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Olarogba OB, Lockyer EJ, Antolinez AK, Button DC. Sex-related differences in corticospinal excitability outcome measures of the biceps brachii during a submaximal elbow flexor contraction. Physiol Rep 2024; 12:e16102. [PMID: 39095333 PMCID: PMC11296885 DOI: 10.14814/phy2.16102] [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: 04/08/2024] [Revised: 05/24/2024] [Accepted: 05/24/2024] [Indexed: 08/04/2024] Open
Abstract
The purpose of this study was to investigate the effects of sex, muscle thickness, and subcutaneous fat thickness (SFT) on corticospinal excitability outcome measures of the biceps brachii. Eighteen participants (10 males and 8 females) completed this study. Ultrasound was used to assess biceps brachii muscle thickness and the overlying SFT. Transcranial magnetic stimulation (TMS) was used to determine corticospinal excitability by inducing motor-evoked potentials (MEPs) at eight different TMS intensities from 90% to 160% of active motor threshold (AMT) from the biceps brachii during an isometric contraction of the elbow flexors at 10% of maximum voluntary contraction (MVC). Biceps brachii maximal compound muscle action potential (Mmax) was also recorded prior to and after TMS. Males had higher (p < 0.001) biceps brachii muscle thickness and lower SFT, produced higher levels of MVC force and had, on average, higher (p < 0.001) MEP amplitudes at lower (p < 0.05) percentages of maximal stimulator output than females during the 10% elbow flexion MVC. Multiple linear regression modeling revealed that sex was not associated with any of the neurophysiological parameters examined, while SFT showed a positive association with the stimulation intensity required at AMT (p = 0.035) and a negative association with biceps brachii pre-stimulus electromyography (EMG) activity (p = 0.021). Additionally, there was a small positive association between muscle thickness and biceps brachii pre-stimulus EMG activity (p = 0.049). Overall, this study suggests that some measures of corticospinal excitability may be different between the sexes and influenced by SFT and muscle thickness.
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Affiliation(s)
- Olalekan B. Olarogba
- Human Neurophysiology LabSchool of Human Kinetics and RecreationSt. John'sNewfoundlandCanada
| | - Evan J. Lockyer
- Human Neurophysiology LabSchool of Human Kinetics and RecreationSt. John'sNewfoundlandCanada
- Faculty of MedicineMemorial University of NewfoundlandSt. John'sNewfoundlandCanada
| | - Angie K. Antolinez
- Human Neurophysiology LabSchool of Human Kinetics and RecreationSt. John'sNewfoundlandCanada
| | - Duane C. Button
- Human Neurophysiology LabSchool of Human Kinetics and RecreationSt. John'sNewfoundlandCanada
- Faculty of MedicineMemorial University of NewfoundlandSt. John'sNewfoundlandCanada
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2
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Pagan JI, Harmon KK, Girts RM, MacLennan RJ, Beausejour JP, Hernandez-Sarabia JA, Coker NA, Carr JC, Ye X, DeFreitas JM, Stock MS. Sex-Specific Reliability of Lower-Limb Corticospinal Excitability and Silent Periods. J Strength Cond Res 2023; 37:1882-1887. [PMID: 37267320 DOI: 10.1519/jsc.0000000000004525] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
ABSTRACT Pagan, JI, Harmon, KK, Girts, RM, MacLennan, RJ, Beausejour, JP, Hernandez-Sarabia, JA, Coker, NA, Carr, JC, Ye, X, DeFreitas, JM, and Stock, MS. Sex-specific reliability of lower-limb corticospinal excitability and silent periods. J Strength Cond Res 37(9): 1882-1887, 2023-Transcranial magnetic stimulation (TMS) is a research tool that has potential to provide new insights into strength training-induced adaptations. However, using TMS to study the lower limbs is challenging, and sex-specific reliability has yet to be reported. We examined the reliability of corticospinal excitability and silent periods for the rectus femoris, vastus lateralis, and biceps femoris in both sexes. Thirteen males and 14 females reported to the laboratory twice. During both trials, a double cone coil was used to deliver 20 pulses to the rectus femoris hotspot with a stimulator output of 130% of active motor threshold. Motor-evoked potential peak-to-peak amplitude, which reflects corticospinal excitability, and silent period duration were quantified. Our results offer 4 novel findings. First, corticospinal excitability and silent period demonstrated higher reliability for the females. Second, regardless of sex and muscle, the silent period was more reliable than corticospinal excitability. Third, reliability was highest for our target muscle (rectus femoris), with lower reliability for the vastus lateralis and biceps femoris, suggesting that these methods cannot be used to study coactivation. Fourth, active motor threshold showed less variability than corticospinal excitability and silent period but increased at trial 2 in females. Many of the intraclass correlation coefficients were excellent (≥0.90), although we attribute this finding to variability between subjects. Reliability of lower-limb TMS measures may be sex, muscle, and variable dependent. Our findings suggest that both males and females should be included in lower-limb TMS research, although combining data between sexes should be approached cautiously.
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Affiliation(s)
- Jason I Pagan
- Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, Florida
| | - Kylie K Harmon
- Department of Exercise Science, Syracuse University, Syracuse, New York
| | - Ryan M Girts
- Department of Natural and Health Sciences, Pfeiffer University, Misenheimer, North Carolina
| | - Rob J MacLennan
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, Oklahoma
| | - Jonathan P Beausejour
- Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, Florida
| | - Jesus A Hernandez-Sarabia
- Posture and Gait Neuromechanics Laboratory, California State University, Bakersfield, Bakersfield, California
| | - Nicholas A Coker
- Department of Exercise Science and Athletic Training, Springfield College, Springfield, Massachusetts
| | - Joshua C Carr
- Department of Kinesiology, Texas Christian University, Fort Worth, Texas
- Department of Medical Education, Texas Christian University School of Medicine, Fort Worth, Texas; and
| | - Xin Ye
- Doctor of Physical Therapy Program, Department of Rehabilitation Sciences, University of Hartford, West Hartford, Connecticut
| | - Jason M DeFreitas
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, Oklahoma
| | - Matt S Stock
- Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, Florida
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3
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Dietmann A, Blanquet M, Rösler KM, Scheidegger O. Effects of high resistance muscle training on corticospinal output during motor fatigue assessed by transcranial magnetic stimulation. Front Physiol 2023; 14:1125974. [PMID: 36969602 PMCID: PMC10036808 DOI: 10.3389/fphys.2023.1125974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 02/27/2023] [Indexed: 03/12/2023] Open
Abstract
Introduction: Central fatigue refers to a reduced drive of motor cortical output during exercise, and performance can be enhanced after training. However, the effects of training on central fatigue remain unclear. Changes in cortical output can be addressed non-invasively using transcranial magnetic stimulation (TMS). The aim of the study was to compare responses to TMS during a fatiguing exercise before and after a 3 weeks lasting resistance training, in healthy subjects.Methods: The triple stimulation technique (TST) was used to quantify a central conduction index (CCI = amplitude ratio of central conduction response and peripheral nerve response) to the abductor digiti minimi muscle (ADM) in 15 subjects. The training consisted of repetitive isometric maximal voluntary contractions (MVC) of ADM for 2 min twice a day. Before and after this training, TST recordings were obtained every 15 s during an 2 min exercise of MVC of the ADM, where subjects performed repetitive contractions of the ADM, and repeatedly during a recovery period of 7 min.Results: There was a consistent decrease of force to approximately 40% of MVC in all experiments and in all subjects, both before and after training. In all subjects, CCI decreased during exercise. While before training, theCCI decreased to 49% (SD 23.7%) after 2 min of exercise, it decreased after training onlyto 79% (SD 26.4%) after exercise (p < 0.01).Discussion: The training regimen increased the proportion of target motor units that could be activated by TMS during a fatiguing exercise. The results point to a reduced intracortical inhibition, which may be a transient physiological response to facilitate the motor task. Possible underlying mechanisms at spinal and supraspinal sites are discussed.
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Affiliation(s)
- Anelia Dietmann
- Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Switzerland, Bern, Switzerland
| | - Marisa Blanquet
- Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Switzerland, Bern, Switzerland
| | - Kai Michael Rösler
- Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Switzerland, Bern, Switzerland
- Neurozentrum Basel, Bellevue Medical Group, Basel, Switzerland
| | - Olivier Scheidegger
- Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Switzerland, Bern, Switzerland
- Institute for Diagnostic and Interventional Neuroradiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- *Correspondence: Olivier Scheidegger ,
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Kourtidou-Papadeli C, Frantzidis CA, Bakirtzis C, Petridou A, Gilou S, Karkala A, Machairas I, Kantouris N, Nday CM, Dermitzakis EV, Bakas E, Mougios V, Bamidis PD, Vernikos J. Therapeutic Benefits of Short-Arm Human Centrifugation in Multiple Sclerosis-A New Approach. Front Neurol 2022; 12:746832. [PMID: 35058870 PMCID: PMC8764123 DOI: 10.3389/fneur.2021.746832] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 12/03/2021] [Indexed: 12/16/2022] Open
Abstract
Short-arm human centrifugation (SAHC) is proposed as a robust countermeasure to treat deconditioning and prevent progressive disability in a case of secondary progressive multiple sclerosis. Based on long-term physiological knowledge derived from space medicine and missions, artificial gravity training seems to be a promising physical rehabilitation approach toward the prevention of musculoskeletal decrement due to confinement and inactivity. So, the present study proposes a novel infrastructure based on SAHC to investigate the hypothesis that artificial gravity ameliorates the degree of disability. The patient was submitted to a 4-week training programme including three weekly sessions of 30 min of intermittent centrifugation at 1.5–2 g. During sessions, cardiovascular, muscle oxygen saturation (SmO2) and electroencephalographic (EEG) responses were monitored, whereas neurological and physical performance tests were carried out before and after the intervention. Cardiovascular parameters improved in a way reminiscent of adaptations to aerobic exercise. SmO2 decreased during sessions concomitant with increased g load, and, as training progressed, SmO2 of the suffering limb dropped, both effects suggesting increased oxygen use, similar to that seen during hard exercise. EEG showed increased slow and decreased fast brain waves, with brain reorganization/plasticity evidenced through functional connectivity alterations. Multiple-sclerosis-related disability and balance capacity also improved. Overall, this study provides novel evidence supporting SAHC as a promising therapeutic strategy in multiple sclerosis, based on mechanical loading, thereby setting the basis for future randomized controlled trials.
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Affiliation(s)
- Chrysoula Kourtidou-Papadeli
- Biomedical Engineering and Aerospace Neuroscience (BEAN), Laboratory of Medical Physics and Digital Innovation, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.,Greek Aerospace Medical Association and Space Research (GASMA-SR), Thessaloniki, Greece.,Laboratory of Aerospace and Rehabilitation Applications "Joan Vernikos", AROGI Rehabilitation Centre, Thessaloniki, Greece.,Aeromedical Center of Thessaloniki (AeMC), Thessaloniki, Greece
| | - Christos A Frantzidis
- Biomedical Engineering and Aerospace Neuroscience (BEAN), Laboratory of Medical Physics and Digital Innovation, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.,Greek Aerospace Medical Association and Space Research (GASMA-SR), Thessaloniki, Greece
| | - Christos Bakirtzis
- Department of Neurology, Multiple Sclerosis Center, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Anatoli Petridou
- Laboratory of Evaluation of Human Biological Performance, School of Physical Education and Sport Science at Thessaloniki, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Sotiria Gilou
- Biomedical Engineering and Aerospace Neuroscience (BEAN), Laboratory of Medical Physics and Digital Innovation, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Aliki Karkala
- Greek Aerospace Medical Association and Space Research (GASMA-SR), Thessaloniki, Greece
| | - Ilias Machairas
- Biomedical Engineering and Aerospace Neuroscience (BEAN), Laboratory of Medical Physics and Digital Innovation, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Nikolaos Kantouris
- Greek Aerospace Medical Association and Space Research (GASMA-SR), Thessaloniki, Greece
| | - Christiane M Nday
- Biomedical Engineering and Aerospace Neuroscience (BEAN), Laboratory of Medical Physics and Digital Innovation, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | | | - Eleftherios Bakas
- Laboratory of Aerospace and Rehabilitation Applications "Joan Vernikos", AROGI Rehabilitation Centre, Thessaloniki, Greece
| | - Vassilis Mougios
- Laboratory of Evaluation of Human Biological Performance, School of Physical Education and Sport Science at Thessaloniki, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Panagiotis D Bamidis
- Biomedical Engineering and Aerospace Neuroscience (BEAN), Laboratory of Medical Physics and Digital Innovation, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.,Greek Aerospace Medical Association and Space Research (GASMA-SR), Thessaloniki, Greece
| | - Joan Vernikos
- Greek Aerospace Medical Association and Space Research (GASMA-SR), Thessaloniki, Greece.,Thirdage LLC, Culpeper, VA, United States
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5
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Chow ZS, Moreland AT, Macpherson H, Teo WP. The Central Mechanisms of Resistance Training and Its Effects on Cognitive Function. Sports Med 2021; 51:2483-2506. [PMID: 34417978 DOI: 10.1007/s40279-021-01535-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2021] [Indexed: 01/17/2023]
Abstract
Resistance exercise is used extensively in athletic and general populations to induce neuromuscular adaptations to increase muscle size and performance. Exercise parameters such as exercise frequency, intensity, duration and modality are carefully manipulated to induce specific adaptations to the neuromuscular system. While the benefits of resistance exercise on the neuromuscular system are well documented, there is growing evidence to suggest that resistance exercise, even when performed acutely, can lead to neuroplastic changes within the central nervous system (CNS) and improve cognitive functioning. As such, resistance exercise has been proposed as a novel adjuvant rehabilitation strategy in populations that suffer from neurological or neurocognitive impairments (i.e. Parkinson's and Alzheimer's dementia) or even to attenuate age-related declines in cognitive health. In this review, we present evidence for the neuroplastic effects and cognitive benefits of resistance exercise and propose some of the underlying mechanisms that drive neuroplasticity following resistance training. We will further discuss the effects of exercise parameters, in particular exercise frequency, intensity, duration and modality to improve cognitive health. Lastly, we will highlight some of the existing limitations in the literature surrounding the use of resistance exercise to improve cognitive function and propose considerations to improve future studies in this field. In summary, the current evidence supports the role of resistance exercise, as a stand alone or in combination with aerobic exercise, for benefiting cognitive health and that it should be considered as an adjuvant therapy to treat age- or disease-related cognitive declines.
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Affiliation(s)
- Zi-Siong Chow
- College of Medicine, Biology and Environment Research, School of Population Health, Australian National University (ANU), Canberra, ACT, Australia
| | - Ashleigh T Moreland
- STEM College, School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, 3000, Australia
| | - Helen Macpherson
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, Australia
| | - Wei-Peng Teo
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, Australia. .,Physical Education and Sports Science Academic Group, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore, 637616, Singapore.
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6
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Garcia MAC, Nogueira-Campos AA, Moraes VH, Souza VH. Can Corticospinal Excitability Shed Light Into the Effects of Handedness on Motor Performance? FRONTIERS IN NEUROERGONOMICS 2021; 2:651501. [PMID: 38235226 PMCID: PMC10790861 DOI: 10.3389/fnrgo.2021.651501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 03/01/2021] [Indexed: 01/19/2024]
Affiliation(s)
- Marco Antonio Cavalcanti Garcia
- Programa de Pós-Graduação em Ciências da Reabilitação e Desempenho Físico-Funcional, Faculdade de Fisioterapia, Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil
- Laboratório de Neurofisiologia Cognitiva (LabNeuro), Departamento de Fisiologia, Instituto de Ciências Biológicas, Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil
- Grupo de Estudos em Neuro Biomecânica, Faculdade de Fisioterapia, Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil
- Núcleo de Pesquisas em Neurociências e Reabilitação Motora, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Anaelli Aparecida Nogueira-Campos
- Laboratório de Neurofisiologia Cognitiva (LabNeuro), Departamento de Fisiologia, Instituto de Ciências Biológicas, Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil
- Grupo de Estudos em Neuro Biomecânica, Faculdade de Fisioterapia, Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil
| | - Victor Hugo Moraes
- Núcleo de Pesquisas em Neurociências e Reabilitação Motora, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Victor Hugo Souza
- Grupo de Estudos em Neuro Biomecânica, Faculdade de Fisioterapia, Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
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7
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Chaves AR, Snow NJ, Alcock LR, Ploughman M. Probing the Brain-Body Connection Using Transcranial Magnetic Stimulation (TMS): Validating a Promising Tool to Provide Biomarkers of Neuroplasticity and Central Nervous System Function. Brain Sci 2021; 11:384. [PMID: 33803028 PMCID: PMC8002717 DOI: 10.3390/brainsci11030384] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/09/2021] [Accepted: 03/12/2021] [Indexed: 01/18/2023] Open
Abstract
Transcranial magnetic stimulation (TMS) is a non-invasive method used to investigate neurophysiological integrity of the human neuromotor system. We describe in detail, the methodology of a single pulse TMS protocol that was performed in a large cohort of people (n = 110) with multiple sclerosis (MS). The aim was to establish and validate a core-set of TMS variables that predicted typical MS clinical outcomes: walking speed, hand dexterity, fatigue, and cognitive processing speed. We provide a brief and simple methodological pipeline to examine excitatory and inhibitory corticospinal mechanisms in MS that map to clinical status. Delayed and longer ipsilateral silent period (a measure of transcallosal inhibition; the influence of one brain hemisphere's activity over the other), longer cortical silent period (suggestive of greater corticospinal inhibition via GABA) and higher resting motor threshold (lower corticospinal excitability) most strongly related to clinical outcomes, especially when measured in the hemisphere corresponding to the weaker hand. Greater interhemispheric asymmetry (imbalance between hemispheres) correlated with poorer performance in the greatest number of clinical outcomes. We also show, not surprisingly, that TMS variables related more strongly to motor outcomes than non-motor outcomes. As it was validated in a large sample of patients with varying severities of central nervous system dysfunction, the protocol described herein can be used by investigators and clinicians alike to investigate the role of TMS as a biomarker in MS and other central nervous system disorders.
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Affiliation(s)
| | | | | | - Michelle Ploughman
- L.A. Miller Centre, Recovery and Performance Laboratory, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL A1A 1E5, Canada; (A.R.C.); (N.J.S.); (L.R.A.)
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8
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Hortobágyi T, Granacher U, Fernandez-Del-Olmo M, Howatson G, Manca A, Deriu F, Taube W, Gruber M, Márquez G, Lundbye-Jensen J, Colomer-Poveda D. Functional relevance of resistance training-induced neuroplasticity in health and disease. Neurosci Biobehav Rev 2020; 122:79-91. [PMID: 33383071 DOI: 10.1016/j.neubiorev.2020.12.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 12/18/2020] [Accepted: 12/19/2020] [Indexed: 01/13/2023]
Abstract
Repetitive, monotonic, and effortful voluntary muscle contractions performed for just a few weeks, i.e., resistance training, can substantially increase maximal voluntary force in the practiced task and can also increase gross motor performance. The increase in motor performance is often accompanied by neuroplastic adaptations in the central nervous system. While historical data assigned functional relevance to such adaptations induced by resistance training, this claim has not yet been systematically and critically examined in the context of motor performance across the lifespan in health and disease. A review of muscle activation, brain and peripheral nerve stimulation, and imaging data revealed that increases in motor performance and neuroplasticity tend to be uncoupled, making a mechanistic link between neuroplasticity and motor performance inconclusive. We recommend new approaches, including causal mediation analytical and hypothesis-driven models to substantiate the functional relevance of resistance training-induced neuroplasticity in the improvements of gross motor function across the lifespan in health and disease.
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Affiliation(s)
- Tibor Hortobágyi
- Center for Human Movement Sciences, University of Groningen, University Medical CenterGroningen, Groningen, Netherlands.
| | - Urs Granacher
- Division of Training and Movement Sciences, Research Focus Cognition Sciences, University of Potsdam, Potsdam, Germany
| | - Miguel Fernandez-Del-Olmo
- Area of Sport Sciences, Faculty of Sports Sciences and Physical Education, Center for Sport Studies, King Juan Carlos University, Madrid, Spain
| | - Glyn Howatson
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle, UK; Water Research Group, North West University, Potchefstroom, South Africa
| | - Andrea Manca
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Franca Deriu
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Wolfgang Taube
- Department of Neurosciences and Movement Sciences, University of Fribourg, Fribourg, Switzerland
| | - Markus Gruber
- Human Performance Research Centre, Department of Sport Science, University of Konstanz, Konstanz, Germany
| | - Gonzalo Márquez
- Department of Physical Education and Sport, Faculty of Sports Sciences and Physical Education, University of A Coruña, A Coruña, Spain
| | - Jesper Lundbye-Jensen
- Movement & Neuroscience, Department of Nutrition, Exercise & Sports Department of Neuroscience, University of Copenhagenk, Faculty of Health Science, Universidad Isabel I, Burgos, Spain
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9
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Škarabot J, Brownstein CG, Casolo A, Del Vecchio A, Ansdell P. The knowns and unknowns of neural adaptations to resistance training. Eur J Appl Physiol 2020; 121:675-685. [PMID: 33355714 PMCID: PMC7892509 DOI: 10.1007/s00421-020-04567-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 11/18/2020] [Indexed: 12/22/2022]
Abstract
The initial increases in force production with resistance training are thought to be primarily underpinned by neural adaptations. This notion is firmly supported by evidence displaying motor unit adaptations following resistance training; however, the precise locus of neural adaptation remains elusive. The purpose of this review is to clarify and critically discuss the literature concerning the site(s) of putative neural adaptations to short-term resistance training. The proliferation of studies employing non-invasive stimulation techniques to investigate evoked responses have yielded variable results, but generally support the notion that resistance training alters intracortical inhibition. Nevertheless, methodological inconsistencies and the limitations of techniques, e.g. limited relation to behavioural outcomes and the inability to measure volitional muscle activity, preclude firm conclusions. Much of the literature has focused on the corticospinal tract; however, preliminary research in non-human primates suggests reticulospinal tract is a potential substrate for neural adaptations to resistance training, though human data is lacking due to methodological constraints. Recent advances in technology have provided substantial evidence of adaptations within a large motor unit population following resistance training. However, their activity represents the transformation of afferent and efferent inputs, making it challenging to establish the source of adaptation. Whilst much has been learned about the nature of neural adaptations to resistance training, the puzzle remains to be solved. Additional analyses of motoneuron firing during different training regimes or coupling with other methodologies (e.g., electroencephalography) may facilitate the estimation of the site(s) of neural adaptations to resistance training in the future.
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Affiliation(s)
- Jakob Škarabot
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Callum G Brownstein
- Laboratoire Interuniversitaire de Biologie de la Motricité, Université Jean Monnet Saint-Etienne, Université Lyon, Saint-Étienne, France
| | - Andrea Casolo
- Department of Bioengineering, Imperial College London, London, UK.,Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Alessandro Del Vecchio
- Department of Artificial Intelligence and Biomedical Engineering, Faculty of Engineering, Friedrich-Alexander University, Erlangen-Nurnberg, 91052, Erlangen, Germany
| | - Paul Ansdell
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK.
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10
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O'Brien SM, Lichtwark GA, Carroll TJ, Barber LA. Impact of Lower Limb Active Movement Training in Individuals With Spastic Type Cerebral Palsy on Neuromuscular Control Outcomes: A Systematic Review. Front Neurol 2020; 11:581892. [PMID: 33324326 PMCID: PMC7726235 DOI: 10.3389/fneur.2020.581892] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 10/22/2020] [Indexed: 01/17/2023] Open
Abstract
Background: Cerebral Palsy (CP) is a non-progressive neurological condition that results in motor impairment which increases proximally to distally along the lower extremity (i.e., greatest impairment at the ankle). Consequently, motor impairment and reduced voluntary muscle activation results in reduced neuromuscular control of the lower limb in this population. CP rehabilitation traditionally aims to improve movement proficiency for functional activities, such as walking, by using a range of active movement modalities that require volitional effort; however, the underlying neural mechanisms of improved control and function remain unknown. The primary purpose of this study was to systematically determine the efficacy of lower limb active movement interventions to improve neuromuscular control in individuals with CP. Methodology: A search for studies involving an active lower limb intervention and neurophysiological outcome measures in individuals with CP was performed in five electronic databases. Studies were assessed for methodological quality using the Downs and Black assessment tool. Results: Nine of 6,263 articles met the inclusion criteria. Methodological quality of all studies was poor, ranging from 2 to 27 out of a possible score of 32 points on the Downs and Black assessment tool. The study interventions varied extensively in modality and prescription as well as in the outcome measures used. Conclusions: Whether active movement improves neuromuscular control of the lower limb in CP is unclear due to high variability in intervention protocols and selected outcomes measures. Future active intervention studies must carefully consider the selection of neurophysiological outcome measures.
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Affiliation(s)
- Shari M O'Brien
- School of Human Movement and Nutrition Sciences, Faculty of Health and Behavioural Sciences, The University of Queensland, Brisbane, QLD, Australia.,Centre for Sensorimotor Performance, The University of Queensland, Brisbane, QLD, Australia
| | - Glen A Lichtwark
- School of Human Movement and Nutrition Sciences, Faculty of Health and Behavioural Sciences, The University of Queensland, Brisbane, QLD, Australia.,Centre for Sensorimotor Performance, The University of Queensland, Brisbane, QLD, Australia
| | - Timothy J Carroll
- School of Human Movement and Nutrition Sciences, Faculty of Health and Behavioural Sciences, The University of Queensland, Brisbane, QLD, Australia.,Centre for Sensorimotor Performance, The University of Queensland, Brisbane, QLD, Australia
| | - Lee A Barber
- School of Allied Health Sciences, Griffith University, Brisbane, QLD, Australia.,Child Health Research Centre, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
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Chaves AR, Devasahayam AJ, Riemenschneider M, Pretty RW, Ploughman M. Walking Training Enhances Corticospinal Excitability in Progressive Multiple Sclerosis-A Pilot Study. Front Neurol 2020; 11:422. [PMID: 32581998 PMCID: PMC7287174 DOI: 10.3389/fneur.2020.00422] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/22/2020] [Indexed: 12/16/2022] Open
Abstract
Background: Inflammatory lesions and neurodegeneration lead to motor, cognitive, and sensory impairments in people with multiple sclerosis (MS). Accumulation of disability is at least partially due to diminished capacity for neuroplasticity within the central nervous system. Aerobic exercise is a potentially important intervention to enhance neuroplasticity since it causes upregulation of neurotrophins and enhances corticospinal excitability, which can be probed using single-pulse transcranial magnetic stimulation (TMS). Whether people with progressive MS who have accumulated substantial disability could benefit from walking rehabilitative training to enhance neuroplasticity is not known. Objective: We aimed to determine whether 10 weeks of task-specific walking training would affect corticospinal excitability over time (pre, post, and 3-month follow-up) among people with progressive MS who required walking aids. Results: Eight people with progressive MS (seven female; 29–74 years old) with an Expanded Disability Status Scale of 6–6.5 underwent harness-supported treadmill walking training in a temperature controlled room at 16°C (10 weeks; three times/week; 40 min at 40–65% heart rate reserve). After training, there was significantly higher corticospinal excitability in both brain hemispheres, reductions in TMS active motor thresholds, and increases in motor-evoked potential amplitudes and slope of the recruitment curve (REC). Decreased intracortical inhibition (shorter cortical silent period) after training was noted in the hemisphere corresponding to the stronger hand only. These effects were not sustained at follow-up. There was a significant relationship between increases in corticospinal excitability (REC, area under the curve) in the hemisphere corresponding to the stronger hand and lessening of both intensity and impact of fatigue on activities of daily living (Fatigue Severity Scale and Modified Fatigue Impact Scale, respectively). Conclusion: Our pilot results support that vigorous treadmill training can potentially improve neuroplastic potential and mitigate symptoms of the disease even among people who have accumulated substantial disability due to MS.
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Affiliation(s)
- Arthur R Chaves
- Recovery and Performance Laboratory, Faculty of Medicine, L. A. Miller Centre, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Augustine J Devasahayam
- Recovery and Performance Laboratory, Faculty of Medicine, L. A. Miller Centre, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Morten Riemenschneider
- Section for Sports Science, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Ryan W Pretty
- Recovery and Performance Laboratory, Faculty of Medicine, L. A. Miller Centre, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Michelle Ploughman
- Recovery and Performance Laboratory, Faculty of Medicine, L. A. Miller Centre, Memorial University of Newfoundland, St. John's, NL, Canada
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Exercise-Induced Brain Excitability Changes in Progressive Multiple Sclerosis: A Pilot Study. J Neurol Phys Ther 2020; 44:132-144. [DOI: 10.1097/npt.0000000000000308] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Manca A, Hortobágyi T, Rothwell J, Deriu F. Neurophysiological adaptations in the untrained side in conjunction with cross-education of muscle strength: a systematic review and meta-analysis. J Appl Physiol (1985) 2018; 124:1502-1518. [DOI: 10.1152/japplphysiol.01016.2017] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We reviewed the evidence from randomized controlled trials (RCTs) focusing on the neurophysiological adaptations in the untrained side associated with cross-education of strength (CE) and pooled data into definite effect estimates for neurophysiological variables assessed in chronic CE studies. Furthermore, scoping directions for future research were provided to enhance the homogeneity and comparability of studies investigating the neural responses to CE. The magnitude of CE was 21.1 ± 18.2% (mean ± SD; P < 0.0001) in 22 RCTs ( n = 467 subjects) that measured at least 1 neurophysiological variable in the untrained side, including the following: electromyography (EMG; 14 studies); motor evoked potential (MEP; 8 studies); short-interval intracortical inhibition (SICI), recruitment curve, and M wave (6 studies); cortical silent period (cSP; 5 studies); interhemispheric inhibition, intracortical facilitation (ICF), and H reflex (2 studies); and V wave, short-interval ICF, short-latency afferent inhibition, and long-latency afferent inhibition (1 study). Only EMG, MEP, ICF, cSP, and SICI could be included in the meta-analysis (18 studies, n = 387). EMG ( P = 0.26, n = 235) and MEP amplitude ( P = 0.11, n = 145) did not change in the untrained limb after CE. cSP duration ( P = 0.02, n = 114) and SICI ( P = 0.001, n = 95) decreased in the untrained hemisphere according to body region and type and intensity of training. The magnitude of CE did not correlate with changes in these transcranial magnetic stimulation (TMS) measures. The design of this meta-analytical study and the lack of correlations prevented the ability to link mechanistically the observed neurophysiological changes to CE. Notwithstanding the limited amount of data available for pooling, the use of TMS to assess the ipsilateral neurophysiological responses to unilateral training still confirms the central neural origin hypothesis of chronic CE induced by strength training. However, how these neural adaptations contribute to CE remains unclear.
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Affiliation(s)
- Andrea Manca
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Tibor Hortobágyi
- Center for Human Movement Sciences, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - John Rothwell
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - Franca Deriu
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
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El-Sayes J, Harasym D, Turco CV, Locke MB, Nelson AJ. Exercise-Induced Neuroplasticity: A Mechanistic Model and Prospects for Promoting Plasticity. Neuroscientist 2018; 25:65-85. [PMID: 29683026 DOI: 10.1177/1073858418771538] [Citation(s) in RCA: 132] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Aerobic exercise improves cognitive and motor function by inducing neural changes detected using molecular, cellular, and systems level neuroscience techniques. This review unifies the knowledge gained across various neuroscience techniques to provide a comprehensive profile of the neural mechanisms that mediate exercise-induced neuroplasticity. Using a model of exercise-induced neuroplasticity, this review emphasizes the sequence of neural events that accompany exercise, and ultimately promote changes in human performance. This is achieved by differentiating between neuroplasticity induced by acute versus chronic aerobic exercise. Furthermore, this review emphasizes experimental considerations that influence the opportunity to observe exercise-induced neuroplasticity in humans. These include modifiable factors associated with the exercise intervention and nonmodifiable factors such as biological sex, ovarian hormones, genetic variations, and fitness level. To maximize the beneficial effects of exercise in health, disease, and following injury, future research should continue to explore the mechanisms that mediate exercise-induced neuroplasticity. This review identifies some fundamental gaps in knowledge that may serve to guide future research in this area.
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Affiliation(s)
- Jenin El-Sayes
- 1 Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Diana Harasym
- 2 School of Biomedical Engineering, McMaster University, Hamilton, Ontario, Canada
| | - Claudia V Turco
- 1 Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Mitchell B Locke
- 1 Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Aimee J Nelson
- 1 Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
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Kidgell DJ, Bonanno DR, Frazer AK, Howatson G, Pearce AJ. Corticospinal responses following strength training: a systematic review and meta-analysis. Eur J Neurosci 2017; 46:2648-2661. [DOI: 10.1111/ejn.13710] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 08/27/2017] [Accepted: 08/31/2017] [Indexed: 01/21/2023]
Affiliation(s)
- Dawson J. Kidgell
- Department of Physiotherapy; School of Primary and Allied Health Care; Faculty of Medicine, Nursing and Health Science; Monash University; Melbourne Vic. 3199 Australia
| | - Daniel R. Bonanno
- Discipline of Podiatry; School of Allied Health; La Trobe University; Melbourne Vic. Australia
- La Trobe Sport and Exercise Medicine Research Centre; School of Allied Health; La Trobe University; Melbourne Vic. Australia
| | - Ashlyn K. Frazer
- Department of Physiotherapy; School of Primary and Allied Health Care; Faculty of Medicine, Nursing and Health Science; Monash University; Melbourne Vic. 3199 Australia
| | - Glyn Howatson
- Faculty of Health and Life Sciences; Northumbria University; Newcastle-upon-Tyne UK
- Water Research Group; School of Environmental Sciences and Development; Northwest University; Potchefstroom South Africa
| | - Alan J. Pearce
- Discipline of Exercise Science; School of Allied Health; La Trobe University; Melbourne Vic. Australia
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Lattari E, de Oliveira BS, Oliveira BRR, de Mello Pedreiro RC, Machado S, Neto GAM. Effects of transcranial direct current stimulation on time limit and ratings of perceived exertion in physically active women. Neurosci Lett 2017; 662:12-16. [PMID: 28993207 DOI: 10.1016/j.neulet.2017.10.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 10/03/2017] [Accepted: 10/05/2017] [Indexed: 02/02/2023]
Abstract
The limiting factors of maximum performance in humans have been extensively investigated. The aim of this study was to verify the acute effects of transcranial direct current stimulation on time limit (i.e., the time by which an individual is able to sustain a certain intensity of effort) at 100% of peak power (tlim@100%PP) and ratings of perceived exertion (RPE). Eleven moderately active women underwent an anthropometric evaluation and a maximal incremental test in the cycle ergometer, in order to obtain peak power (PP). At the two subsequent visits, which were separated by 48-72h, participants were randomly assigned to two experimental conditions: anodal stimulation (a-tDCS) and sham. In the a-tDCS condition, the stimulus was applied in the left dorsolateral prefrontal cortex (DLPFC), with intensity of 2mA for 20min. In the sham condition, the equipment was switched off after 30s of stimulation. Immediately after the conditions, participants performed the tlim@100%PP. Immediately after the tlim@100%PP test, the RPE scale was applied. The results demonstrated that the tlim@100%PP was higher in a-tDCS condition compared to sham condition (p=0.005). No difference was found between the conditions (a-tDCS vs sham) for the RPE (p=0.52). The anodal stimulus increased the tolerance to the exercise performed in the cycloergometer with maximum load, having some ergogenic effect in exercises of cyclic characteristics.
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Affiliation(s)
- Eduardo Lattari
- Physical Activity Neuroscience Laboratory (LABNAF), Physical Activity Sciences Postgraduate Program - Salgado de Oliveira University (UNIVERSO), Niterói, Brazil
| | - Bruno Soares de Oliveira
- Physical Activity Sciences Postgraduate Program - Salgado de Oliveira University (UNIVERSO), Niterói, Brazil
| | | | | | - Sérgio Machado
- Physical Activity Neuroscience Laboratory (LABNAF), Physical Activity Sciences Postgraduate Program - Salgado de Oliveira University (UNIVERSO), Niterói, Brazil; Laboratory of Panic and Respiration, Institute of Psychiatry (IPUB), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
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Mason J, Frazer A, Horvath DM, Pearce AJ, Avela J, Howatson G, Kidgell D. Adaptations in corticospinal excitability and inhibition are not spatially confined to the agonist muscle following strength training. Eur J Appl Physiol 2017; 117:1359-1371. [DOI: 10.1007/s00421-017-3624-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 04/25/2017] [Indexed: 11/25/2022]
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Souron R, Farabet A, Féasson L, Belli A, Millet GY, Lapole T. Eight weeks of local vibration training increases dorsiflexor muscle cortical voluntary activation. J Appl Physiol (1985) 2017; 122:1504-1515. [PMID: 28385918 DOI: 10.1152/japplphysiol.00793.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 03/10/2017] [Accepted: 03/30/2017] [Indexed: 01/03/2023] Open
Abstract
The aim of this study was to evaluate the effects of an 8-wk local vibration training (LVT) program on functional and corticospinal properties of dorsiflexor muscles. Forty-four young subjects were allocated to a training (VIB, n = 22) or control (CON, n = 22) group. The VIB group performed twenty-four 1-h sessions (3 sessions/wk) of 100-Hz vibration applied to the right tibialis anterior. Both legs were tested in each group before training (PRE), after 4 (MID) and 8 (POST) wk of training, and 2 wk after training (POST2W). Maximal voluntary contraction (MVC) torque was assessed, and transcranial magnetic stimulation (TMS) was used to evaluate cortical voluntary activation (VATMS), motor evoked potential (MEP), cortical silent period (CSP), and input-output curve parameters. MVC was significantly increased for VIB at MID for right and left legs [+7.4% (P = 0.001) and +6.2% (P < 0.01), respectively] and remained significantly greater than PRE at POST [+12.0% (P < 0.001) and +10.1% (P < 0.001), respectively]. VATMS was significantly increased for right and left legs at MID [+4.4% (P < 0.01) and +4.7% (P < 0.01), respectively] and at POST [+4.9% (P = 0.001) and +6.2% (P = 0.001), respectively]. These parameters remained enhanced in both legs at POST2W MEP and CSP recorded during MVC and input-output curve parameters did not change at any time point for either leg. Despite no changes in excitability or inhibition being observed, LVT seems to be a promising method to improve strength through an increase of maximal voluntary activation, i.e., neural adaptations. Local vibration may thus be further considered for clinical or aging populations.NEW & NOTEWORTHY The effects of a local vibration training program on cortical voluntary activation measured with transcranial magnetic stimulation were assessed for the first time in dorsiflexors, a functionally important muscle group. We observed that training increased maximal voluntary strength likely because of the strong and repeated activation of Ia spindle afferents during vibration training that led to changes in the cortico-motoneuronal pathway, as demonstrated by the increase in cortical voluntary activation.
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Affiliation(s)
- Robin Souron
- Laboratoire Interuniversitaire de Biologie de la Motricité, Université de Lyon, Université Jean Monnet Saint-Etienne, Saint-Etienne, France
| | - Adrien Farabet
- Laboratoire Interuniversitaire de Biologie de la Motricité, Université de Lyon, Université Jean Monnet Saint-Etienne, Saint-Etienne, France
| | - Léonard Féasson
- Laboratoire Interuniversitaire de Biologie de la Motricité, Université de Lyon, Université Jean Monnet Saint-Etienne, Saint-Etienne, France.,Myology Unit, Referent Center of Rare Neuromuscular Diseases, Centre Hospitalier Universitaire Saint-Etienne, France; and
| | - Alain Belli
- Laboratoire Interuniversitaire de Biologie de la Motricité, Université de Lyon, Université Jean Monnet Saint-Etienne, Saint-Etienne, France
| | - Guillaume Y Millet
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Thomas Lapole
- Laboratoire Interuniversitaire de Biologie de la Motricité, Université de Lyon, Université Jean Monnet Saint-Etienne, Saint-Etienne, France;
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Specific neck training induces sustained corticomotor hyperexcitability as assessed by motor evoked potentials. Spine (Phila Pa 1976) 2013; 38:E979-84. [PMID: 23609207 DOI: 10.1097/brs.0b013e3182975310] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Experimental investigation of short-term and long-term corticomotor effects of specific neck training, coordination training, and no training. OBJECTIVE To determine the effects of different training programs on the motor neurons controlling the neck muscles as well as the effects of training on muscle strength and muscle fatigue, and the correlations between corticomotor control and motor learning. SUMMARY OF BACKGROUND DATA Training is usually recommended for unspecific neck pain and consists of neck and upper body coordination, strengthening, and endurance exercises. However, it is unclear which type of training is the most effective. No studies have previously investigated the neural effect of neck training and the possible differential effect of specific versus coordination training on corticomotor control. METHODS Transcranial magnetic stimulation and electromyography were used to elicit and monitor motor evoked potentials (MEPs) from the trapezius and thumb muscles before and 30 minutes, 1 hour, and 7 days after training. Parameters measured were MEP amplitude, MEP latency, strength, learning effects, and muscle fatigue. RESULTS Only specific neck training yielded a 67% increase in MEP amplitudes for up to 7 days after training compared with baseline (P < 0.001). No significant changes were seen after coordination training, no training, and in the within-subject control muscle. The mean muscle strength increased immediately after specific neck training from 56.6 to 61 kg (P < 0.001). No subjective or objective measures of fatigue were observed. CONCLUSION Specific neck training induced a sustained hyperexcitability of motor neurons controlling the neck muscles compared with coordination training and controls. These findings may prove valuable in the process of developing more effective clinical training programs for unspecific neck pain.
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