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Gallardo P, Giakas G, Sakkas GK, Tsaklis PV. Are Surface Electromyography Parameters Indicative of Post-Activation Potentiation/Post-Activation Performance Enhancement, in Terms of Twitch Potentiation and Voluntary Performance? A Systematic Review. J Funct Morphol Kinesiol 2024; 9:106. [PMID: 38921642 PMCID: PMC11205249 DOI: 10.3390/jfmk9020106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 06/06/2024] [Accepted: 06/10/2024] [Indexed: 06/27/2024] Open
Abstract
The aim was to identify if surface electromyography (sEMG) parameters are indicative of post-activation potentiation (PAP)/post-activation performance enhancement (PAPE), in terms of twitch potentiation and voluntary performance. Three databases were used in April 2024, with the following inclusion criteria: (a) original research, assessed in healthy human adults, and (b) sEMG parameters were measured. The exclusion criteria were (a) studies with no PAP/PAPE protocol and (b) non-randomized control trials. The following data were extracted: study characteristics/demographics, PAP/PAPE protocols, sEMG parameters, twitch/performance outcomes, and study findings. A modified physiotherapy evidence database (PEDro) scale was used for quality assessment. Fifteen randomized controlled trials (RCTs), with a total of 199 subjects, were included. The M-wave amplitude (combined with a twitch torque outcome) was shown to generally be indicative of PAP. The sEMG amplitudes (in some muscles) were found to be indicative of PAPE during ballistic movements, while a small decrease in the MdF (in certain muscles) was shown to reflect PAPE. Changes in the Hmax/Mmax ratio were found to contribute (temporally) to PAP, while the H-reflex amplitude was shown to be neither indicative of PAP nor PAPE. This review provides preliminary findings suggesting that certain sEMG parameters could be indicative of PAP/PAPE. However, due to limited studies, future research is warranted.
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Affiliation(s)
- Philip Gallardo
- Department of Physical Education and Sport Science, ErgoMech-Lab, University of Thessaly, 421 00 Trikala, Greece; (P.G.); (G.G.); (G.K.S.)
| | - Giannis Giakas
- Department of Physical Education and Sport Science, ErgoMech-Lab, University of Thessaly, 421 00 Trikala, Greece; (P.G.); (G.G.); (G.K.S.)
| | - Giorgos K. Sakkas
- Department of Physical Education and Sport Science, ErgoMech-Lab, University of Thessaly, 421 00 Trikala, Greece; (P.G.); (G.G.); (G.K.S.)
| | - Panagiotis V. Tsaklis
- Department of Physical Education and Sport Science, ErgoMech-Lab, University of Thessaly, 421 00 Trikala, Greece; (P.G.); (G.G.); (G.K.S.)
- Department Molecular Medicine and Surgery, Growth and Metabolism, Karolinska Institute, 171 77 Solna, Sweden
- Center of Orthopaedics and Regenerative Medicine (C.O.RE.)/(C.I.R.I.), Aristotle University Thessaloniki, 541 24 Thessaloniki, Greece
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Sergeeva XV, Lvova ID, Sharlo KA. Disuse-Induced Muscle Fatigue: Facts and Assumptions. Int J Mol Sci 2024; 25:4984. [PMID: 38732203 PMCID: PMC11084575 DOI: 10.3390/ijms25094984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Revised: 04/26/2024] [Accepted: 04/29/2024] [Indexed: 05/13/2024] Open
Abstract
Skeletal muscle unloading occurs during a wide range of conditions, from space flight to bed rest. The unloaded muscle undergoes negative functional changes, which include increased fatigue. The mechanisms of unloading-induced fatigue are far from complete understanding and cannot be explained by muscle atrophy only. In this review, we summarize the data concerning unloading-induced fatigue in different muscles and different unloading models and provide several potential mechanisms of unloading-induced fatigue based on recent experimental data. The unloading-induced changes leading to increased fatigue include both neurobiological and intramuscular processes. The development of intramuscular fatigue seems to be mainly contributed by the transformation of soleus muscle fibers from a fatigue-resistant, "oxidative" "slow" phenotype to a "fast" "glycolytic" one. This process includes slow-to-fast fiber-type shift and mitochondrial density decline, as well as the disruption of activating signaling interconnections between slow-type myosin expression and mitochondrial biogenesis. A vast pool of relevant literature suggests that these events are triggered by the inactivation of muscle fibers in the early stages of muscle unloading, leading to the accumulation of high-energy phosphates and calcium ions in the myoplasm, as well as NO decrease. Disturbance of these secondary messengers leads to structural changes in muscles that, in turn, cause increased fatigue.
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Affiliation(s)
| | | | - Kristina A. Sharlo
- Institute of Biomedical Problems, RAS, Khorosevskoye Shosse, 76a, 123007 Moscow, Russia; (X.V.S.); (I.D.L.)
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Zhan J, Yu C, Xiao S, Shen B, Zhang C, Zhou J, Fu W. Effects of high-definition transcranial direct current stimulation on the cortical-muscular functional coupling and muscular activities of ankle dorsi-plantarflexion under running-induced fatigue. Front Physiol 2023; 14:1263309. [PMID: 37841316 PMCID: PMC10570418 DOI: 10.3389/fphys.2023.1263309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 09/22/2023] [Indexed: 10/17/2023] Open
Abstract
Transcranial direct current stimulation (tDCS) can improve motor control performance under fatigue. However, the influences of tDCS on factors contributing to motor control (e.g., cortical-muscular functional coupling, CMFC) are unclear. This double-blinded and randomized study examined the effects of high-definition tDCS (HD-tDCS) on muscular activities of dorsiflexors and plantarflexors and CMFC when performing ankle dorsi-plantarflexion under fatigue. Twenty-four male adults were randomly assigned to receive five sessions of 20-min HD-tDCS targeting primary motor cortex (M1) or sham stimulation. Three days before and 1 day after the intervention, participants completed ankle dorsi-plantarflexion under fatigue induced by prolonged running exercise. During the task, electroencephalography (EEG) of M1 (e.g., C1, Cz) and surface electromyography (sEMG) of several muscles (e.g., tibialis anterior [TA]) were recorded synchronously. The corticomuscular coherence (CMC), root mean square (RMS) of sEMG, blood lactate, and maximal voluntary isometric contraction (MVC) of ankle dorsiflexors and plantarflexors were obtained. Before stimulation, greater beta- and gamma-band CMC between M1 and TA were significantly associated with greater RMS of TA (r = 0.460-0.619, p = 0.001-0.024). The beta- and gamma-band CMC of C1-TA and Cz-TA, and RMS of TA and MVC torque of dorsiflexors were significantly higher after HD-tDCS than those at pre-intervention in the HD-tDCS group and post-intervention in the control group (p = 0.002-0.046). However, the HD-tDCS-induced changes in CMC and muscle activities were not significantly associated (r = 0.050-0.128, p = 0.693-0.878). HD-tDCS applied over M1 can enhance the muscular activities of ankle dorsiflexion under fatigue and related CMFC.
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Affiliation(s)
- Jianglong Zhan
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Changxiao Yu
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Songlin Xiao
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Bin Shen
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Chuyi Zhang
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Junhong Zhou
- The Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife, Boston, MA, United States
- Harvard Medical School, Boston, MA, United States
| | - Weijie Fu
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, School of Exercise and Health, Shanghai University of Sport, Shanghai, China
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Apte S, Prigent G, Stöggl T, Martínez A, Snyder C, Gremeaux-Bader V, Aminian K. Biomechanical Response of the Lower Extremity to Running-Induced Acute Fatigue: A Systematic Review. Front Physiol 2021; 12:646042. [PMID: 34512370 PMCID: PMC8430259 DOI: 10.3389/fphys.2021.646042] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 06/22/2021] [Indexed: 12/02/2022] Open
Abstract
Objective: To investigate (i) typical protocols used in research on biomechanical response to running-induced fatigue, (ii) the effect of sport-induced acute fatigue on the biomechanics of running and functional tests, and (iii) the consistency of analyzed parameter trends across different protocols. Methods: Scopus, Web of Science, Pubmed, and IEEE databases were searched using terms identified with the Population, Interest and Context (PiCo) framework. Studies were screened following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and appraised using the methodological index for non-randomized studies MINORS scale. Only experimental studies with at least 10 participants, which evaluated fatigue during and immediately after the fatiguing run were included. Each study was summarized to record information about the protocol and parameter trends. Summary trends were computed for each parameter based on the results found in individual studies. Results: Of the 68 included studies, most were based on in-lab (77.9%) protocols, endpoint measurements (75%), stationary measurement systems (76.5%), and treadmill environment (54.4%) for running. From the 42 parameters identified in response to acute fatigue, flight time, contact time, knee flexion angle at initial contact, trunk flexion angle, peak tibial acceleration, CoP velocity during balance test showed an increasing behavior and cadence, vertical stiffness, knee extension force during MVC, maximum vertical ground reaction forces, and CMJ height showed a decreasing trend across different fatigue protocols. Conclusion: This review presents evidence that running-induced acute fatigue influences almost all the included biomechanical parameters, with crucial influence from the exercise intensity and the testing environment. Results indicate an important gap in literature caused by the lack of field studies with continuous measurement during outdoor running activities. To address this gap, we propose recommendations for the use of wearable inertial sensors.
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Affiliation(s)
- Salil Apte
- Laboratory of Movement Analysis and Measurement, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Gäelle Prigent
- Laboratory of Movement Analysis and Measurement, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Thomas Stöggl
- Department of Sport and Exercise Science, University of Salzburg, Salzburg, Austria
| | - Aaron Martínez
- Department of Sport and Exercise Science, University of Salzburg, Salzburg, Austria
| | - Cory Snyder
- Department of Sport and Exercise Science, University of Salzburg, Salzburg, Austria
| | - Vincent Gremeaux-Bader
- Institute of Sport Sciences, University of Lausanne,Lausanne, Switzerland.,Swiss Olympic Medical Center, Sport Medicine Unit, Division of Physical Medicine and Rehabilitation, Lausanne University Hospital, Lausanne, Switzerland
| | - Kamiar Aminian
- Laboratory of Movement Analysis and Measurement, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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The Effects of Nicotine on Cortical Excitability After Exercise: A Double-Blind Randomized, Placebo-controlled, Crossover Study. J Clin Psychopharmacol 2021; 40:495-498. [PMID: 32701900 DOI: 10.1097/jcp.0000000000001246] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE The use of smokeless tobacco/nicotine products is common among athletes, but clear evidence for their positive or negative effect on sports performance is lacking. Nicotine is a psychoactive substance involved in numerous neuronal processes including cortical excitability. The aim of this study was to evaluate its effect on cortical excitability associated with aerobic exercise in nicotine-naive healthy volunteers. METHODS Ten nicotine-naive healthy volunteers were recruited for this double-blind, randomized, crossover study to compare the effect of snus (8 mg nicotine), an oral, smokeless tobacco product, to placebo on cortical excitability before and after aerobic exercise. Transcranial magnetic stimulation (TMS) was used to measure changes in corticomotor excitability (motor-evoked potentials, MEPs) and electromyography of leg muscles during maximal voluntary contractions (MVC) to assess changes in muscle contractions. Before and after aerobic exercise and with or without nicotine treatment, MEPs and MVCs were measured. RESULTS Analysis of TMS data showed lower motor cortex activation (lower MEP amplitude) after snus administration compared with placebo, whereas electromyography data showed no difference in muscle contraction between snus and placebo treatment. CONCLUSIONS These findings suggest a general reduction in cortical excitability, without no relevant effect on physical performance.
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Brownstein CG, Millet GY, Thomas K. Neuromuscular responses to fatiguing locomotor exercise. Acta Physiol (Oxf) 2021; 231:e13533. [PMID: 32627930 DOI: 10.1111/apha.13533] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/26/2020] [Accepted: 06/29/2020] [Indexed: 12/26/2022]
Abstract
Over the last two decades, an abundance of research has explored the impact of fatiguing locomotor exercise on the neuromuscular system. Neurostimulation techniques have been implemented prior to and following locomotor exercise tasks of a wide variety of intensities, durations, and modes. These techniques have allowed for the assessment of alterations occurring within the central nervous system and the muscle, while techniques such as transcranial magnetic stimulation and spinal electrical stimulation have permitted further segmentalization of locomotor exercise-induced changes along the motor pathway. To this end, the present review provides a comprehensive synopsis of the literature pertaining to neuromuscular responses to locomotor exercise. Sections of the review were divided to discuss neuromuscular responses to maximal, severe, heavy and moderate intensity, high-intensity intermittent exercise, and differences in neuromuscular responses between exercise modalities. During maximal and severe intensity exercise, alterations in neuromuscular function reside primarily within the muscle. Although post-exercise reductions in voluntary activation following maximal and severe intensity exercise are generally modest, several studies have observed alterations occurring at the cortical and/or spinal level. During prolonged heavy and moderate intensity exercise, impairments in contractile function are attenuated with respect to severe intensity exercise, but are still widely observed. While reductions in voluntary activation are greater during heavy and moderate intensity exercise, the specific alterations occurring within the central nervous system remain unclear. Further work utilizing stimulation techniques during exercise and integrating new and emerging techniques such as high-density electromyography is warranted to provide further insight into neuromuscular responses to locomotor exercise.
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Affiliation(s)
- Callum G. Brownstein
- Inter‐University Laboratory of Human Movement Biology Université LyonUJM‐Saint‐Etienne Saint‐Etienne France
| | - Guillaume Y. Millet
- Inter‐University Laboratory of Human Movement Biology Université LyonUJM‐Saint‐Etienne Saint‐Etienne France
- Institut Universitaire de France (IUF) France
| | - Kevin Thomas
- Faculty of Health and Life Sciences Northumbria University Newcastle upon Tyne United Kingdom
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Espeit L, Brownstein CG, Royer N, Besson T, Martin V, Millet GY, Lapole T. Central fatigue aetiology in prolonged trail running races. Exp Physiol 2021; 106:663-672. [DOI: 10.1113/ep089177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 01/05/2021] [Indexed: 01/15/2023]
Affiliation(s)
- Loic Espeit
- Univ Lyon UJM‐Saint‐Etienne Inter‐university Laboratory of Human Movement Biology EA 7424 Saint‐Etienne F‐42023 France
| | - Callum G Brownstein
- Univ Lyon UJM‐Saint‐Etienne Inter‐university Laboratory of Human Movement Biology EA 7424 Saint‐Etienne F‐42023 France
| | - Nicolas Royer
- Univ Lyon UJM‐Saint‐Etienne Inter‐university Laboratory of Human Movement Biology EA 7424 Saint‐Etienne F‐42023 France
| | - Thibault Besson
- Univ Lyon UJM‐Saint‐Etienne Inter‐university Laboratory of Human Movement Biology EA 7424 Saint‐Etienne F‐42023 France
| | - Vincent Martin
- Clermont‐Auvergne University AME2P Clermont‐Ferrand 63000 France
- Institut Universitaire de France (IUF) France
| | - Guillaume Y Millet
- Univ Lyon UJM‐Saint‐Etienne Inter‐university Laboratory of Human Movement Biology EA 7424 Saint‐Etienne F‐42023 France
- Institut Universitaire de France (IUF) France
| | - Thomas Lapole
- Univ Lyon UJM‐Saint‐Etienne Inter‐university Laboratory of Human Movement Biology EA 7424 Saint‐Etienne F‐42023 France
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8
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Newell ML, Macgregor LJ, Galloway SDR, Hunter AM. Prolonged cycling exercise alters neural control strategy, irrespective of carbohydrate dose ingested. TRANSLATIONAL SPORTS MEDICINE 2021. [DOI: 10.1002/tsm2.187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Michael L. Newell
- School of Sport Science and Physical Activity University of Bedfordshire Bedford England UK
| | - Lewis J. Macgregor
- Faculty of Health Sciences and Sport University of Stirling Stirling Scotland UK
| | | | - Angus M. Hunter
- Faculty of Health Sciences and Sport University of Stirling Stirling Scotland UK
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9
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What are the Limiting Factors During an Ultra-Marathon? A Systematic Review of the Scientific Literature. J Hum Kinet 2020; 72:129-139. [PMID: 32269654 PMCID: PMC7126261 DOI: 10.2478/hukin-2019-0102] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This review aimed to analyse factors that limited performance in ultra-marathons and mountain ultra-marathons. A literature search in one database (PubMed) was conducted in February 2019. Quality of information of the articles was evaluated using the Oxford´s level of evidence and the Physiotherapy Evidence Database (PEDro) scale. The search strategy yielded 111 total citations from which 23 met the inclusion criteria. Twenty one of the 23 included studies had a level of evidence 2b (individual cohort study), while the 2 remaining studies had a level of evidence of 5 (expert opinion). Also, the mean score in the PEDro scale was 3.65 ± 1.61, with values ranging from 0 to 7. Participants were characterised as experienced or well-trained athletes in all of the studies. The total number of participants was 1002 (893 men, 86 women and 23 unknown). The findings of this review suggest that fatigue in ultra-endurance events is a multifactorial phenomenon that includes physiological, neuromuscular, biomechanical and cognitive factors. Improved exercise performance during ultra-endurance events seems to be related to higher VO2max values and maximal aerobic speed (especially during submaximal efforts sustained over a long time), lower oxygen cost of transport and greater running experience.
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10
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Mtibaa K, Zarrouk N, Girard O, Ryu JH, Hautier C, Racinais S. Heat stress impairs proprioception but not running mechanics. J Sci Med Sport 2019; 22:1361-1366. [PMID: 31444035 DOI: 10.1016/j.jsams.2019.07.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 07/14/2019] [Accepted: 07/19/2019] [Indexed: 11/19/2022]
Abstract
OBJECTIVES To determine the effects of heat stress on ankle proprioception and running gait pattern. DESIGN Counterbalanced repeated measures. METHODS 12 trained runners performed a proprioception test (active movement discrimination) before and immediately after a 30min, self-paced treadmill run in HOT (39°C) and COOL (22°C) ambient conditions. Velocity was imposed during the first and last minute (70% of maximal aerobic velocity, 13.3±0.8kmh-1) for determination of running mechanics and spring-mass characteristics. RESULTS Rectal (39.7±0.4 vs. 39.4±0.4°C), skin (36.3±1.1 vs. 31.8±1.1°C) and average body (38.3±0.2 vs. 36.4±0.4°C) temperatures together with heart rate (178±8 vs. 174±6bpm) and thermal discomfort (6.5±0.5 vs. 4.3±1.3) were all higher at the end of the HOT compared to COOL run (all p<0.05). Distance covered was lower in HOT than COOL (-5.1±3.6%, p<0.001). Average error during the proprioception test increased after running in HOT (+11%, p<0.05) but not in COOL (-2%). There was no significant difference for most segmental and joint angles at heel contact, except for a global increase in pelvis retroversion and decrease in ankle dorsi-flexion angles with time (p<0.05). Step frequency decreased (-2.5±3.6%) and step length increased (+2.6±3.8%) over time (p<0.05), independently of condition. Spring-mass characteristics remained unchanged (all p>0.05). CONCLUSIONS Heat stress exacerbates thermal, cardiovascular and perceptual responses, while running velocity was slower during a 30min self-paced treadmill run. Heat stress also impairs ankle proprioception during an active movement discrimination task, but it has no influence on gait pattern assessed at a constant, sub-maximal velocity.
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Affiliation(s)
- Khouloud Mtibaa
- Qatar University, Sports Science Program, College of Arts and Sciences, Doha, Qatar; Inter-university Laboratory of Human Movement Biology (EA 7424), Claude Bernard University Lyon 1, Lyon, France
| | - Nidhal Zarrouk
- Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - Olivier Girard
- Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar; Murdoch Applied Sports Science (MASS) Laboratory, Murdoch University, Perth, Australia
| | | | - Christophe Hautier
- Inter-university Laboratory of Human Movement Biology (EA 7424), Claude Bernard University Lyon 1, Lyon, France
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11
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Garnier YM, Paizis C, Martin A, Lepers R. Corticospinal excitability changes following downhill and uphill walking. Exp Brain Res 2019; 237:2023-2033. [PMID: 31165178 DOI: 10.1007/s00221-019-05576-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 06/01/2019] [Indexed: 11/30/2022]
Abstract
Locomotor exercise may induce corticospinal excitability and/or cortical inhibition change in the knee extensors. This study investigated whether the mode of muscle contraction involved during a locomotor exercise modulates corticospinal and intracortical responsiveness. Eleven subjects performed two 45-min treadmill walking exercises in an uphill (+ 15%) or a downhill (- 15%) condition matched for speed. Maximal voluntary isometric torque (MVIC), voluntary activation level (VAL), doublet (Dt) twitch torque, and M-wave area of the knee extensors were assessed before and after exercise. At the same time-points, motor-evoked potential (MEP), cortical silent period (CSP), and short-interval cortical inhibition (SICI) were recorded in the vastus lateralis (VL) and rectus femoris (RF) muscles. After exercise, uphill and downhill conditions induced a similar loss in MVIC torque (- 9%; p < 0.001), reduction in VAL (- 7%; p < 0.001), and in M-wave area in the VL muscle (- 8%; p < 0.001). Dt twitch torque decreased only after the downhill exercise (- 11%; p < 0.001). MEP area of the VL muscle increased after the downhill condition (p = 0.007), with no change after the uphill condition. MEP area of the RF muscle remained stable after exercises. CSP and SICI did not change in the two conditions for both muscles. Downhill walking induces an increase in MEP area of the VL muscle, with no change of the CSP duration or SICI ratio. The eccentric mode of muscle contraction during a locomotor exercise can modulate specifically corticospinal excitability in the knee extensors.
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Affiliation(s)
- Yoann M Garnier
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, Faculty of Sport Sciences, BP 27 877, 21000, Dijon, France.
| | - Christos Paizis
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, Faculty of Sport Sciences, BP 27 877, 21000, Dijon, France.,Centre for Performance Expertise, Université Bourgogne Franche-Comté, Faculty of Sport Sciences, 21000, Dijon, France
| | - Alain Martin
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, Faculty of Sport Sciences, BP 27 877, 21000, Dijon, France
| | - Romuald Lepers
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, Faculty of Sport Sciences, BP 27 877, 21000, Dijon, France
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12
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Piirainen JM, Rautio T, Tanskanen-Tervo MM, Kyröläinen H, Huovinen J, Linnamo V. Effects of 10 weeks of military training on neuromuscular function in non-overreached and overreached conscripts. J Electromyogr Kinesiol 2019; 47:43-48. [PMID: 31108348 DOI: 10.1016/j.jelekin.2019.05.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 04/26/2019] [Accepted: 05/10/2019] [Indexed: 11/26/2022] Open
Abstract
The purpose of the study was to examine how military training influences neuromuscular function in non-overreached and overreached conscripts. A total of 24 male conscripts participated in the study (8 weeks basic training + 2 weeks specialized training). All measurements were conducted during weeks 1, 5, 8 and 10. After the training period, non-overreached (NOR, n = 16) and overreached (OR, n = 8) groups were compared. Isometric maximal forces (bench press, elbow flexion and knee extension), single twitch (plantar flexors), H-reflex, M-wave (Hmax/Mmax) and V-wave (V/Mmax) (soleus) were measured. In knee extension, force production increased in NOR by 22.5 ± 20.5% (p < 0.01) between weeks 1 and 8, which was not observed in OR (-1.1 ± 18.2%, p > 0.05). In OR, plantarflexion twitch contraction time increased between weeks 5 and 10 by 82.2 ± 34.4% (p < 0.01), which was not observed in NOR. No changes were observed in the H-reflex and V-wave responses in either of the groups. In conclusion, short term overreaching can also reduce the performance of the neuromuscular system, however, it seems to be more muscle than neural based. To avoid overreaching, more individualized periodization should be used during basic training. To enhance neuromuscular performance, maximal and explosive strength training should also be added into the basic training program.
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Affiliation(s)
- J M Piirainen
- Neuromuscular Research Center, Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, Finland.
| | - T Rautio
- Neuromuscular Research Center, Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, Finland
| | - M M Tanskanen-Tervo
- Neuromuscular Research Center, Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, Finland
| | - H Kyröläinen
- Neuromuscular Research Center, Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, Finland
| | - J Huovinen
- Neuromuscular Research Center, Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, Finland
| | - V Linnamo
- Neuromuscular Research Center, Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, Finland
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13
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Pearcey GEP, Noble SA, Munro B, Zehr EP. Spinal Cord Excitability and Sprint Performance Are Enhanced by Sensory Stimulation During Cycling. Front Hum Neurosci 2017; 11:612. [PMID: 29326570 PMCID: PMC5741677 DOI: 10.3389/fnhum.2017.00612] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 12/04/2017] [Indexed: 12/18/2022] Open
Abstract
Spinal cord excitability, as assessed by modulation of Hoffmann (H-) reflexes, is reduced with fatiguing isometric contractions. Furthermore, spinal cord excitability is reduced during non-fatiguing arm and leg cycling. Presynaptic inhibition of Ia terminals is believed to contribute to this suppression of spinal cord excitability. Electrical stimulation to cutaneous nerves reduces Ia presynaptic inhibition, which facilitates spinal cord excitability, and this facilitation is present during arm cycling. Although it has been suggested that reducing presynaptic inhibition may prolong fatiguing contractions, it is unknown whether sensory stimulation can alter the effects of fatiguing exercise on performance or spinal cord excitability. Thus, the aim of this experiment was to determine if sensory stimulation can interfere with fatigue-related suppression of spinal cord excitability, and alter fatigue rates during cycling sprints. Thirteen participants randomly performed three experimental sessions that included: unloaded cycling with sensory stimulation (CONTROL + STIM), sprints with sensory stimulation (SPRINT + STIM) and sprints without stimulation (SPRINT). Seven participants also performed a fourth session (CONTROL), which consisted of unloaded cycling. During SPRINT and SPRINT + STIM, participants performed seven, 10 s cycling sprints interleaved with 3 min rest. For CONTROL and CONTROL + STIM, participants performed unloaded cycling for ~30 min. During SPRINT + STIM and CONTROL + STIM, participants received patterned sensory stimulation to nerves of the right foot. H-reflexes and M-waves of the right soleus were evoked by stimulation of the tibial nerve at multiple time points throughout exercise. Sensory stimulation facilitated soleus H-reflexes during unloaded cycling, whereas sprints suppressed soleus H-reflexes. While receiving sensory stimulation, there was less suppression of soleus H-reflexes and slowed reduction in average power output, compared to sprints without stimulation. These results demonstrate that sensory stimulation can substantially mitigate the fatiguing effects of sprints.
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Affiliation(s)
- Gregory E P Pearcey
- Rehabilitation Neuroscience Laboratory, University of Victoria, Victoria, BC, Canada.,Human Discovery Science, International Collaboration on Repair Discoveries (ICORD), Vancouver, BC, Canada.,Centre for Biomedical Research, University of Victoria, Victoria, BC, Canada
| | - Steven A Noble
- Rehabilitation Neuroscience Laboratory, University of Victoria, Victoria, BC, Canada.,Human Discovery Science, International Collaboration on Repair Discoveries (ICORD), Vancouver, BC, Canada.,Centre for Biomedical Research, University of Victoria, Victoria, BC, Canada
| | - Bridget Munro
- Nike Exploration Team Sport Research Laboratory, Nike Inc., Beaverton, OR, United States
| | - E Paul Zehr
- Rehabilitation Neuroscience Laboratory, University of Victoria, Victoria, BC, Canada.,Human Discovery Science, International Collaboration on Repair Discoveries (ICORD), Vancouver, BC, Canada.,Centre for Biomedical Research, University of Victoria, Victoria, BC, Canada.,Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
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Ansdell P, Dekerle J. Sodium Bicarbonate Supplementation Delays Neuromuscular Fatigue Without Changes in Performance Outcomes During a Basketball Match Simulation Protocol. J Strength Cond Res 2017; 34:1369-1375. [PMID: 29023327 DOI: 10.1519/jsc.0000000000002233] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Ansdell, P and Dekerle, J. Sodium bicarbonate supplementation delays neuromuscular fatigue without changes in performance outcomes during a basketball match simulation protocol. J Strength Cond Res 34(5): 1369-1375, 2020-To investigate the development of neuromuscular fatigue during a basketball game simulation and to ascertain whether sodium bicarbonate (NaHCO3) supplementation attenuates any neuromuscular fatigue that persists. Ten participants ingested 0.2 g·kg of NaHCO3 (or an equimolar placebo dosage of sodium chloride [NaCl]) 90 and 60 minutes before commencing a basketball game simulation (ALK-T vs. PLA-T). Maximal voluntary isometric contractions (MVICs) of the knee extensors and potentiated high- (100 Hz) and low- (10 Hz) frequency doublet twitches were recorded before and after each match quarter for both trials. In addition, 15-m sprint times and layup completion (%) were recorded during each quarter. Maximal voluntary isometric contraction, 100- and 10-Hz twitch forces declined progressively in both trials (p ≤ 0.05) with a less pronounced decrease in MVIC during ALK-T (p < 0.01). Both 100- and 10-Hz twitch forces were also significantly greater in ALK-T (p ≤ 0.05). Fifteen-meter sprint time increased over the course of both trials (∼2%, p < 0.01); however, no significant condition or time effect was found for layup completion (p > 0.05). A basketball simulation protocol induces a substantial amount of neuromuscular (reduction in knee extensor MVICs) and peripheral fatigue with a concomitant increase in 15-m sprint time over the protocol. NaHCO3 supplementation attenuated the rate of fatigue development by protecting contractile elements of the muscle fibers. This study provides coaches with information about the magnitude of fatigue induced by a simulated basketball game and provides evidence of the efficacy of NaHCO3 in attenuating fatigue.
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Affiliation(s)
- Paul Ansdell
- Sport, Exercise Science and Medicine (SESAME), University of Brighton, Eastbourne, United Kingdom; and.,Faculty of Health and Life Sciences, Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle, United Kingdom
| | - Jeanne Dekerle
- Sport, Exercise Science and Medicine (SESAME), University of Brighton, Eastbourne, United Kingdom; and
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Suruagy I, Baltar A, Gomes LP, Berenguer M, Dornelas A, Monte-Silva K. Intensity-dependent effects of cycling exercise on corticospinal excitability in healthy humans: a pilot study. MOTRIZ: REVISTA DE EDUCACAO FISICA 2017. [DOI: 10.1590/s1980-6574201700020002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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16
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Carroll TJ, Taylor JL, Gandevia SC. Recovery of central and peripheral neuromuscular fatigue after exercise. J Appl Physiol (1985) 2017; 122:1068-1076. [DOI: 10.1152/japplphysiol.00775.2016] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 12/02/2016] [Accepted: 12/02/2016] [Indexed: 12/29/2022] Open
Abstract
Sustained physical exercise leads to a reduced capacity to produce voluntary force that typically outlasts the exercise bout. This “fatigue” can be due both to impaired muscle function, termed “peripheral fatigue,” and a reduction in the capacity of the central nervous system to activate muscles, termed “central fatigue.” In this review we consider the factors that determine the recovery of voluntary force generating capacity after various types of exercise. After brief, high-intensity exercise there is typically a rapid restitution of force that is due to recovery of central fatigue (typically within 2 min) and aspects of peripheral fatigue associated with excitation-contraction coupling and reperfusion of muscles (typically within 3–5 min). Complete recovery of muscle function may be incomplete for some hours, however, due to prolonged impairment in intracellular Ca2+ release or sensitivity. After low-intensity exercise of long duration, voluntary force typically shows rapid, partial, recovery within the first few minutes, due largely to recovery of the central, neural component. However, the ability to voluntarily activate muscles may not recover completely within 30 min after exercise. Recovery of peripheral fatigue contributes comparatively little to the fast initial force restitution and is typically incomplete for at least 20–30 min. Work remains to identify what factors underlie the prolonged central fatigue that usually accompanies long-duration single joint and locomotor exercise and to document how the time course of neuromuscular recovery is affected by exercise intensity and duration in locomotor exercise. Such information could be useful to enhance rehabilitation and sports performance.
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Affiliation(s)
- T. J. Carroll
- Centre for Sensorimotor Performance, School of Human Movement and Nutrition Sciences, University of Queensland; and
| | - J. L. Taylor
- Neuroscience Research Australia and University of New South Wales
| | - S. C. Gandevia
- Neuroscience Research Australia and University of New South Wales
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Girard O, Nybo L, Mohr M, Racinais S. Plantar flexor neuromuscular adjustments following match-play football in hot and cool conditions. Scand J Med Sci Sports 2016; 25 Suppl 1:154-63. [PMID: 25943666 DOI: 10.1111/sms.12371] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2014] [Indexed: 11/29/2022]
Abstract
We assessed neuromuscular fatigue and recovery of the plantar flexors after playing football with or without severe heat stress. Neuromuscular characteristics of the plantar flexors were assessed in 17 male players at baseline and ∼30 min, 24, and 48 h after two 90-min football matches in temperate (∼20 °C and 55% rH) and hot (∼43 °C and 20% rH) environments. Measurements included maximal voluntary strength, muscle activation, twitch contractile properties, and rate of torque development and soleus EMG (i.e., root mean square activity) rise from 0 to 30, -50, -100, and -200 ms during maximal isometric contractions for plantar flexors. Voluntary activation and peak twitch torque were equally reduced (-1.5% and -16.5%, respectively; P < 0.05) post-matches relative to baseline in both conditions, the latter persisting for at least 48 h, whereas strength losses (∼5%) were not significant. Absolute explosive force production declined (P < 0.05) 30 ms after contraction onset independently of condition, with no change at any other epochs. Globally, normalized rate of force development and soleus EMG activity rise values remained unchanged. In football, match-induced alterations in maximal and rapid torque production capacities of the plantar flexors are moderate and do not differ after competing in temperate and hot environments.
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Affiliation(s)
- O Girard
- Aspetar Orthopaedic and Sports Medicine Hospital, Athlete Health and Performance Research Centre, Doha, Qatar; ISSUL, Institute of Sport Sciences, Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
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García-Pinillos F, Soto-Hermoso VM, Latorre-Román PA. Acute effects of extended interval training on countermovement jump and handgrip strength performance in endurance athletes: postactivation potentiation. J Strength Cond Res 2015; 29:11-21. [PMID: 25532430 DOI: 10.1519/jsc.0000000000000591] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The purpose of this study was to analyze multiple effects of an extended interval training (EIT) protocol on countermovement jump (CMJ) and handgrip strength in endurance athletes and to determine the relationship between fatigue and potentiation. Thirty experienced sub-elite male long-distance runners (age = 28.26 ± 8.27 years, body mass index = 22.24 ± 2.50 kg·m, and (Equation is included in full-text article.)= 58.7 ± 4.50 ml·kg·min) participated voluntarily in this study. Subjects performed the protocol on an outdoor running track, which consisted of 12 runs of 400 m, grouped into 4 sets of 3 runs, with a passive recovery of 1 minute between runs and 3 minutes between sets (4 × 3 × 400 m). During protocol, fatigue parameters (lactate, heart rate, and rate of perceived exertion) and performance parameters (CMJ, handgrip strength, and time spent in each 400-m run) were controlled. Analysis of variance revealed a significant improvement in CMJ (p < 0.001) throughout the protocol. Cluster analysis grouped according to whether potentiation was experienced (responders group, n = 17) or not (nonresponders group, n = 13) in relation to CMJ change from rest to fatigued condition at the end of activity. Responders group significantly improved (p ≤ 0.05) the performance in CMJ, handgrip strength and time spent in each 400-m run. Results suggest that despite induced fatigue for EIT, trained subjects can maintain their strength and power levels and their work capacity. This fact would support the rationale that improvements in performance may be due not only to metabolic adaptations but also to specific neuromuscular adaptations. Therefore, the evaluation of power should be considered simultaneously with running performance when monitoring endurance athletes.
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Affiliation(s)
- Felipe García-Pinillos
- 1Department of Didactics of Corporal Expression, University of Jaen, Jaen, Spain; and 2Department of Sports Sciences, University of Granada, Granada, Spain
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Grosprêtre S, Martin A. Conditioning effect of transcranial magnetic stimulation evoking motor-evoked potential on V-wave response. Physiol Rep 2014; 2:2/12/e12191. [PMID: 25501438 PMCID: PMC4332197 DOI: 10.14814/phy2.12191] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The aim of this study was to examine the collision responsible for the volitional V‐wave evoked by supramaximal electrical stimulation of the motor nerve during voluntary contraction. V‐wave was conditioned by transcranial magnetic stimulation (TMS) over the motor cortex at several inter‐stimuli intervals (ISI) during weak voluntary plantar flexions (n = 10) and at rest for flexor carpi radialis muscle (FCR; n = 6). Conditioning stimulations were induced by TMS with intensity eliciting maximal motor‐evoked potential (MEPmax). ISIs used were ranging from −20 to +20 msec depending on muscles tested. The results showed that, for triceps surae muscles, conditioning TMS increased the V‐wave amplitude (~ +250%) and the associated mechanical response (~ +30%) during weak voluntary plantar flexion (10% of the maximal voluntary contraction ‐MVC) for ISIs ranging from +6 to +18 msec. Similar effect was observed at rest for the FCR with ISI ranging from +6 to +12 msec. When the level of force was increased from 10 to 50% MVC or the conditioning TMS intensity was reduced to elicit responses of 50% of MEPmax, a significant decrease in the conditioned V‐wave amplitude was observed for the triceps surae muscles, linearly correlated to the changes in MEP amplitude. The slope of this correlation, as well as the electro‐mechanical efficiency, was closed to the identity line, indicating that V‐wave impact at muscle level seems to be similar to the impact of cortical stimulation. All these results suggest that change in V‐wave amplitude is a great index to reflect changes in cortical neural drive addressed to spinal motoneurons. This study aimed to condition V‐wave by transcranial magnetic stimulation (TMS), allowing assessing the amplitude and time‐delays of the descending drive. Thus, by modulating TMS intensities, levels of voluntary contraction and inter‐stimuli intervals, we were able to estimate the possible site of the collision allowing recording of V‐wave and the link with motor‐evoked potential magnitude and V‐wave amplitude. These results bring new knowledge about the modulation of the V‐wave and its interpretation.
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Affiliation(s)
- Sidney Grosprêtre
- Faculté des sciences du sport, INSERM U1093, Université de Bourgogne, Dijon, France
| | - Alain Martin
- Faculté des sciences du sport, INSERM U1093, Université de Bourgogne, Dijon, France
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Latorre-Román PÁ, García-Pinillos F, Martínez-López EJ, Soto-Hermoso VM. Concurrent fatigue and postactivation potentiation during extended interval training in long-distance runners. MOTRIZ: REVISTA DE EDUCACAO FISICA 2014. [DOI: 10.1590/s1980-65742014000400009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The purpose of this study is to analyze acute effect of running extended interval training(EIT) on vertical jump (VJ) and handgrip strength (HS) performance in experienced endurance athletes. In order to analyze mechanical parameters of the VJ and HS between runs, sixteen experienced male athletes performed an EIT (4x3x400m). The results show that fatigue induced by EIT does not impair handgrip strength or VJ performance. A significant improvement (p< .05) was noted for VJ due to the postactivation potentiation (PAP) phenomenon. A positive correlation (r= .619, p= .011) was found between VJ and lactate. The results suggest that experienced long-distance runners can maintain their strength levels and, consequently, work capacity, despite the induced fatigue by the field training demand. Therefore, VJ performance during EIT can be used as an indicator of muscular adaptations to training and, together, with handgrip strength, become indicators of fatigue. These indicators allow proper prescription training routines.
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21
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Modulation of exercise-induced spinal loop properties in response to oxygen availability. Eur J Appl Physiol 2014; 115:471-82. [PMID: 25361617 DOI: 10.1007/s00421-014-3032-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 10/15/2014] [Indexed: 10/24/2022]
Abstract
This study investigated the effects of acute hypoxia on spinal reflexes and soleus muscle function after a sustained contraction of the plantar flexors at 40% of maximal voluntary isometric contraction (MVC). Fifteen males (age 25.3 ± 0.9 year) performed the fatigue task at two different inspired O₂ fractions (FiO₂ = 0.21/0.11) in a randomized and single-blind fashion. Before, at task failure and after 6, 12 and 18 min of passive recovery, the Hoffman-reflex (H max) and M-wave (M max) were recorded at rest and voluntary activation (VA), surface electromyogram (RMSmax), M-wave (M sup) and V-wave (V sup) were recorded during MVC. Normalized H-reflex (H max/M max) was significantly depressed pre-exercise in hypoxia compared with normoxia (0.31 ± 0.08 and 0.36 ± 0.08, respectively, P < 0.05). Hypoxia did not affect time to task failure (mean time of 453.9 ± 32.0 s) and MVC decrease at task failure (-18% in normoxia vs. -16% in hypoxia). At task failure, VA (-8%), RMSmax/M sup (-11%), H max/M max (-27%) and V sup/M sup (-37%) decreased (P < 0.05), but with no FiO2 effect. H max/M max restored significantly throughout recovery in hypoxia but not in normoxia, while V sup/M sup restored significantly during recovery in normoxia but not in hypoxia (P < 0.05). Collectively, these findings indicate that central adaptations resulting from sustained submaximal fatiguing contraction were not different in hypoxia and normoxia at task failure. However, the FiO₂-induced differences in spinal loop properties pre-exercise and throughout recovery suggest possible specific mediation by the hypoxic-sensitive group III and IV muscle afferents, supraspinal regulation mechanisms being mainly involved in hypoxia while spinal ones may be predominant in normoxia.
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Kunstetter AC, Wanner SP, Madeira LG, Wilke CF, Rodrigues LOC, Lima NRV. Association between the increase in brain temperature and physical performance at different exercise intensities and protocols in a temperate environment. ACTA ACUST UNITED AC 2014; 47:679-88. [PMID: 25003543 PMCID: PMC4165295 DOI: 10.1590/1414-431x20143561] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 04/16/2014] [Indexed: 12/31/2022]
Abstract
There is evidence that brain temperature (Tbrain) provides a more
sensitive index than other core body temperatures in determining physical
performance. However, no study has addressed whether the association between
performance and increases in Tbrain in a temperate environment is
dependent upon exercise intensity, and this was the primary aim of the present study.
Adult male Wistar rats were subjected to constant exercise at three different speeds
(18, 21, and 24 m/min) until the onset of volitional fatigue. Tbrain was
continuously measured by a thermistor inserted through a brain guide cannula.
Exercise induced a speed-dependent increase in Tbrain, with the fastest
speed associated with a higher rate of Tbrain increase. Rats subjected to
constant exercise had similar Tbrain values at the time of fatigue,
although a pronounced individual variability was observed (38.7-41.7°C). There were
negative correlations between the rate of Tbrain increase and performance
for all speeds that were studied. These results indicate that performance during
constant exercise is negatively associated with the increase in Tbrain,
particularly with its rate of increase. We then investigated how an incremental-speed
protocol affected the association between the increase in Tbrain and
performance. At volitional fatigue, Tbrain was lower during incremental
exercise compared with the Tbrain resulting from constant exercise
(39.3±0.3 vs 40.3±0.1°C; P<0.05), and no association between the
rate of Tbrain increase and performance was observed. These findings
suggest that the influence of Tbrain on performance under temperate
conditions is dependent on exercise protocol.
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Affiliation(s)
- A C Kunstetter
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Escola de Educação Física, Fisioterapia e Terapia Ocupacional, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - S P Wanner
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Escola de Educação Física, Fisioterapia e Terapia Ocupacional, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - L G Madeira
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Escola de Educação Física, Fisioterapia e Terapia Ocupacional, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - C F Wilke
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Escola de Educação Física, Fisioterapia e Terapia Ocupacional, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - L O C Rodrigues
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Escola de Educação Física, Fisioterapia e Terapia Ocupacional, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - N R V Lima
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Escola de Educação Física, Fisioterapia e Terapia Ocupacional, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
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Singh AM, Duncan RE, Neva JL, Staines WR. Aerobic exercise modulates intracortical inhibition and facilitation in a nonexercised upper limb muscle. BMC Sports Sci Med Rehabil 2014; 6:23. [PMID: 25031838 PMCID: PMC4100033 DOI: 10.1186/2052-1847-6-23] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 06/17/2014] [Indexed: 11/14/2022]
Abstract
Background Despite growing interest in the relationship between exercise and short-term neural plasticity, the effects of exercise on motor cortical (M1) excitability are not well studied. Acute, lower-limb aerobic exercise may potentially modulate M1 excitability in working muscles, but the effects on muscles not involved in the exercise are unknown. Here we examined the excitability changes in an upper limb muscle representation following a single session of lower body aerobic exercise. Investigating the response to exercise in a non-exercised muscle may help to determine the clinical usefulness of lower-body exercise interventions for upper limb neurorehabilitation. Methods In this study, transcranial magnetic stimulation was used to assess input–output curves, short-interval intracortical inhibition (SICI), long-interval intracortical inhibition (LICI) and intracortical facilitation (ICF) in the extensor carpi radialis muscle in twelve healthy individuals following a single session of moderate stationary biking. Additionally, we examined whether the presence of a common polymorphism of the brain-derived neurotrophic factor (BDNF) gene would affect the response of these measures to exercise. Results We observed significant increases in ICF and decreases in SICI following exercise. No changes in LICI were detected, and no differences were observed in input–output curves following exercise, or between BDNF groups. Conclusions The current results demonstrate that the modulation of intracortical excitability following aerobic exercise is not limited to those muscles involved in the exercise, and that while exercise does not directly modulate the excitability of motor neurons, it may facilitate the induction of experience-dependent plasticity via a decrease in intracortical inhibition and increase in intracortical facilitation. These findings indicate that exercise may create favourable conditions for adaptive plasticity in M1 and may be an effective adjunct to traditional training or rehabilitation methods.
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Affiliation(s)
- Amaya M Singh
- Department of Kinesiology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
| | - Robin E Duncan
- Department of Kinesiology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
| | - Jason L Neva
- Department of Kinesiology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
| | - W Richard Staines
- Department of Kinesiology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
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Wüthrich TU, Eberle EC, Spengler CM. Locomotor and diaphragm muscle fatigue in endurance athletes performing time-trials of different durations. Eur J Appl Physiol 2014; 114:1619-33. [DOI: 10.1007/s00421-014-2889-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 04/06/2014] [Indexed: 01/19/2023]
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Girard O, Racinais S. Combining heat stress and moderate hypoxia reduces cycling time to exhaustion without modifying neuromuscular fatigue characteristics. Eur J Appl Physiol 2014; 114:1521-32. [PMID: 24748530 PMCID: PMC4048668 DOI: 10.1007/s00421-014-2883-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 04/01/2014] [Indexed: 11/27/2022]
Abstract
Purpose This study investigated the isolated and combined effects of heat [temperate (22 °C/30 % rH) vs. hot (35 °C/40 % rH)] and hypoxia [sea level (FiO2 0.21) vs. moderate altitude (FiO2 0.15)] on exercise capacity and neuromuscular fatigue characteristics. Methods Eleven physically active subjects cycled to exhaustion at constant workload (66 % of the power output associated with their maximal oxygen uptake in temperate conditions) in four different environmental conditions [temperate/sea level (control), hot/sea level (hot), temperate/moderate altitude (hypoxia) and hot/moderate altitude (hot + hypoxia)]. Torque and electromyography (EMG) responses following electrical stimulation of the tibial nerve (plantar-flexion; soleus) were recorded before and 5 min after exercise. Results Time to exhaustion was reduced (P < 0.05) in hot (−35 ± 15 %) or hypoxia (−36 ± 14 %) compared to control (61 ± 28 min), while hot + hypoxia (−51 ± 20 %) further compromised exercise capacity (P < 0.05). However, the effect of temperature or altitude on end-exercise core temperature (P = 0.089 and P = 0.070, respectively) and rating of perceived exertion (P > 0.05) did not reach significance. Maximal voluntary contraction torque, voluntary activation (twitch interpolation) and peak twitch torque decreased from pre- to post-exercise (−9 ± 1, −4 ± 1 and −6 ± 1 % all trials compounded, respectively; P < 0.05), with no effect of the temperature or altitude. M-wave amplitude and root mean square activity were reduced (P < 0.05) in hot compared to temperate conditions, while normalized maximal EMG activity did not change. Altitude had no effect on any measured parameters. Conclusion Moderate hypoxia in combination with heat stress reduces cycling time to exhaustion without modifying neuromuscular fatigue characteristics. Impaired oxygen delivery or increased cardiovascular strain, increasing relative exercise intensity, may have also contributed to earlier exercise cessation.
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Affiliation(s)
- Olivier Girard
- Athlete Health and Performance Research Centre, Aspetar, Qatar Orthopaedic and Sports Medicine Hospital, PO Box 29222, Doha, Qatar,
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Jastrzębska AD, Błacha R. Effect of exhaustive incremental treadmill effort on force generation repeatability in biathletes. J Mot Behav 2014; 46:239-45. [PMID: 24730731 DOI: 10.1080/00222895.2014.893979] [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] [Indexed: 10/25/2022]
Abstract
The authors examined how force generation repeatability changes as the result of incremental maximal test to volitional exhaustion by well-trained (VO2/kg [mL · kg(-1) · min(-1)] 62.55 ± 5.27) individuals. 13 young biathletes (18.9 ± 1.7 years) performed isometric maximum voluntary contraction (IMVC) and submaximal targeted (98N) pushes against the force transducers by arms: elbow extension (EE), elbow flexion (EF) and legs: knee extensions (KE) in pre- and posttest conditions after incremental exhaustive test performed on treadmill. IMVC did not differ significantly between pre and posttest conditions for upper and statistically decrease in lower extremities measurements (p <.01). The mean force of 10 submaximal targeted force productions (F(mean); N) is similar for pre- and posttest measurements. Standard deviation of F(mean) (Fsd; N) and coefficient variation (CV;%) decrease statistically in elbows flexion p <.02 but not extension. The reduction of force repetition accuracy in left knee extension was noticed (p <.01). The fatigue induced by incremental running test decreases a magnitude of force production variability in specifically trained muscle groups in biathletes.
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Affiliation(s)
- Agnieszka D Jastrzębska
- a University School of Physical Education , Department of Physiology and Biochemistry , Wrocław , Poland
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Jubeau M, Rupp T, Perrey S, Temesi J, Wuyam B, Levy P, Verges S, Millet GY. Changes in voluntary activation assessed by transcranial magnetic stimulation during prolonged cycling exercise. PLoS One 2014; 9:e89157. [PMID: 24586559 PMCID: PMC3931682 DOI: 10.1371/journal.pone.0089157] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 01/15/2014] [Indexed: 01/13/2023] Open
Abstract
Maximal central motor drive is known to decrease during prolonged exercise although it remains to be determined whether a supraspinal deficit exists, and if so, when it appears. The purpose of this study was to evaluate corticospinal excitability and muscle voluntary activation before, during and after a 4-h cycling exercise. Ten healthy subjects performed three 80-min bouts on an ergocycle at 45% of their maximal aerobic power. Before exercise and immediately after each bout, neuromuscular function was evaluated in the quadriceps femoris muscles under isometric conditions. Transcranial magnetic stimulation was used to assess voluntary activation at the cortical level (VATMS), corticospinal excitability via motor-evoked potential (MEP) and intracortical inhibition by cortical silent period (CSP). Electrical stimulation of the femoral nerve was used to measure voluntary activation at the peripheral level (VAFNES) and muscle contractile properties. Maximal voluntary force was significantly reduced after the first bout (13±9%, P<0.01) and was further decreased (25±11%, P<0.001) at the end of exercise. CSP remained unchanged throughout the protocol. Rectus femoris and vastus lateralis but not vastus medialis MEP normalized to maximal M-wave amplitude significantly increased during cycling. Finally, significant decreases in both VATMS and VAFNES (∼8%, P<0.05 and ∼14%, P<0.001 post-exercise, respectively) were observed. In conclusion, reductions in VAFNES after a prolonged cycling exercise are partly explained by a deficit at the cortical level accompanied by increased corticospinal excitability and unchanged intracortical inhibition. When comparing the present results with the literature, this study highlights that changes at the cortical and/or motoneuronal levels depend not only on the type of exercise (single-joint vs. whole-body) but also on exercise intensity and/or duration.
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Affiliation(s)
- Marc Jubeau
- INSERM U1042, Grenoble, France
- Université de Lyon, Saint-Etienne, France
- MIP, Nantes, France
| | - Thomas Rupp
- INSERM U1042, Grenoble, France
- Laboratoire HP2, Grenoble Alpes University, Grenoble, France
| | - Stephane Perrey
- Movement To Health (M2H), Montpellier-I University, Euromov, France
| | | | - Bernard Wuyam
- INSERM U1042, Grenoble, France
- Laboratoire HP2, Grenoble Alpes University, Grenoble, France
| | - Patrick Levy
- INSERM U1042, Grenoble, France
- Laboratoire HP2, Grenoble Alpes University, Grenoble, France
| | - Samuel Verges
- INSERM U1042, Grenoble, France
- Laboratoire HP2, Grenoble Alpes University, Grenoble, France
| | - Guillaume Y. Millet
- INSERM U1042, Grenoble, France
- Université de Lyon, Saint-Etienne, France
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- * E-mail:
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M-wave, H- and V-reflex recruitment curves during maximal voluntary contraction. J Clin Neurophysiol 2013; 30:415-21. [PMID: 23912583 DOI: 10.1097/wnp.0b013e31829ddcf1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
PURPOSE To investigate whether the H reflex-M wave recruitment curves obtained during maximal voluntary contraction (MVC) differ from rest and to determine the stimulation intensities allowing to record stable reflex responses. METHODS Full recruitment curves (precision, 2 mA) were obtained from the soleus muscle in 14 volunteers at rest and during plantar flexion MVCs. RESULTS Maximal M-wave reached significantly larger amplitude during MVC (+2.2 [0.4; 3.9] mV) for a higher stimulation intensity (+7.9 [-0.4; 16] mA). Similarly, maximal H-reflex reached significantly larger amplitude during MVC than at rest (+3.2 [0.9; 5.5] mV) for a much higher stimulation intensity (+17.7 [9.7; 25.7] mA). V-wave amplitude plateaued only when M-wave during MVC plateaued, that is, at higher intensity than M-wave at rest. V-wave was correlated to the maximal H-reflex during MVC (r = 0.79, P < 0.05). CONCLUSION Electrically evoked potentials showed a specific recruitment curve during MVC with higher maximal values attained for higher stimulation intensities. Thus, recording reflex responses during MVC based on intensities determined at rest or as a percentage of M-wave may yield inaccurate results. V-wave presented a plateau for stimulation intensity of 1.5 times the onset of the resting M-wave plateau. Evoked potentials obtained during actual contractions should be normalized to M-waves obtained during contractions of the same force level.
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Racinais S, Cresswell AG. Temperature affects maximum H-reflex amplitude but not homosynaptic postactivation depression. Physiol Rep 2013; 1:e00019. [PMID: 24303108 PMCID: PMC3831915 DOI: 10.1002/phy2.19] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 05/26/2013] [Accepted: 06/04/2013] [Indexed: 11/06/2022] Open
Abstract
This study aimed to determinate the effect of hyperthermia on transmission efficacy of the Ia-afferent spinal pathway. Recruitment curves of the Hoffman reflex (H-reflex) and compound motor potential (M-wave) along with homosynaptic postactivation depression (HPAD) recovery curves were obtained in 14 volunteers in two controlled ambient temperatures that resulted in significantly different core temperatures (CON, core temperature ∼37.3°C; and HOT, core temperature ∼39.0°C). Electromyographic responses were obtained from the soleus (SOL) and medial gastrocnemius (MG) muscles following electrical stimulation of the tibial nerve at varying intensities and paired pulse frequencies (0.07-10 Hz). Results showed that maximal amplitude of the H-reflex was reached for a similar intensity of stimulation in CON and HOT (both muscles P > 0.47), with a similar associated M-wave (both muscles P > 0.69) but was significantly decreased in HOT as compared to CON (all P < 0.05), whether expressed in absolute terms (-50% in SOL, -32% in MG) or when normalized to the maximum M-wave (-23% in SOL, -32% in MG). The HPAD recovery curve was not affected by the elevated core temperature (both muscles P > 0.23). Taken together, these results suggest that hyperthermia can alter neuromuscular transmission across the neuromuscular junction and/or muscle membrane as well as transmission efficacy of the Ia-afferent pathway, albeit the latter not via an increase in HPAD.
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Oliveira AS, Caputo F, Aagaard P, Corvino RB, Gonçalves M, Denadai BS. Isokinetic eccentric resistance training prevents loss in mechanical muscle function after running. Eur J Appl Physiol 2013; 113:2301-11. [PMID: 23680937 DOI: 10.1007/s00421-013-2660-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 05/07/2013] [Indexed: 10/26/2022]
Abstract
The aim of the study was to verify whether 8 weeks of resistance training employing maximal isokinetic eccentric (IERT) knee extensor actions would reduce the acute force loss observed after high-intensity treadmill running exercise. It was hypothesized that specific IERT would induce protective effects against muscle fatigue and ultrastructural damages, preventing or reducing the loss in mechanical muscle function after running. Subjects were tested before and after IERT protocol for maximal isometric, concentric and eccentric isokinetic knee extensor strength (60° and 180° s(-1)). In a second session, subjects performed treadmill running (~35 min) and the previously mentioned measurements were repeated immediately after running. Subsequently, subjects were randomized to training (n = 12) consisting of 24 sessions of maximal IERT knee extensors actions at 180° s(-1), or served as controls (n = 8). The effects of acute running-induced fatigue and training on isokinetic and isometric peak torque, and rate of force development (RFD) were investigated. Before IERT, running-induced eccentric torque loss at 180° s(-1) was -8 %, and RFD loss was -11 %. Longitudinal IERT led to reduced or absent acute running-induced losses in maximal IERT torque at 180° s(-1) (+2 %), being significantly reduced compared to before IERT (p < 0.05), however, RFD loss remained at -11 % (p > 0.05). In conclusion, IERT yields a reduced strength loss after high-intensity running workouts, which may suggest a protective effect against fatigue and/or morphological damages. However, IERT may not avoid reductions in explosive muscle actions. In turn, this may allow more intense training sessions to be performed, facilitating the adaptive response to running training.
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Affiliation(s)
- Anderson Souza Oliveira
- Human Performance Laboratory, São Paulo State University, UNESP, Av. 24 A, 1515, Bela Vista, Rio Claro, SP, CEP-13506-900, Brazil
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Behrens M, Mau-Moeller A, Wassermann F, Bruhn S. Effect of fatigue on hamstring reflex responses and posterior-anterior tibial translation in men and women. PLoS One 2013; 8:e56988. [PMID: 23573178 PMCID: PMC3584125 DOI: 10.1371/journal.pone.0056988] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 01/16/2013] [Indexed: 11/19/2022] Open
Abstract
Anterior cruciate ligament (ACL) rupture ranks among the most common injuries in sports. The incidence of ACL injuries is considerably higher in females than in males and the underlying mechanisms are still under debate. Furthermore, it has been suggested that muscle fatigue can be a risk factor for ACL injuries. We investigated gender differences in hamstring reflex responses and posterior-anterior tibial translation (TT) before and after fatiguing exercise. We assessed the isolated movement of the tibia relative to the femur in the sagittal plane as a consequence of mechanically induced TT in standing subjects. The muscle activity of the hamstrings was evaluated. Furthermore, isometric maximum voluntary torque (iMVT) and rate of torque development (RTD) of the hamstrings (H) and quadriceps (Q) were measured and the MVT H/Q as well as the RTD H/Q ratios were calculated. After fatigue, reflex onset latencies were enhanced in women. A reduction of reflex responses associated with an increased TT was observed in females. Men showed no differences in these parameters. Correlation analysis revealed no significant associations between parameters for TT and MVT H/Q as well as RTD H/Q. The results of the present study revealed that the fatigue protocol used in this study altered the latency and magnitude of reflex responses of the hamstrings as well as TT in women. These changes were not found in men. Based on our results, it is conceivable that the fatigue-induced decrease in neuromuscular function with a corresponding increase in TT probably contributes to the higher incidence of ACL injuries in women.
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Affiliation(s)
- Martin Behrens
- Department of Exercise Science, University of Rostock, Rostock, Germany.
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Froyd C, Millet GY, Noakes TD. The development of peripheral fatigue and short-term recovery during self-paced high-intensity exercise. J Physiol 2012; 591:1339-46. [PMID: 23230235 DOI: 10.1113/jphysiol.2012.245316] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The time course of muscular fatigue that develops during and after an intense bout of self-paced dynamic exercise was characterized by using different forms of electrical stimulation (ES) of the exercising muscles. Ten active subjects performed a time trial (TT) involving repetitive concentric extension/flexion of the right knee using a Biodex dynamometer. Neuromuscular function (NMF), including ES and a 5 s maximal isometric voluntary contraction (MVC), was assessed before the start of the TT and immediately (<5 s) after each 20% of the TT had been completed, as well as 1, 2, 4 and 8 min after TT termination. The TT time was 347 ± 98 s. MVCs were 52% of baseline values at TT termination. Torque responses from ES were reduced to 33-68% of baseline using different methods of stimulation, suggesting that the extent to which peripheral fatigue is documented during exercise depends upon NMF assessment methodology. The major changes in muscle function occurred within the first 40% of exercise. Significant recovery in skeletal muscle function occurs within the first 1-2 min after exercise, showing that previous studies may have underestimated the extent to which peripheral fatigue develops during exercise.
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Affiliation(s)
- Christian Froyd
- UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Sports Science Instituteof South Africa, Boundary Road, Newlands, 7925, South Africa.
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Rossi A, Rossi S, Ginanneschi F. Activity-dependent changes in intrinsic excitability of human spinal motoneurones produced by natural activity. J Neurophysiol 2012; 108:2473-80. [PMID: 22933724 DOI: 10.1152/jn.00477.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The current study was designed to evaluate activity-dependent changes intrinsic to the spinal motoneurones (MNs) associated with sustained contractions. The excitability of spinal MNs (reflected by the antidromically evoked F-wave) innervating the abductor digiti minimi muscle (ADM) was measured in 12 healthy subjects following maximum voluntary contractions (MVCs) of ADM lasting 5 s, 15 s, 30 s, and 60 s. Upon cessation of the contractions, F-waves showed a depression, which increased in depth and duration with increasing duration of contraction. Following a 5-s contraction, there was a 20% decrease, which waned in 2 min, whereas a 60-s contraction produced a 40% decrease and waned in over 15 min. The changes in excitability of peripheral motor axons produced by the MVCs were measured by recording an ADM compound muscle action potential (CMAP) of ~50% of maximum to a constant ulnar nerve electrical stimulation. On cessation of the contractions, there was a prominent decrease in size of the CMAP: following a 5-s MVC, it produced a 10% decrease in the size of the test CMAP, which recovered in 2 min, whereas following a 60-s MVC, it produced a 30% decrease, which recovered in over 15 min. Statistical analysis (correntropy) showed a high-order mutual dependence between F-wave and CMAP, and both were significantly dependent on MVC duration. Because of the parallel excitability changes in peripheral axons and spinal MNs, our interpretation is that intrinsic excitability of the axon initial segment (i.e., where the action potential is generated) and peripheral axon segments changed in a similar, activity-dependent manner.
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Affiliation(s)
- Alessandro Rossi
- Department of Neurological, Neurosurgical and Behavioral Sciences, University of Siena, Siena, Italy.
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Sidhu SK, Cresswell AG, Carroll TJ. Motor cortex excitability does not increase during sustained cycling exercise to volitional exhaustion. J Appl Physiol (1985) 2012; 113:401-9. [DOI: 10.1152/japplphysiol.00486.2012] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The excitability of the motor cortex increases as fatigue develops during sustained single-joint contractions, but there are no previous reports on how corticospinal excitability is affected by sustained locomotor exercise. Here we addressed this issue by measuring spinal and cortical excitability changes during sustained cycling exercise. Vastus lateralis (VL) and rectus femoris (RF) muscle responses to transcranial magnetic stimulation of the motor cortex (motor evoked potentials, MEPs) and electrical stimulation of the descending tracts (cervicomedullary evoked potentials, CMEPs) were recorded every 3 min from nine subjects during 30 min of cycling at 75% of maximum workload (Wmax), and every minute during subsequent exercise at 105% of Wmax until subjective task failure. Responses were also measured during nonfatiguing control bouts at 80% and 110% of Wmax prior to sustained exercise. There were no significant changes in MEPs or CMEPs ( P > 0.05) during the sustained cycling exercise. These results suggest that, in contrast to sustained single-joint contractions, sustained cycling exercise does not increase the excitability of motor cortical neurons. The contrasting corticospinal responses to the two modes of exercise may be due to differences in their associated systemic physiological consequences.
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Affiliation(s)
- Simranjit K. Sidhu
- School of Human Movement Studies, The University of Queensland, Brisbane, Queensland, Australia
| | - Andrew G. Cresswell
- School of Human Movement Studies, The University of Queensland, Brisbane, Queensland, Australia
| | - Timothy J. Carroll
- School of Human Movement Studies, The University of Queensland, Brisbane, Queensland, Australia
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35
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Kelly LA, Girard O, Racinais S. Effect of orthoses on changes in neuromuscular control and aerobic cost of a 1-h run. Med Sci Sports Exerc 2012; 43:2335-43. [PMID: 21552159 DOI: 10.1249/mss.0b013e31822037ca] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE The study's purpose was to determine the effect of foot orthoses on neuromuscular control and the aerobic cost of running. METHODS Twelve recreational athletes ran for 1 h on a treadmill at a constant velocity (i.e., 10% higher than their first ventilatory threshold) with and without custom-molded foot orthoses, in a counterbalanced order. Surface EMG activity of five lower limb muscles, together with oxygen consumption and HR, was recorded at 8-min intervals, starting after 2 min, during the run. A series of neuromuscular tests including voluntary and electrically evoked contractions of the ankle plantar flexors was performed before and after running. RESULTS Peroneus longus root mean square amplitude decreased with time, independently of the condition (-18.9%, P < 0.01). Lower root mean square signal amplitude for vastus medialis (-13.3%, P < 0.02) and gastrocnemius medialis (-10.7%, P < 0.05), combined with increased peroneus longus burst duration (+14.7%, P < 0.05), occurred when running with orthoses. There was no main effect of the condition for oxygen consumption (P > 0.05), whereas HR was significantly lowered while wearing foot orthoses (-3%, P < 0.02). Maximal strength capacity (-9%, P < 0.01), normalized EMG activity (-17%, P < 0.001), and peak twitch torque (-14%, P < 0.01) declined from before to after exercise, independently of the condition. Smaller fatigue-induced decrements in the rate of torque development within the first 200 ms (-6% vs -33%, P < 0.01) were reported after running with foot orthoses. CONCLUSIONS Wearing foot orthoses alters neuromuscular control during a submaximal 1-h treadmill run and partly protects from the resulting fatigue-induced reductions in rapid force development characteristics of the plantar flexors. However, these changes may be too small to alter the aerobic cost of running.
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Affiliation(s)
- Luke A Kelly
- ASPETAR, Qatar Orthopaedic and Sports Medicine Hospital, Doha, Qatar.
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Racinais S, Girard O. Neuromuscular failure is unlikely to explain the early exercise cessation in hot ambient conditions. Psychophysiology 2012; 49:853-65. [DOI: 10.1111/j.1469-8986.2012.01360.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 12/16/2011] [Indexed: 11/28/2022]
Affiliation(s)
- Sébastien Racinais
- Research and Education Centre; ASPETAR-Qatar Orthopaedic and Sports Medicine Hospital; Doha; Qatar
| | - Olivier Girard
- Research and Education Centre; ASPETAR-Qatar Orthopaedic and Sports Medicine Hospital; Doha; Qatar
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Daily muscle vibration amelioration of neural impairments of the soleus muscle during 2weeks of immobilization. J Electromyogr Kinesiol 2011; 21:1017-22. [DOI: 10.1016/j.jelekin.2011.07.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 06/28/2011] [Accepted: 07/18/2011] [Indexed: 11/20/2022] Open
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Girard O, Mendez-Villanueva A, Bishop D. Repeated-sprint ability - part I: factors contributing to fatigue. Sports Med 2011; 41:673-94. [PMID: 21780851 DOI: 10.2165/11590550-000000000-00000] [Citation(s) in RCA: 461] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Short-duration sprints (<10 seconds), interspersed with brief recoveries (<60 seconds), are common during most team and racket sports. Therefore, the ability to recover and to reproduce performance in subsequent sprints is probably an important fitness requirement of athletes engaged in these disciplines, and has been termed repeated-sprint ability (RSA). This review (Part I) examines how fatigue manifests during repeated-sprint exercise (RSE), and discusses the potential underpinning muscular and neural mechanisms. A subsequent companion review to this article will explain a better understanding of the training interventions that could eventually improve RSA. Using laboratory and field-based protocols, performance analyses have consistently shown that fatigue during RSE typically manifests as a decline in maximal/mean sprint speed (i.e. running) or a decrease in peak power or total work (i.e. cycling) over sprint repetitions. A consistent result among these studies is that performance decrements (i.e. fatigue) during successive bouts are inversely correlated to initial sprint performance. To date, there is no doubt that the details of the task (e.g. changes in the nature of the work/recovery bouts) alter the time course/magnitude of fatigue development during RSE (i.e. task dependency) and potentially the contribution of the underlying mechanisms. At the muscle level, limitations in energy supply, which include energy available from phosphocreatine hydrolysis, anaerobic glycolysis and oxidative metabolism, and the intramuscular accumulation of metabolic by-products, such as hydrogen ions, emerge as key factors responsible for fatigue. Although not as extensively studied, the use of surface electromyography techniques has revealed that failure to fully activate the contracting musculature and/or changes in inter-muscle recruitment strategies (i.e. neural factors) are also associated with fatigue outcomes. Pending confirmatory research, other factors such as stiffness regulation, hypoglycaemia, muscle damage and hostile environments (e.g. heat, hypoxia) are also likely to compromise fatigue resistance during repeated-sprint protocols.
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Affiliation(s)
- Olivier Girard
- ASPETAR Qatar Orthopaedic and Sports Medicine Hospital, Research and Education Centre, Doha, Qatar.
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Alteration in neuromuscular function after a 5 km running time trial. Eur J Appl Physiol 2011; 112:2323-30. [PMID: 22012541 DOI: 10.1007/s00421-011-2205-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 10/07/2011] [Indexed: 10/16/2022]
Abstract
The aim of this study was to characterize the effect of a 5 km running time trial on the neuromuscular properties of the plantar flexors. Eleven well-trained triathletes performed a series of neuromuscular tests before and immediately after the run on a 200 m indoor track. Muscle activation (twitch interpolation) and normalized EMG activity were assessed during maximal voluntary contraction (MVC) of plantar flexors. Maximal soleus H-reflexes and M-waves were evoked at rest (i.e. H (MAX) and M (MAX), respectively) and during MVC (i.e. H (SUP) and M (SUP), respectively). MVC significantly declined (-27%; P < 0.001) after the run, due to decrease in muscle activation (-8%; P < 0.05) and M (MAX)-normalized EMG activity (-13%; P < 0.05). Significant reductions in M-wave amplitudes (M (MAX): -13% and M (SUP): -16%; P < 0.05) as well as H (MAX)/M (MAX) (-37%; P < 0.01) and H (SUP)/M (SUP) (-25%; P < 0.05) ratios occurred with fatigue. Following exercise, the single twitch was characterized by lower peak torque (-16%; P < 0.001) as well as shorter contraction (-19%; P < 0.001) and half-relaxation (-24%; P < 0.001) times. In conclusion, the reduction in plantar flexors strength induced by a 5 km running time trial is caused by peripheral adjustments, which are attributable to a failure of the neuromuscular transmission and excitation-contraction coupling. Fatigue also decreased the magnitude of efferent motor outflow from spinal motor neurons to the plantar flexors and part of this suboptimal neural drive is the result of an inhibition of soleus motoneuron pool reflex excitability.
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Millet GY. Can neuromuscular fatigue explain running strategies and performance in ultra-marathons?: the flush model. Sports Med 2011; 41:489-506. [PMID: 21615190 DOI: 10.2165/11588760-000000000-00000] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
While the industrialized world adopts a largely sedentary lifestyle, ultra-marathon running races have become increasingly popular in the last few years in many countries. The ability to run long distances is also considered to have played a role in human evolution. This makes the issue of ultra-long distance physiology important. In the ability to run multiples of 10 km (up to 1000 km in one stage), fatigue resistance is critical. Fatigue is generally defined as strength loss (i.e. a decrease in maximal voluntary contraction [MVC]), which is known to be dependent on the type of exercise. Critical task variables include the intensity and duration of the activity, both of which are very specific to ultra-endurance sports. They also include the muscle groups involved and the type of muscle contraction, two variables that depend on the sport under consideration. The first part of this article focuses on the central and peripheral causes of the alterations to neuromuscular function that occur in ultra-marathon running. Neuromuscular function evaluation requires measurements of MVCs and maximal electrical/magnetic stimulations; these provide an insight into the factors in the CNS and the muscles implicated in fatigue. However, such measurements do not necessarily predict how muscle function may influence ultra-endurance running and whether this has an effect on speed regulation during a real competition (i.e. when pacing strategies are involved). In other words, the nature of the relationship between fatigue as measured using maximal contractions/stimulation and submaximal performance limitation/regulation is questionable. To investigate this issue, we are suggesting a holistic model in the second part of this article. This model can be applied to all endurance activities, but is specifically adapted to ultra-endurance running: the flush model. This model has the following four components: (i) the ball-cock (or buoy), which can be compared with the rate of perceived exertion, and can increase or decrease based on (ii) the filling rate and (iii) the water evacuated through the waste pipe, and (iv) a security reserve that allows the subject to prevent physiological damage. We are suggesting that central regulation is not only based on afferent signals arising from the muscles and peripheral organs, but is also dependent on peripheral fatigue and spinal/supraspinal inhibition (or disfacilitation) since these alterations imply a higher central drive for a given power output. This holistic model also explains how environmental conditions, sleep deprivation/mental fatigue, pain-killers or psychostimulants, cognitive or nutritional strategies may affect ultra-running performance.
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Affiliation(s)
- Guillaume Y Millet
- Université de Lyon, and Laboratoire dePhysiologie de l’Exercice (EA 4338), Médecine du Sport-Myologie, Hôpital Bellevue,F-42023, Saint-Etienne, France.
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Test-retest reliability of v-wave responses in the soleus and gastrocnemius medialis. J Clin Neurophysiol 2011; 28:217-21. [PMID: 21399516 DOI: 10.1097/wnp.0b013e31821215cf] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
This study was designed to assess the reliability of the first volitional (V) wave, which can be used as a measure of efferent neural drive, while also reflecting reflex excitability. Ten subjects volunteered for one familiarization session followed by an experimental test session and an identical retest session spaced 3 to 8 days apart. V-waves were evoked in the tibial nerve during plantar flexion maximal voluntary isometric contractions (MVCs). Test-retest reliability was assessed using the intraclass correlation coefficient (ICC), along with standard error of measurement and 95% confidence intervals for the following variables: MVC force, surface electromyogram activity (EMG), and the peak-to-peak V-wave amplitude in soleus (SOL) and gastrocnemius medialis (GM). The superimposed M-wave (MSUP) accompanying V-wave stimulation was also obtained for normalization purposes. Substantial reliability was documented for V/MSUP in both SOL (ICC = 0.86) and GM (0.90), as well as for the non-normalized V-wave in SOL (0.92). Moderate reliability was displayed for the non-normalized V-wave response in GM (0.78). Substantial reliability was also established for EMG/MSUP (>0.82) and MVC force (0.98). This study provides novel evidence that V-wave responses can be consistently measured in the SOL and GM, thus advocating its continued use in future research.
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Electrical stimulation for testing neuromuscular function: from sport to pathology. Eur J Appl Physiol 2011; 111:2489-500. [PMID: 21590274 DOI: 10.1007/s00421-011-1996-y] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Accepted: 05/02/2011] [Indexed: 10/18/2022]
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Laurin J, Dousset E, Carrivale R, Grélot L, Decherchi P. Recovery pattern of motor reflex after a single bout of neuromuscular electrical stimulation session. Scand J Med Sci Sports 2011; 22:534-44. [PMID: 21362055 DOI: 10.1111/j.1600-0838.2010.01279.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We aimed at determining the recovery pattern of neural properties of soleus muscle after a single bout of neuromuscular electrical stimulation (NMES) session. Thirteen subjects performed an NMES exercise (75 Hz, 40 contractions, 6.25 s per contraction). Maximal voluntary contraction (MVC), H-reflex at rest and during voluntary contraction fixed at 60% of MVC (respectively, H(max) and H(sup) ) and volitional (V) wave were measured before and during the recovery period following this exercise [i.e., immediately after, 2 h (H2), 2 days (D2) and 7 days (D7)]. MVC exhibited an immediate and a delayed declines at 2 days (respectively, -29.8±4.6%, P<0.001; -13.0±3.4%, P<0.05). Likewise, V/M(sup) was decreased immediately and 2 days after NMES session (respectively, -43.3±11.6%, P<0.05; 35.3±6.6%, P<0.05). The delayed decrements in MVC and V-wave occurred concomitantly with muscle soreness peak (P<0.001). It could be concluded that motor command alterations after an NMES resistance session contributed to the immediate and also to the delayed decreases in MVC without affecting resting and active H-reflex excitability. These results suggested that spinal circuitry function of larger motoneurons was inhibited by NMES (as indicated by the depressed V-wave responses) contrary to the smaller one (indicated by the unchanged H-reflex responses).
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Affiliation(s)
- J Laurin
- UMR CNRS 6233, Institut des Sciences du Mouvement (ISM), Parc Scientifique et Technologique de Luminy, Faculté des Sciences du Sport de Marseille, Etienne-Jules MAREY, Université de la Méditerranée (Aix-Marseille II) - Aix-Marseille Université, Cedex, France
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Abstract
This review focuses on the effects of different environmental temperatures on the neuromuscular system. During short duration exercise, performance improves from 2% to 5% with a 1 °C increase in muscle temperature. However, if central temperature increases (i.e., hyperthermia), this positive relation ceases and performance becomes impaired. Performance impairments in both cold and hot environment are related to a modification in neural drive due to protective adaptations, central and peripheral failures. This review highlights, to some extent, the different effects of hot and cold environments on the supraspinal, spinal and peripheral components of the neural drive involved in the up- and down-regulation of neuromuscular function and shows that temperature also affects the neural drive transmission to the muscle and the excitation-contraction coupling.
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Affiliation(s)
- S Racinais
- Research and Education Centre, ASPETAR, Qatar Orthopaedic Sports Medicine Hospital, Doha, Qatar Physical Work Capacity team, Finnish Institute of Occupational Health, Oulu, Finland.
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Seynnes OR, Maffiuletti NA, Horstman AM, Narici MV. Increased H-reflex excitability is not accompanied by changes in neural drive following 24 days of unilateral lower limb suspension. Muscle Nerve 2010; 42:749-55. [PMID: 19229968 DOI: 10.1002/mus.21228] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The purpose of this study was to determine whether the gain in soleus H-reflex excitability induced by unilateral lower limb suspension (ULLS) is associated with changes in neural drive to the plantar flexor muscles. Six male subjects (23 ± 2 years, 187 ± 7 cm, 79 ± 9 kg) underwent 24 days of ULLS of the dominant limb. Plantar flexor maximal voluntary contraction (MVC) torque, activation capacity (twitch interpolation), soleus maximal electromyographic (EMG) activity, Hoffman (H)-reflex, and the first volitional (V) wave normalized to the compound muscle action potential (M-wave) were quantified before and after ULLS. Following ULLS, MVC torque decreased by 15% (P < 0.05). However, neither activation capacity nor EMG activity was significantly altered after the suspension. The V-wave remained unchanged consistently after ULLS, whereas the H-reflex increased significantly (+20%). Furthermore, there was no significant relationship between changes in H-reflex and V-wave over the ULLS period. These findings indicate that 24 days of ULLS can result in a substantial reduction of muscle strength without any apparent change in voluntary activation capacity. H-reflex and V-wave findings suggest that the spinal adaptations that underlie the unloading-induced increase in resting soleus H-reflex excitability did not significantly affect the efferent motor output to the plantar flexor muscles.
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Affiliation(s)
- Olivier R Seynnes
- Institute for Biomedical Research into Human Movement and Health, Manchester Metropolitan University, Alsager, UK.
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Gaoua N, Grantham J, El Massioui F, Girard O, Racinais S. Cognitive decrements do not follow neuromuscular alterations during passive heat exposure. Int J Hyperthermia 2010; 27:10-9. [DOI: 10.3109/02656736.2010.519371] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Papaiordanidou M, Guiraud D, Varray A. Does central fatigue exist under low-frequency stimulation of a low fatigue-resistant muscle? Eur J Appl Physiol 2010; 110:815-23. [DOI: 10.1007/s00421-010-1565-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/24/2010] [Indexed: 11/30/2022]
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Martin V, Kerhervé H, Messonnier LA, Banfi JC, Geyssant A, Bonnefoy R, Féasson L, Millet GY. Central and peripheral contributions to neuromuscular fatigue induced by a 24-h treadmill run. J Appl Physiol (1985) 2010; 108:1224-33. [PMID: 20167672 DOI: 10.1152/japplphysiol.01202.2009] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This experiment investigated the fatigue induced by a 24-h running exercise (24TR) and particularly aimed at testing the hypothesis that the central component would be the main mechanism responsible for neuromuscular fatigue. Neuromuscular function evaluation was performed before, every 4 h during, and at the end of the 24TR on 12 experienced ultramarathon runners. It consisted of a determination of the maximal voluntary contractions (MVC) of the knee extensors (KE) and plantar flexors (PF), the maximal voluntary activation (%VA) of the KE and PF, and the maximal compound muscle action potential amplitude (Mmax) on the soleus and vastus lateralis. Tetanic stimulations also were delivered to evaluate the presence of low-frequency fatigue and the KE maximal muscle force production ability. Strength loss occurred throughout the exercise, with large changes observed after 24TR in MVC for both the KE and PF muscles (−40.9 ± 17.0 and −30.3 ± 12.5%, respectively; P < 0.001) together with marked reductions of %VA (−33.0 ± 21.8 and −14.8 ± 18.9%, respectively; P < 0.001). A reduction of Mmax amplitude was observed only on soleus, and no low-frequency fatigue was observed for any muscle group. Finally, KE maximal force production ability was reduced to a moderate extent at the end of the 24TR (−10.2%; P < 0.001), but these alterations were highly variable ( ± 15.7%). These results suggest that central factors are mainly responsible for the large maximal muscle torque reduction after ultraendurance running, especially on the KE muscles. Neural drive reduction may have contributed to the relative preservation of peripheral function and also affected the evolution of the running speed during the 24TR.
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Affiliation(s)
- Vincent Martin
- Institut National de la Santé et de la Recherche Médicale Unité 902, University of Evry Val d'Essonne, Evry
| | - Hugo Kerhervé
- Exercise Physiology Laboratory, Jean Monnet University, Saint-Etienne
| | | | - Jean-Claude Banfi
- Exercise Physiology Laboratory, Jean Monnet University, Saint-Etienne
| | - André Geyssant
- Exercise Physiology Laboratory, Jean Monnet University, Saint-Etienne
- Department of Clinical Physiology of Exercise, Bellevue Hospital, University Hospital Center, Saint-Etienne, France
| | - Regis Bonnefoy
- Exercise Physiology Laboratory, Jean Monnet University, Saint-Etienne
| | - Léonard Féasson
- Exercise Physiology Laboratory, Jean Monnet University, Saint-Etienne
- Department of Clinical Physiology of Exercise, Bellevue Hospital, University Hospital Center, Saint-Etienne, France
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Place N, Yamada T, Bruton JD, Westerblad H. Muscle fatigue: from observations in humans to underlying mechanisms studied in intact single muscle fibres. Eur J Appl Physiol 2010; 110:1-15. [DOI: 10.1007/s00421-010-1480-0] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2010] [Indexed: 01/01/2023]
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Perrey S, Racinais S, Saimouaa K, Girard O. Neural and muscular adjustments following repeated running sprints. Eur J Appl Physiol 2010; 109:1027-36. [DOI: 10.1007/s00421-010-1445-3] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2010] [Indexed: 11/28/2022]
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