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Jiménez-Lupión D, Chirosa-Ríos L, Martínez-García D, Rodríguez-Pérez M, Jerez-Mayorga D. Effects of Power Training on Functional Capacity Related to Fall Risk in Older Adults: A Systematic Review and Meta-analysis. Arch Phys Med Rehabil 2023; 104:1514-1525. [PMID: 36868491 DOI: 10.1016/j.apmr.2023.01.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 01/12/2023] [Accepted: 01/27/2023] [Indexed: 03/05/2023]
Abstract
OBJECTIVE Functional capacity is 1 of the main risk factors for falls among older adults. The aim of this systematic review and meta-analysis was to determine the effect of power training on functional capacity test (FCT) related to fall risk in older adults. DATA SOURCES Systematic searches were conducted in 4 databases, including PubMed, Web of Science, Scopus, and SPORTDiscus, from inception to November 2021. STUDY SELECTION Randomized controlled trials (RCTs) assessing the effect of power training on functional capacity compared with another type of training program or control group in older adults with the ability to exercise independently. DATA EXTRACTION Two independent researchers evaluated eligibility and used the PEDro scale to assess risk of bias. The information extracted was related to article identification (authors, country and year of publication), participant characteristics (sample, sex, and age), strength training protocols (exercises/intensity/weeks), and the outcome of the FCT used related to fall risk. The Cochran Q statistic and I2 statistics was used to assess heterogeneity. Random-effects model were conducted to pool the effect sizes expressed as mean differences (MD). DATA SYNTHESIS Twelve studies (478 subjects) were selected for systematic review. A meta-analysis comprised 6 studies (217 subjects) where the outcome measure was the 30-second Sit to Stand (30s-STS) test, and another comprised 4 studies (142 subjects) where the outcome measure was the timed Up and Go (TUG) test. There was an improvement in performance in favor of the experimental group in both the TUG subgroup (MD -0.31 s; 95% CI -0.63, 0.00 s; P=.05), and the 30s-STS subgroup (MD 1.71 reps; 95% CI -0.26, 3.67 reps; P=.09). CONCLUSIONS In conclusion, power training increases functional capacity related to fall risk further than other types of exercise in older adults.
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Affiliation(s)
- Daniel Jiménez-Lupión
- Department of Physical Education and Sports, Faculty of Sport Sciences, University of Granada, Granada, Spain
| | - Luis Chirosa-Ríos
- Department of Physical Education and Sports, Faculty of Sport Sciences, University of Granada, Granada, Spain
| | - Darío Martínez-García
- Department of Physical Education and Sports, Faculty of Sport Sciences, University of Granada, Granada, Spain
| | - Manuel Rodríguez-Pérez
- Department of Education, Faculty of Education Sciences, University of Almería, Almería, Spain; SPORT Research Group (CTS-1024), CERNEP Research Center, University of Almería, Almería, Spain
| | - Daniel Jerez-Mayorga
- Department of Physical Education and Sports, Faculty of Sport Sciences, University of Granada, Granada, Spain; Exercise and Rehabilitation Sciences Laboratory, School of Physical Therapy, Faculty of Rehabilitation Sciences, Universidad Andres Bello, Santiago, Chile.
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Siddique U, Frazer AK, Avela J, Walker S, Ahtiainen JP, Howatson G, Tallent J, Kidgell DJ. Determining the cortical, spinal and muscular adaptations to strength-training in older adults: A systematic review and meta-analysis. Ageing Res Rev 2022; 82:101746. [PMID: 36223874 DOI: 10.1016/j.arr.2022.101746] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 09/30/2022] [Accepted: 10/05/2022] [Indexed: 01/31/2023]
Abstract
There are observable decreases in muscle strength as a result of ageing that occur from the age of 40, which are thought to occur as a result of changes within the neuromuscular system. Strength-training in older adults is a suitable intervention that may counteract the age-related loss in force production. The neuromuscular adaptations (i.e., cortical, spinal and muscular) to strength-training in older adults are largely equivocal and a systematic review with meta-analysis will serve to clarify the present circumstances regarding the benefits of strength-training in older adults. 20 studies entered the meta-analysis and were analysed using a random-effects model. A best evidence synthesis that included 36 studies was performed for variables that had insufficient data for meta-analysis. One study entered both. There was strong evidence that strength-training increases maximal force production, rate of force development and muscle activation in older adults. There was limited evidence for strength-training to improve voluntary-activation, the volitional-wave and spinal excitability, but strong evidence for increased muscle mass. The findings suggest that strength-training performed between 2 and 12 weeks increases strength, rate of force development and muscle activation, which likely improves motoneurone excitability by increased motor unit recruitment and improved discharge rates.
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Affiliation(s)
- Ummatul Siddique
- Monash Exercise Neuroplasticity Research Unit, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Australia
| | - Ashlyn K Frazer
- Monash Exercise Neuroplasticity Research Unit, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Australia
| | - Janne Avela
- NeuroMuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Finland
| | - Simon Walker
- NeuroMuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Finland
| | - Juha P Ahtiainen
- NeuroMuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Finland
| | - Glyn Howatson
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle, UK; Water Research Group, North West University, Potchefstroom, South Africa
| | - Jamie Tallent
- Monash Exercise Neuroplasticity Research Unit, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Australia; School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester, UK
| | - Dawson J Kidgell
- Monash Exercise Neuroplasticity Research Unit, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Australia.
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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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Merlo A, Bò MC, Campanini I. Electrode Size and Placement for Surface EMG Bipolar Detection from the Brachioradialis Muscle: A Scoping Review. SENSORS 2021; 21:s21217322. [PMID: 34770627 PMCID: PMC8587451 DOI: 10.3390/s21217322] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/28/2021] [Accepted: 11/01/2021] [Indexed: 11/19/2022]
Abstract
The brachioradialis muscle (BRD) is one of the main elbow flexors and is often assessed by surface electromyography (sEMG) in physiology, clinical, sports, ergonomics, and bioengineering applications. The reliability of the sEMG measurement strongly relies on the characteristics of the detection system used, because of possible crosstalk from the surrounding forearm muscles. We conducted a scoping review of the main databases to explore available guidelines of electrode placement on BRD and to map the electrode configurations used and authors’ awareness on the issues of crosstalk. One hundred and thirty-four studies were included in the review. The crosstalk was mentioned in 29 studies, although two studies only were specifically designed to assess it. One hundred and six studies (79%) did not even address the issue by generically placing the sensors above BRD, usually choosing large disposable ECG electrodes. The analysis of the literature highlights a general lack of awareness on the issues of crosstalk and the need for adequate training in the sEMG field. Three guidelines were found, whose recommendations have been compared and summarized to promote reliability in further studies. In particular, it is crucial to use miniaturized electrodes placed on a specific area over the muscle, especially when BRD activity is recorded for clinical applications.
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Affiliation(s)
- Andrea Merlo
- LAM-Motion Analysis Laboratory, S. Sebastiano Hospital, Neuromotor and Rehabilitation Department, Azienda USL-IRCCS di Reggio Emilia, Via Circondaria 29, 42015 Correggio, Italy;
- Merlo Bioengineering, 43100 Parma, Italy;
| | | | - Isabella Campanini
- LAM-Motion Analysis Laboratory, S. Sebastiano Hospital, Neuromotor and Rehabilitation Department, Azienda USL-IRCCS di Reggio Emilia, Via Circondaria 29, 42015 Correggio, Italy;
- Correspondence:
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Marina M, Torrado P, Baudry S, Duchateau J. Forearm muscles fatigue induced by repetitive braking on a motorcycle is best discriminated by specific kinetic parameters. PLoS One 2021; 16:e0246242. [PMID: 33544741 PMCID: PMC7864446 DOI: 10.1371/journal.pone.0246242] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 01/16/2021] [Indexed: 01/02/2023] Open
Abstract
Maneuvering a motorcycle in racing conditions or for prolonged time is sufficiently demanding that on many occasions forearm muscles reach a state of functional failure when riders cannot properly brake or operate the throttle. This study intends to discriminate which ones of the several dynamometric parameters used in the literature to characterize the Force-time (F-t) curve during voluntary contractions are more sensitive to neuromuscular fatigue in simulated motorcycle-riding conditions. Thirty-three adults performed an intermittent fatiguing protocol (IFP) that simulated the brake-pulling and throttle-twisting actions, by using a hydraulic system equipped with a pressure sensor. Sixty pressure-time (P-t) curve parameters, including the rate of pressure development (RPD) and area under the curve were measured to characterize the time course of the braking maximal voluntary contraction (MVC). Two types of variables were used to analyze the P-t curve: 1) Times interval (from 0 to 30-50-100-500-1000 and 2000 ms); 2) Percentages of MVC (10-30-60-90%MVC). Overall significant (p ≤ 0.05) fatigue-related declines were observed only at time intervals longer than 100 ms and contraction intensities higher than 30%MVC. Strong and significant linear declines (p < 0.001) were observed at 500 ms and 1 s for normalized pressures, as well as for the ratio RPD60%MVC/MVC (p < 0.003) throughout the IFP. Our results suggest considering RPD at time windows of 0–500 ms and 0–1 s, and contraction intensities comprised between 30% and 60% of MVC, as more suitable criteria to study fatigue-related decrements in performance rather than the classical MVC force.
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Affiliation(s)
- Michel Marina
- Research Group in Physical Activity and Health (GRAFiS), Institut National d’Educació Física de Catalunya–University of Barcelona, Barcelona, Spain
- * E-mail:
| | - Priscila Torrado
- Research Group in Physical Activity and Health (GRAFiS), Institut National d’Educació Física de Catalunya–University of Barcelona, Barcelona, Spain
- School of Health Sciences, TecnoCampus Mataró–Universitat Pompeu Fabra, Mataró, Spain
| | - Stéphane Baudry
- Laboratory of Applied Biology and Neurophysiology, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Jacques Duchateau
- Laboratory of Applied Biology and Neurophysiology, Université Libre de Bruxelles, Bruxelles, Belgium
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Kwon M, Senefeld JW, Hunter SK. Attenuated activation of knee extensor muscles during fast contractions in older men and women. Eur J Appl Physiol 2020; 120:2289-2299. [PMID: 32789699 DOI: 10.1007/s00421-020-04451-0] [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: 02/11/2020] [Accepted: 07/30/2020] [Indexed: 01/07/2023]
Abstract
AIM Reduced physical function and increased risk of falls in older adults are accompanied by age-related reductions in torque development of leg muscles, although the mechanisms and potential sex differences are not understood. PURPOSE To determine the mechanistic origins (neural vs. muscular) for the age-related reduction in torque development, we compared the peak rates of torque development (RTD) during electrically-evoked and fast voluntary contractions of the knee extensors between young and older men and women. METHODS Sets of single- and double-pulse electrical stimulations evoked contractions of the knee extensor muscles in 20 young (23.0 ± 0.8 years; 10 women) and 20 older adults (78.2 ± 1.5 years; 10 women), followed by voluntary isometric knee extension contractions with torque development as fast as possible that matched the torque during electrically-evoked contraction (10-40% maximal torque). RESULTS Peak RTD during fast-voluntary contractions was 41% less than electrically-evoked contractions (p < 0.001), but more so for older adults (44%) than young (38%, p = 0.04), with no sex differences. Peak RTD during fast-voluntary contractions was more variable between contractions for the older than young adults (77%MVC s-1 vs. 47%MVC s-1, p < 0.001). Additionally, older women exhibited greater variability than older men (81%MVC s-1 vs. 72%MVC s-1, p = 0.04) with no sex-related differences within the young adults. CONCLUSION Older adults had slower and more variable RTD during voluntary contractions than young adults, particularly older women. The limited age-related differences in electrically-evoked RTD suggest the primary mechanism for the slower torque development of the knee extensor muscles in older men and women involve reduced neural activation.
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Affiliation(s)
- MinHyuk Kwon
- Exercise Science Program, Department of Physical Therapy, Marquette University, Milwaukee, WI, USA.,Department of Kinesiology and Health Promotion, California State Polytechnic University, Pomona, CA, USA
| | - Jonathon W Senefeld
- Exercise Science Program, Department of Physical Therapy, Marquette University, Milwaukee, WI, USA.,Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
| | - Sandra K Hunter
- Exercise Science Program, Department of Physical Therapy, Marquette University, Milwaukee, WI, USA.
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Aagaard P, Bojsen-Møller J, Lundbye-Jensen J. Assessment of Neuroplasticity With Strength Training. Exerc Sport Sci Rev 2020; 48:151-162. [DOI: 10.1249/jes.0000000000000229] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Olmos AA, Stratton MT, Ha PL, Dalton BE, VanDusseldorp TA, Mangine GT, Feito Y, Poisal MJ, Jones JA, Smith TM, Hester GM. Early and late rapid torque characteristics and select physiological correlates in middle-aged and older males. PLoS One 2020; 15:e0231907. [PMID: 32324776 PMCID: PMC7179893 DOI: 10.1371/journal.pone.0231907] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 04/02/2020] [Indexed: 12/02/2022] Open
Abstract
Purpose The purpose of this study was to compare early and late rapid torque parameters of the plantar flexors (PFs) in middle-aged (MM) and older (OM) males, and determine the effect of normalization to peak torque (PT) and muscle cross-sectional area (CSA). Methods Twenty-nine healthy, MM (n = 14; 45 ± 2 yrs) and OM (n = 15; 65 ± 3 yrs) performed rapid, maximal isometric contractions of the PFs. PT, as well as rate of torque development and impulse during the early (0–50 ms; RTD0-50, IMP0-50) and late (100–200 ms; RTD100-200, IMP100-200) contraction phases were calculated. Torque at 50 (TQ50), 100 (TQ100), and 200 (TQ200) ms was also obtained. CSA and echo-intensity (EI) of the gastrocnemii were acquired via ultrasonography. Torque variables were normalized to PT and CSA. Rate of EMG rise (RER) for the medial gastrocnemius was calculated at 30, 50 and 75 ms. Results TQ100 (MM = 69.71 ± 16.85 vs. OM = 55.99 ± 18.54 Nm; p = 0.046), TQ200 (MM = 114.76 ± 26.79 vs. OM = 91.56 ± 28.10 Nm; p = 0.031), and IMP100-200 (MM = 4.79 ± 1.11 vs. OM = 3.83 ± 1.17 Nm·s; p = 0.032) were lower in OM. PT, TQ50, RTD0-50, IMP0-50, RTD100-200, RER, CSA, and EI were similar between groups (p > 0.05). No differences were found for normalized torque variables (p > 0.05). EI was moderately associated with normalized torque parameters only (r = -0.38 –-0.45). RER, at 75 ms, was moderately correlated with early, absolute torque measures and rapid torque variables made relative to PT and CSA (r = 0.41 –-0.64). Conclusion Late rapid torque parameters of the PFs were preferentially impaired in OM compared to MM, and PT as well as CSA appeared to mediate this result.
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Affiliation(s)
- Alex A. Olmos
- Department of Exercise Science and Sport Management, Kennesaw State University, Kennesaw, Georgia, United States of America
| | - Matthew T. Stratton
- Department of Kinesiology and Sport Management, Texas Tech University, Lubbock, Texas, United States of America
| | - Phuong L. Ha
- Department of Exercise Science and Sport Management, Kennesaw State University, Kennesaw, Georgia, United States of America
| | - Benjamin E. Dalton
- Department of Exercise Science and Sport Management, Kennesaw State University, Kennesaw, Georgia, United States of America
| | - Trisha A. VanDusseldorp
- Department of Exercise Science and Sport Management, Kennesaw State University, Kennesaw, Georgia, United States of America
| | - Gerald T. Mangine
- Department of Exercise Science and Sport Management, Kennesaw State University, Kennesaw, Georgia, United States of America
| | - Yuri Feito
- Department of Exercise Science and Sport Management, Kennesaw State University, Kennesaw, Georgia, United States of America
| | - Micah J. Poisal
- Department of Exercise Science and Sport Management, Kennesaw State University, Kennesaw, Georgia, United States of America
| | - Joshua A. Jones
- Department of Exercise Science and Sport Management, Kennesaw State University, Kennesaw, Georgia, United States of America
| | - Tyler M. Smith
- Department of Exercise Science and Sport Management, Kennesaw State University, Kennesaw, Georgia, United States of America
| | - Garrett M. Hester
- Department of Exercise Science and Sport Management, Kennesaw State University, Kennesaw, Georgia, United States of America
- * E-mail:
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9
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Hester GM, Ha PL, Dalton BE, VanDusseldorp TA, Olmos AA, Stratton MT, Bailly AR, Vroman TM. Rate of Force Development as a Predictor of Mobility in Community-dwelling Older Adults. J Geriatr Phys Ther 2020; 44:74-81. [PMID: 31917715 DOI: 10.1519/jpt.0000000000000258] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND AND PURPOSE Rate of force development (RFD) is influential, and possibly more influential than other muscular performance parameters, for mobility in older adults. However, only a few studies have investigated this matter, and this has not been examined for the plantar flexors (PFs). The purpose of this study was to examine the contribution of PF RFD and other common tests of muscular performance to Up-and-Go (UG) performance and walking speed (WS) in older adults. METHODS Twenty-six (19 females) healthy, community-dwelling older adults (73.7 ± 4.9 years) were recruited from a senior citizen center for this observational study. Handgrip strength, UG performance, as well as preferred and maximal WS were obtained. Time taken to complete 5-chair rises and the number of chair rises completed in 30 seconds were recorded. Rate of force development of the PFs was obtained during a rapid, bilateral calf raise performed on a force plate. Hierarchical multiple linear regression was used to identify significant predictors, after adjusting for physical activity level and body mass index, of mobility (ie, UG, preferred and maximal WS). RESULTS AND DISCUSSION No muscular performance variables correlated with preferred WS. Rate of force development (adjusted R2 = 0.356; P = .008) and handgrip strength (adjusted R2 = 0.293; P = .026) were the only predictors of maximal WS and accounted for a 21.7% and 16.1% change in R2, respectively, after accounting for physical activity level and body mass index. Rate of force development was the only predictor of UG performance (adjusted R2 = 0.212; P = .006) and accounted for a 29.2% change in R2 after adjustment variables were applied. CONCLUSIONS Compared to common assessments of muscular performance, such as handgrip strength and chair rise performance, PF RFD was a greater predictor of mobility in older adults. These findings, in conjunction with recent reports, indicate that the assessment of RFD likely complements strength testing, thereby enabling a more robust assessment of functional decline in older adults.
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Affiliation(s)
- Garrett M Hester
- Department of Exercise Science and Sport Management, Kennesaw State University, Georgia
| | - Phuong L Ha
- Department of Exercise Science and Sport Management, Kennesaw State University, Georgia
| | - Benjamin E Dalton
- Department of Exercise Science and Sport Management, Kennesaw State University, Georgia
| | | | - Alex A Olmos
- Department of Exercise Science and Sport Management, Kennesaw State University, Georgia
| | - Matthew T Stratton
- Department of Exercise Science and Sport Management, Kennesaw State University, Georgia
| | - Alyssa R Bailly
- Department of Exercise Science and Sport Management, Kennesaw State University, Georgia
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Fragala MS, Cadore EL, Dorgo S, Izquierdo M, Kraemer WJ, Peterson MD, Ryan ED. Resistance Training for Older Adults: Position Statement From the National Strength and Conditioning Association. J Strength Cond Res 2019; 33:2019-2052. [PMID: 31343601 DOI: 10.1519/jsc.0000000000003230] [Citation(s) in RCA: 526] [Impact Index Per Article: 105.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Fragala, MS, Cadore, EL, Dorgo, S, Izquierdo, M, Kraemer, WJ, Peterson, MD, and Ryan, ED. Resistance training for older adults: position statement from the national strength and conditioning association. J Strength Cond Res 33(8): 2019-2052, 2019-Aging, even in the absence of chronic disease, is associated with a variety of biological changes that can contribute to decreases in skeletal muscle mass, strength, and function. Such losses decrease physiologic resilience and increase vulnerability to catastrophic events. As such, strategies for both prevention and treatment are necessary for the health and well-being of older adults. The purpose of this Position Statement is to provide an overview of the current and relevant literature and provide evidence-based recommendations for resistance training for older adults. As presented in this Position Statement, current research has demonstrated that countering muscle disuse through resistance training is a powerful intervention to combat the loss of muscle strength and muscle mass, physiological vulnerability, and their debilitating consequences on physical functioning, mobility, independence, chronic disease management, psychological well-being, quality of life, and healthy life expectancy. This Position Statement provides evidence to support recommendations for successful resistance training in older adults related to 4 parts: (a) program design variables, (b) physiological adaptations, (c) functional benefits, and (d) considerations for frailty, sarcopenia, and other chronic conditions. The goal of this Position Statement is to a) help foster a more unified and holistic approach to resistance training for older adults, b) promote the health and functional benefits of resistance training for older adults, and c) prevent or minimize fears and other barriers to implementation of resistance training programs for older adults.
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Affiliation(s)
| | - Eduardo L Cadore
- School of Physical Education, Physiotherapy and Dance, Exercise Research Laboratory, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Sandor Dorgo
- Department of Kinesiology, University of Texas at El Paso, El Paso, Texas
| | - Mikel Izquierdo
- Department of Health Sciences, Public University of Navarre, CIBER of Frailty and Healthy Aging (CIBERFES), Navarrabiomed, Pamplona, Navarre, Spain
| | - William J Kraemer
- Department of Human Sciences, The Ohio State University, Columbus, Ohio
| | - Mark D Peterson
- Department of Physical Medicine and Rehabilitation, University of Michigan-Medicine, Ann Arbor, Michigan
| | - Eric D Ryan
- Department of Exercise and Sport Science, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina
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11
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Carr JC, Ye X, Stock MS, Bemben MG, DeFreitas JM. The time course of cross-education during short-term isometric strength training. Eur J Appl Physiol 2019; 119:1395-1407. [PMID: 30949806 DOI: 10.1007/s00421-019-04130-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 03/26/2019] [Indexed: 10/27/2022]
Abstract
PURPOSE This study examined the time course of contralateral adaptations in maximal isometric strength (MVC), rate of force development (RFD), and rate of electromyographic (EMG) rise (RER) during 4 weeks of unilateral isometric strength training with the non-dominant elbow flexors. METHODS Twenty participants were allocated to strength training (n = 10, three female, two left hand dominant) or control (n = 10, three female, two left hand dominant) groups. Both groups completed testing at baseline and following each week of training to evaluate MVC strength, EMG amplitude, RFD and RER at early (RFD50, RER50) and late (RFD200, RER200) contraction phases for the dominant 'untrained' elbow flexors. The training group completed 11 unilateral isometric training sessions across 4 weeks. RESULTS The contralateral improvements for MVC strength (P < 0.01) and RFD200 (P = 0.017) were evidenced after 2 weeks, whereas RFD50 (P < 0.01) and RER50 (P = 0.02) showed significant improvements after 3 weeks. Each of the dependent variables was significantly (P < 0.05) greater than baseline values at the end of the training intervention for the trained arm. No changes in any of the variables were observed for the control group (P > 0.10). CONCLUSIONS Unilateral isometric strength training for 2-3 weeks can produce substantial increases in isometric muscle strength and RFD for both the trained and untrained arms. These data have implications for rehabilitative exercise design and prescription.
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Affiliation(s)
- Joshua C Carr
- Department of Health & Exercise Science, University of Oklahoma, 1401 Asp Ave, Room 104, Norman, OK, 73019, USA.
| | - Xin Ye
- Department of Health, Exercise Science, & Recreation Management, University of Mississippi, University, MS, USA
| | - Matt S Stock
- School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, FL, USA
| | - Michael G Bemben
- Department of Health & Exercise Science, University of Oklahoma, 1401 Asp Ave, Room 104, Norman, OK, 73019, USA
| | - Jason M DeFreitas
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, OK, USA
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12
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Cross-education: effects of age on rapid and maximal voluntary contractile characteristics in males. Eur J Appl Physiol 2019; 119:1313-1322. [DOI: 10.1007/s00421-019-04123-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 03/08/2019] [Indexed: 10/27/2022]
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13
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Age Does Not Attenuate Maximal Velocity Adaptations in the Ipsilateral and Contralateral Limbs During Unilateral Resistance Training. J Aging Phys Act 2019; 27:1-8. [DOI: 10.1123/japa.2017-0297] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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14
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Influence of signal filtering and sample rate on isometric torque – time parameters using a traditional isokinetic dynamometer. J Biomech 2019; 83:235-242. [DOI: 10.1016/j.jbiomech.2018.12.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 11/29/2018] [Accepted: 12/01/2018] [Indexed: 01/09/2023]
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15
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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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16
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Pereira-Baldon VS, Avila MA, Dalarmi CB, de Oliveira AB, Driusso P. Effects of different regimens for pelvic floor muscle training in young continent women: Randomized controlled clinical trial. J Electromyogr Kinesiol 2018; 44:31-35. [PMID: 30481699 DOI: 10.1016/j.jelekin.2018.11.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 10/30/2018] [Accepted: 11/08/2018] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Physical therapy is recommended as first-line treatment to urinary incontinence (UI), and pelvic floor muscles (PFM) training is one of the most used resources for this purpose, no ideal PFM training protocol has been established. OBJECTIVES The purpose of the present study was to verify whether more daily sessions of PFM training lead to better PFM function. METHODS Twenty-five young continent women volunteered and were randomly assigned to 2 different groups; group 1, in which they performed one PFM training session daily, and group 2, in which they performed 3 daily PFM training sessions. All volunteers were evaluated regarding PFM function, based on the Modified Oxford Scale, maximum voluntary contraction, with a manometer, and PFM activation, with electromyography. Both groups trained during 8 consecutive weeks and were evaluated before and after treatment. All evaluations had the reproducibility tested by intraclass correlation coefficients. Statistical analyzes included data normality (Shapiro-Wilks), intragroup (Wilcoxon) and intergroup (Mann-Whitney U) comparisons. Effect sizes were calculated to all variables analyzed. Significance level was set al p < 0.05. RESULTS Even though an increase in PFM strength, pressure and muscle activation was achieved by both groups (p < 0.05, effect sizes from 0.24 to 0.81), no differences between groups for any variables were detected (p > 0.05). CONCLUSIONS The number of daily training sessions does not interfere in the improvement of PFM function in young women without PFM dysfunction.
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Affiliation(s)
- Vanessa S Pereira-Baldon
- Physical Education and Physical Therapy Faculty, Universidade Federal de Uberlândia (UFU), Uberlândia, MG, Brazil
| | - Mariana Arias Avila
- Physical Therapy Department, Universidade Federal de São Carlos (UFSCar), São Carlos, SP, Brazil
| | | | - Ana Beatriz de Oliveira
- Physical Therapy Department, Universidade Federal de São Carlos (UFSCar), São Carlos, SP, Brazil
| | - Patricia Driusso
- Physical Therapy Department, Universidade Federal de São Carlos (UFSCar), São Carlos, SP, Brazil.
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17
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Del Vecchio A, Negro F, Falla D, Bazzucchi I, Farina D, Felici F. Higher muscle fiber conduction velocity and early rate of torque development in chronically strength-trained individuals. J Appl Physiol (1985) 2018; 125:1218-1226. [DOI: 10.1152/japplphysiol.00025.2018] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Strength-trained individuals (ST) develop greater levels of force compared with untrained subjects. These differences are partly of neural origin and can be explained by training-induced changes in the neural drive to the muscles. In the present study we hypothesize a greater rate of torque development (RTD) and faster recruitment of motor units with greater muscle fiber conduction velocity (MFCV) in ST compared with a control cohort. MFCV was assessed during maximal voluntary isometric explosive contractions of the elbow flexors in eight ST and eight control individuals. MFCV was estimated from high-density surface electromyogram recordings (128 electrodes) in intervals of 50 ms starting from the onset of the electromyogram. RTD and MFCV were computed and normalized to their maximal voluntary torque (MVT) values. The explosive torque of the ST was greater than in the control group in all time intervals analyzed ( P < 0.001). The absolute MFCV values were also greater for the ST than for controls at all time intervals ( P < 0.001). ST also achieved greater normalized RTD in the first 50 ms of contraction [887.6 (152) vs. 568.5 (148.66)%MVT/s, mean (SD), P < 0.001] and normalized MFCV before the rise in force compared with controls. We have shown for the first time that ST can recruit motor units with greater MFCV in a shorter amount of time compared with untrained subjects during maximal voluntary isometric explosive contractions. NEW & NOTEWORTHY Strength-trained individuals show neuromuscular adaptations. These adaptations have been partly related to changes in the neural drive to the muscles. Here, we show for the first time that during the initial phase of a maximal isometric explosive contraction, strength-trained individuals achieve higher levels of force and recruit motor units with greater conduction velocities.
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Affiliation(s)
- A. Del Vecchio
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico,” Rome, Italy
- Neuromechanics and Rehabilitation Technology Group, Department of Bioengineering, Imperial College London, London, United Kingdom
| | - F. Negro
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | - D. Falla
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - I. Bazzucchi
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico,” Rome, Italy
| | - D. Farina
- Neuromechanics and Rehabilitation Technology Group, Department of Bioengineering, Imperial College London, London, United Kingdom
| | - F. Felici
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico,” Rome, Italy
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18
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Debenham MIB, Power GA. The influence of preceding activity and muscle length on voluntary and electrically evoked contractions. Appl Physiol Nutr Metab 2018; 44:301-308. [PMID: 30189152 DOI: 10.1139/apnm-2018-0104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Muscle length and preceding activity independently influence rate of torque development (RTD) and electromechanical delay (EMD), but it is unclear whether these parameters interact to optimize RTD and EMD. The purpose of this study was to determine the influence of muscle length and preceding activity on RTD and EMD during voluntary and electrically stimulated (e-stim) contractions. Participants (n = 17, males, 24 ± 3 years) performed isometric knee extensions on a dynamometer. Explosive maximal contractions were performed at 2 knee angles (35° and 100° referenced to a 0° straight leg) without preceding activity (unloaded, UNL) and with preceding activities of 20%, 40%, 60%, and 80% of maximal voluntary contraction (MVC) torque. Absolute and normalized voluntary RTD were slowed with preceding activities ≥40% MVC for long muscle lengths and all preceding activities for short muscle lengths compared with UNL (p < 0.001). Absolute and normalized e-stim RTD were slower with preceding activities ≥40% MVC compared with UNL (p < 0.001) for both muscle lengths. Normalized RTD was faster at short muscle lengths than at long muscle lengths (p < 0.001) for e-stim (∼50%) and voluntary (∼32%) UNL contractions, but this effect was not present for absolute RTD. Muscle length did not affect EMD (p > 0.05). EMD was shorter at 80% MVC compared with UNL (∼35%; p < 0.001) for both muscle lengths during voluntary but not e-stim contractions. While RTD is limited by preceding activity at both muscle lengths, long muscle lengths require greater preceding activity to limit RTD than short muscle lengths, which indicates long muscle lengths may offer a "protective effect" for RTD against preceding activity.
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Affiliation(s)
- Mathew I B Debenham
- Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada.,Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Geoffrey A Power
- Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada.,Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
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19
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Carson RG. Get a grip: individual variations in grip strength are a marker of brain health. Neurobiol Aging 2018; 71:189-222. [PMID: 30172220 DOI: 10.1016/j.neurobiolaging.2018.07.023] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 07/06/2018] [Accepted: 07/29/2018] [Indexed: 02/06/2023]
Abstract
Demonstrations that grip strength has predictive power in relation to a range of health conditions-even when these are assessed decades later-has motivated claims that hand-grip dynamometry has the potential to serve as a "vital sign" for middle-aged and older adults. Central to this belief has been the assumption that grip strength is a simple measure of physical performance that provides a marker of muscle status in general, and sarcopenia in particular. It is now evident that while differences in grip strength between individuals are influenced by musculoskeletal factors, "lifespan" changes in grip strength within individuals are exquisitely sensitive to integrity of neural systems that mediate the control of coordinated movement. The close and pervasive relationships between age-related declines in maximum grip strength and expressions of cognitive dysfunction can therefore be understood in terms of the convergent functional and structural mediation of cognitive and motor processes by the human brain. In the context of aging, maximum grip strength is a discriminating measure of neurological function and brain health.
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Affiliation(s)
- Richard G Carson
- Trinity College Institute of Neuroscience, School of Psychology, Trinity College Dublin, Dublin, Ireland; School of Psychology, Queen's University Belfast, Belfast, Northern Ireland, UK; School of Human Movement and Nutrition Sciences, The University of Queensland, Australia.
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20
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Rodríguez-Rosell D, Pareja-Blanco F, Aagaard P, González-Badillo JJ. Physiological and methodological aspects of rate of force development assessment in human skeletal muscle. Clin Physiol Funct Imaging 2017; 38:743-762. [DOI: 10.1111/cpf.12495] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/29/2017] [Indexed: 12/22/2022]
Affiliation(s)
- David Rodríguez-Rosell
- Centro de Investigación en Rendimiento Físico y Deportivo, Universidad Pablo de Olavide, Seville, Spain
| | - Fernando Pareja-Blanco
- Centro de Investigación en Rendimiento Físico y Deportivo, Universidad Pablo de Olavide, Seville, Spain
| | - Per Aagaard
- Department of Sports Science and Clinical Biomechanics, SDU Muscle Research Cluster (SMRC), University of Southern Denmark, Odense, Denmark
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21
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Knee Extensor Rate of Torque Development Before and After Arthroscopic Partial Meniscectomy, With Analysis of Neuromuscular Mechanisms. J Orthop Sports Phys Ther 2017; 47:945-956. [PMID: 28992769 DOI: 10.2519/jospt.2017.7310] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Study Design Descriptive, prospective single-cohort longitudinal study. Background Though rapid torque development is essential in activities of daily living and sports, it hasn't been specifically tested by most physical therapists or incorporated into rehabilitation programs until late in the treatment process. Little evidence is available on quadriceps torque development capacity before and after arthroscopic knee surgery. Objectives To study knee extensor rate of torque development, contributing mechanisms, and associations with strength and patient-reported outcomes before and during the first 6 weeks after arthroscopic partial meniscectomy. Methods Twenty subjects (mean ± SD age, 42.3 ± 13.7 years; body mass index, 26.6 ± 3.1 kg/m2) were tested before surgery, and at 2 and 5 weeks after surgery. Quadriceps muscle volume, strength, activation, rate of torque development, and patient-reported outcomes were evaluated across the study period. Results Significant side-to-side differences in quadriceps strength and voluntary rate of torque development were observed at each time point (P<.05). Changes in muscle activity were associated with changes in rapid torque development capacity. Side-to-side rate of torque development deficits after surgery were associated with lower patient-reported outcomes scores. Conclusion Diminished rapid torque development capacity is common in arthroscopic meniscal debridement patients. This reduced capacity is associated with an inability to quickly recruit and drive the quadriceps muscles (neural mechanisms) and not muscle atrophy or other peripheral factors tested. Patient-reported outcomes are associated with quadriceps rate of torque development, but not strength or muscle size. Rapid torque development warrants greater attention in rehabilitation. J Orthop Sports Phys Ther 2017;47(12):945-956. Epub 9 Oct 2017. doi:10.2519/jospt.2017.7310.
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22
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Ema R, Ohki S, Takayama H, Kobayashi Y, Akagi R. Effect of calf-raise training on rapid force production and balance ability in elderly men. J Appl Physiol (1985) 2017; 123:424-433. [PMID: 28572499 PMCID: PMC5583613 DOI: 10.1152/japplphysiol.00539.2016] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 05/30/2017] [Accepted: 05/31/2017] [Indexed: 11/22/2022] Open
Abstract
This study examined whether home-based, high-speed calf-raise training changes the rate of torque development (RTD) during plantar flexion contractions and balance performance in elderly men. Thirty-four healthy elderly men (73 ± 5 yr) were randomly assigned to a training or control group (n = 17 in each group). The subjects in the training group completed 8 wk (3 times/wk) of home-based bilateral calf-raise training using body mass. Before and after the intervention, RTD during plantar flexion contractions and center-of-pressure (COP) displacement during single-leg standing were measured. Surface electromyographic amplitude of the triceps surae and tibialis anterior during the strength and single-leg standing was measured. Clinical magnitude-based inferences were used to interpret the training effect, with the smallest worthwhile effect assumed to be 0.2 of the baseline SD. The peak RTD increased 21% (90% confidence limits, ±19%) relative to the control group, which was accompanied by corresponding changes of the medial gastrocnemius (MG) and soleus (SOL) activations. The effect on COP displacement was possibly trivial (0%, ±13%), whereas substantial reduction in the MG (-19%, ±15%) and SOL (-25%, ±13%) activations during standing was observed. Our findings indicate that calf-raise training at home, performed without special equipment or venue, induces a substantial increase in the plantar flexors' rapid force-generating capability and triceps surae activations. Although the training effect on standing balance performance was not substantial, observed changes in the triceps surae activations during standing are expected to contribute to future balance performance improvement.NEW & NOTEWORTHY Calf-raise training with the intent to move rapidly, without special equipment or venue, induces an improvement of explosive plantar flexion force, which is attributable to neuromuscular rather than musculotendinous adaptations. Although the training effect on balance performance was trivial, we found a sign of improvement (i.e., neuromuscular adaptations during standing). In conclusion, functional neuromuscular capacity can be enhanced by home-based calf-raise exercise in elderly men, which may protect against mobility loss with aging.
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Affiliation(s)
- Ryoichi Ema
- Graduate School of Engineering and Science, Shibaura Institute of Technology, Saitama, Japan.,Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | - Shunsuke Ohki
- College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, Japan; and
| | - Hirokazu Takayama
- College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, Japan; and
| | - Yuji Kobayashi
- Institute for Education and Student Services, Okayama University, Okayama, Japan
| | - Ryota Akagi
- College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, Japan; and
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23
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Mike JN, Cole N, Herrera C, VanDusseldorp T, Kravitz L, Kerksick CM. The Effects of Eccentric Contraction Duration on Muscle Strength, Power Production, Vertical Jump, and Soreness. J Strength Cond Res 2017; 31:773-786. [PMID: 27787464 DOI: 10.1519/jsc.0000000000001675] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Mike, JN, Cole, N, Herrera, C, VanDusseldorp, T, Kravitz, L, and Kerksick, CM. The effects of eccentric contraction duration on muscle strength, power production, vertical jump, and soreness. J Strength Cond Res 31(3): 773-786, 2017-Previous research has investigated the effects of either eccentric-only training or comparing eccentric and concentric exercise on changes related to strength and power expression, but no research to date has investigated the impact of altering the duration of either the concentric or the eccentric component on these parameters. Therefore, the purpose of this study was to assess the duration of eccentric (i.e., 2-second, 4-second vs. 6-second) muscle contractions and their effect on muscle strength, power production, vertical jump, and soreness using a plate-loaded barbell Smith squat exercise. Thirty college-aged men (23 ± 3.5 years, 178 ± 6.8 cm, 82 ± 12 kg, and 11.6 ± 5.1% fat) with 3.0 ± 1.0 years of resistance training experience and training frequency of 4.3 ± 0.9 days per week were randomized and assigned to 1 of 3 eccentric training groups that incorporated different patterns of contraction. For every repetition, all 3 groups used 2-second concentric contractions and paused for 1 second between the concentric and eccentric phases. The control group (2S) used 2-second eccentric contractions, whereas the 4S group performed 4-second eccentric contractions and the 6S group performed 6-second eccentric contractions. All repetitions were completed using the barbell Smith squat exercise. All participants completed a 4-week training protocol that required them to complete 2 workouts per week using their prescribed contraction routine for 4 sets of 6 repetitions at an intensity of 80-85% one repetition maximum (1RM). For all performance data, significant group × time (G × T) interaction effects were found for average power production across all 3 sets of a squat jump protocol (p = 0.04) while vertical jump did not reach significance but there was a trend toward a difference (G × T, p = 0.07). No other significant (p > 0.05) G × T interaction effects were found for the performance variables. All groups showed significant main effects for time in 1RM (p < 0.001), vertical jump (p = 0.004), peak power (p < 0.001), and average power (p < 0.001). Peak velocity data indicated that the 6S group experienced a significant reduction in peak velocity during the squat jump protocol as a result of the 4-week training program (p = 0.03). Soreness data revealed significant increases across time in all groups at both week 0 and week 4. Paired sample t-tests revealed greater differences in soreness values across time in the 2S group. The results provide further evidence that resistance training with eccentrically dominated movement patterns can be an effective method to acutely increase maximal strength and power expression in trained college age men. Furthermore, longer eccentric contractions may negatively impact explosive movements such as the vertical jump, whereas shorter eccentric contractions may instigate greater amounts of soreness. These are important considerations for the strength and conditioning professional to more fully understand that expressions of strength and power through eccentric training and varying durations of eccentric activity can have a significant impact for populations ranging from athletes desiring peak performance.
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Affiliation(s)
- Jonathan N Mike
- 1Department of Health, Exercise, and Sports Science, University of New Mexico, Albuquerque, New Mexico; and 2School of Health Sciences, Lindenwood University, St. Charles, Missouri
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24
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Follmer B, Dellagrana RA, de Lima LAP, Herzog W, Diefenthaeler F. Analysis of elbow muscle strength parameters in Brazilian jiu-jitsu practitioners. J Sports Sci 2016; 35:2373-2379. [DOI: 10.1080/02640414.2016.1267388] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Bruno Follmer
- Biomechanics Laboratory, Centre of Sports, Federal University of Santa Catarina, Florianópolis, Brazil
| | - Rodolfo André Dellagrana
- Biomechanics Laboratory, Centre of Sports, Federal University of Santa Catarina, Florianópolis, Brazil
| | | | - Walter Herzog
- Human Performance Laboratory, University of Calgary, Calgary, Canada
| | - Fernando Diefenthaeler
- Biomechanics Laboratory, Centre of Sports, Federal University of Santa Catarina, Florianópolis, Brazil
- Human Performance Laboratory, University of Calgary, Calgary, Canada
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25
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Zbidi S, Zinoubi B, Vandewalle H, Driss T. Diurnal Rhythm of Muscular Strength Depends on Temporal Specificity of Self-Resistance Training. J Strength Cond Res 2016; 30:717-24. [PMID: 26907843 DOI: 10.1519/jsc.0000000000001144] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The study investigated the effect of the time-of-day at which maximal isometric voluntary co-contraction (MIVCC) training is conducted on the adaptation and diurnal variation of maximal and explosive force production. Twenty active men underwent a 6-week (3 times per week) MIVCC training of the right elbow joint. The participants were randomly assigned to a morning training group (MTG, 07:00-08:00 hours) and evening training group (ETG, 17:00-18:00 hours). The maximal voluntary force (MVF) and maximal rate of force development (MRFD) during isometric elbow flexion (MVFF and MRFD(F)) and extension (MVF(E) and MRFD(E)) were recorded before (T0) and after (T1) training in the morning and evening. At T0, MVF and MRFD were higher in the evening compared with those in the morning for the MTG and ETG (p ≤ 0.05). At T1, MVFF and MVFE increased in the morning and evening for both groups (p < 0.001). The MRFD(F) and MRFD(E) increased only if training and test session were scheduled at the same time. The relative increase of MVF was greater at the specific time of training for the MTG (12 and 17.6% in MVF(F) and MVF(E), respectively) and ETG (9.8 and 13.4% in MVF(F) and MVF(E), respectively). The diurnal variations in MVF and MRF(D) during flexion and extension disappeared in the MTG and persisted in the ETG. Maximal isometric voluntary co-contraction training enhanced muscle strength whatever the time-of-day at which the training was scheduled without alteration of explosive force. In contrast, to optimize the muscle strength, our results suggested that morning training may be accompanied by the greatest muscle strength gain and blunted muscle strength variation observed between the morning and evening.
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Affiliation(s)
- Sana Zbidi
- 1Research Center on Sport and Movement (CeRSM, EA 2931), Sciences and Techniques of the Physical and Sporting Activities (UFR STAPS), University of Paris West Nanterre La Defense, Nanterre, France; and2Laboratory of Physiology, UFR Health, Medicine and Human Biology, University of Paris XIII, Bobigny, France
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Pereira PMG, Araújo ALFD, Oliveira ERLD, Costa MDGDS, Geraldes AAR, Cirilo-Sousa MDS. TAXA DE DESENVOLVIMENTO DE FORÇA E ATIVAÇÃO NEURAL EM MULHERES PÓS-MENOPAUSADAS. REV BRAS MED ESPORTE 2016. [DOI: 10.1590/1517-869220162205156276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
RESUMO Introdução: O envelhecimento associa-se à redução da velocidade de contração e ativação das fibras musculares, influenciando a aptidão física e o desempenho funcional. Objetivo: Verificar o comportamento da taxa de desenvolvimento de força (TDF) e ativação neural em mulheres pós-menopausadas. Métodos: Vinte e quatro mulheres pós-menopausadas (63,2 ± 5,6 anos; 154,5 ± 7,3 cm e 64,7 ± 7,6 kg), funcionalmente independentes e fisicamente ativas, foram submetidas simultaneamente, à mensuração da força isométrica máxima e dos sinais eletromiográficos (EMG) dos seguintes músculos: vasto lateral (VL), reto femoral (RF) e vasto medial (VM), durante uma extensão unilateral do joelho do membro dominante. Tais resultados foram utilizados para calcular a TDF, o impulso contrátil, em intervalos de 20 ms nos primeiros 200 ms da contração muscular pelo uso da curva força/tempo, a taxa de ativação EMG (TAE) e a amplitude média EMG, em intervalos de 40 a 80 ms do início da integração EMG pelo uso da curva EMG/tempo. Resultados: Os valores da força variaram entre 29,19 a 86,04 N.m; a TDF variou de 1459,42 N.m.s-1 para 430,21 N.m.s-1 em 20 ms e 200 ms respectivamente, apontando valores decrescentes com o tempo; para o impulso foram observados valores entre 0,65 a 11,07 N.m.s; na mesma direção da TDF, a TAE apresentou valores decrescentes para o VL (1676,08 a 844,41 µVs-1), para o RF (1320,88 a 637,59 µVs-1) e para o VM (1747,63 a 914,09 µVs-1) em 20 e 200 ms, enquanto a amplitude EMG média teve valores de 33,77 a 50,32 µV para o VL, de 24,93 a 38,07 µV para o RF e de 37,07 a 54,78 µV para o VM em 40 ms e 80 ms, respectivamente. Conclusão: Em mulheres pós-menopausadas, a velocidade de aumento, a manutenção da força e a ativação EMG não são suficientes para manter TDF e TAE crescentes, demonstrando um possível risco de incapacidades funcionais e ocorrência de quedas.
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Balshaw TG, Massey GJ, Maden-Wilkinson TM, Tillin NA, Folland JP. Training-specific functional, neural, and hypertrophic adaptations to explosive- vs. sustained-contraction strength training. J Appl Physiol (1985) 2016; 120:1364-73. [PMID: 27055984 DOI: 10.1152/japplphysiol.00091.2016] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 04/05/2016] [Indexed: 11/22/2022] Open
Abstract
Training specificity is considered important for strength training, although the functional and underpinning physiological adaptations to different types of training, including brief explosive contractions, are poorly understood. This study compared the effects of 12 wk of explosive-contraction (ECT, n = 13) vs. sustained-contraction (SCT, n = 16) strength training vs. control ( n = 14) on the functional, neural, hypertrophic, and intrinsic contractile characteristics of healthy young men. Training involved 40 isometric knee extension repetitions (3 times/wk): contracting as fast and hard as possible for ∼1 s (ECT) or gradually increasing to 75% of maximum voluntary torque (MVT) before holding for 3 s (SCT). Torque and electromyography during maximum and explosive contractions, torque during evoked octet contractions, and total quadriceps muscle volume (QUADSVOL) were quantified pre and post training. MVT increased more after SCT than ECT [23 vs. 17%; effect size (ES) = 0.69], with similar increases in neural drive, but greater QUADSVOL changes after SCT (8.1 vs. 2.6%; ES = 0.74). ECT improved explosive torque at all time points (17–34%; 0.54 ≤ ES ≤ 0.76) because of increased neural drive (17–28%), whereas only late-phase explosive torque (150 ms, 12%; ES = 1.48) and corresponding neural drive (18%) increased after SCT. Changes in evoked torque indicated slowing of the contractile properties of the muscle-tendon unit after both training interventions. These results showed training-specific functional changes that appeared to be due to distinct neural and hypertrophic adaptations. ECT produced a wider range of functional adaptations than SCT, and given the lesser demands of ECT, this type of training provides a highly efficient means of increasing function.
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Affiliation(s)
- Thomas G. Balshaw
- Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, Loughborough University, Loughborough, United Kingdom
- School of Sport, Exercise, and Health Sciences, Loughborough University, Loughborough, United Kingdom; and
| | - Garry J. Massey
- Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, Loughborough University, Loughborough, United Kingdom
- School of Sport, Exercise, and Health Sciences, Loughborough University, Loughborough, United Kingdom; and
| | - Thomas M. Maden-Wilkinson
- School of Sport, Exercise, and Health Sciences, Loughborough University, Loughborough, United Kingdom; and
| | - Neale A. Tillin
- Department of Life Sciences, University of Roehampton, London, United Kingdom
| | - Jonathan P. Folland
- Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, Loughborough University, Loughborough, United Kingdom
- School of Sport, Exercise, and Health Sciences, Loughborough University, Loughborough, United Kingdom; and
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Ruddy KL, Rudolf AK, Kalkman B, King M, Daffertshofer A, Carroll TJ, Carson RG. Neural Adaptations Associated with Interlimb Transfer in a Ballistic Wrist Flexion Task. Front Hum Neurosci 2016; 10:204. [PMID: 27199722 PMCID: PMC4853797 DOI: 10.3389/fnhum.2016.00204] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 04/21/2016] [Indexed: 12/14/2022] Open
Abstract
Cross education is the process whereby training of one limb gives rise to increases in the subsequent performance of its opposite counterpart. The execution of many unilateral tasks is associated with increased excitability of corticospinal projections from primary motor cortex (M1) to the opposite limb. It has been proposed that these effects are causally related. Our aim was to establish whether changes in corticospinal excitability (CSE) arising from prior training of the opposite limb determine levels of interlimb transfer. We used three vision conditions shown previously to modulate the excitability of corticospinal projections to the inactive (right) limb during wrist flexion movements performed by the training (left) limb. These were: (1) mirrored visual feedback of the training limb; (2) no visual feedback of either limb; and (3) visual feedback of the inactive limb. Training comprised 300 discrete, ballistic wrist flexion movements executed as rapidly as possible. Performance of the right limb on the same task was assessed prior to, at the mid point of, and following left limb training. There was no evidence that variations in the excitability of corticospinal projections (assessed by transcranial magnetic stimulation (TMS)) to the inactive limb were associated with, or predictive of, the extent of interlimb transfer that was expressed. There were however associations between alterations in muscle activation dynamics observed for the untrained limb, and the degree of positive transfer that arose from training of the opposite limb. The results suggest that the acute adaptations that mediate the bilateral performance gains realized through unilateral practice of this ballistic wrist flexion task are mediated by neural elements other than those within M1 that are recruited at rest by single-pulse TMS.
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Affiliation(s)
- Kathy L Ruddy
- Trinity College Institute of Neuroscience and School of Psychology, Trinity College DublinDublin, Ireland; School of Psychology, Queen's University BelfastNorthern Ireland, UK; Neural Control of Movement Lab, ETH ZurichZurich, Switzerland
| | - Anne K Rudolf
- Trinity College Institute of Neuroscience and School of Psychology, Trinity College DublinDublin, Ireland; Department of Neurocognitive Psychology, Goethe UniversityFrankfurt, Germany
| | - Barbara Kalkman
- Trinity College Institute of Neuroscience and School of Psychology, Trinity College DublinDublin, Ireland; Faculty of Human Movement Sciences, Vrije University AmsterdamAmsterdam, Netherlands
| | - Maedbh King
- Trinity College Institute of Neuroscience and School of Psychology, Trinity College Dublin Dublin, Ireland
| | - Andreas Daffertshofer
- Faculty of Human Movement Sciences, Vrije University Amsterdam Amsterdam, Netherlands
| | - Timothy J Carroll
- Centre for Sensorimotor Performance, School of Human Movement Studies, University of Queensland Brisbane, QLD, Australia
| | - Richard G Carson
- Trinity College Institute of Neuroscience and School of Psychology, Trinity College DublinDublin, Ireland; School of Psychology, Queen's University BelfastNorthern Ireland, UK
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Positive effects of 1-year football and strength training on mechanical muscle function and functional capacity in elderly men. Eur J Appl Physiol 2016; 116:1127-38. [PMID: 27068158 DOI: 10.1007/s00421-016-3368-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 03/16/2016] [Indexed: 10/22/2022]
Abstract
PURPOSE A decline in physical capacity takes place with increasing age that negatively affects overall physical function including work ability and the ability to perform typical activities of daily living (ADL). The overall aim of the present study was to determine the neuromuscular adaptations to long-term (1 year) football and strength training in older untrained adults, and to assess the concurrent effect on functional ADL capacity. METHODS Twenty-seven healthy elderly males (68.2 ± 3.2 years) were randomly assigned to 12 months of either recreational football training (FT: n = 10), strength training (ST: n = 9) or served as inactive controls (CON: n = 8). Recreational football training consisted of small-sided training sessions whereas strength training consisted of high intensity exercises targeting the lower extremity and upper body. Maximal thigh muscle strength and rate of force development (RFD) were assessed with isokinetic dynamometry, while postural balance and vertical jumping performance were evaluated using force plate analysis. Furthermore, functional ability was evaluated by stair-ascent and chair-rising testing. RESULTS A total of nine, nine and seven participants from FT, ST and CON, respectively, were included in the analysis. Both exercise regimens led to substantial gains in functional ability, evidenced by 24 and 18 % reduced stair-ascent time, and 32 and 21 % increased chair-rising performance in FT and ST, respectively (all P < 0.05). Long-term strength training led to increased concentric (14 %; P < 0.01) and isometric (23 %; P < 0.001) quadriceps and isometric hamstring strength (44 %; P < 0.0001), whereas football training mainly resulted in enhanced hamstring strength (18 %, P < 0.05) and RFD (89 %, P < 0.0001). CONCLUSIONS Long-term (1 year) strength training led to increased quadriceps and hamstring strength, whereas the adaptations to football training mainly included enhanced strength and rapid force capacity of the hamstring muscles. Gains in functional ability were observed in response to both training regimens, evidenced by reduced stair-ascent time and increased chair-rising performance. Long-term football exercise and strength training both appear to be effective interventional strategies to improve factors of importance for ADL by counteracting the age-related decline in lower limb strength and functional capacity among old male adults. This could potentially be a way to improve work ability of senior workers.
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Maffiuletti NA, Aagaard P, Blazevich AJ, Folland J, Tillin N, Duchateau J. Rate of force development: physiological and methodological considerations. Eur J Appl Physiol 2016; 116:1091-116. [PMID: 26941023 PMCID: PMC4875063 DOI: 10.1007/s00421-016-3346-6] [Citation(s) in RCA: 761] [Impact Index Per Article: 95.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 02/17/2016] [Indexed: 11/26/2022]
Abstract
The evaluation of rate of force development during rapid contractions has recently become quite popular for characterising explosive strength of athletes, elderly individuals and patients. The main aims of this narrative review are to describe the neuromuscular determinants of rate of force development and to discuss various methodological considerations inherent to its evaluation for research and clinical purposes. Rate of force development (1) seems to be mainly determined by the capacity to produce maximal voluntary activation in the early phase of an explosive contraction (first 50–75 ms), particularly as a result of increased motor unit discharge rate; (2) can be improved by both explosive-type and heavy-resistance strength training in different subject populations, mainly through an improvement in rapid muscle activation; (3) is quite difficult to evaluate in a valid and reliable way. Therefore, we provide evidence-based practical recommendations for rational quantification of rate of force development in both laboratory and clinical settings.
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Affiliation(s)
- Nicola A Maffiuletti
- Human Performance Lab, Schulthess Clinic, Lengghalde 6, 8008, Zurich, Switzerland.
| | - Per Aagaard
- Department of Sports Science and Clinical Biomechanics, SDU Muscle Research Cluster (SMRC), University of Southern Denmark, Odense, Denmark
| | - Anthony J Blazevich
- Centre for Exercise and Sports Science Research (CESSR), School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia
| | - Jonathan Folland
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Neale Tillin
- Department of Life Sciences, University of Roehampton, London, UK
| | - Jacques Duchateau
- Laboratory of Applied Biology, ULB Neurosciences Institute, Université Libre de Bruxelles (ULB), Brussels, Belgium
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Wallace JW, Power GA, Rice CL, Dalton BH. Time-dependent neuromuscular parameters in the plantar flexors support greater fatigability of old compared with younger males. Exp Gerontol 2015; 74:13-20. [PMID: 26657724 DOI: 10.1016/j.exger.2015.12.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 11/29/2015] [Accepted: 12/01/2015] [Indexed: 11/19/2022]
Abstract
Older adults are more fatigable than young during dynamic tasks, especially those that involve moderate to fast unconstrained velocity shortening contractions. Rate of torque development (RTD), rate of velocity development (RVD) and rate of neuromuscular activation are time-dependent neuromuscular parameters which have not been explored in relation to age-related differences in fatigability. The purpose was to determine whether these time-dependent measures affect the greater age-related fatigability in peak power during moderately fast and maximal effort shortening plantar flexions. Neuromuscular properties were recorded from 10 old (~ 78 years) and 10 young (~ 24 years) men during 50 maximal-effort unconstrained velocity shortening plantar flexions against a resistance equivalent to 20% maximal voluntary isometric contraction torque. At task termination, peak power, and angular velocity, and torque at peak power were decreased by 30, 18, and 16%, respectively, for the young (p < 0.05), and 46, 28, 30% for the old (p < 0.05) compared to pre-fatigue values with the old exhibiting greater reductions across all measures (p<0.05). Voluntary RVD and RTD decreased, respectively, by 24 and 26% in the young and by 47 and 40% in the old at task termination, with greater decrements in the old (p < 0.05). Rate of neuromuscular activation of the soleus decreased over time for both age groups (~ 47%; p < 0.05), but for the medial gastrocnemius (MG) only the old experienced significant decrements (46%) by task termination. All parameters were correlated strongly with the fatigue-related reduction in peak power (r = 0.81-0.94, p < 0.05), except for MG and soleus rates of neuromuscular activation (r = 0.25-0.30, p > 0.10). Fatigue-related declines in voluntary RTD and RVD were both moderately correlated with MG rate of neuromuscular activation (r = 0.51-0.52, p < 0.05), but exhibited a trend with soleus (r = 0.39-0.41, p = 0.07-0.09). Thus, time-dependent factors, RVD and RTD, are likely important indicators of intrinsic muscle properties leading to the greater age-related decline in peak power when performing a repetitive dynamic fatigue task, which may be due to greater fatigue-related central impairments for the older men than young.
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Affiliation(s)
- Jonathan W Wallace
- Department of Human Physiology, University of Oregon, Eugene, OR, United States
| | - Geoffrey A Power
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Canada
| | - Charles L Rice
- Canadian Centre for Activity and Aging, School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Ontario, Canada; Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Brian H Dalton
- Department of Human Physiology, University of Oregon, Eugene, OR, United States.
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Callahan DM, Tourville TW, Slauterbeck JR, Ades PA, Stevens-Lapsley J, Beynnon BD, Toth MJ. Reduced rate of knee extensor torque development in older adults with knee osteoarthritis is associated with intrinsic muscle contractile deficits. Exp Gerontol 2015; 72:16-21. [PMID: 26343257 PMCID: PMC4654635 DOI: 10.1016/j.exger.2015.08.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 07/21/2015] [Accepted: 08/10/2015] [Indexed: 11/17/2022]
Abstract
We examined the effect of knee osteoarthritis on the rate of torque development (RTD) of the knee extensors in older adults with advanced-stage knee osteoarthritis (OA; n=15) and recreationally-active controls (n=15) of similar age, sex and health status, as well as the relationship between RTD and the size and contractility of single muscle fibers. OA participants had lower RTD when expressed in absolute terms (Nm/ms). There were sex differences in peak RTD (P<0.05), with greater RTD in men, but no group by sex interaction effects for any variables. The lower RTD in OA versus controls was not explained by variation between groups in the fiber type admixture of the muscle, and was mitigated when RTD was normalized to peak torque (PT). In knee OA volunteers, we found strong correlations between the RTD expressed relative to PT and the velocity of contraction of single myosin heavy chain (MHC) I and IIA/X muscle fibers (r=0.652 and 0.862; both P<0.05) and power output of MHC I fibers (r=0.642; P<0.05). In controls, RTD relative to PT was related to fiber cross-sectional area of MHC IIA/X fibers (r=0.707; P<0.05), but not measures of single fiber contractile performance. To our knowledge, these results represent the first demonstration that variation in whole muscle contractile kinetics in patients with advanced-stage knee osteoarthritis and healthy older adults is related, in part, to the size and function of single muscle fibers.
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Affiliation(s)
- Damien M Callahan
- Department of Medicine, University of Vermont, College of Medicine, Burlington, VT, United States
| | - Timothy W Tourville
- Department of Orthopaedics and Rehabilitation, University of Vermont, College of Medicine, Burlington, VT, United States
| | - James R Slauterbeck
- Department of Orthopaedics and Rehabilitation, University of Vermont, College of Medicine, Burlington, VT, United States
| | - Philip A Ades
- Department of Medicine, University of Vermont, College of Medicine, Burlington, VT, United States
| | - Jennifer Stevens-Lapsley
- Department of Physical Medicine and Rehabilitation, University of Colorado, Denver, CO, United States
| | - Bruce D Beynnon
- Department of Orthopaedics and Rehabilitation, University of Vermont, College of Medicine, Burlington, VT, United States
| | - Michael J Toth
- Department of Medicine, University of Vermont, College of Medicine, Burlington, VT, United States; Department of Orthopaedics and Rehabilitation, University of Vermont, College of Medicine, Burlington, VT, United States; Department of Molecular Physiology and Biophysics, University of Vermont, College of Medicine, Burlington, VT, United States.
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Hernández-Davó JL, Sabido R, Moya-Ramón M, Blazevich AJ. Load knowledge reduces rapid force production and muscle activation during maximal-effort concentric lifts. Eur J Appl Physiol 2015; 115:2571-81. [DOI: 10.1007/s00421-015-3276-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 09/27/2015] [Indexed: 11/28/2022]
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Conchola EC, Thiele RM, Palmer TB, Smith DB, Thompson BJ. Effects of neuromuscular fatigue on electromechanical delay of the leg extensors and flexors in young men and women. Muscle Nerve 2015; 52:844-51. [PMID: 25664987 DOI: 10.1002/mus.24598] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 01/30/2015] [Accepted: 02/04/2015] [Indexed: 11/10/2022]
Abstract
INTRODUCTION We examined the effects of neuromuscular fatigue on volitional electromechanical delay (EMD) of leg extensors and flexors between genders. METHODS Twenty-one men and 20 women performed 2 maximal voluntary contractions (MVCs), followed by intermittent isometric contractions of leg extensors and flexors using a 0.6 duty cycle (6-s contraction, 4-s relaxation) at 50% of MVC until volitional fatigue was achieved. MVCs were again performed at 0, 7, 15, and 30 min post-fatigue. RESULTS EMD was greater compared with baseline at all post-fatigue time phases for the leg flexors (P = 0.001-0.007), while EMD was greater at Post0, Post15 and Post30 (P = 0.001-0.023) for the leg extensors. EMD was also greater for leg extensors compared with leg flexors only at Post0. CONCLUSION No differential gender-related fatigue effects on EMD were shown. There were different fatigue-induced responses between leg extensors and flexors, with leg extensors exhibiting higher EMD immediately post-fatigue.
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Affiliation(s)
- Eric C Conchola
- Department of Wellness, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Ryan M Thiele
- Applied Musculoskeletal and Human Physiology Laboratory, Department of Health and Human Performance, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Ty B Palmer
- School of Health Sciences, Kent State University, Kent, Ohio, USA
| | - Doug B Smith
- Applied Musculoskeletal and Human Physiology Laboratory, Department of Health and Human Performance, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Brennan J Thompson
- Human Performance Laboratory, Department of Health, Exercise and Sport Sciences, Texas Tech University, Lubbock, Texas, 79409, USA
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Wang JH, Hsu WL, Lee SC, Wang TG, Rolf C, Su SC, Shih TTF, Wang HK. Neuromechanical characteristics in the knees of patients who had primary conservative treatment for a torn cruciate ligament and reconstruction afterward. J Formos Med Assoc 2015; 114:1240-9. [PMID: 25624115 DOI: 10.1016/j.jfma.2014.10.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 10/06/2014] [Accepted: 10/08/2014] [Indexed: 10/24/2022] Open
Abstract
BACKGROUND/PURPOSE To compare the neuromechanical characteristics and subjective outcomes for knees of patients with a cruciate ligament tear and reconstruction with those for knees of controls at three time intervals, and to determine correlations between the characteristics and subjective outcomes. METHODS Ten participants with a cruciate ligament tear and at least a 12-week conservative treatment prior to ligament reconstruction were prospectively measured prior to and 3 months and 6 months after surgery. Ten healthy individuals were recruited as controls. Questionnaire surveys regarding the injured knee were conducted, as were bilateral measurements of root mean square electromyography (EMG), the rate of EMG rise, the median frequency in the vastus medialis of the quadriceps muscles and antagonist coactivation from the semitendinosus muscle, and force capacities, including peak torque, rate of force development, and total works of the knee extension. Correlations between the EMG variables (of the vastus medialis and semitendinosus) and the force capacities, and between the EMG variables and the knee injury and osteoarthritis outcome scores (KOOS), and between force capacities and the KOOS were assessed in the participants with a ligament reconstruction. RESULTS Pre- and postoperative results of EMG variable and force capacities were lower in both knees of the experimental group participants than in the control group participants (all p < 0.05). Correlations between EMG and force capacities, and between these parameters and the KOOS were found. CONCLUSION There were bilateral neuromechanical defects in the knees of the participants who had undergone conservative treatment as well as reconstruction after a cruciate ligament tear.
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Affiliation(s)
- Jyh-Horng Wang
- Department of Orthopedic Surgery, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC; Department of Orthopedic Surgery, National Taiwan University Hospital, Taipei, Taiwan, ROC
| | - Wei-Li Hsu
- School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC; Center of Physical Therapy, National Taiwan University Hospital, Taipei, Taiwan, ROC
| | - Song-Ching Lee
- Department of Physical Medicine & Rehabilitation, National Taiwan University Hospital, Taipei, Taiwan, ROC
| | - Tyng-Guey Wang
- Department of Physical Medicine & Rehabilitation, National Taiwan University Hospital, Taipei, Taiwan, ROC; Department of Rehabilitation, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC
| | - Christer Rolf
- Department of Orthopaedics, Clintec, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Sheng-Chu Su
- Department of Business Administration, Hwa Hsia Institute of Technology, Taipei, Taiwan, ROC
| | - Tiffany T F Shih
- Department of Medical Image, National Taiwan University Hospital, Taipei, Taiwan, ROC; Department of Surgery, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC
| | - Hsing-Kuo Wang
- School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC; Center of Physical Therapy, National Taiwan University Hospital, Taipei, Taiwan, ROC.
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Boccia G, Dardanello D, Rosso V, Pizzigalli L, Rainoldi A. The Application of sEMG in Aging: A Mini Review. Gerontology 2014; 61:477-84. [DOI: 10.1159/000368655] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 09/24/2014] [Indexed: 11/19/2022] Open
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Increase in rate of force development with skin cooling during isometric knee extension. J Electromyogr Kinesiol 2014; 24:895-901. [DOI: 10.1016/j.jelekin.2014.08.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 07/22/2014] [Accepted: 08/15/2014] [Indexed: 11/22/2022] Open
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Buckthorpe M, Erskine RM, Fletcher G, Folland JP. Task-specific neural adaptations to isoinertial resistance training. Scand J Med Sci Sports 2014; 25:640-9. [PMID: 25077768 DOI: 10.1111/sms.12292] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2014] [Indexed: 11/28/2022]
Abstract
This study aimed to delineate the contribution of adaptations in agonist, antagonist, and stabilizer muscle activation to changes in isometric and isoinertial lifting strength after short-term isoinertial resistance training (RT). Following familiarization, 45 men (23.2 ± 2.8 years) performed maximal isometric and isoinertial strength tests of the elbow flexors of their dominant arms before and after 3 weeks of isoinertial RT. During these tasks, surface electromyography (EMG) amplitude was recorded from the agonist (biceps brachii short and long heads), antagonist (triceps brachii lateral head), and stabilizer (anterior deltoid, pectoralis major) muscles and normalized to either Mmax (agonists) or to maximum EMG during relevant reference tasks (antagonist, stabilizers). After training, there was more than a twofold greater increase in training task-specific isoinertial than isometric strength (17% vs 7%). There were also task-specific adaptations in agonist EMG, with greater increases during the isoinertial than isometric strength task [analysis of variance (ANOVA), training × task, P = 0.005]. A novel finding of this study was that training increased stabilizer muscle activation during all the elbow flexion strength tasks (P < 0.001), although these were not task-specific training effects. RT elicited specific neural adaptations to the training task that appeared to explain the greater increase in isoinertial than isometric strength.
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Affiliation(s)
- M Buckthorpe
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK.,Isokinetic Medical Group, London, UK
| | - R M Erskine
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - G Fletcher
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - J P Folland
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
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Thompson BJ, Ryan ED, Herda TJ, Costa PB, Herda AA, Cramer JT. Age-related changes in the rate of muscle activation and rapid force characteristics. AGE (DORDRECHT, NETHERLANDS) 2014; 36:839-49. [PMID: 24338233 PMCID: PMC4039274 DOI: 10.1007/s11357-013-9605-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 11/27/2013] [Indexed: 04/17/2023]
Abstract
Declines in muscle size and strength are commonly reported as a consequence of aging; however, few studies have investigated the influence of aging on the rate of muscle activation and rapid force characteristics across the lifespan. This study aims to investigate the effects of aging on the rate of muscle activation and rapid force characteristics of the plantar flexors. Plantar flexion peak force (PF), absolute (peak, 50, and 100-200 ms), and relative (10 %, 30 %, and 50 %) rate of force development (RFD), the rapid to maximal force ratio (RFD/PF), and the rate of electromyography rise (RER) were examined during an isometric maximal voluntary contraction (MVC) in young (age = 22 ± 2 years), middle-aged (43 ± 2 years), and old (69 ± 5 years) men. The old men exhibited lower PF (30.7 % and 27.6 % lower, respectively) and absolute (24.4-55.1 %) and relative (16.4-28.9 %) RFD values compared to the young and middle-aged men (P ≤ 0.03). RER values were similar between the young and old men (P ≥ 0.30); however, RER values were greater for the middle-aged men when compared to the young and old men for the soleus (P < 0.01) and the old men for the medial gastrocnemius (P ≤ 0.02). Likewise, RFD/PF ratios were similar between young and old men (P ≥ 0.26); however, these ratios were greater for the middle-aged men at early (P ≤ 0.03), but not later (P ≥ 0.10), time intervals. The lower PF and absolute and relative RFD values for the old men may contribute to the increased functional limitations often observed in older adults. Interestingly, higher rates of muscle activation and greater early RFD/PF ratios in middle-aged men may be a reflection of physiological alterations in the neuromuscular system occurring in the fifth decade.
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Affiliation(s)
- Brennan J. Thompson
- />Human Performance Laboratory, Department of Health, Exercise, and Sport Sciences, Texas Tech University, Lubbock, TX USA
| | - Eric D. Ryan
- />Neuromuscular Research Laboratory, Department of Exercise and Sport Science, University of North Carolina – Chapel Hill, 209 Fetzer Hall, Campus Box 8700, Chapel Hill, NC 27599-8700 USA
| | - Trent J. Herda
- />Neuromechanics Laboratory, Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, KS USA
| | - Pablo B. Costa
- />Human Performance Laboratory, Department of Kinesiology, California State University – San Bernardino, San Bernardino, CA USA
| | - Ashley A. Herda
- />Department of Health, Sport & Exercise Science, University of Kansas – Edwards, Overland Park, KS USA
| | - Joel T. Cramer
- />Department of Nutrition and Health Sciences, University of Nebraska – Lincoln, Lincoln, NE USA
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Neuromuscular adaptations following 12-week maximal voluntary co-contraction training. Eur J Appl Physiol 2013; 114:663-73. [DOI: 10.1007/s00421-013-2801-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 12/14/2013] [Indexed: 10/25/2022]
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41
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Maximal and explosive strength training elicit distinct neuromuscular adaptations, specific to the training stimulus. Eur J Appl Physiol 2013; 114:365-74. [DOI: 10.1007/s00421-013-2781-x] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 11/20/2013] [Indexed: 10/26/2022]
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Effects of neuromuscular fatigue on the electromechanical delay of the leg extensors and flexors in young and old men. Eur J Appl Physiol 2013; 113:2391-9. [PMID: 23771530 DOI: 10.1007/s00421-013-2675-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 05/31/2013] [Indexed: 10/26/2022]
Abstract
PURPOSE The purpose of this study was to investigate the effects of a fatigue-inducing bout of submaximal, intermittent isometric contractions on the electromechanical delay (EMD) of the leg extensors and flexors in young and old men. METHODS Twenty young (mean ± SD: age = 25 ± 2.8 years) and sixteen old (age = 70.8 ± 3.8) recreationally active men performed maximal voluntary contractions (MVCs) followed by a fatigue-inducing protocol consisting of intermittent isometric contractions of the leg extensors or flexors using a 0.6 duty cycle (6 s contraction, 4 s relaxation) at 60 % of MVC until volitional fatigue. MVCs were again performed at 0, 7, 15, and 30 min post fatigue. A three-way mixed factorial ANOVA was used to analyze the EMD data. RESULTS There was a two-way muscle × time interaction (P = 0.039) where the EMD of the leg flexors was greater (P = 0.001-0.034) compared with baseline at all post fatigue time periods, but was only greater at immediately post fatigue for the extensors (P = 0.001). A significant two-way interaction for muscle × age (P = 0.009) revealed that the EMD was greater (P = 0.003) for the extensors for the old compared with the young men, but not different for the flexors (P = 0.506). CONCLUSIONS These findings showed differential fatigue-induced EMD recovery patterns between the leg extensors and flexors with the flexors being slower to recover and also that age-related increases of EMD are muscle group specific. The sustained increased EMD of the flexors during recovery may have important injury and performance implications in a variety of populations and settings.
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Allison SJ, Brooke-Wavell K, Folland JP. Multiple joint muscle function with ageing: the force-velocity and power-velocity relationships in young and older men. Aging Clin Exp Res 2013; 25:159-66. [PMID: 23739901 DOI: 10.1007/s40520-013-0024-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 03/08/2012] [Indexed: 12/25/2022]
Abstract
BACKGROUND AND AIMS Whilst extensive research has detailed the loss of muscle strength with ageing for isolated single joint actions, there has been little attention to power production during more functionally relevant multiple joint movements. The extent to which force or velocity are responsible for the loss in power with ageing is also equivocal. The aim of this study was to evaluate the contribution of force and velocity to the differences in power with age by comparing the force-velocity and power-velocity relationships in young and older men during a multiple joint leg press movement. METHODS Twenty-one older men (66 ± 3 years) and twenty-three young men (24 ± 2 years) completed a series of isometric (maximum and explosive) and dynamic contractions on a leg press dynamometer instrumented to record force and displacement. RESULTS The force-velocity relationship was lower for the older men as reflected by their 19 % lower maximum isometric strength (p < 0.001). Explosive isometric strength (peak rate of force development) was 21 % lower for the older men (p < 0.05) but was similar between groups when normalised to maximum strength (p = 0.58). The power-velocity relationship was lower for the older men as shown by reduced maximum power (-28 %, p < 0.001) and lower force (-20 %, p < 0.001) and velocity (-11 %, p < 0.05). CONCLUSIONS Whilst force and velocity were lower in older men, the decrement in force was greater and therefore the major explanation for the attenuation of power during a functionally relevant multiple joint movement.
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Affiliation(s)
- Sarah J Allison
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK.
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Dotan R, Mitchell CJ, Cohen R, Gabriel D, Klentrou P, Falk B. Explosive sport training and torque kinetics in children. Appl Physiol Nutr Metab 2013; 38:740-5. [PMID: 23980732 DOI: 10.1139/apnm-2012-0330] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A high rate of force development (RFD) is often more important than maximal force in daily and sports activities. In children, resistance training has been shown to increase maximal force. It is unclear whether, or to what extent, can children improve RFD and force kinetics. For this study, we compared strength and force kinetics of boy gymnasts with those of untrained boys and untrained men. Eight boy gymnasts (age, 9.5 ± 1.2 y), 20 untrained boys (age, 10.1 ± 1.3 y), and 20 untrained men (age, 22.9 ± 4.4 y) performed maximal, explosive, isometric elbow flexions (EF) and knee flexions (KF). Peak torque (maximal voluntary contraction (MVC)), elapsed times to 10%-100% MVC, peak rate of torque development (RTDpk), and other kinetics parameters were determined. When gymnasts were compared with untrained boys, size-normalized EF MVC was 11%-20% higher, RTDpk was 32% higher, and times to 30% and 80% MVC were 16% and 55% shorter, respectively (p < 0.05). No corresponding differences were observed in KF. Furthermore, although the normalized EF MVC was 28% lower in gymnasts than in men (p < 0.001), their torque kinetics parameters were similar. These findings highlight the specificity of gymnastics training, which markedly elevated the torque kinetics of young, prepubertal boys to adult levels, but only moderately affected peak torque. It is suggested that neurologic adaptations, such as enhanced firing and activation rates or increased type II motor-unit recruitment, as well as changes in musculotendinous stiffness, could explain these findings.
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Affiliation(s)
- Raffy Dotan
- Faculty of Applied Health Sciences, Brock University, 500 Glenridge Ave., St. Catharines, ON L2S 3A1, Canada.
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de Oliveira FBD, Rizatto GF, Denadai BS. Are early and late rate of force development differently influenced by fast-velocity resistance training? Clin Physiol Funct Imaging 2013; 33:282-7. [PMID: 23692617 DOI: 10.1111/cpf.12025] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 12/20/2012] [Indexed: 11/30/2022]
Abstract
This study examined the effect of fast-velocity concentric isokinetic resistance training (FV) on the rate of force development (RFD) at early (<100 ms) and late phases (>100 ms) of rising muscle force. Nine men participated in a 6-week resistance training intervention for the lower body, and nine matched subjects participated as controls (CON). During concentric isokinetic (180°s(-1)) knee extension training, subjects were instructed to do each contraction 'as fast and forcefully as possible'. Maximal muscle strength (MVC) and RFD (0-10, 0-20, …, 0-250 ms from the onset of contraction) were measured during maximal voluntary isometric contraction of the knee extensors (KE). There were no significant changes in MVC of KE in both groups after intervention (FV = 314·2 ± 101·1 versus 338·7 ± 88·0 N∙m, P>0·05; CON = 293·3 ± 94·8 versus 280·0 ± 72·2 N∙m, P>0·05). The RFD increased 39-71% at time intervals up to 90 ms from the onset of the contraction (P<0·05), whereas no change occurred at later time intervals. Similarly, relative RFD (i.e.%MVC∙s(-1)) (RFDr) increased 33-56% at time intervals up to 70 ms from the onset of the contraction (P<0·05). It can be concluded that a short period of resistance training performed with concentric fast-velocity isokinetic muscle contractions is able to enhance RFD and RFDr obtained at the early phase of rising muscle force.
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Dotan R, Mitchell C, Cohen R, Gabriel D, Klentrou P, Falk B. Child-adult differences in the kinetics of torque development. J Sports Sci 2013; 31:945-53. [PMID: 23320937 DOI: 10.1080/02640414.2012.757343] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Children have lower size-normalised maximal voluntary force, speed, and power than adults. It has been hypothesised that these and other age-related performance differences are due to lesser type-II motor-unit utilisation in children. This should be manifested as slower force kinetics in explosive muscle contractions. The purpose of this study was to investigate the nature of child-adult force-kinetics differences and whether the latter could support that hypothesis. Untrained boys (n = 20) and men (n = 20) (10.1 ± 1.3 and 22.9 ± 4.4 years, respectively), performed maximal, explosive, isometric elbow flexions and knee extensions on a Biodex dynamometer. Peak torque (MVC), times to 10-100% MVC, and other kinetics parameters were determined. The boys' body-mass-normalised knee extension MVC, peak rate of torque development, and %MVC at 100 ms were 26, 17 and 23% lower compared with the men and their times to 30% and 80% MVC were 24 and 48% longer, respectively. Elbow flexion kinetics showed similar or greater differences. The findings illuminate boys' inherent disadvantage in tasks requiring speed or explosive force. It is demonstrated that the extent of the boys-men kinetics disparity cannot be explained by muscle-composition and/or musculo-tendinous-stiffness differences. We suggest therefore that the findings indirectly support children's lower utilisation of type-II motor units.
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Affiliation(s)
- Raffy Dotan
- Faculty of Applied Health Sciences, Brock University, St Catharines, Ontario, Canada.
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Tillin NA, Pain MTG, Folland J. Explosive force production during isometric squats correlates with athletic performance in rugby union players. J Sports Sci 2013; 31:66-76. [DOI: 10.1080/02640414.2012.720704] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Un CP, Lin KH, Shiang TY, Chang EC, Su SC, Wang HK. Comparative and reliability studies of neuromechanical leg muscle performances of volleyball athletes in different divisions. Eur J Appl Physiol 2012; 113:457-66. [DOI: 10.1007/s00421-012-2454-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Accepted: 06/28/2012] [Indexed: 10/27/2022]
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Gurjão ALD, Gobbi LTB, Carneiro NH, Gonçalves R, Ferreira de Moura R, Cyrino ES, Altimari LR, Gobbi S. Effect of strength training on rate of force development in older women. RESEARCH QUARTERLY FOR EXERCISE AND SPORT 2012; 83:268-75. [PMID: 22808712 DOI: 10.1080/02701367.2012.10599857] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We analyzed the effect of an 8-week strength training (ST) program on the rate of force development (RFD) and electromyographic activity (EMG) in older women. Seventeen women (M age = 63.4 years, SD = 4.9) without previous ST experience were randomly assigned to either a control (n=7) or training (n=10) group. A leg-press isometric test was used for assessment. ST (three sessions/ week, three sets of 10-12 repetition maximum, five different exercises) induced significant increases (p < .05) on peak RPD (48.4%) and on RFD) and EMG of vastus medialis at time intervals of 0-50, 0-100, 0-150, and 0-200 ms (41.1-69.2% and 43.8-64.3%, respectively). Therefore, ST resulted in favorable changes in neuromuscular responses in older women.
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Tillin NA, Pain MTG, Folland JP. Short-term training for explosive strength causes neural and mechanical adaptations. Exp Physiol 2012; 97:630-41. [DOI: 10.1113/expphysiol.2011.063040] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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