained greater in proportion to exogenous CHO oxidation, these findings suggest that even a relatively small amount of RDC can increase exogenous CHO oxidation and blood glucose in normal-weight children. To further examine shifts in endogenous versus exogenous CHO utilization, we recommend that future studies take steps to minimize 13C variation before breath tests and examine changes in substrate metabolism at rest and during exercise in normal weight and overweight pre-pubescent children. CLINICAL TRIAL REGISTRATION NUMBER NCT03185884.
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Affiliation(s)
- Marni E. Shoemaker
- College of Health Sciences, The University of Texas at El Paso, El Paso, TX, 79968, United States
| | - Zachary M. Gillen
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68583, United States
| | - Brianna D. Mckay
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68583, United States
| | - Todd J. Leutzinger
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68583, United States
| | - Vikkie A. Mustad
- Abbott Nutrition, 2900 Easton Square Place, Columbus, OH, 43219, United States
| | - Joel T. Cramer
- College of Health Sciences, The University of Texas at El Paso, El Paso, TX, 79968, United States
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Gillen ZM, Shoemaker ME, McKay BD, Bohannon NA, Gibson SM, Cramer JT. Peak Torque Explains More Unique Variability in Growth Measurements than Rate of Torque Development in Young Boys and Girls. J Strength Cond Res 2020; 34:2507-2514. [PMID: 32639374 DOI: 10.1519/jsc.0000000000003728] [Citation(s) in RCA: 0] [Impact Index Per Article: 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, Shoemaker, ME, McKay, BD, Bohannon, NA, Gibson, SM, and Cramer, JT. Peak torque explains more unique variability in growth measurements than rate of torque development in young boys and girls. J Strength Cond Res 34(9): 2507-2514, 2020-This study reported test-retest reliability and evaluated collinearity for isometric leg extension and flexion peak torque (PT) and rate of torque development (RTD) in young boys and girls. Measurements of growth included height, body mass, fat-free mass, maturity offset, and leg extensor and flexor muscle cross-sectional area. Maximal isometric contractions quantified PT and RTD. Intraclass correlation coefficients (ICCs), SEM, coefficients of variation, and minimum detectable changes quantified test-retest reliability. Zero-order correlations and first-order partial correlations evaluated collinearity. Peak torque from leg extension and flexion exhibited ICCs ≥ 0.90, RTD from leg extension and flexion exhibited ICCs ≥ 0.38. Partialing out leg flexion PT reduced the relationships between leg extension PT and growth (rPText, growth.PTflex = 0.392-0.605). Partialing out leg extension PT eliminated the relationships between leg flexion PT and growth (rPTflex, growth.PText = 0.098-0.263). Partialing out leg extension RTD reduced the relationships between PT and growth (rPText, growth.RTDext = 0.516-0.775). Partialing out leg extension PT eliminated the relationships between RTD and growth (|rRTDext, growth.PText| = 0.001-0.148). Leg extension PT was more reliable and explained the most unique variability in growth among young boys and girls. In contrast, RTD was less reliable and was fully accounted for by PT, indicating that RTD may be an unnecessary measurement in studies of young boys and girls.
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Affiliation(s)
- Zachary M Gillen
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
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Shoemaker ME, Gillen ZM, Bohannon NA, Gibson SM, Cramer JT. Vastus Lateralis Muscle Oxygenation Measured By Near-infrared Spectroscopy During Voluntary Isometric Leg Extension Muscle Actions. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000675148.44126.44] [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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Bohannon NA, Gillen ZM, Shoemaker ME, Gibson SM, Cramer JT. Effects Of Eccentric Pre-loading On Vertical Jump Performance In 9-17-year-old Female Athletes. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000676312.01677.d8] [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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17
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Gillen ZM, Shoemaker ME, Bohannon NA, Bohannon NA, Cramer JT. Strength And Power As Indicators Of Differences In Fiber Type Contributions In Children And Adolescents. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000676296.61012.c2] [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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Gillen ZM, Shoemaker ME, McKay BD, Bohannon NA, Gibson SM, Cramer JT. Influences of the Stretch-Shortening Cycle and Arm Swing on Vertical Jump Performance in Children and Adolescents. J Strength Cond Res 2020; 36:1245-1256. [PMID: 32483060 DOI: 10.1519/jsc.0000000000003647] [Citation(s) in RCA: 3] [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
Gillen, ZM, Shoemaker, ME, McKay, BD, Bohannon, NA, Gibson, SM, and Cramer, JT. Influences of the stretch-shortening cycle and arm swing on vertical jump performance in children and adolescents. J Strength Cond Res XX(X): 000-000, 2020-This study compared the influences of the stretch-shortening cycle and arm swing on vertical jump performance during static jumps (SJs), counter-movement jumps (CMJs), and CMJs with arm swing (CMJAs) in young male and female athletes. Twenty-one boys (age = 12.1 ± 1.1 years) and 21 girls (age = 12.1 ± 1.1 years) performed SJs, CMJs, and CMJAs on force plates that sampled at 1 kHz. Measurements included peak force, rate of force development, peak power (PP), eccentric impulse (ECC), concentric impulse (CON), estimated jump height (JH), and changes in PP and JH across vertical jumps. Measurements of growth included age, maturity offset, height, body mass, fat-free mass, and thigh muscle cross-sectional area. Analyses of variance were used to analyze growth measurements across sex, as well as vertical jump outcome measures. Pearson product moment correlation coefficients were used to determine the relationships between changes in PP and JH across vertical jumps and growth measurements. There were differences in PP and JH such that SJ < CMJ < CMJA (p < 0.001), and ECC such that SJ < CMJA < CMJ (p ≤ 0.048). Changes in PP were greater from the SJ to CMJ than CMJ to CMJA (p ≤ 0.001). The change in PP from the SJ to CMJ exhibited moderate-to-high relationships with growth measurements for boys and girls (r = 0.543-0.803). Because young children may not have the skeletal musculature or strength necessary to absorb and reapply large eccentric preloading forces, future studies should consider using the CMJA, rather than the CMJ, to maximize vertical jump performance and minimize ECC. Coaches and practitioners can expect approximately 27-33% greater PP and 15-17% greater estimated JH when an arm swing is included during the CMJ.
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Affiliation(s)
- Zachary M Gillen
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
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Shoemaker ME, Gillen ZM, Mckay BD, Bohannon NA, Gibson SM, Koehler K, Cramer JT. Sex-specific relationships among iron status biomarkers, athletic performance, maturity, and dietary intakes in pre-adolescent and adolescent athletes. J Int Soc Sports Nutr 2019; 16:42. [PMID: 31533743 PMCID: PMC6751686 DOI: 10.1186/s12970-019-0306-7] [Citation(s) in RCA: 3] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 08/26/2019] [Indexed: 01/22/2023] Open
Abstract
Background The purpose of this study was to examine relationships among biomarkers of iron status, athletic performance, growth and development, and dietary intakes in pre-adolescent and adolescent male and female athletes. Methods Two-hundred and forty-nine male (n = 179) (mean ± standard deviation for age = 12.0 ± 2.1 years, height = 156.3 ± 13.9 cm, and weight = 49.1 ± 16.5 kg) and female (n = 70) (12.0 ± 2.2 years, 152.4 ± 12.3 cm, 45.3 ± 14.5 kg) athletes volunteered for capillary blood sample, anthropometric, athletic performance, and dietary intake assessments. Outcomes included maturity offset from peak height velocity, percent body fat, estimated muscle cross-sectional areas, vertical jump height (VJ), broad jump distance (BJ), pro-agility time (PA), L-cone time, 20-yard dash time (20YD), power push up (PPU) force, dietary intakes, and ferritin, soluble transferrin receptor (sTfR), and hemoglobin (Hb) concentrations. Results Athletic performance was consistently correlated with Hb in males (r = .237–.375, p < 0.001–0.05) and with sTfR (r = .521–.649, p < 0.001–0.004) and iron intake (r = .397–.568, p = 0.001–0.027) in females. There were no relationships between dietary intakes and ferritin, sTfR, or Hb (p > 0.05). After partialing out age and height, VJ, PA, LC, and 20YD remained correlated with Hb in males (|rHb,y.Age| = .208–.322, p = 0.001–0.041; |rHb,y.Height| = .211–.321, p = 0.001–0.038). After partialing out iron intake, PA and LC remained correlated with sTfR in females (|rsTfR,y.ironintake| = .516–.569, p = 0.014–0.028). Conclusions Iron status biomarkers demonstrated sex-specific relationships with anaerobic exercise performance in youth athletes, which may be more dependent on maturity status and dietary intake than age. Moderate relationships between sTfR and athletic performance in adolescent female athletes emphasizes the importance of iron intake in this demographic.
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Affiliation(s)
- Marni E Shoemaker
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Ruth Leverton Hall, Lincoln, NE, 68583, USA
| | - Zachary M Gillen
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Ruth Leverton Hall, Lincoln, NE, 68583, USA
| | - Brianna D Mckay
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Ruth Leverton Hall, Lincoln, NE, 68583, USA
| | - Nicholas A Bohannon
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Ruth Leverton Hall, Lincoln, NE, 68583, USA
| | - Sydney M Gibson
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Ruth Leverton Hall, Lincoln, NE, 68583, USA
| | - Karsten Koehler
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Ruth Leverton Hall, Lincoln, NE, 68583, USA
| | - Joel T Cramer
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Ruth Leverton Hall, Lincoln, NE, 68583, USA.
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Shoemaker ME, Gillen ZM, McKay BD, Koehler K, Cramer JT. High Prevalence of Poor Iron Status Among 8- to 16-Year-Old Youth Athletes: Interactions Among Biomarkers of Iron, Dietary Intakes, and Biological Maturity. J Am Coll Nutr 2019; 39:155-162. [PMID: 31339828 DOI: 10.1080/07315724.2019.1621229] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [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: 12/13/2022]
Abstract
Objective: The purpose of this study was to determine the prevalence of poor iron status in young athletes throughout the stages of iron deficiency and assess sex differences with iron deficiency in relation to growth and development and dietary intake.Methods: A cross-sectional analysis evaluated young male and female athletes (n = 91) between the ages 8 and 16 years. Anthropometric assessments, body composition, dietary intakes, and blood samples measuring ferritin, soluble transferrin receptor (sTfR), and hemoglobin (Hb) were examined. Prevalence was calculated as percentages, and independent samples t tests examined sex differences. Pearson product-moment correlation coefficient analyses quantified relationships among variables for the composite sample and each sex separately.Results: Iron depletion (low ferritin) was present in 65% and 86%, low iron levels (sTfR) in 51% and 68%, and anemia (low Hb) in 46% and 53% of the males and females, respectively. As iron deficiency progressed from low ferritin to high sTfR to anemia, prevalence decreased in both sexes, but always remained higher in females. Males were greater than females for weight, arm muscle size, and ferritin concentrations, while females were greater than males for biological maturity (p ≤ 0.05). Dietary iron intake was moderately to highly correlated (r = 0.543-0.723, p ≤ 0.05) with growth and development in females, but not males.Conclusions: Prevalence of poor iron status was higher than expected, particularly in adolescent females. Since rapid growth combined with sports participation may create high demands for iron bioavailability, emphasis may need to be placed on dietary iron intake for young athletes, particularly females.
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Affiliation(s)
- Marni E Shoemaker
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Zachary M Gillen
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Brianna D McKay
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Karsten Koehler
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Joel T Cramer
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
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Gillen ZM, Shoemaker ME, McKay BD, Bohannon NA, Mendez AI, Jahn LE, Cramer JT. Effects of Arm Swing and Overhead Target on Vertical Jump Performance in Children and Adolescents. Med Sci Sports Exerc 2019. [DOI: 10.1249/01.mss.0000562329.70360.25] [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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22
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Gillen ZM, Shoemaker ME, McKay BD, Cramer JT. Performance Differences between National Football League and High School American Football Combine Participants. Res Q Exerc Sport 2019; 90:227-233. [PMID: 30794113 DOI: 10.1080/02701367.2019.1571679] [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: 06/06/2018] [Accepted: 12/22/2018] [Indexed: 06/09/2023]
Abstract
PURPOSE The purpose of this study was to determine magnitudes of differences for anthropometric and athletic performance scores between high school and elite college-level American football players. METHOD Participants included high school-age (n = 3,666) athletes who participated in American football combines, as well as elite college-level (n = 5,537) athletes who participated in the National Football League (NFL) scouting combine. Combine data included position; height; weight; 10-, 20-, and 40-yard dash; pro-agility (PA); L-cone drill (LC); vertical jump (VJ); and broad jump (BJ). Athletes were separated into their respective position group, defensive back (DB), wide receiver (WR), linebacker (LB), quarterback (QB), running back (RB), tight end (TE), defensive line (DL), and offensive line (OL) for analysis of performance differences. Percent differences for each dependent variable were calculated to quantify magnitudes of differences. RESULTS NFL combine participants scored 3% to 25% better on all measurements, with the largest differences between weight and VJ (14%-25%). CONCLUSION The largest measurement-specific differences between high school-age and elite college-level American football players were body size and power. Although it may seem intuitive that elite college-level players would perform better, these data provide a unique perspective to high school players, parents, and coaches, giving new information to use when designing measurement-specific athletic development programs. Thus, strength and conditioning professionals may benefit from emphasizing increases in muscle mass and power output in strength and conditioning programs.
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Shoemaker ME, Gillen ZM, McKay BD, Bohannon NA, Mendez AI, Cramer JT. Effects Of An Online Sports Nutrition Curriculum On Biomarkers Of Iron Status In Youth Athletes. Med Sci Sports Exerc 2019. [DOI: 10.1249/01.mss.0000563166.44129.0e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [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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Gillen ZM, Shoemaker ME, McKay BD, Bohannon NA, Gibson SM, Cramer JT. Muscle strength, size, and neuromuscular function before and during adolescence. Eur J Appl Physiol 2019; 119:1619-1632. [PMID: 31087141 DOI: 10.1007/s00421-019-04151-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [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: 12/22/2018] [Accepted: 04/24/2019] [Indexed: 12/24/2022]
Abstract
PURPOSE To compare measurements of muscle strength, size, and neuromuscular function among pre-adolescent and adolescent boys and girls with distinctly different strength capabilities. METHODS Fifteen boys (mean age ± confidence interval: 13.0 ± 1.0 years) and 13 girls (12.9 ± 1.1 years) were categorized as low strength (LS, n = 14) or high strength (HS, n = 14) based on isometric maximal voluntary contraction strength of the leg extensors. Height (HT), seated height, and weight (WT) determined maturity offset, while percent body fat and fat-free mass (FFM) were estimated from skinfold measurements. Quadriceps femoris muscle cross-sectional area (CSA) was assessed from ultrasound images. Isometric ramp contractions of the leg extensors were performed while surface electromyographic amplitude (EMGRMS) and mechanomyographic amplitude (MMGRMS) were recorded for the vastus lateralis (VL). Neuromuscular efficiency from the EMG and MMG signals (NMEEMG and NMEMMG, respectively) and log-transformed EMG and MMG vs. torque relationships were also used to examine neuromuscular responses. RESULTS HS was 99-117% stronger, 2.3-2.8 years older, 14.0-15.7 cm taller, 20.9-22.3 kg heavier, 2.3-2.4 years more biologically mature, and exhibited 39-43% greater CSA than LS (p ≤ 0.001). HS exhibited 74-81% higher NMEEMG than LS (p ≤ 0.022), while HS girls exhibited the highest NMEMMG (p ≤ 0.045). Even after scaling for HT, WT, CSA, and FFM, strength was still 36-90% greater for HS than LS (p ≤ 0.031). The MMGRMS patterns in the LS group displayed more type I motor unit characteristics. CONCLUSIONS Neuromuscular adaptations likely influence strength increases from pre-adolescence to adolescence, particularly when examining large, force-producing muscles and large strength differences explained by biological maturity, rather than simply age.
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Affiliation(s)
- Zachary M Gillen
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 211 Ruth Leverton Hall, Lincoln, NE, 68583, USA
| | - Marni E Shoemaker
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 211 Ruth Leverton Hall, Lincoln, NE, 68583, USA
| | - Brianna D McKay
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 211 Ruth Leverton Hall, Lincoln, NE, 68583, USA
| | - Nicholas A Bohannon
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 211 Ruth Leverton Hall, Lincoln, NE, 68583, USA
| | - Sydney M Gibson
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 211 Ruth Leverton Hall, Lincoln, NE, 68583, USA
| | - Joel T Cramer
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 211 Ruth Leverton Hall, Lincoln, NE, 68583, USA.
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Mendez AI, Miramonti AA, Gillen ZM, McKay BD, Leutzinger TJ, Cramer JT. Stature, Body Mass, and Body Mass Index in High School American Football Players: Appropriate Determinants of Obesity Prevalence? J Strength Cond Res 2018; 32:3119-3126. [PMID: 30540280 DOI: 10.1519/jsc.0000000000002347] [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
Mendez, AI, Miramonti, AA, Gillen, ZM, McKay, BD, Leutzinger, TJ, and Cramer, JT. Stature, body mass, and BMI in high school american football players: Appropriate determinants of obesity prevalence? J Strength Cond Res 32(11): 3119-3126, 2018-The purpose of this study was to evaluate stature (HT), mass (BM), body mass index (BMI), and obesity prevalence based on BMI categories in a large sample (n = 7,175) of high school American football players enrolled as freshmen, sophomores, or juniors. Players were categorized by their positions: offensive linemen (OLs), defensive linemen (DLs), tight end, defensive end, linebacker, running back, quarterback, defensive back, and wide receiver. The HT, BM, and BMI increased as grade increased among all positions. Offensive lineman and DL had the greatest HT, BM, and BMI (p ≤ 0.05). Obesity prevalence was greatest in OL and DL. When accounting for age-related increases in BMI, BM increased to a greater degree than HT. If HT is an indirect indicator of skeletal size, although BM is more influenced by soft tissue, then the age-related BMI increases in this study may be largely accounted for by soft-tissue changes rather than skeletal growth. Although obesity prevalence in OL (94.5%) and DL (78.4%) positions was greater than all other positions as determined from BMI, it is impossible to know the allocations of fat-free and fat mass-particularly in American football athletes. If obesity continues to be defined as an unhealthy accumulation of fat, then athletes who may have a greater relative proportion of lean soft tissue should not be classified as obese using BMI (BM ÷ HT). More sophisticated, reliable, and sensitive measure of body composition, such as skinfolds, may be more appropriate field measurements.
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Affiliation(s)
- Alegra I Mendez
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE
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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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Tomko PM, Miramonti A, Hill EC, Smith CM, Cochrane-Snyman KC, Colquhoun RJ, Housh TJ, Cramer JT, Jenkins ND. Mechanomyographic Amplitude Is Sensitive To Neuromuscular Adaptations Following High- Versus Low-load Resistance Training. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000536508.41183.4c] [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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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, Leutzinger TJ, Cramer JT. Test-Retest Reliability and Concurrent Validity of Athletic Performance Combine Tests in 6-15-Year-Old Male Athletes. J Strength Cond Res 2018; 32:2783-2794. [PMID: 29465606 DOI: 10.1519/jsc.0000000000002498] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Gillen, ZM, Miramonti, AA, McKay, BD, Leutzinger, TJ, and Cramer, JT. Test-retest reliability and concurrent validity of athletic performance combine tests in 6-15-year-old male athletes. J Strength Cond Res 32(10): 2783-2794, 2018-Athletic performance combine tests are used by high school, collegiate, and professional American football programs to evaluate performance; however, limited evidence is available on performance combine test results in youth athletes. The purposes of this study were to report test-retest reliability statistics and evaluate concurrent validity among combine performance tests in 6-15-year-old male athletes. Sixty-nine young male athletes (mean ± SD; age = 10.9 ± 2.1 years, height = 154.4 ± 13.6 cm, body mass = 46.8 ± 16.0 kg) were divided into 3 age groups: 6-9 years (n = 16), 10-11 years (n = 26), and 12-15 years (n = 27). Participants completed 2 attempts of the vertical jump (VJ), broad jump (BJ), pro-agility (PA), L-cone (LC) drill, and 10-, 20-, 40-yd dashes. The results indicated that the older age groups performed better on most performance assessments compared with the 6-9-year group (p ≤ 0.05). The combine tests demonstrated consistently adequate reliability for all age groups, except for the 10-yd dash, which was deemed unreliable. Evidence of concurrent validity, and possible measurement redundancy were observed in the VJ vs. BJ, PA vs. LC, and 20 vs. 40 yd, but zero- and first-order partial correlations suggested that only the PA and LC were redundant, and the PA may be superior for this age group over the LC. Although the VJ and BJ provide independent performance information regarding lower-body power, questions regarding the redundancy of the 20 vs. 40 yd remain unanswered from a measurement perspective.
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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
| | - Todd J Leutzinger
- Department of Biomechanics, University of Nebraska-Omaha, Omaha, Nebraska
| | - Joel T Cramer
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
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Leutzinger TJ, Gillen ZM, Miramonti AM, McKay BD, Mendez AI, Cramer JT. Anthropometric and Athletic Performance Combine Test Results Among Positions Within Grade Levels of High School-Aged American Football Players. J Strength Cond Res 2018; 32:1288-1296. [PMID: 29389695 DOI: 10.1519/jsc.0000000000002481] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Leutzinger, TJ, Gillen, ZM, Miramonti, AM, McKay, BD, Mendez, AI, and Cramer, JT. Anthropometric and athletic performance combine test results among positions within grade levels of high school-aged American football players. J Strength Cond Res 32(5): 1288-1296, 2018-The purpose of this study was to investigate differences among player positions at 3 grade levels in elite, collegiate-prospective American football players. Participants' data (n = 7,160) were analyzed for this study (mean height [Ht] ± SD = 178 ± 7 cm, mass [Bm] = 86 ± 19 kg). Data were obtained from 12 different high school American football recruiting combines hosted by Zybek Sports (Boulder, Colorado). Eight 2-way (9 × 3) mixed factorial analysis of variances {position (defensive back [DB], defensive end, defensive lineman, linebacker, offensive lineman [OL], quarterback, running back, tight end, and wide receiver [WR]) × grade (freshmen, sophomores, and juniors)} were used to test for differences among the mean test scores for each combine measure (Ht, Bm, 40-yard [40 yd] dash, proagility [PA] drill, L-cone [LC] drill, vertical jump [VJ], and broad jump [BJ]). There were position-related differences (p ≤ 0.05) for Ht, 40 yd dash, and BJ, within each grade level and for Bm, PA, LC, and VJ independent of grade level. Generally, the results showed that OL were the tallest, weighed the most, and exhibited the lowest performance scores among positions. Running backs were the shortest, whereas DBs and WRs weighed the least and exhibited the highest performance scores among positions. These results demonstrate the value of classifying high school-aged American football players according to their specific position rather than categorical groupings such as "line" vs. "skill" vs. "big skill" when evaluating anthropometric and athletic performance combine test results.
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Affiliation(s)
- Todd J Leutzinger
- Department of Nutrition and Health Science, University of Nebraska-Lincoln, Lincoln, Nebraska 68583
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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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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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Miramonti AA, Cramer JT, Jenkins ND, Gillen ZM, McKay BD, Leutzinger TJ. Effects of Speed and Agility Training on Combine Performance in Young Male Athletes. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000519643.86847.ff] [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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Gillen ZM, Cramer JT, Miramonti AA, Jenkins NDM, McKay BD, Leutzinger TJ. Power Push-up Tests Performed from the Knees and Toes in Young Male Athletes. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000519017.95110.31] [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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Cramer JT, Cruz-Jentoft AJ, Landi F, Hickson M, Zamboni M, Pereira SL, Hustead DS, Mustad VA. Impacts of High-Protein Oral Nutritional Supplements Among Malnourished Men and Women with Sarcopenia: A Multicenter, Randomized, Double-Blinded, Controlled Trial. J Am Med Dir Assoc 2016; 17:1044-1055. [DOI: 10.1016/j.jamda.2016.08.009] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 08/22/2016] [Indexed: 12/24/2022]
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Jenkins ND, Housh TJ, Buckner SL, Bergstrom HC, Cochrane KC, Hill EC, Smith CM, Schmidt RJ, Johnson GO, Cramer JT. Neuromuscular Adaptations After 2 and 4 Weeks of 80% Versus 30% 1 Repetition Maximum Resistance Training to Failure. J Strength Cond Res 2016; 30:2174-85. [DOI: 10.1519/jsc.0000000000001308] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Hill EC, Housh TJ, Camic CL, Smith CM, Cochrane KC, Jenkins ND, Cramer JT, Schmidt RJ, Johnson GO. Effects of Velocity on Electromyographic, Mechanomyographic, and Torque Responses to Repeated Eccentric Muscle Actions. J Strength Cond Res 2016; 30:1743-51. [DOI: 10.1519/jsc.0000000000001266] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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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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Miramonti AA, Housh TJ, Jenkins ND, Cochrane KC, Hill EC, Smith CM, Schmidt RJ, Johnson GO, Cramer JT. Relationships Among Cognitive Function and Handgrip Strength And Endurance In Older Men And Women. Med Sci Sports Exerc 2016. [DOI: 10.1249/01.mss.0000485116.08418.a3] [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, Miramonti A, Smith C, Hill EC, Cochrane KC, Housh TJ, Cramer JT. Are Voluntary Activation Determined By The Interpolated Twitch Technique And Mechanomyographic Amplitude Synonymous? Med Sci Sports Exerc 2016. [DOI: 10.1249/01.mss.0000487687.18681.bf] [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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Hill EC, Housh TJ, Smith CM, Cochrane KC, Jenkins ND, Miramonti AA, Cramer JT, Schmidt RJ, Johnson GO. Effects of Work-to-Rest Ratios on Peak Torque and Neuromuscular Responses during Submaximal, Isometric Muscle Actions. Med Sci Sports Exerc 2016. [DOI: 10.1249/01.mss.0000486238.86755.09] [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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Cochrane K, Housh TJ, Smith CM, Hill EC, Jenkins ND, Miramonti A, Schmidt RJ, Johnson GO, Cramer JT, Coburn JW. Physiological Responses Underlying The Perception Of Effort During Moderate And Heavy Intensity Cycle Ergometry. Med Sci Sports Exerc 2016. [DOI: 10.1249/01.mss.0000485348.14253.d5] [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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Bergstrom HC, Housh TJ, Jenkins ND, Cochrane KC, Byrd MT, Schmidt RJ, Johnson GO, Cramer JT. Neuromuscular and Perceptual Responses, but not Metabolic, Consistently Driven to Peak During Severe Intensity Running. Med Sci Sports Exerc 2016. [DOI: 10.1249/01.mss.0000485359.19198.26] [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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Moon JR, Moon SE, Smith-Ryan AE, Fukuda DH, Kendall KL, Lockwood CM, Cramer JT, Stout JR. The Effects Of Dual-Energy X-Ray Absorptiometry-Derived Body Volumes On Percent Body Fat. Med Sci Sports Exerc 2016. [DOI: 10.1249/01.mss.0000488016.66226.b8] [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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Smith CM, Housh TJ, Hill EC, Cochrane KC, Jenkins NDM, Miramonti A, Cramer JT, Schmidt RJ, Johnson GO. Effects of Varied Intensity on Torque and Neuromuscular Parameters during Intermittent Isometric Muscle Actions. Med Sci Sports Exerc 2016. [DOI: 10.1249/01.mss.0000485338.30393.dc] [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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Hill EC, Housh TJ, Camic CL, Jenkins ND, Smith CM, Cochrane KC, Cramer JT, Schmidt RJ, Monaghan MM, Johnson GO. The effects of velocity on peak torque and neuromuscular responses during eccentric muscle actions. ISOKINET EXERC SCI 2016. [DOI: 10.3233/ies-150591] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Ethan C. Hill
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Terry J. Housh
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Clayton L. Camic
- Department of Exercise and Sport Science, University of Wisconsin-La Crosse, La Crosse, WI, USA
| | - Nathaniel D.M. Jenkins
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Cory M. Smith
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Kristen C. Cochrane
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Joel T. Cramer
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Richard J. Schmidt
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Molly M. Monaghan
- Department of Exercise and Sport Science, University of Wisconsin-La Crosse, La Crosse, WI, USA
| | - Glen O. Johnson
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, NE, USA
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