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Giuriato G, Romanelli MG, Bartolini D, Vernillo G, Pedrinolla A, Moro T, Franchi M, Locatelli E, Andani ME, Laginestra FG, Barbi C, Aloisi GF, Cavedon V, Milanese C, Orlandi E, De Simone T, Fochi S, Patuzzo C, Malerba G, Fabene P, Donadelli M, Stabile AM, Pistilli A, Rende M, Galli F, Schena F, Venturelli M. Sex differences in neuromuscular and biological determinants of isometric maximal force. Acta Physiol (Oxf) 2024; 240:e14118. [PMID: 38385696 DOI: 10.1111/apha.14118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/29/2024] [Accepted: 02/09/2024] [Indexed: 02/23/2024]
Abstract
AIM Force expression is characterized by an interplay of biological and molecular determinants that are expected to differentiate males and females in terms of maximal performance. These include muscle characteristics (muscle size, fiber type, contractility), neuromuscular regulation (central and peripheral factors of force expression), and individual genetic factors (miRNAs and gene/protein expression). This research aims to comprehensively assess these physiological variables and their role as determinants of maximal force difference between sexes. METHODS Experimental evaluations include neuromuscular components of isometric contraction, intrinsic muscle characteristics (proteins and fiber type), and some biomarkers associated with muscle function (circulating miRNAs and gut microbiome) in 12 young and healthy males and 12 females. RESULTS Male strength superiority appears to stem primarily from muscle size while muscle fiber-type distribution plays a crucial role in contractile properties. Moderate-to-strong pooled correlations between these muscle parameters were established with specific circulating miRNAs, as well as muscle and plasma proteins. CONCLUSION Muscle size is crucial in explaining the differences in maximal voluntary isometric force generation between males and females with similar fiber type distribution. Potential physiological mechanisms are seen from associations between maximal force, skeletal muscle contractile properties, and biological markers.
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Affiliation(s)
- Gaia Giuriato
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
- Surgical, Medical and Dental Department of Morphological Sciences Related to Transplant, Oncology and Regenerative Medicine, University of Modena and Reggio Emilia, Modena, Italy
| | - Maria Grazia Romanelli
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Desirée Bartolini
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Gianluca Vernillo
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
- Department of Social Sciences, University of Alberta - Augustana Campus, Camrose, Alberta, Canada
| | - Anna Pedrinolla
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Tatiana Moro
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Martino Franchi
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Elena Locatelli
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Mehran Emadi Andani
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Fabio Giuseppe Laginestra
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
- Department of Anesthesiology, University of Utah, Utah, USA
| | - Chiara Barbi
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Gloria Fiorini Aloisi
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Valentina Cavedon
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Chiara Milanese
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Elisa Orlandi
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Tonia De Simone
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Stefania Fochi
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Cristina Patuzzo
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Giovanni Malerba
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Paolo Fabene
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Massimo Donadelli
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Anna Maria Stabile
- Department of Medicine and Surgery, Section of Human Anatomy, Clinical and Forensic, School of Medicine, University of Perugia, Perugia, Italy
| | - Alessandra Pistilli
- Department of Medicine and Surgery, Section of Human Anatomy, Clinical and Forensic, School of Medicine, University of Perugia, Perugia, Italy
| | - Mario Rende
- Department of Medicine and Surgery, Section of Human Anatomy, Clinical and Forensic, School of Medicine, University of Perugia, Perugia, Italy
| | - Francesco Galli
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Federico Schena
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Massimo Venturelli
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
- Department of Internal Medicine, University of Utah, Utah, USA
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Kim S, Glaviano NR, Park J. Sex Differences in Knee Extensor Neuromuscular Function in Individuals With and Without Patellofemoral Pain. Sports Health 2023:19417381231209318. [PMID: 37978417 DOI: 10.1177/19417381231209318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND Impaired knee extensor neuromuscular function has been frequently observed in individuals with patellofemoral pain (PFP); however, few researchers have aimed to understand the influence of sex on knee extensor neuromuscular function in this pathological population. The authors aimed to determine whether there are differences in knee extensor neuromuscular function between sexes in individuals with and without PFP. HYPOTHESIS Women with PFP would exhibit greater deficits in knee extensor neuromuscular function than men with PFP, compared with sex-matched individuals without PFP. STUDY DESIGN Cross-sectional, case-control study. LEVEL OF EVIDENCE Level 4. METHODS A total of 110 individuals were classified into 4 groups: women with PFP (n = 25); men with PFP (n = 30); women without PFP (n = 25); and men without PFP (n = 30). Knee extensor strength (isometric peak torque [PT]), activation (central activation ratio), early, late, and total phase rate of torque development (RTD0-100, RTD100-200, and RTD20-80%), and endurance (isokinetic average PT) were assessed using an isokinetic dynamometer. Group differences were assessed using a 2-way multivariate analysis of variance (sex by PFP). RESULTS Both women and men with PFP exhibited lower knee extensor strength, activation, early, late, and total phase RTD, and endurance versus sex-matched individuals without PFP (P < 0.05 for all comparisons). Women with PFP exhibited lower early phase (7.91 ± 2.02 versus 9.78 ± 2.43 N·m/s/kg; P < 0.01; Cohen d = 0.83), late phase (5.34 ± 1.02 versus 7.28±2.28 N·m/s/kg; P < 0.01; Cohen d = 1.37), and total phase (7.40 ± 2.57 versus 8.72 ± 2.57 N·m/s/kg; P = 0.03; Cohen d = 0.51) RTD than men with PFP. CONCLUSION Compared with sex-matched pain-free individuals, women with PFP displayed lower RTD than men with PFP. Clinicians should note that among individuals with PFP, women are more likely to experience a greater impairment in their knee extensor torque-generating capacity than men. CLINICAL RELEVANCE Additional treatment strategies that effectively improve the ability to rapidly generate torque should be developed and implemented, especially when treating women with PFP.
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Affiliation(s)
- Sungwan Kim
- Department of Sports Medicine, Kyung Hee University, Yongin, Republic of Korea
| | - Neal R Glaviano
- Department of Kinesiology, University of Connecticut, Storrs, Connecticut, USA
| | - Jihong Park
- Department of Sports Medicine, Kyung Hee University, Yongin, Republic of Korea
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Gabriel DA. Teaching Essential EMG Theory to Kinesiologists and Physical Therapists Using Analogies Visual Descriptions, and Qualitative Analysis of Biophysical Concepts. SENSORS (BASEL, SWITZERLAND) 2022; 22:6555. [PMID: 36081014 PMCID: PMC9460425 DOI: 10.3390/s22176555] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/24/2022] [Accepted: 08/28/2022] [Indexed: 06/15/2023]
Abstract
Electromyography (EMG) is a multidisciplinary field that brings together allied health (kinesiology and physical therapy) and the engineering sciences (biomedical and electrical). Since the physical sciences are used in the measurement of a biological process, the presentation of the theoretical foundations of EMG is most conveniently conducted using math and physics. However, given the multidisciplinary nature of EMG, a course will most likely include students from diverse backgrounds, with varying levels of math and physics. This is a pedagogical paper that outlines an approach for teaching foundational concepts in EMG to kinesiologists and physical therapists that uses a combination of analogies, visual descriptions, and qualitative analysis of biophysical concepts to develop an intuitive understanding for those who are new to surface EMG. The approach focuses on muscle fiber action potentials (MFAPs), motor unit action potentials (MUAPs), and compound muscle action potentials (CMAPs) because changes in these waveforms are much easier to identify and describe in comparison to the surface EMG interference pattern (IP).
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Affiliation(s)
- David A Gabriel
- Electromyographic Kinesiology Laboratory, Faculty of Applied Health Sciences, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
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Lulic-Kuryllo T, Greig Inglis J. Sex differences in motor unit behaviour: A review. J Electromyogr Kinesiol 2022; 66:102689. [DOI: 10.1016/j.jelekin.2022.102689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 07/28/2022] [Accepted: 07/29/2022] [Indexed: 10/15/2022] Open
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Howard SL, Grenet D, Bellumori M, Knight CA. Measures of motor segmentation from rapid isometric force pulses are reliable and differentiate Parkinson's disease from age-related slowing. Exp Brain Res 2022; 240:2205-2217. [PMID: 35768733 DOI: 10.1007/s00221-022-06398-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 06/09/2022] [Indexed: 11/04/2022]
Abstract
Some people with Parkinson's disease (PD) have disruptions in motor output during rapid isometric muscle contractions. Measures of such disruptions (motor segmentation) may help clarify disease subtype, progression, or effects of therapeutic interventions. We investigated the potential utility of segmentation measures by testing two hypotheses that are fundamental to measurement and evaluation. First, measures of motor segmentation are reliable from day to day (intraclass correlation coefficient > 0.8). Second, that measures of motor segmentation have the sensitivity to differentiate between people with PD and older adults. 10 subjects with PD had a mean age of 70.1 years, Hoehn-Yahr stage < 3, and median levodopa equivalent daily dose of 350 mg. Older adult (mean age 81.9 years) reference data are from a previously published study. Each subject provided approximately 87 rapid isometric index finger abduction force pulses up to 65% of their maximal isometric force for calculation of force pulse measures. Measures were computed for the excitation, transition, and relaxation phases of each force pulse. Measures of motor segmentation had high reliability and presented large (Cohen's D > 0.8) and significant (p < 0.05) group differences. In bivariate plots of selected measures, motor segmentation marked a departure of PD from age-related slowing. Across all subjects, greater segmentation was associated with greater impairments in rate control and a longer time to reach peak force (all Spearman's ρ > 0.8). These results support the potential utility of the motor segmentation measures by satisfying requirements for reliability and the sensitivity to indicate deviations from age-related slowing in motor output.
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Affiliation(s)
- Sherron L Howard
- Dept. of Kinesiology and Health Education, The University of Texas at Austin, Austin, TX, USA
| | - David Grenet
- Department of Psychology, Concordia University, Montreal, QC, Canada
| | - Maria Bellumori
- Kinesiology Department, California State University, Monterey Bay, Seaside, CA, USA
| | - Christopher A Knight
- Department of Kinesiology and Applied Physiology, University of Delaware, 344 The Tower at STAR, 100 Discovery Blvd., Newark, DE, 19716, USA.
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Guo Y, Jones EJ, Inns TB, Ely IA, Stashuk DW, Wilkinson DJ, Smith K, Piasecki J, Phillips BE, Atherton PJ, Piasecki M. Neuromuscular recruitment strategies of the vastus lateralis according to sex. Acta Physiol (Oxf) 2022; 235:e13803. [PMID: 35184382 PMCID: PMC9286427 DOI: 10.1111/apha.13803] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 02/03/2022] [Accepted: 02/16/2022] [Indexed: 12/19/2022]
Abstract
AIM Despite males typically exhibiting greater muscle strength and fatigability than females, it remains unclear if there are sex-based differences in neuromuscular recruitment strategies e.g. recruitment and modulation of motor unit firing rate (MU FR) at normalized forces and during progressive increases in force. METHODS The study includes 29 healthy male and 31 healthy female participants (18-35 years). Intramuscular electromyography (iEMG) was used to record individual motor unit potentials (MUPs) and near-fibre MUPs from the vastus lateralis (VL) during 10% and 25% maximum isometric voluntary contractions (MVC), and spike-triggered averaging was used to obtain motor unit number estimates (MUNE) of the VL. RESULTS Males exhibited greater muscle strength (P < .001) and size (P < .001) than females, with no difference in force steadiness at 10% or 25% MVC. Females had 8.4% and 6.5% higher FR at 10% and 25% MVC, respectively (both P < .03), while the MUP area was 33% smaller in females at 10% MVC (P < .02) and 26% smaller at 25% MVC (P = .062). However, both sexes showed similar increases in MU size and FR when moving from low- to mid-level contractions. There were no sex differences in any near-fibre MUP parameters or in MUNE. CONCLUSION In the vastus lateralis, females produce muscle force via different neuromuscular recruitment strategies to males which is characterized by smaller MUs discharging at higher rates. However, similar strategies are employed to increase force production from low- to mid-level contractions. These findings of similar proportional increases between sexes support the use of mixed sex cohorts in studies of this nature.
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Affiliation(s)
- Yuxiao Guo
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Eleanor J. Jones
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Thomas B. Inns
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Isabel A. Ely
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Daniel W. Stashuk
- Department of Systems Design Engineering University of Waterloo Waterloo Ontario Canada
| | - Daniel J. Wilkinson
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Kenneth Smith
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Jessica Piasecki
- Musculoskeletal Physiology Research Group Sport, Health and Performance Enhancement Research Centre Nottingham Trent University Nottingham UK
| | - Bethan E. Phillips
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Philip J. Atherton
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Mathew Piasecki
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
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Role of Knee and Ankle Extensors' Muscle-Tendon Properties in Dynamic Balance Recovery from a Simulated Slip. SENSORS 2022; 22:s22093483. [PMID: 35591172 PMCID: PMC9104373 DOI: 10.3390/s22093483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/24/2022] [Accepted: 04/29/2022] [Indexed: 02/05/2023]
Abstract
Participants exposed to a simulated slip with forward loss of balance (FLB) develop large lower limb joint moments which may be a limiting factor for those whose muscle-tendon units’ (MTUs) properties are deteriorated. Whether the age-related decline in these properties limits participants’ capacity to recover their balance following a slip with FLB remains unclear. We combined isokinetic dynamometry, ultrasound and EMG to understand how knee extensor and ankle plantarflexor muscle strength and power, rate of moment development, electromechanical delay, and tendon stiffness affected the balance of young (25.3 ± 3.9 years) and older adults (62.8 ± 7.1 years) when recovering from a single slip with FLB triggered whilst walking on a split-belt instrumented treadmill. Except for the patellar tendon’s stiffness, knee extensor and ankle plantarflexor electromechanical delays, older adults’ MTUs properties were deteriorated compared to those of young participants (p < 0.05). We found no significant relationship between age or the MTUs properties of participants and balance recovery. These findings provide additional support that neither maximal nor explosive strength training are likely to be successful in preventing a fall for healthy older adults, and that other type of interventions, such as task-specific training that has already proved efficacious in reducing the risk of falling, should be developed.
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Kozinc Ž, Smajla D, Šarabon N. The rate of force development scaling factor: a review of underlying factors, assessment methods and potential for practical applications. Eur J Appl Physiol 2022; 122:861-873. [DOI: 10.1007/s00421-022-04889-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 01/06/2022] [Indexed: 11/24/2022]
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Green LA, McGuire J, Gabriel DA. Effects of the Proprioceptive Neuromuscular Facilitation Contraction Sequence on Motor Skill Learning-Related Increases in the Maximal Rate of Wrist Flexion Torque Development. Front Hum Neurosci 2021; 15:764660. [PMID: 34803640 PMCID: PMC8595484 DOI: 10.3389/fnhum.2021.764660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/13/2021] [Indexed: 11/30/2022] Open
Abstract
Background: The proprioceptive neuromuscular facilitation (PNF) reciprocal contraction pattern has the potential to increase the maximum rate of torque development. However, it is a more complex resistive exercise task and may interfere with improvements in the maximum rate of torque development due to motor skill learning, as observed for unidirectional contractions. The purpose of this study was to examine the cost-benefit of using the PNF exercise technique to increase the maximum rate of torque development. Methods: Twenty-six participants completed isometric maximal extension-to-flexion (experimental PNF group) or flexion-only (control group) contractions at the wrist. Ten of the assigned contractions were performed on each of three sessions separated by 48-h for skill acquisition. Retention was assessed with 5 contractions performed 2-weeks after acquisition. Torque and surface electromyographic (sEMG) activity were analyzed for evidence of facilitated contractions between groups, as well as alterations in muscle coordination assessed across test sessions. The criterion measures were: mean maximal isometric wrist flexion toque; the maximal rate of torque development (dτ/dtmax); root-mean-square error (RMSE) variability of the rate of torque versus torque phase-plane; the rate of wrist flexion muscle activation (Q30); a coactivation ratio for wrist flexor and extensor sEMG activity; and wrist flexor electromechanical delay (EMD). Results: There were no significant differences between groups with respect to maximal wrist flexion torque, dτ/dtmax or RMSE variability of torque trajectories. Both groups exhibited a progressive increase in maximal strength (+23.35% p < 0.01, η2 = 0.655) and in dτ/dtmax (+19.84% p = 0.08, η2 = 0.150) from the start of acquisition to retention. RMSE was lowest after a 2-week rest interval (−18.2% p = 0.04, η2 = 0.198). There were no significant differences between groups in the rate of muscle activation or the coactivation ratio. There was a reduction in coactivation that was retained after a 2-week rest interval (−32.60%, p = 0.02, η2 = 0.266). Alternatively, EMD was significantly greater in the experimental group (Δ 77.43%, p < 0.01, η2 = 0.809) across all sessions. However, both groups had a similar pattern of improvement to the third consecutive day of testing (−16.82%, p = 0.049, η2 = 0.189), but returned close to baseline value after the 2-week rest interval. Discussion: The wrist extension-to-flexion contraction pattern did not result in a greater maximal rate of torque development than simple contractions of the wrist flexors. There was no difference between groups with respect to motor skill learning. The main adaptation in neuromotor control was a decrease in coactivation, not the maximal rate of muscle activation.
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Affiliation(s)
- Lara A Green
- Electromyographic Kinesiology Laboratory, Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, Canada.,Exercise Neuroscience Laboratory, Department of Kinesiology, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Jessica McGuire
- Electromyographic Kinesiology Laboratory, Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, Canada
| | - David A Gabriel
- Electromyographic Kinesiology Laboratory, Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, Canada
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Pierce KC, Hornsby WG, Stone MH. Weightlifting for Children and Adolescents: A Narrative Review. Sports Health 2021; 14:45-56. [PMID: 34781771 DOI: 10.1177/19417381211056094] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The involvement of youth in the sport of weightlifting and the use of weightlifting methods as part of training for youth sport performance appears to be increasing. Weightlifting for children and adolescents has been criticized in some circles and is a controversial aspect of resistance training for young people. Although injuries can occur during weightlifting and related activities, the incidence and rate of injury appear to be relatively low and severe injury is uncommon. A number of performance, physical, and physiological variables, such as body composition, strength, and power, are improved by weightlifting training in children, adolescents, and young athletes. Manipulating program variables, when appropriate, can have a substantial and profound influence on the psychological, physiological, physical, and performance aspects of weightlifters. An understanding of the sport, scientific training principles, and musculoskeletal growth development is necessary to properly construct a reasonable and appropriate training program. A scientific background aids in providing an evidenced basis and sound rationale in selecting appropriate methods and directing adaptations toward more specific goals and enables the coach to make choices about training and competition that might not otherwise be possible. If weightlifting training and competition are age group appropriate and are properly supervised, the sport can be substantially safe and efficacious.
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Affiliation(s)
- Kyle C Pierce
- Department of Kinesiology and Health Science, Louisiana State University Shreveport, Shreveport, Louisiana
| | - W Guy Hornsby
- College of Physical Activity and Sport Sciences, West Virginia University, Morgantown, West Virginia
| | - Michael H Stone
- Center of Excellence for Sport Science and Coach Education, Sports, Exercise, Recreation and Kinesiology, East Tennessee State University, Johnson City, Tennessee
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Inglis JG, Gabriel DA. Sex differences in motor unit discharge rates at maximal and submaximal levels of force output. Appl Physiol Nutr Metab 2020; 45:1197-1207. [DOI: 10.1139/apnm-2019-0958] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study evaluated potential sex differences in motor unit (MU) behaviour at maximal and submaximal force outputs. Forty-eight participants, 24 females and 24 males, performed isometric dorsiflexion contractions at 20%, 40%, 60%, 80%, and 100% of a maximum voluntary contraction (MVC). Tibialis anterior electromyography was recorded both by surface and intramuscular electrodes. Compared with males, females had a greater MU discharge rate (MUDR) averaged across all submaximal intensities (Δ 0.45 pps, 2.56%). Males exhibited greater increases in MUDR above 40% MVC, surpassing females at 100% MVC (p’s < 0.01). Averaged across all force outputs, females had a greater incidence of doublet and rapid discharges and a greater percentage of MU trains with doublet and rapid (5–10 ms) discharges (Δ 75.55% and 61.48%, respectively; p’s < 0.01). A subset of males (n = 8) and females (n = 8), matched for maximum force output, revealed that females had even greater MUDR (Δ 1.38 pps, 7.47%) and percentage of MU trains with doublet and rapid discharges (Δ 51.62%, 56.68%, respectively; p’s < 0.01) compared with males at each force output, including 100% MVC. Analysis of the subset of strength-matched males and females suggest that sex differences in MU behaviour may be a result of females needing to generate greater neural drive to achieve fused tetanus. Novelty Females had higher MUDRs and greater percentage of MU trains with doublets across submaximal force outputs (20%–80% MVC). Differences were even greater for a strength matched subset. Differences in motor unit behaviour may arise from musculoskeletal differences, requiring greater neural drive in females.
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Affiliation(s)
- J. Greig Inglis
- Electromyographic Kinesiology Laboratory, Kinesiology Department, Brock University, St. Catharines, ON L2S 3A1, Canada
- Electromyographic Kinesiology Laboratory, Kinesiology Department, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - David A. Gabriel
- Electromyographic Kinesiology Laboratory, Kinesiology Department, Brock University, St. Catharines, ON L2S 3A1, Canada
- Electromyographic Kinesiology Laboratory, Kinesiology Department, Brock University, St. Catharines, ON L2S 3A1, Canada
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Age- and Sex-Related Differences in the Maximum Muscle Performance and Rate of Force Development Scaling Factor of Precision Grip Muscles. Motor Control 2020; 24:274-290. [PMID: 31972538 DOI: 10.1123/mc.2019-0021] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 11/23/2019] [Accepted: 11/30/2019] [Indexed: 11/18/2022]
Abstract
The aim of this study was to explore the effects of age and sex on the rate of force development scaling factor (RFD-SF) and maximum performance (i.e., maximum grip force [GFMax] and maximum rate of grip force development [RGFDMax]) of precision handgrip muscles. Sixty-four subjects, allocated in four groups according to their age and sex, were asked to hold an instrumented handle with the tip of the digits and perform two tests: maximum voluntary contraction and RFD-SF tests. In the maximum voluntary contraction test, GFMax and RGFDMax were assessed. In the RFD-SF test, the subjects generated quick isometric force pulses to target amplitudes varying between 20% and 100% of their GFMax. The RFD-SF and R2 values were obtained from the linear relationship between the peak values of the force pulses and the corresponding peak values of the rate of force development. Younger adults and males produced higher GFMax and RGFDMax and presented higher R2 and RFD-SF than older adults and females, respectively. No correlations between GFMax and RFD-SF and between RGFDMax and RFD-SF were observed.
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Neuromuscular and Torque Kinetic Changes After 10 Months of Explosive Sport Training in Prepubertal Gymnasts. Pediatr Exerc Sci 2019; 31:77-84. [PMID: 30606075 DOI: 10.1123/pes.2018-0034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
PURPOSE To determine neuromuscular and torque kinetic changes after 10 months of explosive sport training in the elbow of prepubertal gymnasts compared with untrained age-matched controls. METHODS In 15 young gymnasts (9.02 [0.41] y) and 15 age-matched untrained males (8.76 [0.51] y), the rate of torque development (RTD) using the Biodex System 4 and the coactivation index were evaluated using electromyography. Explosive strength variables were normalized to the peak torque. Measures were determined twice: before and after a 10-month period of gymnastic training. Covariation analysis was used to account for differences in baseline values between gymnasts and controls. RESULTS After 10 months of training, gymnasts demonstrated a significantly (P < .05) greater increase in normalized peak RTD values in elbow flexion compared with controls (7.76% vs 0.65%). Covariation analysis also revealed a significantly (P < .05) greater reduction in the coactivation index of elbow extension in the gymnasts (-7.81% [5.44%] points) compared with controls (-1.23% [6.32%] points). CONCLUSIONS Compared with physical development alone, 10 months of explosive-strength training of young gymnasts is sufficient to increase torque-normalized RTD in the elbow joint of prepubertal boys. The RTD changes the authors observed in antagonistic elbow functions vary among gymnasts due to the specific demands of gymnastic training.
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Josephson MD, Knight CA. Comparison of neural excitation measures from the surface electromyogram during rate-dependent muscle contractions. J Electromyogr Kinesiol 2018; 44:15-20. [PMID: 30465942 DOI: 10.1016/j.jelekin.2018.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/01/2018] [Accepted: 11/08/2018] [Indexed: 12/01/2022] Open
Abstract
Peak power and peak rate of isometric force development (RFD) predict performance and functional mobility. Surface electromyography (EMG) is used to quantify the amplitude and rate of neuromuscular excitation. To inform the selection of EMG measures in research on rate-dependent muscle contractions, this methodological study compared amplitude-, area- and rate-based measures based on their correlations with RFD. Considering populations in whom a quiet EMG baseline is challenging, we included measures that do not require the determination of EMG onset. Twenty-one young adults performed isometric dorsiflexion contractions to 40% of their maximal force at increasing RFD. EMG was recorded from tibialis anterior. Relationships between EMG measures and RFD were quantified with Spearman's rho. RMS amplitude of the initial 75 ms of EMG had the strongest correlation with peak RFD (ρ = 0.80) among measures computed from EMG onset. Peak rate of EMG rise (RER) had the strongest relationship with peak RFD (ρ = 0.69) among measures that did not require determination of EMG onset. The strength of the relationship between RER and RFD and the strong correlation between RER and RMS75 during rapid contractions (ρ = 0.86) supports the use of RER in experiments where neural excitation might not be initiated from a quiet baseline.
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Affiliation(s)
- Micah D Josephson
- Shenandoah University, Department of Exercise Science, United States.
| | - Christopher A Knight
- University of Delaware, Department of Kinesiology and Applied Physiology, United States
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