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Cleary CJ, Herda TJ, Quick AM, Herda AA. Acute muscle swelling effects of a knee rehabilitation exercise performed with and without blood flow restriction. PLoS One 2022; 17:e0278540. [PMID: 36548274 PMCID: PMC9778495 DOI: 10.1371/journal.pone.0278540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 11/17/2022] [Indexed: 12/24/2022] Open
Abstract
This study assessed the acute effect of adding blood flow restriction (BFR) to quad sets on muscle-cross sectional area (mCSA), muscle thickness (MT), echo intensity (EI), and subcutaneous fat-normalized EI (EINORM) of the superficial quadriceps muscles. Twelve males and 12 females (mean±SD; age (yrs): 21.4±2.9; stature (m): 1.76±0.1; body mass (kg): 77.7±2.9) performed 70 repetitions (one set of 30, three sets of 15 repetitions) of bodyweight quad sets separately on each leg, with or without BFR (CON) applied. Rating of perceived exertion was recorded following each set. Panoramic ultrasound images of the vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF) were captured prior to (PRE), immediately after (IMM-POST), 30- (30-POST), and 60-minutes after (60-POST) after exercise. Sex x condition x time repeated measures ANOVAs assessed differences at p<0.05 for each muscle and dependent variable separately. Although males had larger VM and VL mCSA and VL MT (p<0.05), there were no acute changes from PRE to IMM-POST (p>0.05). There was a 3-way interaction in VL mCSA (p = 0.025) which indicated BFR was greater than CON at IMM-POST by 7.6% (p = 0.019) for males only. Females had greater EI in the VM and VL than males (p<0.05), yet males had greater EINORM for each muscle (p>0.05) and EINORM did not change over time or treatment (p>0.05). The lack of changes in MT, EI, and EINORM indicate that unloaded quad sets do not provide a stimulus to promote fluid shifts or acute changes in muscle size with the exception of IMM-POST in the VL for males. Future research should attempt to elucidate the acute muscular responses of BFR application for lightly loaded rehabilitation exercises in the clinical populations for which they are prescribed.
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Affiliation(s)
- Christopher J. Cleary
- Department of Health, Sport, and Exercise Sciences, University of Kansas Edwards Campus, Overland Park, Kansas, United States of America
| | - Trent J. Herda
- Department of Health, Sport, and Exercise Sciences, University of Kansas Lawrence Campus, Lawrence, Kansas, United States of America
| | - Austin M. Quick
- Department of Health, Sport, and Exercise Sciences, University of Kansas Lawrence Campus, Lawrence, Kansas, United States of America
| | - Ashley A. Herda
- Department of Health, Sport, and Exercise Sciences, University of Kansas Edwards Campus, Overland Park, Kansas, United States of America
- * E-mail:
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Arieta LR, Giuliani-Dewig HK, Gerstner GR, Mota JA, Ryan ED. Segmental bioelectrical impedance spectroscopy: A novel field assessment of muscle size and quality in normal weight and obese older men. Exp Gerontol 2022; 162:111745. [DOI: 10.1016/j.exger.2022.111745] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 02/02/2022] [Accepted: 02/15/2022] [Indexed: 11/26/2022]
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Stock MS, Thompson BJ. Echo intensity as an indicator of skeletal muscle quality: applications, methodology, and future directions. Eur J Appl Physiol 2020; 121:369-380. [PMID: 33221942 DOI: 10.1007/s00421-020-04556-6] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 11/07/2020] [Indexed: 12/14/2022]
Abstract
PURPOSE This narrative review provides an overview of the current knowledge of B-mode ultrasound-derived echo intensity (EI) as an indicator of skeletal muscle quality. METHOD PubMed and Google Scholar were used to search the literature. Advanced search functions were used to find original studies with the terms 'echo intensity' and/or 'muscle quality' in the title and/or abstract. Publications that conceptually described muscle quality but did not include measurement of EI were not a focus of the review. RESULT Importantly, the foundational premise of EI remains unclear. While it is likely that EI reflects intramuscular adiposity, data suggesting that these measurements are influenced by fibrous tissue is limited to diseased muscle and animal models. EI appears to show particular promise in studying muscular aging. Studies have consistently reported an association between EI and muscle function, though not all chronic interventions have demonstrated improvements. Based on the existing literature, it is unclear if EI can be used as a marker of muscle glycogen following exercise and nutritional interventions, or if EI is influenced by hydration status. Inconsistent methodological approaches used across laboratories have made comparing EI studies challenging. Image depth, rest duration, participant positioning, probe tilt, and the decision to correct for subcutaneous adipose tissue thickness are all critical considerations when interpreting the literature and planning studies. CONCLUSION While some areas show conflicting evidence, EI shows promise as a novel tool for studying muscle quality. Collaborative efforts focused on methodology are necessary to enhance the consistency and quality of the EI literature.
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Affiliation(s)
- Matt S Stock
- School of Kinesiology and Physical Therapy, University of Central Florida, 12805 Pegasus Drive, HPA 1, Room 258, Orlando, FL, 32816-2205, USA. .,Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, USA.
| | - Brennan J Thompson
- Department of Kinesiology and Health Science, Utah State University, Logan, UT, USA.,Sorenson Legacy Foundation Center for Clinical Excellence, Movement Research Clinic, Utah State University, Logan, UT, USA
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Bali AU, Harmon KK, Burton AM, Phan DC, Mercer NE, Lawless NW, Stock MS. Muscle strength, not age, explains unique variance in echo intensity. Exp Gerontol 2020; 139:111047. [DOI: 10.1016/j.exger.2020.111047] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/26/2020] [Accepted: 07/27/2020] [Indexed: 02/07/2023]
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Bell ZW, Abe T, Wong V, Spitz RW, Viana RB, Chatakondi RN, Dankel SJ, Yamada Y, Loenneke JP. Muscle swelling following blood flow-restricted exercise does not differ between cuff widths in the proximal or distal portions of the upper leg. Clin Physiol Funct Imaging 2020; 40:269-276. [PMID: 32319156 DOI: 10.1111/cpf.12635] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 03/31/2020] [Accepted: 04/14/2020] [Indexed: 12/01/2022]
Abstract
The purpose was to understand how wider cuffs, covering larger portions of the limb, may affect acute muscle swelling when used during low-load knee extension exercise with blood flow restriction. A total of 96 individuals (53 females and 43 males) completed two visits, with visit one used for measuring maximal strength and arterial occlusion pressure (AOP), and visit two to compare between a narrow (5 cm) and a wide (12 cm) cuff for acute changes in muscle thickness and echo intensity following exercise. Ultrasound measurements were completed at a proximal and distal site within both legs, with the proximal site located beneath the cuff within the leg exercising using the wide cuff. Study findings indicate that the difference in acute changes for muscle thickness [median difference (95% credible interval) of 0.009 (-0.03, 0.05) cm] and echo intensity [median difference (95% credible interval) of 0.79 (-0.28, 1.89) AU] between cuff widths did not differ between proximal and distal sites. Additionally, acute changes in muscle thickness did not differ between cuff widths, sexes or participants who had AOP measured and those who were estimated. Lastly, acute changes in echo intensity did not differ between cuff widths and those who had AOP measured and those who were estimated. However, there was evidence showing how there might be greater reductions in echo intensity for females at the distal site. The previously observed attenuation of muscle growth under the cuff is unlikely to be related to differences in the acute muscle swelling response.
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Affiliation(s)
- Zachary W Bell
- Kevser Ermin Applied Physiology Laboratory, Department of Health, & Recreation Management, The University of Mississippi, University, MS, USA
| | - Takashi Abe
- Kevser Ermin Applied Physiology Laboratory, Department of Health, & Recreation Management, The University of Mississippi, University, MS, USA
| | - Vickie Wong
- Kevser Ermin Applied Physiology Laboratory, Department of Health, & Recreation Management, The University of Mississippi, University, MS, USA
| | - Robert W Spitz
- Kevser Ermin Applied Physiology Laboratory, Department of Health, & Recreation Management, The University of Mississippi, University, MS, USA
| | - Ricardo B Viana
- Kevser Ermin Applied Physiology Laboratory, Department of Health, & Recreation Management, The University of Mississippi, University, MS, USA.,Faculty of Physical Education and Dance, Federal University of Goiás, Goiânia, Brazil
| | - Raksha N Chatakondi
- Kevser Ermin Applied Physiology Laboratory, Department of Health, & Recreation Management, The University of Mississippi, University, MS, USA
| | - Scott J Dankel
- Exercise Physiology Laboratory, Department of Health and Exercise Science, Rowan University, Glassboro, NJ, USA
| | - Yujiro Yamada
- Kevser Ermin Applied Physiology Laboratory, Department of Health, & Recreation Management, The University of Mississippi, University, MS, USA
| | - Jeremy P Loenneke
- Kevser Ermin Applied Physiology Laboratory, Department of Health, & Recreation Management, The University of Mississippi, University, MS, USA
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MacLennan RJ, Sahebi M, Becker N, Davis E, Garcia JM, Stock MS. Declines in skeletal muscle quality vs. size following two weeks of knee joint immobilization. PeerJ 2020; 8:e8224. [PMID: 31976172 PMCID: PMC6964688 DOI: 10.7717/peerj.8224] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 11/15/2019] [Indexed: 12/27/2022] Open
Abstract
Background Disuse of a muscle group, which occurs during bedrest, spaceflight, and limb immobilization, results in atrophy. It is unclear, however, if the magnitude of decline in skeletal muscle quality is similar to that for muscle size. The purpose of this study was to examine the effects of two weeks of knee joint immobilization on vastus lateralis and rectus femoris echo intensity and cross-sectional area. Methods Thirteen females (mean ± SD age = 21 ± 2 years) underwent two weeks of left knee joint immobilization via ambulating on crutches and use of a brace. B-mode ultrasonography was utilized to obtain transverse plane images of the immobilized and control vastus lateralis and rectus femoris at pretest and following immobilization. Effect size statistics and two-way repeated measures analyses of variance were used to interpret the data. Results No meaningful changes were demonstrated for the control limb and the rectus femoris of the immobilized limb. Analyses showed a large increase in vastus lateralis echo intensity (i.e., decreased muscle quality) for the immobilized limb (p = .006, Cohen’s d = .918). For vastus lateralis cross-sectional area, no time × limb interaction was observed (p = .103), but the effect size was moderate (d = .570). There was a significant association between the increase in vastus lateralis echo intensity and the decrease in cross-sectional area (r = − .649, p = .016). Conclusion In female participants, two weeks of knee joint immobilization resulted in greater deterioration of muscle quality than muscle size. Echo intensity appears to be an attractive clinical tool for monitoring muscle quality during disuse.
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Affiliation(s)
- Rob J MacLennan
- School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, FL, United States of America
| | - Michael Sahebi
- School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, FL, United States of America
| | - Nathan Becker
- School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, FL, United States of America
| | - Ethan Davis
- School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, FL, United States of America
| | - Jeanette M Garcia
- Department of Health Sciences, University of Central Florida, Orlando, FL, United States of America
| | - Matt S Stock
- School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, FL, United States of America
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Yitzchaki N, Kuehne TE, Mouser JG, Buckner SL. Can changes in echo intensity be used to detect the presence of acute muscle swelling? Physiol Meas 2019; 40:045002. [PMID: 30897561 DOI: 10.1088/1361-6579/ab122a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
OBJECTIVE The purpose of this study was to examine acute changes in muscle thickness (MTH) and echo-intensity (EI), following four sets of biceps curls, when it is known that the change in MTH is due entirely to swelling. APPROACH Forty-nine resistance-trained men and women participated in this study. Individuals in the experimental group (n = 23) visited the lab on two separate occasions. During the first visit, paperwork and one repetition maximum (1RM) strength were measured. During the second visit (3-5 d after visit 1), individuals performed four sets of biceps curls to failure using 70% of their 1RM. MTH and EI measurements were taken before and immediately following exercise using B-mode ultrasound. The ultrasound probe was equipped with a level to minimize the influence of probe tilt on the EI measurement. A time-matched control group (n = 26) was included to account for measurement error for both MTH and EI. Results are presented as means (95% CI). MAIN RESULTS For MTH there was a group (Experimental versus Control) by time (Pre-Post) interaction (p < 0.001). MTH increased in the experimental group (mean value change = 0.44 (0.33-0.54) cm), but not in the control group (mean value change = -0.015 (-0.03-0.01) cm). For EI, there was no group by time interaction (p =.074). In addition, there were no main effects for group (p = 0.254) or time (p = 0.314). The mean difference in the change in EI between groups was -2.99 (-6.25-3.03) arbitrary units. SIGNIFICANCE EI cannot be used to detect exercise induced changes in muscle thickness.
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Affiliation(s)
- Noam Yitzchaki
- USF Muscle Lab, Exercise Science Program, University of South Florida, Tampa, FL, United States of America
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Wong V, Abe T, Chatakondi RN, Bell ZW, Spitz RW, Dankel SJ, Loenneke JP. The influence of biological sex and cuff width on muscle swelling, echo intensity, and the fatigue response to blood flow restricted exercise. J Sports Sci 2019; 37:1865-1873. [PMID: 30945606 DOI: 10.1080/02640414.2019.1599316] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The purpose was to determine if the muscle swelling, echo intensity, and fatigue responses to blood flow restriction differs based on cuff width (Experiment 1), applied pressure (Experiment 2), and sex. Ultrasound of muscle was taken before and after exercise. In Experiment 1 (n = 96), men swelled more than women and more with a narrow cuff than a wide cuff (0.60 cm vs. 0.52 cm). Expressed as a percentage change, there were no longer differences between cuffs (Narrow: 15% vs. Wide: 14%) or sex (Men: 14% vs. Women: 15%). Echo intensity remained unchanged. Women required more repetitions to reach task failure in sets 2, 3, and 4. In Experiment 2 (n = 87), men swelled more than women (Men: 0.46 cm vs. Women: 0.31 cm). Expressed as a percentage change, there were no differences. Echo intensity decreased in both conditions and to a greater extent with a higher applied pressure. If the acute muscle swelling response is important for initiating long term adaptation, then our results indicate that neither cuff width, sex, nor applied pressure will differentially impact the adaptation observed via this mechanism. Changes in echo intensity were inconsistent and the utility of this measurement may need to be reconsidered.
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Affiliation(s)
- Vickie Wong
- a Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory , The University of Mississippi , University , MS , USA
| | - Takashi Abe
- a Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory , The University of Mississippi , University , MS , USA
| | - Raksha N Chatakondi
- a Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory , The University of Mississippi , University , MS , USA
| | - Zachary W Bell
- a Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory , The University of Mississippi , University , MS , USA
| | - Robert W Spitz
- a Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory , The University of Mississippi , University , MS , USA
| | - Scott J Dankel
- a Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory , The University of Mississippi , University , MS , USA
| | - Jeremy P Loenneke
- a Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory , The University of Mississippi , University , MS , USA
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Muddle TW, Magrini MA, Colquhoun RJ, Luera MJ, Tomko PM, Jenkins ND. Impact of Fatiguing, Submaximal High- vs. Low-Torque Isometric Exercise on Acute Muscle Swelling, and Echo Intensity in Resistance-Trained Men. J Strength Cond Res 2019; 33:1007-1019. [DOI: 10.1519/jsc.0000000000003033] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Hornsby WG, Gentles JA, Haff GG, Stone MH, Buckner SL, Dankel SJ, Bell ZW, Abe T, Loenneke JP. What is the Impact of Muscle Hypertrophy on Strength and Sport Performance? Strength Cond J 2018. [DOI: 10.1519/ssc.0000000000000432] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Stock MS, Whitson M, Burton AM, Dawson NT, Sobolewski EJ, Thompson BJ. Echo Intensity Versus Muscle Function Correlations in Older Adults are Influenced by Subcutaneous Fat Thickness. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:1597-1605. [PMID: 29776601 DOI: 10.1016/j.ultrasmedbio.2018.04.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 03/19/2018] [Accepted: 04/13/2018] [Indexed: 06/08/2023]
Abstract
Recently, an equation that allows investigators to correct echo intensity for subcutaneous fat was developed. We evaluated correlations between uncorrected and corrected echo intensity versus measures of lower-extremity function. Twenty-three older adults (11 men, 12 women; mean age = 72 y) participated. B-Mode ultrasonography was used to quantify rectus femoris echo intensity and subcutaneous fat thickness. Knee extensor isometric peak torque and rate of torque development at 200 ms (RTD200) were determined (joint angle = 90°). Fast gait speed was evaluated at 10- and 400-m distances. Partial correlations between normalized peak torque, RTD200 and 10- and 400-m gait speed versus uncorrected echo intensity were weak and insignificant. Correction for subcutaneous fat strengthened the correlations (peak torque r = -0.500, RTD200 r= -0.425, 10-m r = -0.409, 400-m r = -0.410). Correcting echo intensity values for subcutaneous fat strengthened the associations with lower-extremity muscle function in older adults.
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Affiliation(s)
- Matt S Stock
- Applied Physiology Laboratory, Doctor of Physical Therapy Program, University of Central Florida, Orlando, Florida, USA.
| | | | - Adam M Burton
- Applied Physiology Laboratory, Doctor of Physical Therapy Program, University of Central Florida, Orlando, Florida, USA
| | - Nicole T Dawson
- Innovative Mobility Initiative Laboratory, Doctor of Physical Therapy Program, University of Central Florida, Orlando, Florida, USA
| | - Eric J Sobolewski
- Molnar Human Performance Laboratory, Health Science, Furman University, Greenville, South Carolina, USA
| | - Brennan J Thompson
- Neuromuscular Research Laboratory, Kinesiology and Health Science, Utah State University, Logan, Utah, USA
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Burton AM, Stock MS. Consistency of novel ultrasound equations for estimating percent intramuscular fat. Clin Physiol Funct Imaging 2018; 38:1062-1066. [PMID: 29888525 DOI: 10.1111/cpf.12532] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 05/17/2018] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Echo intensity reflects both intramuscular adiposity and fibrous tissue content. Recently, equations that allow investigators to estimate the percentage of intramuscular fat for individual muscles via measurements of echo intensity and subcutaneous fat were created. However, as the trial-to-trial consistency of these values has not been reported in the literature, it is unclear if they can be used to track changes during physical activity and/or nutritional interventions. The purpose of this study was to examine the test-retest reliability of rectus femoris percent intramuscular fat. METHODS Nineteen healthy adults (mean ± SD age = 22 ± 3 year; ten females, nine males) with a body mass index ≤ 30 kg/m2 participated. On three occasions, B-mode ultrasonography was used to acquire panoramic images of the dominant rectus femoris in the transverse plane. ImageJ software was used to quantify echo intensity, subcutaneous fat thickness and cross-sectional area. Rectus femoris percent intramuscular fat was estimated with sex-specific equations. RESULTS Uncorrected and corrected echo intensity, subcutaneous fat and cross-sectional area exhibited excellent consistency (P > 0·05, intraclass correlation coefficients [ICCs] ≥ .900, standard errors of measurement [SEMs] ≤ 7·26%). Percent intramuscular fat for all participants also demonstrated satisfactory reliability (ICC = 0·980, SEM = 3·07%), with similar findings for males (ICC = 0·970, SEM = 3·63%) and females (ICC = 0·968, SEM = 1·41%). DISCUSSION The high ICCs and low SEMs suggest that ultrasonography-derived rectus femoris percent fat may be a reliable tool for tracking changes in lower extremity intramuscular adiposity.
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Affiliation(s)
- Adam M Burton
- Applied Physiology Laboratory, School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, FL, USA
| | - Matt S Stock
- Applied Physiology Laboratory, School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, FL, USA
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Mota JA, Stock MS. Rectus Femoris Echo Intensity Correlates with Muscle Strength, but Not Endurance, in Younger and Older Men. ULTRASOUND IN MEDICINE & BIOLOGY 2017; 43:1651-1657. [PMID: 28533003 DOI: 10.1016/j.ultrasmedbio.2017.04.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 04/10/2017] [Accepted: 04/12/2017] [Indexed: 06/07/2023]
Abstract
We examined correlations between echo intensity and muscle strength and endurance. Rectus femoris echo intensity, maximal voluntary contraction (MVC) force and time to task failure during a 50% MVC task were determined for 12 younger (mean age = 25 y) and 13 older (mean age = 74 y) men. Bivariate correlations between echo intensity and normalized MVC force were similar for younger and older men, but was only statistically significant for the latter (younger r = -0.559, p = 0.059; older r = -0.580, p = 0.038). When all patients were combined, the correlation was significant (r = -0.733, p < 0.001). Significant correlations were not observed for time to task failure (younger r = -0.382, p = 0.221; older r = -0.347, p = 0.246; all patients r = -0.229, p = 0.270). Rectus femoris echo intensity is associated with muscle strength, but not endurance, in younger and older men.
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Affiliation(s)
- Jacob A Mota
- Neuromuscular Research Laboratory, Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA
| | - Matt S Stock
- Applied Physiology Laboratory, Doctor of Physical Therapy Program, Department of Health Professions, University of Central Florida, Orlando, Florida, USA.
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Mota JA, Stock MS, Thompson BJ. Vastus lateralis and rectus femoris echo intensity fail to reflect knee extensor specific tension in middle-school boys. Physiol Meas 2017; 38:1529-1541. [DOI: 10.1088/1361-6579/aa791a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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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: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [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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