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Mornas A, Brocherie F, Hollville E, Derouck T, Racinais S, Guilhem G. Running 40 Minutes under Temperate or Hot Environment Does Not Affect Operating Fascicle Length. Med Sci Sports Exerc 2024; 56:1140-1150. [PMID: 38233977 DOI: 10.1249/mss.0000000000003387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
PURPOSE Muscle mechanics is paramount in our understanding of motor performance. However, little is known regarding the sensitivity of fascicle dynamics and connective tissues stiffness to exercise duration and ambient temperature during running, both increasing muscle temperature. This study aimed to determine gastrocnemius medialis (GM) fascicle dynamics in vivo during running in temperate and hot conditions, as well as muscle-tendon unit responses. METHODS Using ultrafast ultrasound, 15 participants (8 men, 7 women; 26 ± 3 yr) were tested before, during (2 and 40 min), and after a running task (40 min at 10 km·h -1 ) in temperate (TEMP; ~23°C) and hot (HOT: ~38°C) conditions. RESULTS Although core, skin temperatures, and heart rate increased from the beginning to the end of the exercise and in a larger extent in HOT than TEMP ( P < 0.001), the physiological stress elicited did not alter running temporal parameters and GM fascicle operating lengths, with similar behavior of the fascicles on their force-length relationship, over time (2 vs 40 min) or across condition (TEMP vs HOT; P ≥ 0.248). Maximal voluntary force production did not reported statistical changes after exercise ( P = 0.060), and the connective tissues stiffness measured (i.e., passive muscle and stiffness of the series-elastic elements) did not show neither time ( P ≥ 0.281), condition ( P ≥ 0.256) nor time-condition interaction ( P ≥ 0.465) effect. CONCLUSIONS This study revealed that prolonged running exercise does not alter muscle-tendon unit properties and interplay, which are not influenced by ambient temperature. These findings may rule out potential detrimental effects of heat on muscle properties and encourage further investigations on longer and more intense running exercise.
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Affiliation(s)
| | - Franck Brocherie
- French Institute of Sport (INSEP), Laboratory Sport, Expertise and Performance (EA 7370), Paris, FRANCE
| | - Enzo Hollville
- French Institute of Sport (INSEP), Laboratory Sport, Expertise and Performance (EA 7370), Paris, FRANCE
| | | | | | - GaËL Guilhem
- French Institute of Sport (INSEP), Laboratory Sport, Expertise and Performance (EA 7370), Paris, FRANCE
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Li SN, Peeling P, Scott BR, Peiffer JJ, Shaykevich A, Girard O. Maintenance of internal load despite a stepwise reduction in external load during moderate intensity heart rate clamped cycling with acute graded normobaric hypoxia in males. J Sci Med Sport 2023; 26:628-635. [PMID: 37852804 DOI: 10.1016/j.jsams.2023.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 09/07/2023] [Accepted: 09/11/2023] [Indexed: 10/20/2023]
Abstract
OBJECTIVES To investigate the acute effects of graded hypoxia on external and internal loads during 60 min of endurance cycling at a clamped heart rate. DESIGN Repeated measures. METHODS On separate visits, 16 trained males cycled for 60 min at a clamped heart rate corresponding to 80 % of their first ventilatory threshold at sea-level and 2500 m, 3000 m, 3500 m and 4000 m simulated altitudes (inspired oxygen fractions of 20.9 %, 15.4 %, 14.5 %, 13.6 % and 12.7 %, respectively). Markers of external (power output) and internal (blood lactate concentration, tissue saturation index, cardio-respiratory and perceptual responses) loads were measured every 15 min during cycling. Neuromuscular function of knee extensors was characterised pre- and post-exercise. RESULTS Compared to sea-level (101 ± 22 W), there was a stepwise reduction in power output with increasing hypoxia severity (-17.9 ± 8.9 %, -27.1 ± 10.7 %, -34.2 ± 12.0 % and - 44.6 ± 15.1 % at 2500 m, 3000 m, 3500 m, and 4000 m, respectively, all p < 0.05). Blood lactate and tissue saturation index were not different across hypoxia severities, and perceptual responses were exacerbated at 4000 m only, with increased breathing difficulty. Knee extensor torque decreased post-exercise (-14.5 ± 9.0 %, p < 0.05), independent of condition. CONCLUSIONS Increasing hypoxia severity reduces cycling power output and arterial oxygen saturation in a stepwise fashion without affecting exercise responses between sea-level and simulated altitudes up to 3500 m despite breathing difficulty being elevated at 4000 m.
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Affiliation(s)
- Siu Nam Li
- School of Human Sciences (Exercise and Sports Science), The University of Western Australia, Australia.
| | - Peter Peeling
- School of Human Sciences (Exercise and Sports Science), The University of Western Australia, Australia; Department of Sport Science, Western Australian Institute of Sport, Australia
| | - Brendan R Scott
- Murdoch Applied Sport Science Laboratory, Discipline of Exercise Science, Murdoch University, Australia; Centre for Healthy Ageing, Murdoch University, Australia
| | - Jeremiah J Peiffer
- Murdoch Applied Sport Science Laboratory, Discipline of Exercise Science, Murdoch University, Australia; Centre for Healthy Ageing, Murdoch University, Australia
| | - Alex Shaykevich
- School of Human Sciences (Exercise and Sports Science), The University of Western Australia, Australia; Perron Institute for Neurological and Translational Science, Australia
| | - Olivier Girard
- School of Human Sciences (Exercise and Sports Science), The University of Western Australia, Australia.
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3
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Mornas A, Brocherie F, Guilhem G, Guillotel A, LE Garrec S, Gouwy R, Gennisson JL, Beuve S, Racinais S. Active Heat Acclimation Does Not Alter Muscle-Tendon Unit Properties. Med Sci Sports Exerc 2023; 55:1076-1086. [PMID: 36719653 DOI: 10.1249/mss.0000000000003129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
PURPOSE Heat acclimation (HA) is recommended before competing in hot and humid conditions. HA has also been recently suggested to increase muscle strength, but its effects on human's muscle and tendon mechanical properties are not yet fully understood. This study investigated the effect of active HA on gastrocnemius medialis (GM) muscle-tendon properties. METHODS Thirty recreationally active participants performed 13 low-intensity cycling sessions, distributed over a 17-d period in hot (HA = ~38°C, ~58% relative humidity; n = 15) or in temperate environment (CON = ~23°C, ~35% relative humidity; n = 15). Mechanical data and high-frame rate ultrasound images were collected during electrically evoked and voluntary contractions pre- and postintervention. Shear modulus was measured at rest in GM, and vertical jump performance was assessed. RESULTS Core temperature decreased from the first to the last session in HA (-0.4°C ± 0.3°C; P = 0.015), while sweat rate increased (+0.4 ± 0.3 L·h -1 ; P = 0.010), suggesting effective HA, whereas no changes were observed in CON (both P ≥ 0.877). Heart rate was higher in HA versus CON and decreased throughout intervention in groups (both P ≤ 0.008), without an interaction effect ( P = 0.733). Muscle-tendon unit properties (i.e., maximal and explosive isometric torque production, contractile properties, voluntary activation, joint and fascicular force-velocity relationship, passive muscle, and active tendon stiffness) and vertical jump performance did not show training ( P ≥ 0.067) or group-training interaction ( P ≥ 0.232) effects. CONCLUSIONS Effective active HA does not alter muscle-tendon properties. Preparing hot and humid conditions with active HA can be envisaged in all sporting disciplines without the risk of impairing muscle performance.
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Affiliation(s)
| | - Franck Brocherie
- Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport (INSEP), Paris, FRANCE
| | - Gaël Guilhem
- Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport (INSEP), Paris, FRANCE
| | - Arthur Guillotel
- Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport (INSEP), Paris, FRANCE
| | | | | | - Jean-Luc Gennisson
- Laboratoire d'Imagerie Biomédicale Multimodale (BioMaps), CEA, CNRS, Inserm, Service Hospitalier Frédéric Joliot, Université Paris-Saclay, Orsay, FRANCE
| | - Steve Beuve
- Laboratoire d'Imagerie Biomédicale Multimodale (BioMaps), CEA, CNRS, Inserm, Service Hospitalier Frédéric Joliot, Université Paris-Saclay, Orsay, FRANCE
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4
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Mornas A, Racinais S, Brocherie F, Alhammoud M, Hager R, Desmedt Y, Guilhem G. Faster early rate of force development in a warmer muscle: an in vivo exploration of fascicle dynamics and muscle-tendon mechanical properties. Am J Physiol Regul Integr Comp Physiol 2022; 323:R123-R132. [PMID: 35579335 DOI: 10.1152/ajpregu.00280.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
While heat exposure has been shown to increase the rate of force development (RFD), the underlying processes remain unknown. This study investigated the effect of heat on gastrocnemius medialis (GM) muscle-tendon properties and interactions. Sixteen participants performed electrically-evoked and voluntary contractions combined with ultrafast ultrasound under thermoneutral (CON: 26°C, core temperature 37.0±0.3°C, muscle temperature 34.0±1.1°C) and passive heat exposure (HOT: 47°C, core temperature 38.4±0.3°C, muscle temperature 37.0±0.8°C) conditions. Maximal voluntary force was unchanged while voluntary activation decreased (-4.6±8.7%, P=0.038) in HOT. Heat exposure increased RFD before 100 ms from contraction onset (+48.2±62.7%; P=0.013), without further changes after 100 ms. GM fascicle dynamics during electrically-evoked and voluntary contractions remained unchanged between conditions. Joint velocity at a given force was higher in HOT (+7.1±6.6%; P=0.004), while the fascicle force-velocity relationship was unchanged. Passive muscle stiffness and active tendon stiffness were lower in HOT than CON (P≤0.030). This study showed that heat-induced increases in early RFD may not be attributed to changes in contractile properties. Late RFD was unaltered, probably explained by decreased soft tissues' stiffness in heat. Investigations are required to explore the possible influence of neural drive and motor unit recruitment in the enhancement of explosive strength elicited by heat exposure.
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Affiliation(s)
- Adèle Mornas
- French Institute of Sport (INSEP), Laboratory Sport, Expertise and Performance (EA 7370), Paris, France.,University of Paris, Paris, France
| | - Sebastien Racinais
- French Institute of Sport (INSEP), Laboratory Sport, Expertise and Performance (EA 7370), Paris, France.,Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - Franck Brocherie
- French Institute of Sport (INSEP), Laboratory Sport, Expertise and Performance (EA 7370), Paris, France
| | | | - Robin Hager
- French Institute of Sport (INSEP), Laboratory Sport, Expertise and Performance (EA 7370), Paris, France
| | - Yanis Desmedt
- French Institute of Sport (INSEP), Laboratory Sport, Expertise and Performance (EA 7370), Paris, France
| | - Gaël Guilhem
- French Institute of Sport (INSEP), Laboratory Sport, Expertise and Performance (EA 7370), Paris, France
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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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Ao D, Shourijeh MS, Patten C, Fregly BJ. Evaluation of Synergy Extrapolation for Predicting Unmeasured Muscle Excitations from Measured Muscle Synergies. Front Comput Neurosci 2020; 14:588943. [PMID: 33343322 PMCID: PMC7746870 DOI: 10.3389/fncom.2020.588943] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 11/09/2020] [Indexed: 12/14/2022] Open
Abstract
Electromyography (EMG)-driven musculoskeletal modeling relies on high-quality measurements of muscle electrical activity to estimate muscle forces. However, a critical challenge for practical deployment of this approach is missing EMG data from muscles that contribute substantially to joint moments. This situation may arise due to either the inability to measure deep muscles with surface electrodes or the lack of a sufficient number of EMG channels. Muscle synergy analysis (MSA) is a dimensionality reduction approach that decomposes a large number of muscle excitations into a small number of time-varying synergy excitations along with time-invariant synergy weights that define the contribution of each synergy excitation to all muscle excitations. This study evaluates how well missing muscle excitations can be predicted using synergy excitations extracted from muscles with available EMG data (henceforth called "synergy extrapolation" or SynX). The method was evaluated using a gait data set collected from a stroke survivor walking on an instrumented treadmill at self-selected and fastest-comfortable speeds. The evaluation process started with full calibration of a lower-body EMG-driven model using 16 measured EMG channels (collected using surface and fine wire electrodes) per leg. One fine wire EMG channel (either iliopsoas or adductor longus) was then treated as unmeasured. The synergy weights associated with the unmeasured muscle excitation were predicted by solving a nonlinear optimization problem where the errors between inverse dynamics and EMG-driven joint moments were minimized. The prediction process was performed for different synergy analysis algorithms (principal component analysis and non-negative matrix factorization), EMG normalization methods, and numbers of synergies. SynX performance was most influenced by the choice of synergy analysis algorithm and number of synergies. Principal component analysis with five or six synergies consistently predicted unmeasured muscle excitations the most accurately and with the greatest robustness to EMG normalization method. Furthermore, the associated joint moment matching accuracy was comparable to that produced by initial EMG-driven model calibration using all 16 EMG channels per leg. SynX may facilitate the assessment of human neuromuscular control and biomechanics when important EMG signals are missing.
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Affiliation(s)
- Di Ao
- Rice Computational Neuromechanics Lab, Department of Mechanical Engineering, Rice University, Houston, TX, United States
| | - Mohammad S. Shourijeh
- Rice Computational Neuromechanics Lab, Department of Mechanical Engineering, Rice University, Houston, TX, United States
| | - Carolynn Patten
- Biomechanics, Rehabilitation, and Integrative Neuroscience (BRaIN) Lab, VA Northern California Health Care System, Martinez, CA, United States
- Department of Physical Medicine and Rehabilitation, Davis School of Medicine, University of California, Sacramento, CA, United States
| | - Benjamin J. Fregly
- Rice Computational Neuromechanics Lab, Department of Mechanical Engineering, Rice University, Houston, TX, United States
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Labidi M, Ihsan M, Behan FP, Alhammoud M, Smith T, Mohamed M, Tourny C, Racinais S. Six weeks of localized heat therapy does not affect muscle mass, strength and contractile properties in healthy active humans. Eur J Appl Physiol 2020; 121:573-582. [PMID: 33159573 DOI: 10.1007/s00421-020-04545-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 10/27/2020] [Indexed: 11/25/2022]
Abstract
PURPOSE Animal and human studies have shown that repeated heating may induce skeletal muscle adaptations, increasing muscle strength. The aim of this study is to investigate the effect of 6 weeks of localized heating on skeletal muscle strength, volume and contractile properties in healthy humans. METHODS Fifteen active participants (8 males/7 females, 35 ± 6 years, 70 ± 14 kg, 173 ± 7 cm, average training of 87 min per week) were subjected to 6 weeks of single-leg heat therapy. Heat pads were applied for 8 h/day, 5 days/week, on one randomly selected calf of each participant, while the contralateral leg acted as control. The heat pads increased muscle temperature by 4.6 ± 1.2 °C (p < 0.001). Every 2 weeks, participants were tested for morphological (MRI), architectural (ultrasound), contractile (electrically evoked twitch), and force (isometric and isokinetic) adaptations. RESULTS Repeated localized heating did not affect the cross-sectional area (p = 0.873) or pennation angle (p = 0.345) of the gastrocnemius muscles; did not change the evoked peak twitch amplitude (p = 0.574) or rate of torque development (p = 0.770) of the plantar flexors; and did not change maximal voluntary isometric (p = 0.214) or isokinetic (p = 0.973) plantar flexor torque. CONCLUSION Whereas previous studies have observed improved skeletal muscle function following whole-body and localized heating in active and immobilized humans, respectively, the current data suggested that localized heating may not be a potent stimulus for muscle adaptations in active humans.
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Affiliation(s)
- Mariem Labidi
- Research and Scientific Support Department, Aspetar Orthopaedic and Sports Medicine Hospital, PO Box 29222, Doha, Qatar
- Faculty of Sport Sciences and Physical Education, CETAPS, University of Rouen, Mont-Saint-Aignan, France
| | - Mohammed Ihsan
- Research and Scientific Support Department, Aspetar Orthopaedic and Sports Medicine Hospital, PO Box 29222, Doha, Qatar
- Human Potential and Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore
| | - Fearghal P Behan
- Research and Scientific Support Department, Aspetar Orthopaedic and Sports Medicine Hospital, PO Box 29222, Doha, Qatar
- School of Health and Human Performance, Dublin City University, Dublin, Ireland
| | - Marine Alhammoud
- Surgery Department, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - Tessa Smith
- Radiology Department, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - Mohamed Mohamed
- Radiology Department, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - Claire Tourny
- Faculty of Sport Sciences and Physical Education, CETAPS, University of Rouen, Mont-Saint-Aignan, France
| | - Sébastien Racinais
- Research and Scientific Support Department, Aspetar Orthopaedic and Sports Medicine Hospital, PO Box 29222, Doha, Qatar.
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Townsend N, Brocherie F, Millet GP, Girard O. Central and peripheral muscle fatigue following repeated‐sprint running in moderate and severe hypoxia. Exp Physiol 2020; 106:126-138. [DOI: 10.1113/ep088485] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 06/15/2020] [Indexed: 01/08/2023]
Affiliation(s)
- Nathan Townsend
- Athlete Health and Performance Research Centre Aspetar Orthopaedic and Sports Medicine Hospital Doha Qatar
- College of Health and Life Sciences Hamad Bin Khalifa University Doha Qatar
| | - Franck Brocherie
- Laboratory Sport Expertise and Performance French Institute of Sport Paris France
| | | | - Olivier Girard
- Athlete Health and Performance Research Centre Aspetar Orthopaedic and Sports Medicine Hospital Doha Qatar
- School of Human Sciences (Exercise and Sport Science) The University of Western Australia Crawley Western Australia Australia
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Grosprêtre S, Gimenez P, Mourot L, Coratella G. Elastic band exercise induces greater neuromuscular fatigue than phasic isometric contractions. J Electromyogr Kinesiol 2019; 47:113-120. [DOI: 10.1016/j.jelekin.2018.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 11/01/2018] [Accepted: 12/10/2018] [Indexed: 10/27/2022] Open
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Barrué-Belou S, Marque P, Duclay J. Supraspinal Control of Recurrent Inhibition during Anisometric Contractions. Med Sci Sports Exerc 2019; 51:2357-2365. [PMID: 31107836 DOI: 10.1249/mss.0000000000002042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Increase in recurrent inhibition was observed during eccentric compared with isometric and concentric maximal voluntary contractions but the neural mechanisms involved in this specific control of the Renshaw cell activity are unknown. This study was designed to investigate the supraspinal control of the recurrent inhibition during anisometric contractions of the plantar flexor muscles. METHODS To that purpose, the paired Hoffmann-reflex (H-reflex) technique permitted to assess changes in homonymous recurrent pathway by comparing the modulations of test and conditioning H-reflexes (H' and H1, respectively) in the soleus (SOL) muscle during maximal and submaximal isometric, concentric and eccentric contractions. Submaximal contraction intensity was set at 50% of the SOL electromyographic activity recorded during maximal isometric contraction. Fourteen volunteer subjects participated in an experimental session designed to assess the activity of the recurrent inhibition pathway. RESULTS The results indicate that the amplitude of H1 normalized to the maximal M-wave were similar (P > 0.05) regardless of the muscle contraction type and intensity. Whatever the contraction intensity, the ratio between H' and H1 amplitudes was significantly decreased (P < 0.05) during eccentric compared with isometric and concentric contractions. Furthermore, this ratio was significantly smaller (P < 0.05) during submaximal compared with maximal contractions whatever the muscle contraction type. CONCLUSION Together, the current results confirm the supraspinal control of the Renshaw cell activity when muscle contraction intensity is modulated and show that this control remains similar for isometric, concentric and eccentric contractions. Data further suggest that recurrent inhibition pathway may serve as variable gain regulator at motoneuronal level to improve resolution in the control of motor output for the SOL during eccentric contractions.
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Affiliation(s)
- Simon Barrué-Belou
- Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, FRANCE
| | - Philippe Marque
- Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, FRANCE.,Service de Médecine Physique et Réadaptation, CHU Toulouse Rangueil, Toulouse, FRANCE
| | - Julien Duclay
- Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, FRANCE
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Barrué-Belou S, Marque P, Duclay J. Recurrent inhibition is higher in eccentric compared to isometric and concentric maximal voluntary contractions. Acta Physiol (Oxf) 2018; 223:e13064. [PMID: 29575639 DOI: 10.1111/apha.13064] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 03/07/2018] [Accepted: 03/08/2018] [Indexed: 11/30/2022]
Abstract
AIM This study was designed to investigate the influence of muscle contraction type on spinal recurrent inhibition during maximal voluntary contractions (MVC) of the plantar flexor muscles. METHODS To that purpose, the paired Hoffmann-reflex (H-reflex) technique permitted to assess changes in recurrent pathway by comparing the modulations of test, reference and conditioning H-reflexes (H', Href and H1 respectively) in the soleus muscle during isometric, concentric and eccentric MVC. Twenty-five subjects participated in an experimental session designed to assess the activity of the recurrent inhibition pathway. RESULTS The results indicate that both the electromyographic activity and the amplitude of H1 normalized to the maximal M-wave (Mmax ) were similar regardless of the muscle contraction type while the ratio between H' and H1 amplitudes was significantly smaller during eccentric compared with isometric and concentric MVC. Furthermore, Href and H' amplitudes did not differ significantly during both isometric and concentric MVCs while H' amplitude was significantly lower than Href amplitude during eccentric MVC. In addition, the V/Mmax ratio was similar for all muscle contraction type and greater H' amplitude was significantly correlated with greater V-wave amplitude regardless of the muscle contraction type. CONCLUSION Together, the current results indicate that recurrent inhibition is elevated for the soleus muscle during eccentric compared to isometric and concentric MVC. Data further suggest that the Renshaw cell activity is specifically controlled by the descending neural drive and/or peripheral neural mechanisms during eccentric MVC.
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Affiliation(s)
- S. Barrué-Belou
- Toulouse NeuroImaging Center; Université de Toulouse, Inserm, UPS; Toulouse France
| | - P. Marque
- Toulouse NeuroImaging Center; Université de Toulouse, Inserm, UPS; Toulouse France
- Service de Médecine Physique et Réadaptation; CHU Toulouse Rangueil; Toulouse France
| | - J. Duclay
- Toulouse NeuroImaging Center; Université de Toulouse, Inserm, UPS; Toulouse France
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12
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Girard O, Banzet S, Koulmann N, Chennaoui M, Drogou C, Chalabi H, Racinais S. Larger strength losses and muscle activation deficits in plantar flexors induced by backward downhill in reference to distance-matched forward uphill treadmill walk. Eur J Sport Sci 2018; 18:1346-1356. [PMID: 30016189 DOI: 10.1080/17461391.2018.1497091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
We tested the hypothesis that backward downhill walking (eccentric component) impairs both voluntary activation and muscle contractile properties in the plantar flexors and delays recovery as compared to a gradient and distance-matched uphill walk. Fourteen males performed two 30-min walking exercises (velocity: 1 m/ s; grade: 25%; load: 12% of body weight), one downhill (DW) and one uphill (UP), in a counterbalanced order, separated by 6 weeks. Neuromuscular test sessions were performed before, after, 24-, 48- and 72-h post-exercise, including motor nerve stimulations during brief (5 s) and sustained (1 min) maximal isometric voluntary contractions of the plantar flexors. DW (-18.1 ± 11.1%, P < .001), but not UP (-6.0 ± 7.7%, P =.15), decreased torque production during brief contractions for at least three days post-exercise (P < .05). Voluntary activation during brief contractions decreased after DW (P < .05), but not UP, and recovered by 24 h. Both UP (-9.3 ± 9.0%, P = .024) and DW (-25.6 ± 10.3%, P < .001) decreased torque production during sustained contractions but voluntary activation (P = .001) was lower in DW than UP. Peak twitch torque and maximum rates of torque development and relaxation were equally reduced after UP and DW (P < .05), and recovered by 24 h. DW induced an increase in muscle soreness with peak values observed 48 h post-walking (P < .001), whereas post-UP exercise changes were non-significant (all P > .05). Using a direct comparison, the capacity to drive the plantar flexors during sustained contractions remains sub-optimal during the three-day recovery period in response to non-exhaustive, downhill backward walking in reference to an uphill exercise matched for distance covered.
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Affiliation(s)
- Olivier Girard
- a Aspetar Orthopaedic and Sports Medicine Hospital , Doha , Qatar.,b School of Psychology and Exercise Science , Murdoch University , Perth , Australia
| | - Sébastien Banzet
- c French Armed Forces Biomedical Research Institute (IRBA) , Brétigny sur Orge , France.,d UMR-MD-1197 , Clamart , France
| | - Nathalie Koulmann
- c French Armed Forces Biomedical Research Institute (IRBA) , Brétigny sur Orge , France.,e Ecole du Val-de-Grâce , Paris , France
| | - Mounir Chennaoui
- c French Armed Forces Biomedical Research Institute (IRBA) , Brétigny sur Orge , France.,f University of Paris Descartes, Hôtel Dieu, EA7330 VIFASOM (Fatigue Vigilance and Sleep) , Paris , France
| | - Catherine Drogou
- c French Armed Forces Biomedical Research Institute (IRBA) , Brétigny sur Orge , France.,f University of Paris Descartes, Hôtel Dieu, EA7330 VIFASOM (Fatigue Vigilance and Sleep) , Paris , France
| | - Hakim Chalabi
- a Aspetar Orthopaedic and Sports Medicine Hospital , Doha , Qatar
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Hight RE, Quarshie AT, Black CD. Voluntary muscle activation and evoked volitional-wave responses as a function of torque. J Electromyogr Kinesiol 2018; 41:1-8. [PMID: 29709787 DOI: 10.1016/j.jelekin.2018.04.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 02/28/2018] [Accepted: 04/14/2018] [Indexed: 10/17/2022] Open
Abstract
INTRODUCTION This study employed a unique stimulation paradigm which allowed for the simultaneous assessment of voluntary activation levels (VA) via twitch-interpolation, and the evoked V-wave responses of the plantar flexors during submaximal and maximal contractions. Test-retest reliability was also examined. METHODS Fourteen participants repeated a stimulation protocol over four visits to assess VA and evoked V-wave amplitude across torque levels ranging from 20% to 100% MVC. MVC torque and EMG amplitude were also measured. RESULTS VA increased nonlinearly with torque production and plateaued by 80% MVC. V-wave amplitude increased linearly from 20% to 100% MVC. There were no differences in any dependent variable across visits (p > 0.05). VA demonstrated moderate to substantial reliability across all torque levels (ICC = 0.76-0.91) while V-wave amplitude exhibited fair to moderate reliability from 40% to 100% (ICC = 0.48-0.74). DISCUSSION We were able to reliably collect VA and the V-wave simultaneously in the plantar flexors. Collection of VA and V-wave during the same contraction provides distinct information regarding the contribution of motor-unit recruitment and descending cortico-spinal drive/excitability to force production.
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Affiliation(s)
- Robert E Hight
- The Department of Health and Exercise Science, The University of Oklahoma, Norman, OK, United States.
| | - Alwyn T Quarshie
- The Department of Health and Exercise Science, The University of Oklahoma, Norman, OK, United States
| | - Christopher D Black
- The Department of Health and Exercise Science, The University of Oklahoma, Norman, OK, United States
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Changes in central and peripheral neuromuscular fatigue indices after concentric versus eccentric contractions of the knee extensors. Eur J Appl Physiol 2018; 118:805-816. [PMID: 29411127 DOI: 10.1007/s00421-018-3816-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/23/2018] [Indexed: 10/18/2022]
Abstract
PURPOSE To better understand neuromuscular characteristics of eccentric exercise-induced muscle damage, this study compared between concentric (CONC) and eccentric (ECC) exercises of knee extensor muscles, and the first (ECC1) and second bouts of the eccentric exercise (ECC2) for central and peripheral parameters associated with neuromuscular fatigue. METHODS Twelve young men performed three exercise bouts separated by at least 1 week between CONC and ECC1, and 2 weeks between ECC1 and ECC2. In each exercise, maximal voluntary concentric or eccentric contractions of the knee extensors were performed until a reduction in maximal voluntary isometric contraction (MVC) torque of at least 40% MVC was achieved immediately post-exercise. MVC torque, central (voluntary activation and normalised electromyographic activity), and peripheral neuromuscular indices (evoked torque and M-wave amplitude), and muscle soreness were assessed before (PRE), immediately after (POST), 1 h (1H), and 1-4 days after exercise (D1, D2, D3, and D4). RESULTS MVC torque decreased at only POST for CONC (- 52.8%), but remained below the baseline at POST (- 48.6%), 1H (- 34.1%), and D1-D4 (- 34.1 to - 18.2%) after ECC1, and at POST (- 45.2%), 1H (- 24.4%) and D1 (- 13.4%) after ECC2 (p < 0.05). Voluntary activation decreased immediately after ECC1 (- 21.6%) and ECC2 (- 21.1%), but not after CONC. Electrically evoked torques decreased similarly at POST and 1H for the three conditions, but remained below the baseline at D1 only post-ECC1. CONCLUSION These results showed that both central and peripheral factors contributed to the MVC decrease after ECC1 and ECC2, but the decrease was mainly due to peripheral factors after CONC.
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Mtibaa K, Thomson A, Nichols D, Hautier C, Racinais S. Hyperthermia-induced Neural Alterations Impair Proprioception and Balance. Med Sci Sports Exerc 2017; 50:46-53. [PMID: 28863075 DOI: 10.1249/mss.0000000000001418] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
PURPOSE Hyperthermia has been shown to affect both central and peripheral nervous systems. However, the consequences of these alterations on the proprioceptive mechanisms underlying human movement control remain unclear. The aim of this study was to investigate the effect of passive hyperthermia on various measures of proprioception and balance, two key components of injury prevention and movement efficiency. METHODS After a familiarization session, 14 volunteers (8 males, 6 females) completed two experimental sessions in temperate (CON, 24°C) and hot (HOT, 44°C-50°C) conditions, in a counterbalanced order. Participants were tested for neural function (electrically evoked M-wave and Hoffman reflex, Soleus), active movement discrimination (five positions, 50 trials, dorsiflexion), dynamic balance (Star Excursion Balance Test, three directions), and static balance (single-leg stance). RESULTS Both rectal (39.0°C ± 0.3°C vs 36.9°C ± 0.6°C) and mean skin (37.9°C ± 1.0°C vs 32.0°C ± 2.7°C) temperatures were significantly higher in HOT than CON (P < 0.05). Hyperthermia significantly reduced the Hoffman reflex (P < 0.05) but not the M-wave (P > 0.05) amplitudes, increased the mean error for active movement discrimination (0.58°± 0.13° vs 0.50° ± 0.11°, +17%, P < 0.05), decreased the average distance reached in the posteromedial direction during dynamic balance (88.6 ± 7.9 cm vs 90.9 ± 6.1 cm, P < 0.05), and increased the contact area of the foot (126 ± 14 cm vs 122 ± 13 cm, +2.7%, P < 0.05) and the center of pressure excursion (64 ± 14 vs 57 ± 9 cm, +11.1%, P < 0.10) during single-leg stance. CONCLUSIONS The current study suggests that hyperthermia impairs the proprioception and balance parameters measured. These observations might be due to heat-induced alterations in efferent and afferent signals to and from the muscle.
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Affiliation(s)
- Khouloud Mtibaa
- 1Sport Science Program, College of Arts and Sciences, Qatar University, Doha, QATAR; 2Inter-university Laboratory of Human Movement Biology, University Claude Bernard Lyon 1, Villeurbanne, FRANCE; and 3Aspetar Orthopaedic and Sports Medicine Hospital, Doha, QATAR
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Meyer AJ, Patten C, Fregly BJ. Lower extremity EMG-driven modeling of walking with automated adjustment of musculoskeletal geometry. PLoS One 2017; 12:e0179698. [PMID: 28700708 PMCID: PMC5507406 DOI: 10.1371/journal.pone.0179698] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 06/02/2017] [Indexed: 12/13/2022] Open
Abstract
Neuromusculoskeletal disorders affecting walking ability are often difficult to manage, in part due to limited understanding of how a patient’s lower extremity muscle excitations contribute to the patient’s lower extremity joint moments. To assist in the study of these disorders, researchers have developed electromyography (EMG) driven neuromusculoskeletal models utilizing scaled generic musculoskeletal geometry. While these models can predict individual muscle contributions to lower extremity joint moments during walking, the accuracy of the predictions can be hindered by errors in the scaled geometry. This study presents a novel EMG-driven modeling method that automatically adjusts surrogate representations of the patient’s musculoskeletal geometry to improve prediction of lower extremity joint moments during walking. In addition to commonly adjusted neuromusculoskeletal model parameters, the proposed method adjusts model parameters defining muscle-tendon lengths, velocities, and moment arms. We evaluated our EMG-driven modeling method using data collected from a high-functioning hemiparetic subject walking on an instrumented treadmill at speeds ranging from 0.4 to 0.8 m/s. EMG-driven model parameter values were calibrated to match inverse dynamic moments for five degrees of freedom in each leg while keeping musculoskeletal geometry close to that of an initial scaled musculoskeletal model. We found that our EMG-driven modeling method incorporating automated adjustment of musculoskeletal geometry predicted net joint moments during walking more accurately than did the same method without geometric adjustments. Geometric adjustments improved moment prediction errors by 25% on average and up to 52%, with the largest improvements occurring at the hip. Predicted adjustments to musculoskeletal geometry were comparable to errors reported in the literature between scaled generic geometric models and measurements made from imaging data. Our results demonstrate that with appropriate experimental data, joint moment predictions for walking generated by an EMG-driven model can be improved significantly when automated adjustment of musculoskeletal geometry is included in the model calibration process.
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Affiliation(s)
- Andrew J. Meyer
- Department of Mechanical & Aerospace Engineering, University of Florida, Gainesville, FL, United States of America
| | - Carolynn Patten
- Department of Physical Therapy, University of Florida, Gainesville, FL, United States of America
- Neural Control of Movement Lab, Malcom Randall VA Medical Center, Gainesville, FL, United States of America
| | - Benjamin J. Fregly
- Department of Mechanical & Aerospace Engineering, University of Florida, Gainesville, FL, United States of America
- * E-mail:
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Racinais S, Wilson MG, Gaoua N, Périard JD. Heat acclimation has a protective effect on the central but not peripheral nervous system. J Appl Physiol (1985) 2017; 123:816-824. [PMID: 28684590 DOI: 10.1152/japplphysiol.00430.2017] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 07/05/2017] [Accepted: 07/05/2017] [Indexed: 11/22/2022] Open
Abstract
This study aimed to clarify the pathway mediating hyperthermia-induced alterations in neural drive transmission and determine if heat acclimation protects voluntary muscle activation and cognitive function in hyperthermic humans. Electrically evoked potentials (H reflex and M wave), executive function (special planning and working memory), and maximal voluntary isometric contractions (120 s) were assessed in 14 participants in control conditions [CON, 24°C, 40% relative humidity (RH)] and in a hyperthermic state (HYP, 44-50°C, 50% RH) on consecutive days in a counterbalanced order. Thereafter, participants were passively heat acclimated for 11 days (1 h per day, 48-50°C, 50% RH) before repeating the initial assessments. Heat acclimation decreased rectal temperature in CON (-0.2°C, P < 0.05), but participants were maintained at ~39°C in HYP. Heat acclimation increased the time required to reach 39°C (+9 min), along with sweat rate (+0.7 l/h), and serum extracellular expression of heat shock protein 72 (eHSP72; +20%) in HYP (P < 0.05). M-wave and H-reflex amplitudes were lower in HYP than CON (P < 0.05) and were not protected by heat acclimation. Nerve conduction velocity was faster in HYP than CON (P < 0.05) without being influenced by heat acclimation. These results suggest that peripheral neural drive transmission in the hyperthermic state is primarily affected by axonal conduction velocity rather than synaptic failure. Executive function, voluntary activation, and the ability to sustain torque were impaired in HYP (P < 0.05). However, despite no perceptual changes (P > 0.05), heat acclimation restored executive function, while protecting the ability to sustain voluntary activation and torque production during a prolonged contraction in hyperthermia (P < 0.05). Ultimately, heat acclimation induces beneficial central but not peripheral neural adaptations.NEW & NOTEWORTHY Heat acclimation restores planning accuracy and working memory in hyperthermic humans, together with the supraspinal capacity to sustain motor drive during a sustained maximal voluntary contraction. Electrically evoked potential data (M wave, H reflex) indicate that heat acclimation does not protect against hyperthermia-induced impairments in peripheral neural drive transmission. Heat acclimation induces beneficial central but not peripheral neural adaptations.
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Affiliation(s)
- Sebastien Racinais
- Aspetar Orthopaedic and Sports Medicine Hospital, Athlete Health and Performance Research Centre, Doha, Qatar; .,University of Queensland, Centre for Sensorimotor Neuroscience, School of Human Movement Studies, Brisbane, Australia
| | - Mathew G Wilson
- Aspetar Orthopaedic and Sports Medicine Hospital, Athlete Health and Performance Research Centre, Doha, Qatar
| | - Nadia Gaoua
- School of Applied Sciences, London South Bank University, London, United Kingdom; and
| | - Julien D Périard
- Aspetar Orthopaedic and Sports Medicine Hospital, Athlete Health and Performance Research Centre, Doha, Qatar.,University of Canberra, Research Institute for Sport and Exercise, Canberra, Australian Capital Territory, Australia
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Meyer AJ, Eskinazi I, Jackson JN, Rao AV, Patten C, Fregly BJ. Muscle Synergies Facilitate Computational Prediction of Subject-Specific Walking Motions. Front Bioeng Biotechnol 2016; 4:77. [PMID: 27790612 PMCID: PMC5061852 DOI: 10.3389/fbioe.2016.00077] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 09/21/2016] [Indexed: 12/18/2022] Open
Abstract
Researchers have explored a variety of neurorehabilitation approaches to restore normal walking function following a stroke. However, there is currently no objective means for prescribing and implementing treatments that are likely to maximize recovery of walking function for any particular patient. As a first step toward optimizing neurorehabilitation effectiveness, this study develops and evaluates a patient-specific synergy-controlled neuromusculoskeletal simulation framework that can predict walking motions for an individual post-stroke. The main question we addressed was whether driving a subject-specific neuromusculoskeletal model with muscle synergy controls (5 per leg) facilitates generation of accurate walking predictions compared to a model driven by muscle activation controls (35 per leg) or joint torque controls (5 per leg). To explore this question, we developed a subject-specific neuromusculoskeletal model of a single high-functioning hemiparetic subject using instrumented treadmill walking data collected at the subject's self-selected speed of 0.5 m/s. The model included subject-specific representations of lower-body kinematic structure, foot-ground contact behavior, electromyography-driven muscle force generation, and neural control limitations and remaining capabilities. Using direct collocation optimal control and the subject-specific model, we evaluated the ability of the three control approaches to predict the subject's walking kinematics and kinetics at two speeds (0.5 and 0.8 m/s) for which experimental data were available from the subject. We also evaluated whether synergy controls could predict a physically realistic gait period at one speed (1.1 m/s) for which no experimental data were available. All three control approaches predicted the subject's walking kinematics and kinetics (including ground reaction forces) well for the model calibration speed of 0.5 m/s. However, only activation and synergy controls could predict the subject's walking kinematics and kinetics well for the faster non-calibration speed of 0.8 m/s, with synergy controls predicting the new gait period the most accurately. When used to predict how the subject would walk at 1.1 m/s, synergy controls predicted a gait period close to that estimated from the linear relationship between gait speed and stride length. These findings suggest that our neuromusculoskeletal simulation framework may be able to bridge the gap between patient-specific muscle synergy information and resulting functional capabilities and limitations.
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Affiliation(s)
- Andrew J Meyer
- Department of Mechanical and Aerospace Engineering, University of Florida , Gainesville, FL , USA
| | - Ilan Eskinazi
- Department of Mechanical and Aerospace Engineering, University of Florida , Gainesville, FL , USA
| | - Jennifer N Jackson
- Department of Biomedical Engineering, University of Florida , Gainesville, FL , USA
| | - Anil V Rao
- Department of Mechanical and Aerospace Engineering, University of Florida , Gainesville, FL , USA
| | - Carolynn Patten
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA; Neural Control of Movement Lab, Malcom-Randall VA Medical Center, Gainesville, FL, USA
| | - Benjamin J Fregly
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, USA; Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
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Girard O, Brocherie F, Millet GP. High Altitude Increases Alteration in Maximal Torque but Not in Rapid Torque Development in Knee Extensors after Repeated Treadmill Sprinting. Front Physiol 2016; 7:97. [PMID: 27014095 PMCID: PMC4789550 DOI: 10.3389/fphys.2016.00097] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 02/29/2016] [Indexed: 12/05/2022] Open
Abstract
We assessed knee extensor neuromuscular adjustments following repeated treadmill sprints in different normobaric hypoxia conditions, with special reference to rapid muscle torque production capacity. Thirteen team- and racquet-sport athletes undertook 8 × 5-s “all-out” sprints (passive recovery = 25 s) on a non-motorized treadmill in normoxia (NM; FiO2 = 20.9%), at low (LA; FiO2 = 16.8%) and high (HA; FiO2 = 13.3%) normobaric hypoxia (simulated altitudes of ~1800 m and ~3600 m, respectively). Explosive (~1 s; “fast” instruction) and maximal (~5 s; “hard” instruction) voluntary isometric contractions (MVC) of the knee extensors (KE), with concurrent electromyographic (EMG) activity recordings of the vastus lateralis (VL) and rectus femoris (RF) muscles, were performed before and 1-min post-exercise. Rate of torque development (RTD) and EMG (i.e., Root Mean Square or RMS) rise from 0 to 30, −50, −100, and −200 ms were recorded, and were also normalized to maximal torque and EMG values, respectively. Distance covered during the first 5-s sprint was similar (P > 0.05) in all conditions. A larger (P < 0.05) sprint decrement score and a shorter (P < 0.05) cumulated distance covered over the eight sprints occurred in HA (−8 ± 4% and 178 ± 11 m) but not in LA (−7 ± 3% and 181 ± 10 m) compared to NM (−5 ± 2% and 183 ± 9 m). Compared to NM (−9 ± 7%), a larger (P < 0.05) reduction in MVC torque occurred post-exercise in HA (−14 ± 9%) but not in LA (-12 ± 7%), with no difference between NM and LA (P > 0.05). Irrespectively of condition (P > 0.05), peak RTD (−6 ± 11%; P < 0.05), and normalized peak RMS activity for VL (−8 ± 11%; P = 0.07) and RF (−14 ± 11%; P < 0.01) muscles were reduced post-exercise, whereas reductions (P < 0.05) in absolute RTD occurred within the 0–100 (−8 ± 9%) and 0–200 ms (−10 ± 8%) epochs after contraction onset. After normalization to MVC torque, there was no difference in RTD values. Additionally, the EMG rise for VL muscle was similar (P > 0.05), whereas it increased (P < 0.05) for RF muscle during all epochs post-exercise, independently of the conditions. In summary, alteration in repeated-sprint ability and post-exercise MVC decrease were greater at high altitude than in normoxia or at low altitude. However, the post-exercise alterations in RTD were similar between normoxia and low-to-high hypoxia.
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Affiliation(s)
- Olivier Girard
- ISSUL, Institute of Sport Sciences, Faculty of Biology and Medicine, University of LausanneLausanne, Switzerland; Athlete Health and Performance Research Centre, Orthopaedic and Sports Medicine HospitalAspetar, Doha, Qatar
| | - Franck Brocherie
- ISSUL, Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne Lausanne, Switzerland
| | - Grégoire P Millet
- ISSUL, Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne Lausanne, Switzerland
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Papaiordanidou M, Mustacchi V, Stevenot JD, Vanoncini M, Martin A. Spinal and supraspinal mechanisms affecting torque development at different joint angles. Muscle Nerve 2015; 53:626-32. [DOI: 10.1002/mus.24895] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 08/31/2015] [Accepted: 09/03/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Maria Papaiordanidou
- UMR7287, CNRS, Aix-Marseille University; 163 avenue de Luminy 13288 Marseille France
| | - Valérie Mustacchi
- UMR7287, CNRS, Aix-Marseille University; 163 avenue de Luminy 13288 Marseille France
| | - Jean-Damien Stevenot
- UMR7287, CNRS, Aix-Marseille University; 163 avenue de Luminy 13288 Marseille France
| | - Michele Vanoncini
- UMR7287, CNRS, Aix-Marseille University; 163 avenue de Luminy 13288 Marseille France
| | - Alain Martin
- INSERM U1093 Cognition, Action et Plasticité Sensorimotrice, Université de Bourgogne, UFR STAPS; Campus Universitaire Dijon France
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Alexandre F, Derosiere G, Papaiordanidou M, Billot M, Varray A. Cortical motor output decreases after neuromuscular fatigue induced by electrical stimulation of the plantar flexor muscles. Acta Physiol (Oxf) 2015; 214:124-34. [PMID: 25740017 DOI: 10.1111/apha.12478] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 07/29/2014] [Accepted: 03/02/2015] [Indexed: 11/30/2022]
Abstract
AIM Neuromuscular electrical stimulation (NMES) causes early onset of neuromuscular fatigue. Peripheral electrophysiological explorations suggest that supra-spinal alterations are involved through sensitive afferent pathways. As sensory input is projected over the primary somatosensory cortex (S1), S1 area involvement in inhibiting the central motor drive can be hypothesized. This study assessed cortical activity under a fatiguing NMES protocol at low frequency. METHODS Twenty healthy males performed five NMES sequences of 17 trains over the plantar flexors (30 Hz, 4 s on/6 s off). Before and after each sequence, neuromuscular tests composed of maximal voluntary contractions (MVCs) were carried out. Cortical activity was assessed during MVCs with functional near-infrared spectroscopy over S1 and primary motor (M1) areas, through oxy- [HbO] and deoxy-haemoglobin [HbR] variation. Electrophysiological data (H-reflex during MVC, EMG activity and level of voluntary activation) were also recorded. RESULTS MVC torque significantly decreased after the first 17 NMES trains (P < 0.001). The electrophysiological data were consistent with supra-spinal alterations. In addition, [HbO] declined significantly during the protocol over the S1 and M1 areas from the first 17 NMES trains (P < 0.01 and P < 0.001 respectively), while [HbR] increased (P < 0.05 and P < 0.01 respectively), indicating early decline in cortical activity over both primary cortical areas. CONCLUSIONS The declining cortical activity over the M1 area is highly consistent with the electrophysiological findings and supports motor cortex involvement in the loss of force after a fatiguing NMES protocol. In addition, the declining cortical activity over the S1 area indicates that the decreased motor output from M1 is not due to increased S1 inhibitory activity.
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Affiliation(s)
- F. Alexandre
- Movement To Health; Euromov; Montpellier University; Montpellier France
- Fontalvie; Clinique du Souffle ‘la Vallonie’; Lodève France
| | - G. Derosiere
- Movement To Health; Euromov; Montpellier University; Montpellier France
- Biomedical Engineering Research Group; National University of Ireland; Maynooth Ireland
| | - M. Papaiordanidou
- Movement To Health; Euromov; Montpellier University; Montpellier France
- Institut des Sciences du Mouvement; Aix-Marseille University; Marseille France
| | - M. Billot
- Movement To Health; Euromov; Montpellier University; Montpellier France
| | - A. Varray
- Movement To Health; Euromov; Montpellier University; Montpellier France
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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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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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Cattagni T, Martin A, Scaglioni G. Is spinal excitability of the triceps surae mainly affected by muscle activity or body position? J Neurophysiol 2014; 111:2525-32. [DOI: 10.1152/jn.00455.2013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of this study was to determine how muscle activity and body orientation contribute to the triceps surae spinal transmission modulation, when moving from a sitting to a standing position. Maximal Hoffmann-reflex (Hmax) and motor potential (Mmax) were evoked in the soleus (SOL), medial and lateral gastrocnemius in 10 male subjects and in three conditions, passive sitting, active sitting and upright standing, with the same SOL activity in active sitting and upright standing. Moreover volitional wave (V) was evoked in the two active conditions (i.e., active sitting and upright standing). The results showed that SOL Hmax/Mmax was lower in active sitting than in passive sitting, while for the gastrocnemii it was not significantly altered. For the three plantar flexors, Hmax/Mmax was lower in upright standing than in active sitting, whereas V/Mmax was not modulated. SOL H-reflex is therefore affected by the increase in muscle activity and change in body orientation, while, in the gastrocnemii, it was only affected by a change in posture. In conclusion, passing from a sitting to a standing position affects the Hmax/Mmax of the whole triceps surae, but the mechanisms responsible for this change differ among the synergist muscles. The V/Mmax does not change when upright stance is assumed. This means that the increased inhibitory activity in orthostatic position is compensated by an increased excitatory inflow to the α-motoneurons of central and/or peripheral origin.
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Affiliation(s)
- T. Cattagni
- Institut National de la Santé et de la Recherche Médicale 1093, Faculty of Sport Science, University of Burgundy, Dijon, France
| | - A. Martin
- Institut National de la Santé et de la Recherche Médicale 1093, Faculty of Sport Science, University of Burgundy, Dijon, France
| | - G. Scaglioni
- Institut National de la Santé et de la Recherche Médicale 1093, Faculty of Sport Science, University of Burgundy, Dijon, France
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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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