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Martino G, Valli G, Sarto F, Franchi MV, Narici MV, DE Vito G. Neuromodulatory Contribution to Muscle Force Production after Short-Term Unloading and Active Recovery. Med Sci Sports Exerc 2024; 56:1830-1839. [PMID: 38689447 DOI: 10.1249/mss.0000000000003473] [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: 05/02/2024]
Abstract
PURPOSE Prior evidence has shown that neural factors contribute to the loss of muscle force after skeletal muscle disuse. However, little is known about the specific neural mechanisms altered by disuse. Persistent inward current (PIC) is an intrinsic property of motoneurons responsible for prolonging and amplifying the synaptic input, proportionally to the level of neuromodulation, thus influencing motoneuron discharge rate and force production. Here, we hypothesized that short-term unilateral lower limb suspension (ULLS) would reduce the neuromodulatory input associated with PIC, contributing to the reduction of force generation capacity. In addition, we tested whether physical exercise would restore the force generation capacity by reestablishing the initial level of neuromodulatory input. METHODS In 12 young adults, we assessed maximal voluntary contraction pre- and post-10 d of ULLS and after 21 d of active recovery (AR) based on resistance exercise. PIC was estimated from high-density surface electromyograms of the vastus lateralis muscle as the delta frequency (Δ F ) of paired motor units calculated during isometric ramped contractions. RESULTS The values of Δ F were reduced after 10 d of ULLS (-33%, P < 0.001), but were fully reestablished after the AR (+29.4%, P < 0.001). The changes in estimated PIC values were correlated ( r = 0.63, P = 0.004) with the reduction in maximal voluntary contraction after ULLS (-29%, P = 0.002) and its recovery after the AR (+28.5%, P = 0.003). CONCLUSIONS Our findings suggest that PIC estimates are reduced by muscle disuse and may contribute to the loss of force production and its recovery with exercise. Overall, this is the first study demonstrating that, in addition to peripheral neuromuscular changes, central neuromodulation is a major contributor to the loss of force generation capacity after disuse, and can be recovered after resistance exercise.
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Affiliation(s)
- Giovanni Martino
- Department of Biomedical Sciences, University of Padova, Padova, ITALY
| | - Giacomo Valli
- Department of Biomedical Sciences, University of Padova, Padova, ITALY
| | - Fabio Sarto
- Department of Biomedical Sciences, University of Padova, Padova, ITALY
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McKendry J, Coletta G, Nunes EA, Lim C, Phillips SM. Mitigating disuse-induced skeletal muscle atrophy in ageing: Resistance exercise as a critical countermeasure. Exp Physiol 2024. [PMID: 39106083 DOI: 10.1113/ep091937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Accepted: 07/17/2024] [Indexed: 08/07/2024]
Abstract
The gradual deterioration of physiological systems with ageing makes it difficult to maintain skeletal muscle mass (sarcopenia), at least partly due to the presence of 'anabolic resistance', resulting in muscle loss. Sarcopenia can be transiently but markedly accelerated through periods of muscle disuse-induced (i.e., unloading) atrophy due to reduced physical activity, sickness, immobilisation or hospitalisation. Periods of disuse are detrimental to older adults' overall quality of life and substantially increase their risk of falls, physical and social dependence, and early mortality. Disuse events induce skeletal muscle atrophy through various mechanisms, including anabolic resistance, inflammation, disturbed proteostasis and mitochondrial dysfunction, all of which tip the scales in favour of a negative net protein balance and subsequent muscle loss. Concerningly, recovery from disuse atrophy is more difficult for older adults than their younger counterparts. Resistance training (RT) is a potent anabolic stimulus that can robustly stimulate muscle protein synthesis and mitigate muscle losses in older adults when implemented before, during and following unloading. RT may take the form of traditional weightlifting-focused RT, bodyweight training and lower- and higher-load RT. When combined with sufficient dietary protein, RT can accelerate older adults' recovery from a disuse event, mitigate frailty and improve mobility; however, few older adults regularly participate in RT. A feasible and practical approach to improving the accessibility and acceptability of RT is through the use of resistance bands. Moving forward, RT must be prescribed to older adults to mitigate the negative consequences of disuse atrophy.
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Affiliation(s)
- James McKendry
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Giulia Coletta
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Everson A Nunes
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Changhyun Lim
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Stuart M Phillips
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
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3
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Pabla P, Jones E, Piasecki M, Phillips B. Skeletal muscle dysfunction with advancing age. Clin Sci (Lond) 2024; 138:863-882. [PMID: 38994723 PMCID: PMC11250095 DOI: 10.1042/cs20231197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 06/15/2024] [Accepted: 06/20/2024] [Indexed: 07/13/2024]
Abstract
As a result of advances in medical treatments and associated policy over the last century, life expectancy has risen substantially and continues to increase globally. However, the disconnect between lifespan and 'health span' (the length of time spent in a healthy, disease-free state) has also increased, with skeletal muscle being a substantial contributor to this. Biological ageing is accompanied by declines in both skeletal muscle mass and function, termed sarcopenia. The mechanisms underpinning sarcopenia are multifactorial and are known to include marked alterations in muscle protein turnover and adaptations to the neural input to muscle. However, to date, the relative contribution of each factor remains largely unexplored. Specifically, muscle protein synthetic responses to key anabolic stimuli are blunted with advancing age, whilst alterations to neural components, spanning from the motor cortex and motoneuron excitability to the neuromuscular junction, may explain the greater magnitude of function losses when compared with mass. The consequences of these losses can be devastating for individuals, their support networks, and healthcare services; with clear detrimental impacts on both clinical (e.g., mortality, frailty, and post-treatment complications) and societal (e.g., independence maintenance) outcomes. Whether declines in muscle quantity and quality are an inevitable component of ageing remains to be completely understood. Nevertheless, strategies to mitigate these declines are of vital importance to improve the health span of older adults. This review aims to provide an overview of the declines in skeletal muscle mass and function with advancing age, describes the wide-ranging implications of these declines, and finally suggests strategies to mitigate them, including the merits of emerging pharmaceutical agents.
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Affiliation(s)
- Pardeep Pabla
- Centre of Metabolism, Ageing and Physiology (COMAP), School of Medicine, University of Nottingham, Royal Derby Hospital, Derby, DE22 3DT, U.K
| | - Eleanor J. Jones
- Centre of Metabolism, Ageing and Physiology (COMAP), School of Medicine, University of Nottingham, Royal Derby Hospital, Derby, DE22 3DT, U.K
| | - Mathew Piasecki
- Centre of Metabolism, Ageing and Physiology (COMAP), School of Medicine, University of Nottingham, Royal Derby Hospital, Derby, DE22 3DT, U.K
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research (CMAR), U.K
- NIHR Nottingham Biomedical Research Centre (BRC), U.K
| | - Bethan E. Phillips
- Centre of Metabolism, Ageing and Physiology (COMAP), School of Medicine, University of Nottingham, Royal Derby Hospital, Derby, DE22 3DT, U.K
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research (CMAR), U.K
- NIHR Nottingham Biomedical Research Centre (BRC), U.K
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Deane C, Piasecki M, Atherton P. Skeletal muscle immobilisation-induced atrophy: mechanistic insights from human studies. Clin Sci (Lond) 2024; 138:741-756. [PMID: 38895777 PMCID: PMC11186857 DOI: 10.1042/cs20231198] [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: 02/16/2024] [Revised: 05/28/2024] [Accepted: 06/04/2024] [Indexed: 06/21/2024]
Abstract
Periods of skeletal muscle disuse lead to rapid declines in muscle mass (atrophy), which is fundamentally underpinned by an imbalance between muscle protein synthesis (MPS) and muscle protein breakdown (MPB). The complex interplay of molecular mechanisms contributing to the altered regulation of muscle protein balance during disuse have been investigated but rarely synthesised in the context of humans. This narrative review discusses human models of muscle disuse and the ensuing inversely exponential rate of muscle atrophy. The molecular processes contributing to altered protein balance are explored, with a particular focus on growth and breakdown signalling pathways, mitochondrial adaptations and neuromuscular dysfunction. Finally, key research gaps within the disuse atrophy literature are highlighted providing future avenues to enhance our mechanistic understanding of human disuse atrophy.
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Affiliation(s)
- Colleen S. Deane
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton General Hospital, U.K
| | - Matthew Piasecki
- Centre of Metabolism, Ageing and Physiology (CoMAP), Medical Research Council/Versus Arthritis UK Centre of Excellence for Musculoskeletal Ageing Research (CMAR), National Institute of Health Research (NIHR) Biomedical Research Centre (BRC), University of Nottingham, U.K
| | - Philip J. Atherton
- Centre of Metabolism, Ageing and Physiology (CoMAP), Medical Research Council/Versus Arthritis UK Centre of Excellence for Musculoskeletal Ageing Research (CMAR), National Institute of Health Research (NIHR) Biomedical Research Centre (BRC), University of Nottingham, U.K
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Olmos AA, Montgomery TR, Sears KN, Dinyer TK, Hammer SM, Bergstrom HC, Hill EC, Succi PJ, Lawson J, Trevino MA. Blood flow restriction increases necessary muscle excitation of the elbow flexors during a single high-load contraction. Eur J Appl Physiol 2024; 124:1807-1820. [PMID: 38236301 DOI: 10.1007/s00421-023-05405-y] [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: 07/03/2023] [Accepted: 12/09/2023] [Indexed: 01/19/2024]
Abstract
PURPOSE To investigate the effects of blood flow restriction (BFR) on electromyographic amplitude (EMGRMS)-force relationships of the biceps brachii (BB) during a single high-load muscle action. METHODS Twelve recreationally active males and eleven recreationally active females performed maximal voluntary contractions (MVCs), followed by an isometric trapezoidal muscle action of the elbow flexors at 70% MVC. Surface EMG was recorded from the BB during BFR and control (CON) visits. For BFR, cuff pressure was 60% of the pressure required to completely occlude blood at rest. Individual b (slope) and a terms (gain) were calculated from the log-transformed EMGRMS-force relationships during the linearly increasing and decreasing segments of the trapezoid. EMGRMS during the steady force segment was normalized to MVC EMGRMS. RESULTS For BFR, the b terms were greater during the linearly increasing segment than the linearly decreasing segment (p < 0.001), and compared to the linearly increasing segment for CON (p < 0.001). The a terms for BFR were greater during the linearly decreasing than linearly increasing segment (p = 0.028). Steady force N-EMGRMS was greater for BFR than CON collapsed across sex (p = 0.041). CONCLUSION BFR likely elicited additional recruitment of higher threshold motor units during the linearly increasing- and steady force-segment. The differences between activation and deactivation strategies were only observed with BFR, such as the b terms decreased and the a terms increased for the linearly decreasing segment in comparison to the increasing segment. However, EMGRMS-force relationships during the linearly increasing- and decreasing-segments were not different between sexes during BFR and CON.
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Affiliation(s)
- Alex A Olmos
- Applied Neuromuscular Physiology Laboratory, Department of Health and Human Performance, Oklahoma State University, 191 CRC, Stillwater, OK, 74074, USA
| | - Tony R Montgomery
- Applied Neuromuscular Physiology Laboratory, Department of Health and Human Performance, Oklahoma State University, 191 CRC, Stillwater, OK, 74074, USA
| | - Kylie N Sears
- Applied Neuromuscular Physiology Laboratory, Department of Health and Human Performance, Oklahoma State University, 191 CRC, Stillwater, OK, 74074, USA
| | - Taylor K Dinyer
- Applied Neuromuscular Physiology Laboratory, Department of Health and Human Performance, Oklahoma State University, 191 CRC, Stillwater, OK, 74074, USA
| | - Shane M Hammer
- Applied Neuromuscular Physiology Laboratory, Department of Health and Human Performance, Oklahoma State University, 191 CRC, Stillwater, OK, 74074, USA
| | - Haley C Bergstrom
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY, 40506, USA
| | - Ethan C Hill
- School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, FL, 32816, USA
| | - Pasquale J Succi
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY, 40506, USA
| | - John Lawson
- School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, FL, 32816, USA
| | - Michael A Trevino
- Applied Neuromuscular Physiology Laboratory, Department of Health and Human Performance, Oklahoma State University, 191 CRC, Stillwater, OK, 74074, USA.
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Hirono T, Takeda R, Nishikawa T, Watanabe K. Prediction of 1-year change in knee extension strength by neuromuscular properties in older adults. GeroScience 2024; 46:2561-2569. [PMID: 38093024 PMCID: PMC10828468 DOI: 10.1007/s11357-023-01035-6] [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: 10/23/2023] [Accepted: 12/04/2023] [Indexed: 02/01/2024] Open
Abstract
Improving muscle strength and preventing muscle weakness are important for older adults. The change in strength can be effectively explained by skeletal muscle mass and neural factors. Neural factors are important for older adults because the variation of neural components is greater in older than in young adults, and any decline in strength cannot solely be explained by a decrease in skeletal muscle mass. The purpose of the present study was to investigate whether skeletal muscle mass or motor unit firing properties could explain the change in muscle strength after 1 year. Thirty-eight older adults (75.0 ± 4.7 years, 156.6 ± 7.7 cm, 55.5 ± 9.4 kg, 26 women) performed maximum voluntary knee extension and their skeletal muscle mass was measured using a bioimpedance device. During a submaximal contraction task, high-density surface electromyography was recorded and the signals were decomposed into individual motor unit firing. As an index of motor unit firing properties, the slope and y-intercept (MU intercept) were calculated from the regression line between recruitment thresholds and firing rates in each participant. After 1 year, their maximum knee extension torque was evaluated again. A stepwise multiple regression linear model with sex and age as covariates indicated that MU intercept was a significant explanation with a negative association for the 1-year change in muscle strength (β = - 0.493, p = 0.004), but not skeletal muscle mass (p = 0.364). The results suggest that neural components might be predictors of increasing and decreasing muscle strength rather than skeletal muscle mass.
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Affiliation(s)
- Tetsuya Hirono
- Laboratory of Neuromuscular Biomechanics, School of Health and Sport Sciences, Chukyo University, 101 Tokodachi, Kaizu-Cho, Toyota, Aichi, Japan.
- Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 Kawahara-Cho, Shogoin, Sakyo-Ku, Kyoto, Japan.
| | - Ryosuke Takeda
- Laboratory of Neuromuscular Biomechanics, School of Health and Sport Sciences, Chukyo University, 101 Tokodachi, Kaizu-Cho, Toyota, Aichi, Japan
| | - Taichi Nishikawa
- Laboratory of Neuromuscular Biomechanics, School of Health and Sport Sciences, Chukyo University, 101 Tokodachi, Kaizu-Cho, Toyota, Aichi, Japan
- Graduate School of Health and Sport Sciences, Chukyo University, 101 Tokodachi, Kaizu-Cho, Toyota, Aichi, Japan
| | - Kohei Watanabe
- Laboratory of Neuromuscular Biomechanics, School of Health and Sport Sciences, Chukyo University, 101 Tokodachi, Kaizu-Cho, Toyota, Aichi, Japan
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7
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Valli G, Sarto F, Casolo A, Del Vecchio A, Franchi MV, Narici MV, De Vito G. Lower limb suspension induces threshold-specific alterations of motor units properties that are reversed by active recovery. JOURNAL OF SPORT AND HEALTH SCIENCE 2024; 13:264-276. [PMID: 37331508 PMCID: PMC10980901 DOI: 10.1016/j.jshs.2023.06.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 03/17/2023] [Accepted: 05/16/2023] [Indexed: 06/20/2023]
Abstract
PURPOSE This study aimed to non-invasively test the hypothesis that (a) short-term lower limb unloading would induce changes in the neural control of force production (based on motor units (MUs) properties) in the vastus lateralis muscle and (b) possible changes are reversed by active recovery (AR). METHODS Ten young males underwent 10 days of unilateral lower limb suspension (ULLS) followed by 21 days of AR. During ULLS, participants walked exclusively on crutches with the dominant leg suspended in a slightly flexed position (15°-20°) and with the contralateral foot raised by an elevated shoe. The AR was based on resistance exercise (leg press and leg extension) and executed at 70% of each participant's 1 repetition maximum, 3 times/week. Maximal voluntary isometric contraction (MVC) of knee extensors and MUs properties of the vastus lateralis muscle were measured at baseline, after ULLS, and after AR. MUs were identified using high-density electromyography during trapezoidal isometric contractions at 10%, 25%, and 50% of the current MVC, and individual MUs were tracked across the 3 data collection points. RESULTS We identified 1428 unique MUs, and 270 of them (18.9%) were accurately tracked. After ULLS, MVC decreased by 29.77%, MUs absolute recruitment/derecruitment thresholds were reduced at all contraction intensities (with changes between the 2 variables strongly correlated), while discharge rate was reduced at 10% and 25% but not at 50% MVC. Impaired MVC and MUs properties fully recovered to baseline levels after AR. Similar changes were observed in the pool of total as well as tracked MUs. CONCLUSION Our novel results demonstrate, non-invasively, that 10 days of ULLS affected neural control predominantly by altering the discharge rate of lower-threshold but not of higher-threshold MUs, suggesting a preferential impact of disuse on motoneurons with a lower depolarization threshold. However, after 21 days of AR, the impaired MUs properties were fully restored to baseline levels, highlighting the plasticity of the components involved in neural control.
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Affiliation(s)
- Giacomo Valli
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy.
| | - Fabio Sarto
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy
| | - Andrea Casolo
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy
| | - Alessandro Del Vecchio
- Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander University, Erlangen-Nürnberg 91052, Germany
| | - Martino V Franchi
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy
| | - Marco V Narici
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy
| | - Giuseppe De Vito
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy
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Zampieri S, Bersch I, Smeriglio P, Barbieri E, Boncompagni S, Maccarone MC, Carraro U. Program with last minute abstracts of the Padua Days on Muscle and Mobility Medicine, 27 February - 2 March, 2024 (2024Pdm3). Eur J Transl Myol 2024; 34:12346. [PMID: 38305708 PMCID: PMC11017178 DOI: 10.4081/ejtm.2024.12346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 02/01/2024] [Indexed: 02/03/2024] Open
Abstract
During the 2023 Padua Days on Muscle and Mobility Medicine the 2024 meeting was scheduled from 28 February to 2 March 2024 (2024Pdm3). During autumn 2023 the program was expanded with Scientific Sessions which will take place over five days (in 2024 this includes February 29), starting from the afternoon of 27 February 2024 in the Conference Rooms of the Hotel Petrarca, Thermae of Euganean Hills (Padua), Italy. As per consolidated tradition, the second day will take place in Padua, for the occasion in the Sala San Luca of the Monastery of Santa Giustina in Prato della Valle, Padua, Italy. Confirming the attractiveness of the Padua Days on Muscle and Mobility Medicine, over 100 titles were accepted until 15 December 2023 (many more than expected), forcing the organization of parallel sessions on both 1 and 2 March 2024. The five days will include lectures and oral presentations of scientists and clinicians from Argentina, Austria, Belgium, Brazil, Bulgaria, Canada, Denmark, Egypt, France, Germany, Iceland, Ireland, Italy, Romania, Russia, Slovenia, Switzerland, UK and USA. Only Australia, China, India and Japan are missing from this edition. But we are confident that authors from those countries who publish articles in the PAGEpress: European Journal of Translational Myology (EJTM: 2022 ESCI Clarivate's Impact Factor: 2.2; SCOPUS Cite Score: 3.2) will decide to join us in the coming years. Together with the program established by 31 January 2024, the abstracts will circulate during the meeting only in the electronic version of the EJTM Issue 34 (1) 2024. See you soon in person at the Hotel Petrarca in Montegrotto Terme, Padua, for the inauguration scheduled the afternoon of 27 February 2024 or on-line for free via Zoom. Send us your email address if you are not traditional participants listed in Pdm3 and EJTM address books.
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Affiliation(s)
- Sandra Zampieri
- Department of Surgery, Oncology and Gastroenterology, University of Padova, Padua, Italy; Department of Biomedical Sciences, University of Padova, Padua, Italy; Interdepartmental Research Centre of Myology, University of Padova, Padua, Italy; Armando Carraro & Carmela Mioni-Carraro Foundation for Translational Myology, Padua.
| | - Ines Bersch
- Swiss Paraplegic Centre Nottwil, Nottwil, Switzerland; International FES Centre®, Swiss Paraplegic Centre Nottwil, Nottwil.
| | - Piera Smeriglio
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, Paris.
| | - Elena Barbieri
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino (PU).
| | - Simona Boncompagni
- Center for Advanced Studies and Technology, University G. d'Annunzio of Chieti-Pescara, Chieti, Italy; Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara, Chieti.
| | | | - Ugo Carraro
- Department of Biomedical Sciences, University of Padova, Padua, Italy; Interdepartmental Research Centre of Myology, University of Padova, Padua, Italy; Armando Carraro & Carmela Mioni-Carraro Foundation for Translational Myology, Padua.
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Valli G, Ritsche P, Casolo A, Negro F, De Vito G. Tutorial: Analysis of central and peripheral motor unit properties from decomposed High-Density surface EMG signals with openhdemg. J Electromyogr Kinesiol 2024; 74:102850. [PMID: 38065045 DOI: 10.1016/j.jelekin.2023.102850] [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: 07/20/2023] [Revised: 10/05/2023] [Accepted: 11/28/2023] [Indexed: 01/29/2024] Open
Abstract
High-Density surface Electromyography (HD-sEMG) is the most established technique for the non-invasive analysis of single motor unit (MU) activity in humans. It provides the possibility to study the central properties (e.g., discharge rate) of large populations of MUs by analysis of their firing pattern. Additionally, by spike-triggered averaging, peripheral properties such as MUs conduction velocity can be estimated over adjacent regions of the muscles and single MUs can be tracked across different recording sessions. In this tutorial, we guide the reader through the investigation of MUs properties from decomposed HD-sEMG recordings by providing both the theoretical knowledge and practical tools necessary to perform the analyses. The practical application of this tutorial is based on openhdemg, a free and open-source community-based framework for the automated analysis of MUs properties built on Python 3 and composed of different modules for HD-sEMG data handling, visualisation, editing, and analysis. openhdemg is interfaceable with most of the available recording software, equipment or decomposition techniques, and all the built-in functions are easily adaptable to different experimental needs. The framework also includes a graphical user interface which enables users with limited coding skills to perform a robust and reliable analysis of MUs properties without coding.
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Affiliation(s)
- Giacomo Valli
- Department of Biomedical Sciences, University of Padova, Padova, Italy; Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy.
| | - Paul Ritsche
- Department of Sport, Exercise and Health, University of Basel, Basel, Switzerland.
| | - Andrea Casolo
- Department of Biomedical Sciences, University of Padova, Padova, Italy.
| | - Francesco Negro
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy.
| | - Giuseppe De Vito
- Department of Biomedical Sciences, University of Padova, Padova, Italy.
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Rubin N, Hinson R, Saul K, Filer W, Hu X, Huang H(H. Modified motor unit properties in residual muscle following transtibial amputation. J Neural Eng 2024; 21:10.1088/1741-2552/ad1ac2. [PMID: 38176027 PMCID: PMC11214693 DOI: 10.1088/1741-2552/ad1ac2] [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: 05/23/2023] [Accepted: 01/04/2024] [Indexed: 01/06/2024]
Abstract
Objective.Neural signals in residual muscles of amputated limbs are frequently decoded to control powered prostheses. Yet myoelectric controllers assume muscle activities of residual muscles are similar to that of intact muscles. This study sought to understand potential changes to motor unit (MU) properties after limb amputation.Approach.Six people with unilateral transtibial amputation were recruited. Surface electromyogram (EMG) of residual and intacttibialis anterior(TA) andgastrocnemius(GA) muscles were recorded while subjects traced profiles targeting up to 20% and 35% of maximum activation for each muscle (isometric for intact limbs). EMG was decomposed into groups of MU spike trains. MU recruitment thresholds, action potential amplitudes (MU size), and firing rates were correlated to model Henneman's size principle, the onion-skin phenomenon, and rate-size associations. Organization (correlation) and modulation (rates of change) of relations were compared between intact and residual muscles.Main results.The residual TA exhibited significantly lower correlation and flatter slopes in the size principle and onion-skin, and each outcome covaried between the MU relations. The residual GA was unaffected for most subjects. Subjects trained prior with myoelectric prostheses had minimally affected slopes in the TA. Rate-size association correlations were preserved, but both residual muscles exhibited flatter decay rates.Significance.We showed peripheral neuromuscular damage also leads to spinal-level functional reorganizations. Our findings suggest models of MU recruitment and discharge patterns for residual muscle EMG generation need reparameterization to account for disturbances observed. In the future, tracking MU pool adaptations may also provide a biomarker of neuromuscular control to aid training with myoelectric prostheses.
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Affiliation(s)
- Noah Rubin
- UNC/NC State Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States of America
| | - Robert Hinson
- UNC/NC State Joint Department of Biomedical Engineering, North Carolina State University, Raleigh, NC 27695, United States of America
- UNC/NC State Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States of America
- School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States of America
| | - Katherine Saul
- Department of Mechanical & Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, United States of America
| | - William Filer
- School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States of America
| | - Xiaogang Hu
- Department of Mechanical Engineering, Pennsylvania State University, University Park, PA 16802, United States of America
| | - He (Helen) Huang
- UNC/NC State Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States of America
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Piasecki J, Guo Y, Jones EJ, Phillips BE, Stashuk DW, Atherton PJ, Piasecki M. Menstrual Cycle Associated Alteration of Vastus Lateralis Motor Unit Function. SPORTS MEDICINE - OPEN 2023; 9:97. [PMID: 37874413 PMCID: PMC10597975 DOI: 10.1186/s40798-023-00639-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 09/21/2023] [Indexed: 10/25/2023]
Abstract
BACKGROUND Estrogen and progesterone are the primary female sex hormones and have net excitatory and inhibitory effects, respectively, on neuronal function. Fluctuating concentrations across the menstrual cycle has led to several lines of research in relation to neuromuscular function and performance; however evidence from animal and cell culture models has yet to be demonstrated in human motor units coupled with quantification of circulating hormones. Intramuscular electromyography was used to record motor unit potentials and corresponding motor unit potential trains from the vastus lateralis of nine eumenorrheic females during the early follicular, ovulation and mid luteal phases of the menstrual cycle, alongside assessments of neuromuscular performance. Multi-level regression models were applied to explore effects of time and of contraction level. Statistical significance was accepted as p < 0.05. RESULTS Knee extensor maximum voluntary contraction, jump power, force steadiness, and balance did not differ across the menstrual phases (all p > 0.4). Firing rate of low threshold motor units (10% maximum voluntary contraction) was lower during the ovulation and mid luteal phases (β = - 0.82 Hz, p < 0.001), with no difference in motor unit potentials analysed from 25% maximum voluntary contraction contractions. Motor unit potentials were more complex during ovulation and mid luteal phase (p < 0.03), with no change in neuromuscular junction transmission instability (p > 0.3). CONCLUSIONS Assessments of neuromuscular performance did not differ across the menstrual cycle. The suppression of low threshold motor unit firing rate during periods of increased progesterone may suggest a potential inhibitory effect and an alteration of recruitment strategy; however this had no discernible effect on performance. These findings highlight contraction level-dependent modulation of vastus lateralis motor unit function over the eumenorrheic cycle, occurring independently of measures of performance.
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Affiliation(s)
- Jessica Piasecki
- Musculoskeletal Physiology Research Group, Sport, Health and Performance Enhancement Research Centre, Nottingham Trent University, Nottingham, UK.
| | - Yuxiao Guo
- Centre of Metabolism, Ageing and Physiology (COMAP), MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Eleanor J Jones
- Centre of Metabolism, Ageing and Physiology (COMAP), MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Bethan E Phillips
- Centre of Metabolism, Ageing and Physiology (COMAP), MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Daniel W Stashuk
- Department of Systems Design Engineering, University of Waterloo, Waterloo, ON, Canada
| | - Philip J Atherton
- Centre of Metabolism, Ageing and Physiology (COMAP), MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Mathew Piasecki
- Centre of Metabolism, Ageing and Physiology (COMAP), MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
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Sherman DA, Rush J, Stock MS, D. Ingersoll C, E. Norte G. Neural drive and motor unit characteristics after anterior cruciate ligament reconstruction: implications for quadriceps weakness. PeerJ 2023; 11:e16261. [PMID: 37818333 PMCID: PMC10561646 DOI: 10.7717/peerj.16261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 09/18/2023] [Indexed: 10/12/2023] Open
Abstract
Purpose The purpose of this investigation was to compare the quality of neural drive and recruited quadriceps motor units' (MU) action potential amplitude (MUAPAMP) and discharge rate (mean firing rate (MFR)) relative to recruitment threshold (RT) between individuals with anterior cruciate ligament reconstruction (ACLR) and controls. Methods Fourteen individuals with ACLR and 13 matched controls performed trapezoidal knee extensor contractions at 30%, 50%, 70%, and 100% of their maximal voluntary isometric contraction (MVIC). Decomposition electromyography (dEMG) and torque were recorded concurrently. The Hoffmann reflex (H-reflex) and central activation ratio (CAR) were acquired bilaterally to detail the proportion of MU pool available and volitionally activated. We examined MUAPAMP-RT and MFR-RT relationships with linear regression and extracted the regression line slope, y-intercept, and RT range for each contraction. Linear mixed effect modelling used to analyze the effect of group and limb on regression line slope and RT range. Results Individuals with ACLR demonstrated lower MVIC torque in the involved limb compared to uninvolved limb. There were no differences in H-reflex or CAR between groups or limbs. The ACLR involved limb demonstrated smaller mass-normalized RT range and slower MU firing rates at high contraction intensities (70% and 100% MVIC) compared to uninvolved and control limbs. The ACLR involved limb also demonstrated larger MU action potentials in the VM compared to the contralateral limb. These differences were largely attenuated with relative RT normalization. Conclusions These results suggest that persistent strength deficits following ACLR may be attributable to a diminished quadriceps motor neuron pool and inability to upregulate the firing rate of recruited MUs.
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Affiliation(s)
- David A. Sherman
- Live4 Physical Therapy and Wellness, Acton, Massachusetts, United States of America
- Chobanian & Avedisian School of Medicine, Boston University, Boston, Massachusetts, United States of America
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, United States of America
| | - Justin Rush
- Division of Physical Therapy, School of Rehabilitation and Communication Sciences, College of Health Sciences and Professions, Ohio University, Athens, Ohio, United States of America
| | - Matt S. Stock
- Cognition, Neuroplasticity, & Sarcopenia (CNS) Lab, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, United States of America
| | - Christopher D. Ingersoll
- College of Health Professions and Sciences, School of Kinesiology and Rehabilitation Sciences, University of Central Florida, Orlando, Florida, United States of America
| | - Grant E. Norte
- Cognition, Neuroplasticity, & Sarcopenia (CNS) Lab, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, United States of America
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Jones EJ, Guo Y, Martinez‐Valdes E, Negro F, Stashuk DW, Atherton PJ, Phillips BE, Piasecki M. Acute adaptation of central and peripheral motor unit features to exercise-induced fatigue differs with concentric and eccentric loading. Exp Physiol 2023; 108:827-837. [PMID: 37018481 PMCID: PMC10988466 DOI: 10.1113/ep091058] [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: 12/01/2022] [Accepted: 03/14/2023] [Indexed: 04/07/2023]
Abstract
NEW FINDINGS What is the central question of this study? Conflicting evidence exists on motor unit (MU) firing rate in response to exercise-induced fatigue, possibly due to the contraction modality used: Do MU properties adapt similarly following concentric and eccentric loading? What is the main finding and its importance? MU firing rate increased following eccentric loading only despite a decline in absolute force. Force steadiness deteriorated following both loading methods. Central and peripheral MU features are altered in a contraction type-dependant manner, which is an important consideration for training interventions. ABSTRACT Force output of muscle is partly mediated by the adjustment of motor unit (MU) firing rate (FR). Disparities in MU features in response to fatigue may be influenced by contraction type, as concentric (CON) and eccentric (ECC) contractions demand variable amounts of neural input, which alters the response to fatigue. This study aimed to determine the effects of fatigue following CON and ECC loading on MU features of the vastus lateralis (VL). High-density surface (HD-sEMG) and intramuscular (iEMG) electromyography were used to record MU potentials (MUPs) from bilateral VLs of 12 young volunteers (six females) during sustained isometric contractions at 25% and 40% of the maximum voluntary contraction (MVC), before and after completing CON and ECC weighted stepping exercise. Multi-level mixed effects linear regression models were performed with significance assumed as P < 0.05. MVC decreased in both CON and ECC legs post-exercise (P < 0.0001), as did force steadiness at both 25% and 40% MVC (P < 0.004). MU FR increased in ECC at both contraction levels (P < 0.001) but did not change in CON. FR variability increased in both legs at 25% and 40% MVC following fatigue (P < 0.01). From iEMG measures at 25% MVC, MUP shape did not change (P > 0.1) but neuromuscular junction transmission instability increased in both legs (P < 0.04), and markers of fibre membrane excitability increased following CON only (P = 0.018). These data demonstrate that central and peripheral MU features are altered following exercise-induced fatigue and differ according to exercise modality. This is important when considering interventional strategies targeting MU function.
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Affiliation(s)
- Eleanor J. Jones
- Centre of Metabolism, Ageing and Physiology (COMAP), MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research CentreUniversity of NottinghamNottinghamUK
| | - Yuxiao Guo
- Centre of Metabolism, Ageing and Physiology (COMAP), MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research CentreUniversity of NottinghamNottinghamUK
| | - Eduardo Martinez‐Valdes
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental SciencesUniversity of BirminghamBirminghamUK
| | - Francesco Negro
- Department of Clinical and Experimental SciencesUniversità degli Studi di BresciaBresciaItaly
| | - Daniel W. Stashuk
- Department of Systems Design EngineeringUniversity of WaterlooWaterlooOntarioCanada
| | - Philip J. Atherton
- Centre of Metabolism, Ageing and Physiology (COMAP), MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research CentreUniversity of NottinghamNottinghamUK
| | - Bethan E. Phillips
- Centre of Metabolism, Ageing and Physiology (COMAP), MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research CentreUniversity of NottinghamNottinghamUK
| | - Mathew Piasecki
- Centre of Metabolism, Ageing and Physiology (COMAP), MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research CentreUniversity of NottinghamNottinghamUK
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Jones EJ, Atherton PJ, Piasecki M, Phillips BE. Contrast-enhanced ultrasound repeatability for the measurement of skeletal muscle microvascular blood flow. Exp Physiol 2023; 108:549-553. [PMID: 36738267 PMCID: PMC10103852 DOI: 10.1113/ep091034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/24/2023] [Indexed: 02/05/2023]
Abstract
NEW FINDINGS What is the central question of this study? Contrast-enhanced ultrasound (CEUS) can be used to directly assess skeletal muscle perfusion but its day-to-day repeatability over time has not yet been validated: is CEUS a repeatable method for the measurement of skeletal muscle microvascular blood flow (MBF) at rest and in response to exercise, across independent assessment sessions? What is the main finding and its importance? A strong agreement between CEUS MBF measures across sessions suggests it is a repeatable method for assessing skeletal muscle perfusion over time. This validation provides confidence for incorporating these measures into longitudinal studies such as a chronic intervention or disease progression to gain further knowledge of skeletal muscle microvascular function. ABSTRACT Contrast-enhanced ultrasound (CEUS) can be used to directly assess skeletal muscle perfusion. However, its repeatability over time has not yet been validated and therefore its use in longitudinal measures (i.e., exploring the impact of a chronic intervention or disease progression) is limited. This study aimed to determine the repeatability of CEUS for the measurement of skeletal muscle microvascular blood flow (MBF) at baseline and in response to exercise, across independent assessment sessions. Ten healthy volunteers (five female; 30 ± 6 years) had CEUS of the right vastus lateralis recorded in two separate sessions, 14 days apart. Measurements were taken at baseline, during an isometric leg extension and during recovery. Acoustic intensity data from a region of interest were plotted as a replenishment curve to obtain blood volume (A) and flow velocity (β) values from a one-phase association non-linear regression of mean tissue echogenicity. Linear regression and Bland-Altman analyses of A and β values were performed, with significance assumed as P < 0.05. Strong positive correlations were observed across sessions for all A and β values (both P < 0.0001). Bland-Altman analysis showed a bias (SD) of -0.013 ± 1.24 for A and -0.014 ± 0.31 for β. A bias of 0.201 ± 0.770 at baseline, 0.527 ± 1.29 during contraction and -0.203 ± 1.29 at recovery was observed for A, and -0.0328 ± 0.0853 (baseline), -0.0446 ± 0.206 (contraction) and 0.0382 ± 0.233 (recovery) for β. A strong agreement between CEUS MBF measures across independent sessions suggests it to be a repeatable method for assessing skeletal muscle perfusion over time, and therefore facilitates wider use in longitudinal studies.
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Affiliation(s)
- Eleanor J. Jones
- Centre of Metabolism, Ageing and Physiology, MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research CentreUniversity of NottinghamDerbyUK
| | - Philip J. Atherton
- Centre of Metabolism, Ageing and Physiology, MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research CentreUniversity of NottinghamDerbyUK
| | - Mathew Piasecki
- Centre of Metabolism, Ageing and Physiology, MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research CentreUniversity of NottinghamDerbyUK
| | - Bethan E. Phillips
- Centre of Metabolism, Ageing and Physiology, MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research CentreUniversity of NottinghamDerbyUK
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Saveko A, Bekreneva M, Ponomarev I, Zelenskaya I, Riabova A, Shigueva T, Kitov V, Abu Sheli N, Nosikova I, Rukavishnikov I, Sayenko D, Tomilovskaya E. Impact of different ground-based microgravity models on human sensorimotor system. Front Physiol 2023; 14:1085545. [PMID: 36875039 PMCID: PMC9974674 DOI: 10.3389/fphys.2023.1085545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 01/30/2023] [Indexed: 02/17/2023] Open
Abstract
This review includes current and updated information about various ground-based microgravity models and their impact on the human sensorimotor system. All known models of microgravity are imperfect in a simulation of the physiological effects of microgravity but have their advantages and disadvantages. This review points out that understanding the role of gravity in motion control requires consideration of data from different environments and in various contexts. The compiled information can be helpful to researchers to effectively plan experiments using ground-based models of the effects of space flight, depending on the problem posed.
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Affiliation(s)
- Alina Saveko
- Russian Federation State Scientific Center—Institute of Biomedical Problems of the Russian Academy of Sciences, Moscow, Russia
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Sirago G, Pellegrino MA, Bottinelli R, Franchi MV, Narici MV. Loss of neuromuscular junction integrity and muscle atrophy in skeletal muscle disuse. Ageing Res Rev 2023; 83:101810. [PMID: 36471545 DOI: 10.1016/j.arr.2022.101810] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 11/25/2022] [Accepted: 11/25/2022] [Indexed: 11/27/2022]
Abstract
Physical inactivity (PI) is a major risk factor of chronic diseases. A major aspect of PI is loss of muscle mass and strength. The latter phenomenon significantly impacts daily life and represent a major issue for global health. Understandably, skeletal muscle itself has been the major focus of studies aimed at understanding the mechanisms underlying loss of mass and strength. Relatively lesser attention has been given to the contribution of alterations in somatomotor control, despite the fact that these changes can start very early and can occur at multiple levels, from the cortex down to the neuromuscular junction (NMJ). It is well known that exposure to chronic inactivity or immobilization causes a disproportionate loss of force compared to muscle mass, i.e. a loss of specific or intrinsic whole muscle force. The latter phenomenon may be partially explained by the loss of specific force of individual muscle fibres, but several other players are very likely to contribute to such detrimental phenomenon. Irrespective of the length of the disuse period, the loss of force is, in fact, more than two-fold greater than that of muscle size. It is very likely that somatomotor alterations may contribute to this loss in intrinsic muscle force. Here we review evidence that alterations of one component of somatomotor control, namely the neuromuscular junction, occur in disuse. We also discuss some of the novel players in NMJ stability (e.g., homer, bassoon, pannexin) and the importance of new established and emerging molecular markers of neurodegenerative processes in humans such as agrin, neural-cell adhesion molecule and light-chain neurofilaments.
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Affiliation(s)
- Giuseppe Sirago
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy.
| | - Maria A Pellegrino
- Department of Molecular Medicine, University of Pavia, Pavia 27100, Italy
| | - Roberto Bottinelli
- Department of Molecular Medicine, University of Pavia, Pavia 27100, Italy; IRCCS Mondino Foundation, Pavia 27100, Italy
| | - Martino V Franchi
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy
| | - Marco V Narici
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy; CIR-MYO Myology Center, University of Padova, Padova 35131, Italy.
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Are Skeletal Muscle Changes during Prolonged Space Flights Similar to Those Experienced by Frail and Sarcopenic Older Adults? LIFE (BASEL, SWITZERLAND) 2022; 12:life12122139. [PMID: 36556504 PMCID: PMC9781047 DOI: 10.3390/life12122139] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/13/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022]
Abstract
Microgravity exposure causes several physiological and psychosocial alterations that challenge astronauts' health during space flight. Notably, many of these changes are mostly related to physical inactivity influencing different functional systems and organ biology, in particular the musculoskeletal system, dramatically resulting in aging-like phenotypes, such as those occurring in older persons on Earth. In this sense, sarcopenia, a syndrome characterized by the loss in muscle mass and strength due to skeletal muscle unloading, is undoubtedly one of the most critical aging-like adverse effects of microgravity and a prevalent problem in the geriatric population, still awaiting effective countermeasures. Therefore, there is an urgent demand to identify clinically relevant biological markers and to underline molecular mechanisms behind these effects that are still poorly understood. From this perspective, a lesson from Geroscience may help tailor interventions to counteract the adverse effects of microgravity. For instance, decades of studies in the field have demonstrated that in the older people, the clinical picture of sarcopenia remarkably overlaps (from a clinical and biological point of view) with that of frailty, primarily when referred to the physical function domain. Based on this premise, here we provide a deeper understanding of the biological mechanisms of sarcopenia and frailty, which in aging are often considered together, and how these converge with those observed in astronauts after space flight.
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Soendenbroe C. Neuromuscular function in experimental disuse - a prime suspect? J Physiol 2022; 600:4539-4540. [PMID: 36161657 PMCID: PMC9828185 DOI: 10.1113/jp283800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Accepted: 09/20/2022] [Indexed: 01/12/2023] Open
Affiliation(s)
- Casper Soendenbroe
- Department of Orthopaedic SurgeryInstitute of Sports Medicine CopenhagenCopenhagen University Hospital Bispebjerg and FrederiksbergCopenhagenDenmark
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Sarto F, Valli G, Monti E. Motor unit alterations with muscle disuse: what's new? J Physiol 2022; 600:4811-4813. [PMID: 36200458 DOI: 10.1113/jp283868] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Affiliation(s)
- Fabio Sarto
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Giacomo Valli
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Elena Monti
- Blau Laboratory, Stanford School of Medicine, Stanford, CA, USA.,Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford School of Medicine, Stanford, CA, USA
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