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Nuccio S, Germer CM, Casolo A, Borzuola R, Labanca L, Rocchi JE, Mariani PP, Felici F, Farina D, Falla D, Macaluso A, Sbriccoli P, Del Vecchio A. Neuroplastic alterations in common synaptic inputs and synergistic motor unit clusters controlling the vastii muscles of individuals with ACL reconstruction. J Appl Physiol (1985) 2024; 137:835-847. [PMID: 39024407 DOI: 10.1152/japplphysiol.00056.2024] [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: 01/19/2024] [Revised: 07/12/2024] [Accepted: 07/14/2024] [Indexed: 07/20/2024] Open
Abstract
This cross-sectional study aims to elucidate the neural mechanisms underlying the control of knee extension forces in individuals with anterior cruciate ligament reconstruction (ACLR). Eleven soccer players with ACLR and nine control players performed unilateral isometric knee extensions at 10% and 30% of their maximum voluntary force (MVF). Simultaneous recordings of high-density surface electromyography (HDEMG) and force output were conducted for each lower limb, and HDEMG data from the vastus lateralis (VL) and vastus medialis (VM) muscles were decomposed into individual motor unit spike trains. Force steadiness was estimated using the coefficient of variation of force. An intramuscular coherence analysis was adopted to estimate the common synaptic input (CSI) converging to each muscle. A factor analysis was applied to investigate the neural strategies underlying the control of synergistic motor neuron clusters, referred to as motor unit modes. Force steadiness was similar between lower limbs. However, motor neurons innervating the VL on the reconstructed side received a lower proportion of CSI at low-frequency bandwidths (<5 Hz) compared with the unaffected lower limbs (P < 0.01). Furthermore, the reconstructed side demonstrated a higher proportion of motor units associated with the neural input common to the synergistic muscle, as compared with the unaffected lower limbs (P < 0.01). These findings indicate that the VL muscle of reconstructed lower limbs contribute marginally to force steadiness and that a plastic rearrangement in synergistic clusters of motor units involved in the control of knee extension forces is evident following ACLR.NEW & NOTEWORTHY Chronic quadriceps dysfunction is common after anterior cruciate ligament reconstruction (ACLR). We investigated voluntary force control strategies by estimating common inputs to motor neurons innervating the vastii muscles. Our results showed attenuated common inputs to the vastus lateralis and plastic rearrangements in functional clusters of motor neurons modulating knee extension forces in the reconstructed limb. These findings suggest neuroplastic adjustments following ACLR that may occur to fine-tune the control of quadriceps forces.
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Affiliation(s)
- Stefano Nuccio
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Rome, Italy
| | - Carina M Germer
- Departamento de Eletrônica e Engenharia Biomédica, Faculdade de Engenharia Elétrica e de Computação, Universidade Estadual de Campinas, São Paulo, Brazil
- Laboratório de Pesquisa em Neuroengenharia, Centro de Engenharia Biomédica, Universidade Estadual de Campinas, São Paulo, Brazil
| | - Andrea Casolo
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Riccardo Borzuola
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Rome, Italy
| | - Luciana Labanca
- Physical Medicine and Rehabilitation Unit, IRCSS-Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Jacopo E Rocchi
- Villa Stuart Sport Clinic - FIFA Medical Centre of Excellence, Rome, Italy
| | - Pier Paolo Mariani
- Villa Stuart Sport Clinic - FIFA Medical Centre of Excellence, Rome, Italy
| | - Francesco Felici
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Rome, Italy
| | - Dario Farina
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Deborah Falla
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Andrea Macaluso
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Rome, Italy
| | - Paola Sbriccoli
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Rome, Italy
| | - Alessandro Del Vecchio
- Department of Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
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Hunt NL, Robinett MV, Brown TN. Knee muscle strength and steadiness for individuals with anterior cruciate ligament reconstruction and knee osteoarthritis. Clin Biomech (Bristol, Avon) 2024; 119:106331. [PMID: 39173446 PMCID: PMC11414746 DOI: 10.1016/j.clinbiomech.2024.106331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 08/02/2024] [Accepted: 08/16/2024] [Indexed: 08/24/2024]
Abstract
BACKGROUND Strength and neuromuscular decrements following knee musculoskeletal injury may accelerate knee osteoarthritis development. This study assessed isometric knee extensor and flexor strength and steadiness between individuals with knee injury, i.e., ligament reconstruction, and knee osteoarthritis to healthy age-matched controls. METHODS Four cohorts (1: knee injury and 2: age-matched controls, and 3: radiographic knee osteoarthritis and 4: age-matched controls) were recruited. Participants performed maximal voluntary isometric knee extensor and flexor contractions. Then, strength (e.g., peak and rate of torque development) and steadiness (e.g., peak power, mean, and median frequency) were derived from each raw torque-time curve and associated power spectral density. A Kruskal-Wallis H test and Spearman's rho correlation analysis assessed cohort differences and association between knee extensor and flexor strength and steadiness. FINDINGS The young adult control and knee injury cohorts exhibited greater knee extensor and flexor strength than the older, knee osteoarthritis cohort (p < 0.043). The knee injury cohort, despite being as strong as their healthy counterparts, were significantly less steady with a 92% increase in peak power frequency (p = 0.046). The osteoarthritis cohort exhibited 157% less total power compared to the knee injury and young control cohorts (p < 0.019). Knee extensor and flexor peak torque, rate of torque development, and mean torque exhibit a significant, positive relation with total power (p < 0.018). INTERPRETATION Individuals with knee injury and disease may exhibit weaker or less steady knee musculature, predisposing them to degenerative joint disease. Clinicians may need to restore knee extensor and flexor steadiness to facilitate better joint neuromuscular control.
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Affiliation(s)
- Nicholas L Hunt
- Biomedical Engineering Doctorate Program, Boise State University, Boise, ID, USA
| | | | - Tyler N Brown
- Biomedical Engineering Doctorate Program, Boise State University, Boise, ID, USA.
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Clark NC. Sensorimotor control of functional joint stability: Scientific concepts, clinical considerations, and the articuloneuromuscular cascade paradigm in peripheral joint injury. Musculoskelet Sci Pract 2024; 74:103198. [PMID: 39362022 DOI: 10.1016/j.msksp.2024.103198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2024] [Revised: 09/22/2024] [Accepted: 09/28/2024] [Indexed: 10/05/2024]
Abstract
Human movement depends on sensorimotor control. Sensorimotor control refers to central nervous system (CNS) control of joint stability, posture, and movement, all of which are effected via the sensorimotor system. Given the nervous, muscular, and skeletal systems function as an integrated "neuromusculoskeletal system" for the purpose of executing movement, musculoskeletal conditions can result in a cascade of impairments that affect negatively all three systems. The purpose of this article is to revisit concepts in joint stability, sensorimotor control of functional joint stability (FJS), joint instability, and sensorimotor impairments contributing to functional joint instability. This article differs from historical work because it updates previous models of joint injury and joint instability by incorporating more recent research on CNS factors, skeletal muscle factors, and tendon factors. The new 'articuloneuromuscular cascade paradigm' presented here offers a framework for facilitating further investigation into physiological and biomechanical consequences of joint injury and, in turn, how these follow on to affect physical activity (functional) capability. Here, the term 'injury' represents traumatic joint injury with a focus is on peripheral joint injury. Understanding the configuration of the sensorimotor system and the cascade of post-injury sensorimotor impairments is particularly important for clinicians reasoning rational interventions for patients with mechanical instability and functional instability. Concurrently, neurocognitive processing and neurocognitive performance are also addressed relative to feedforward neuromuscular control of FJS. This article offers itself as an educational resource and scientific asset to contribute to the ongoing research and applied practice journey for developing optimal peripheral joint injury rehabilitation strategies.
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Affiliation(s)
- Nicholas C Clark
- School of Sport, Rehabilitation, and Exercise Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, CO4 3SQ, UK, United Kingdom.
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Smith CC, Nascimento F, Özyurt MG, Beato M, Brownstone RM. Kv2 channels do not function as canonical delayed rectifiers in spinal motoneurons. iScience 2024; 27:110444. [PMID: 39148717 PMCID: PMC11325356 DOI: 10.1016/j.isci.2024.110444] [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: 02/09/2024] [Revised: 04/29/2024] [Accepted: 07/01/2024] [Indexed: 08/17/2024] Open
Abstract
The increased muscular force output required for some behaviors is achieved via amplification of motoneuron output via cholinergic C-bouton synapses. Work in neonatal mouse motoneurons suggested that modulation of currents mediated by post-synaptically clustered KV2.1 channels is crucial to C-bouton amplification. By focusing on more mature motoneurons, we show that conditional knockout of KV2.1 channels minimally affects either excitability or response to exogenously applied muscarine. Similarly, unlike in neonatal motoneurons or cortical pyramidal neurons, pharmacological blockade of KV2 currents has minimal effect on mature motoneuron firing in vitro. Furthermore, in vivo amplification of electromyography activity and high-force task performance was unchanged following KV2.1 knockout. Finally, we show that KV2.2 is also expressed by spinal motoneurons, colocalizing with KV2.1 opposite C-boutons. We suggest that the primary function of KV2 proteins in motoneurons is non-conducting and that KV2.2 can function in this role in the absence of KV2.1.
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Affiliation(s)
- Calvin C Smith
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Filipe Nascimento
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - M Görkem Özyurt
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Marco Beato
- Department of Neuroscience, Physiology, and Pharmacology, University College London, London WC1E 6BT, UK
| | - Robert M Brownstone
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
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Arvanitidis M, Jiménez-Grande D, Haouidji-Javaux N, Falla D, Martinez-Valdes E. Eccentric exercise-induced delayed onset trunk muscle soreness alters high-density surface EMG-torque relationships and lumbar kinematics. Sci Rep 2024; 14:18589. [PMID: 39127797 PMCID: PMC11316813 DOI: 10.1038/s41598-024-69050-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Accepted: 07/31/2024] [Indexed: 08/12/2024] Open
Abstract
We aimed to assess high-density surface electromyography (HDsEMG)-torque relationships in the presence of delayed onset trunk muscle soreness (DOMS) and the effect of these relationships on torque steadiness (TS) and lumbar movement during concentric/eccentric submaximal trunk extension contractions. Twenty healthy individuals attended three laboratory sessions (24 h apart). HDsEMG signals were recorded unilaterally from the thoracolumbar erector spinae with two 64-electrode grids. HDsEMG-torque signal relationships were explored via coherence (0-5 Hz) and cross-correlation analyses. Principal component analysis was used for HDsEMG-data dimensionality reduction and improvement of HDsEMG-torque-based estimations. DOMS did not reduce either concentric or eccentric trunk extensor muscle strength. However, in the presence of DOMS, improved TS, alongside an altered HDsEMG-torque relationship and kinematic changes were observed, in a contraction-dependent manner. For eccentric trunk extension, improved TS was observed, with greater lumbar flexion movement and a reduction in δ-band HDsEMG-torque coherence and cross-correlation. For concentric trunk extensions, TS improvements were observed alongside reduced thoracolumbar sagittal movement. DOMS does not seem to impair the ability to control trunk muscle force, however, perceived soreness induced changes in lumbar movement and muscle recruitment strategies, which could alter motor performance if the exposure to pain is maintained in the long term.
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Affiliation(s)
- Michail Arvanitidis
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - David Jiménez-Grande
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Nadège Haouidji-Javaux
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Deborah Falla
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Eduardo Martinez-Valdes
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
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Sawers A, Fatone S. The relationship of hip strength to walking and balance performance in unilateral lower limb prosthesis users differs by amputation level. PM R 2024. [PMID: 39119804 DOI: 10.1002/pmrj.13245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 04/25/2024] [Accepted: 05/24/2024] [Indexed: 08/10/2024]
Abstract
BACKGROUND Safe and efficient locomotion is a frequently stated goal of lower limb prosthesis users, for which hip strength may play a central yet poorly understood role. Additional research to identify associations between hip strength, balance, and mobility among transtibial and transfemoral prosthesis users is required. OBJECTIVE To test whether residual and/or intact limb isometric hip strength was associated with lower limb prosthesis users' walking speed, endurance, and balance. DESIGN Cross-sectional study. SETTING Research laboratory. PARTICIPANTS Convivence sample of 14 transtibial and 14 transfemoral prosthesis users. METHODS Multiple linear regression was used to evaluate the relationship between isometric measures of residual and intact limb hip strength and walking and balance performance. MAIN OUTCOME MEASUREMENTS Measures of isometric hip muscle strength, including peak torque, average torque, torque impulse, and torque steadiness (i.e. consistency with which an isometric torque can be sustained) were derived from maximum voluntary hip flexion, extension, abduction and adduction torque signals collected with a motor-driven dynamometer. Walking speed, endurance, and balance were assessed by administering the 10-meter walk test, 2-minute walk test, Four Square Step Test, and Narrowing Beam Walking Test, respectively. RESULTS Residual limb hip extensor max torque and abductor torque steadiness explained between 51% and 69% of the variance in transtibial prosthesis users' walking speed, endurance, and balance. In contrast, intact limb hip abductor torque impulse explained between 33% and 48% of the variance in transfemoral prosthesis users' walking speed, endurance, and balance. CONCLUSIONS Our results suggest that unilateral transtibial and transfemoral prosthesis users' walking and balance performance may depend on different hip muscles, and different facets of hip strength. Amputation level-specific hip strength interventions may therefore be required to improve walking and balance performance in unilateral transtibial and transfemoral prosthesis users. The "intact leg strategy" adopted by transfemoral prosthesis users may be due to a variety of prosthesis and biomechanical factors that limit the efficiency with which transfemoral prosthesis users can exploit the strength of their residual limb hip muscles while walking.
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Affiliation(s)
- Andrew Sawers
- Department of Kinesiology, University of Illinois Chicago, Chicago, Illinois, USA
| | - Stefania Fatone
- Physical Medicine and Rehabilitation, Northwestern University, Chicago, Illinois, USA
- Department of Rehabilitation Medicine, University of Washington, Seattle, Washington DC, USA
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Daneshgar S, Tvrdy T, Enoka RM. Explaining the influence of practice on the grooved pegboard times of older adults: role of force steadiness. Exp Brain Res 2024; 242:1971-1982. [PMID: 38916760 DOI: 10.1007/s00221-024-06878-9] [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: 03/18/2024] [Accepted: 06/18/2024] [Indexed: 06/26/2024]
Abstract
The purpose was to identify the variables that can explain the variance in the grooved pegboard times of older adults categorized as either fast or slow performers. Participants (n = 28; 60-83 years) completed two experimental sessions, before and after 6 practice sessions of the grooved pegboard test. The 2 groups were identified based on average pegboard times during the practice sessions. Average pegboard time during practice was 73 ± 11 s for the fast group and 85 ± 13 s for the slow group. Explanatory variables for the pegboard times before and after practice were the durations of 4 peg-manipulation phases and 12 measures of force steadiness (coefficient of variation [CV] for force) during isometric contractions with the index finger abductor and wrist extensor muscles. Time to complete the grooved pegboard test after practice decreased by 25 ± 11% for the fast group and by 28 ± 10% for the slow group. Multiple regression models explained more of the variance in the pegboard times for the fast group before practice (Adjusted R2 = 0.85) than after practice (R2 = 0.51), whereas the variance explained for the slow group was similar before (Adjusted R2 = 0.67) and after (Adjusted R2 = 0.64) practice. The explanatory variables differed between before and after practice for the fast group but only slightly for the slow group. These findings indicate that performance-based stratification of older adults can identify unique adjustments in motor function that are independent of chronological age.
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Affiliation(s)
- Sajjad Daneshgar
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, 80309, USA
| | - Taylor Tvrdy
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, 80309, USA
| | - Roger M Enoka
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, 80309, USA.
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Rangel BO, Novembre G, Wessel JR. Measuring the nonselective effects of motor inhibition using isometric force recordings. Behav Res Methods 2024; 56:4486-4503. [PMID: 37550468 DOI: 10.3758/s13428-023-02197-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2023] [Indexed: 08/09/2023]
Abstract
Inhibition is a key cognitive control mechanism humans use to enable goal-directed behavior. When rapidly exerted, inhibitory control has broad, nonselective motor effects, typically demonstrated using corticospinal excitability measurements (CSE) elicited by transcranial magnetic stimulation (TMS). For example, during rapid action-stopping, CSE is suppressed at both stopped and task-unrelated muscles. While such TMS-based CSE measurements have provided crucial insights into the fronto-basal ganglia circuitry underlying inhibitory control, they have several downsides. TMS is contraindicated in many populations (e.g., epilepsy or deep-brain stimulation patients), has limited temporal resolution, produces distracting auditory and haptic stimulation, is difficult to combine with other imaging methods, and necessitates expensive, immobile equipment. Here, we attempted to measure the nonselective motor effects of inhibitory control using a method unaffected by these shortcomings. Thirty male and female human participants exerted isometric force on a high-precision handheld force transducer while performing a foot-response stop-signal task. Indeed, when foot movements were successfully stopped, force output at the task-irrelevant hand was suppressed as well. Moreover, this nonselective reduction of isometric force was highly correlated with stop-signal performance and showed frequency dynamics similar to established inhibitory signatures typically found in neural and muscle recordings. Together, these findings demonstrate that isometric force recordings can reliably capture the nonselective effects of motor inhibition, opening the door to many applications that are hard or impossible to realize with TMS.
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Affiliation(s)
- Benjamin O Rangel
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA, 52245, USA.
- Cognitive Control Collaborative, University of Iowa, Iowa City, IA, 52245, USA.
- University of Iowa, 444 Medical Research Center, Iowa City, IA, 52242, USA.
| | - Giacomo Novembre
- Neuroscience of Perception & Action Laboratory, Italian Institute of Technology, Rome, Italy
| | - Jan R Wessel
- Cognitive Control Collaborative, University of Iowa, Iowa City, IA, 52245, USA
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA, 52245, USA
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, IA, 52242, USA
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Sahinis C, Amiridis IG, Varvariotis N, Lykidis A, Kannas TM, Negro F, Enoka RM. Foot-dominance does not influence force variability during ankle dorsiflexion and foot adduction. J Sports Sci 2024:1-11. [PMID: 39023311 DOI: 10.1080/02640414.2024.2379699] [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: 01/11/2024] [Accepted: 07/05/2024] [Indexed: 07/20/2024]
Abstract
The aim of our study was to compare the force steadiness and the discharge characteristics of motor units in the tibialis anterior (TA) during ankle dorsiflexion and foot adduction produced by submaximal isometric contractions with the dominant and non-dominant foot. Fifteen young men performed maximal and submaximal contractions at five target forces with both legs, and motor unit activity in TA was recorded using high-density electromyography. Maximal force and the fluctuations in force during submaximal contractions were similar between the two legs (p > 0.05). Motor unit activity was characterized by measures of mean discharge rate (MDR), coefficient of variation for interspike interval (CoV for ISI), and standard deviation of the filtered cumulative spike train (SD of fCST). There were no statistically significant differences in motor unit activity between legs during ankle dorsiflexion. In contrast, the MDR and the CoV for ISI but not the SD of fCST, were greater for the non-dominant foot compared with the dominant foot during foot adduction. Nonetheless, these differences in motor unit activity were not sufficient to influence the force fluctuations during the submaximal contractions. These results indicate that control of the force produced by TA during the two actions was not influenced by limb dominance.
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Affiliation(s)
- Chrysostomos Sahinis
- Laboratory of Neuromechanics, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Ioannis G Amiridis
- Laboratory of Neuromechanics, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Nikolaos Varvariotis
- Laboratory of Neuromechanics, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Anastasios Lykidis
- Laboratory of Neuromechanics, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Theodoros M Kannas
- Laboratory of Neuromechanics, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Francesco Negro
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | - Roger M Enoka
- Department of Integrative Physiology, University of Colorado, Boulder, CO, USA
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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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11
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Cabral HV, Cudicio A, Bonardi A, Del Vecchio A, Falciati L, Orizio C, Martinez-Valdes E, Negro F. Neural Filtering of Physiological Tremor Oscillations to Spinal Motor Neurons Mediates Short-Term Acquisition of a Skill Learning Task. eNeuro 2024; 11:ENEURO.0043-24.2024. [PMID: 38866498 PMCID: PMC11255391 DOI: 10.1523/eneuro.0043-24.2024] [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: 01/30/2024] [Revised: 04/17/2024] [Accepted: 05/23/2024] [Indexed: 06/14/2024] Open
Abstract
The acquisition of a motor skill involves adaptations of spinal and supraspinal pathways to alpha motoneurons. In this study, we estimated the shared synaptic contributions of these pathways to understand the neural mechanisms underlying the short-term acquisition of a new force-matching task. High-density surface electromyography (HDsEMG) was acquired from the first dorsal interosseous (FDI; 7 males and 6 females) and tibialis anterior (TA; 7 males and 4 females) during 15 trials of an isometric force-matching task. For two selected trials (pre- and post-skill acquisition), we decomposed the HDsEMG into motor unit spike trains, tracked motor units between trials, and calculated the mean discharge rate and the coefficient of variation of interspike interval (COVISI). We also quantified the post/pre ratio of motor units' coherence within delta, alpha, and beta bands. Force-matching improvements were accompanied by increased mean discharge rate and decreased COVISI for both muscles. Moreover, the area under the curve within alpha band decreased by ∼22% (TA) and ∼13% (FDI), with no delta or beta bands changes. These reductions correlated significantly with increased coupling between force/neural drive and target oscillations. These results suggest that short-term force-matching skill acquisition is mediated by attenuation of physiological tremor oscillations in the shared synaptic inputs. Supported by simulations, a plausible mechanism for alpha band reductions may involve spinal interneuron phase-cancelling descending oscillations. Therefore, during skill learning, the central nervous system acts as a matched filter, adjusting synaptic weights of shared inputs to suppress neural components unrelated to the specific task.
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Affiliation(s)
- Hélio V Cabral
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia 25123, Italy
| | - Alessandro Cudicio
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia 25123, Italy
| | - Alberto Bonardi
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia 25123, Italy
| | - Alessandro Del Vecchio
- Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander University, Erlangen 91052, Germany
| | - Luca Falciati
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia 25123, Italy
| | - Claudio Orizio
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia 25123, Italy
| | - Eduardo Martinez-Valdes
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham B152TT, United Kingdom
| | - Francesco Negro
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia 25123, Italy
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12
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Silva-Santos T, Guerra RS, Valdiviesso R, Amaral TF. Hand Grip Force-Time Curve Indicators Evaluated by Dynamometer: A Systematic Review. Nutrients 2024; 16:1951. [PMID: 38931305 PMCID: PMC11206825 DOI: 10.3390/nu16121951] [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: 05/11/2024] [Revised: 06/14/2024] [Accepted: 06/17/2024] [Indexed: 06/28/2024] Open
Abstract
BACKGROUND Handgrip strength (HGS) is an indicator of muscular strength, used in the diagnosis of sarcopenia, undernutrition, and physical frailty as well as recovery. Typically, the maximum HGS value is used; however, recent evidence suggests the exploration of new indicators provided based on the force-time curve to achieve a more comprehensive assessment of muscle function. Therefore, the objective was to identify indicators of the HGS profile beyond maximum HGS, based on force-time curves, and to systematize knowledge about their applications to various types of samples, health issues, and physical performance. METHODS A systematic review was performed including studies whose participants' HGS was assessed with a digital or adapted dynamometer. The outcome measures were HGS profile indicators calculated from the force-time curve. RESULTS a total of 15 studies were included, and the following indicators were identified: grip fatigue, fatigability index, fatigue rate, fatigue resistance, time to 80% maximal voluntary contraction, plateau coefficient of variability, time to maximum value, T-90%, release rate, power factor, grip work, average integrated area, endurance, cycle duration, time between cycles, maximum and minimum force-velocity, rate of grip force, final force, inflection point, integrated area, submaximal control, and response time. CONCLUSIONS Various indicators based on the force-time curve can be assessed through digital or adapted dynamometers. Future research should analyze these indicators to understand their implications for muscle function assessment, to standardize evaluation procedures, to identify clinically relevant measures, and to clarify their implications in clinical practice.
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Affiliation(s)
- Tânia Silva-Santos
- LAETA-INEGI/FEUP, Associated Laboratory of Energy, Transports and Aerospace, Institute of Science and Innovation in Mechanical and Industrial Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal; (T.S.-S.); (R.S.G.)
| | - Rita S. Guerra
- LAETA-INEGI/FEUP, Associated Laboratory of Energy, Transports and Aerospace, Institute of Science and Innovation in Mechanical and Industrial Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal; (T.S.-S.); (R.S.G.)
- FP-I3ID, FP-BHS, Faculty of Health Sciences, University Fernando Pessoa, 4200-150 Porto, Portugal
| | - Rui Valdiviesso
- FCNAUP, Faculty of Nutrition and Food Sciences, University of Porto, 4150-180 Porto, Portugal;
- CINTESIS@RISE, MEDCIDS, Faculty of Medicine, University of Porto, 4200-450 Porto, Portugal
| | - Teresa F. Amaral
- LAETA-INEGI/FEUP, Associated Laboratory of Energy, Transports and Aerospace, Institute of Science and Innovation in Mechanical and Industrial Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal; (T.S.-S.); (R.S.G.)
- FCNAUP, Faculty of Nutrition and Food Sciences, University of Porto, 4150-180 Porto, Portugal;
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13
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Cabral HV, Inglis JG, Cudicio A, Cogliati M, Orizio C, Yavuz US, Negro F. Muscle contractile properties directly influence shared synaptic inputs to spinal motor neurons. J Physiol 2024; 602:2855-2872. [PMID: 38709959 DOI: 10.1113/jp286078] [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: 12/01/2023] [Accepted: 04/18/2024] [Indexed: 05/08/2024] Open
Abstract
Alpha band oscillations in shared synaptic inputs to the alpha motor neuron pool can be considered an involuntary source of noise that hinders precise voluntary force production. This study investigated the impact of changing muscle length on the shared synaptic oscillations to spinal motor neurons, particularly in the physiological tremor band. Fourteen healthy individuals performed low-level dorsiflexion contractions at ankle joint angles of 90° and 130°, while high-density surface electromyography (HDsEMG) was recorded from the tibialis anterior (TA). We decomposed the HDsEMG into motor units spike trains and calculated the motor units' coherence within the delta (1-5 Hz), alpha (5-15 Hz), and beta (15-35 Hz) bands. Additionally, force steadiness and force spectral power within the tremor band were quantified. Results showed no significant differences in force steadiness between 90° and 130°. In contrast, alpha band oscillations in both synaptic inputs and force output decreased as the length of the TA was moved from shorter (90°) to longer (130°), with no changes in delta and beta bands. In a second set of experiments (10 participants), evoked twitches were recorded with the ankle joint at 90° and 130°, revealing longer twitch durations in the longer TA muscle length condition compared to the shorter. These experimental results, supported by a simple computational simulation, suggest that increasing muscle length enhances the muscle's low-pass filtering properties, influencing the oscillations generated by the Ia afferent feedback loop. Therefore, this study provides valuable insights into the interplay between muscle biomechanics and neural oscillations. KEY POINTS: We investigated whether changes in muscle length, achieved by changing joint position, could influence common synaptic oscillations to spinal motor neurons, particularly in the tremor band (5-15 Hz). Our results demonstrate that changing muscle length from shorter to longer induces reductions in the magnitude of alpha band oscillations in common synaptic inputs. Importantly, these reductions were reflected in the oscillations of muscle force output within the alpha band. Longer twitch durations were observed in the longer muscle length condition compared to the shorter, suggesting that increasing muscle length enhances the muscle's low-pass filtering properties. Changes in the peripheral contractile properties of motor units due to changes in muscle length significantly influence the transmission of shared synaptic inputs into muscle force output. These findings prove the interplay between muscle mechanics and neural adaptations.
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Affiliation(s)
- Hélio V Cabral
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia, Italy
| | - J Greig Inglis
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia, Italy
| | - Alessandro Cudicio
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia, Italy
| | - Marta Cogliati
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia, Italy
| | - Claudio Orizio
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia, Italy
| | - Utku S Yavuz
- Biomedical Signals and Systems, University of Twente, Enschede, Netherlands
| | - Francesco Negro
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia, Italy
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14
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Cobian DG, Oppenheim ZR, Roehl TJ, Joachim MR, Heiderscheit BC. Knee Extensor Torque Steadiness and Quadriceps Activation Variability in Collegiate Athletes 4, 6, and 12 Months After ACL Reconstruction. Orthop J Sports Med 2024; 12:23259671241253843. [PMID: 38867919 PMCID: PMC11168251 DOI: 10.1177/23259671241253843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 11/16/2023] [Indexed: 06/14/2024] Open
Abstract
Background Quadriceps performance after anterior cruciate ligament reconstruction (ACLR) is typically characterized by peak force/torque, but the ability to generate consistent knee extensor torque may be clinically meaningful. Purpose/Hypothesis The purpose of this study was to evaluate knee extensor torque steadiness and quadriceps activation variability in collegiate athletes 4 to 12 months after ACLR. It was hypothesized that between-limb asymmetries in torque steadiness and activation variability would be observed and that steadiness would be associated with activation variability and peak knee extensor torque symmetry. Study Design Case-control study; Level of evidence, 3. Methods A total of 30 National Collegiate Athletic Association Division I athletes completed maximal voluntary isometric contractions 4, 6, and 12 months after ACLR. Torque and surface electromyography of the superficial quadriceps were recorded. Torque steadiness was calculated as the mean difference between initial and low-pass filtered torque signals and was expressed as a percentage of peak torque. Quadriceps activation variability was calculated similarly and was expressed as a percentage of peak electromyography. Linear mixed models were used to assess change in torque steadiness and activation variability over time. Associations between torque steadiness of the operated limb, activation variability, and quadriceps strength symmetry were evaluated using the Spearman correlation coefficient. Results Limb-by-time interactions were detected for torque steadiness and activation variability (P < .001), with reductions (improvements) in limb steadiness and activation variability observed with increasing time since surgery. Between-limb differences in torque steadiness and activation variability were observed at 4 and 6 months postoperatively (P < .05). Significant associations between operated limb torque steadiness and quadriceps activation variability were observed at 4 months (P < .001) and 6 months (P < .01). Torque steadiness of the operated limb was associated with peak knee extensor torque symmetry at 4 months (r S = -0.49; P < .01) and 6 months (r S = -0.49; P < .01). Conclusion In collegiate athletes, impaired knee extensor torque steadiness of the operated limb and associated abnormal quadriceps activation patterns were observed 4 to 12 months after ACLR, and the consistency of knee extensor torque production was associated with greater quadriceps strength asymmetries, particularly 4 to 6 months after surgery. Operated limb torque steadiness and activation variability improved from 4 to 12 months after ACLR. Clinical assessment of knee extensor torque steadiness after ACLR may improve prognosis and specificity of rehabilitation efforts.
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Affiliation(s)
- Daniel G. Cobian
- Orthopedics and Rehabilitation, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Badger Athletic Performance Program, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Doctor of Physical Therapy Program, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Zachary R. Oppenheim
- Badger Athletic Performance Program, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Tyler J. Roehl
- Badger Athletic Performance Program, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Doctor of Physical Therapy Program, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Mikel R. Joachim
- Orthopedics and Rehabilitation, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Badger Athletic Performance Program, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Bryan C. Heiderscheit
- Orthopedics and Rehabilitation, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Badger Athletic Performance Program, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, Wisconsin, USA
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15
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Caillet AH, Phillips ATM, Modenese L, Farina D. NeuroMechanics: Electrophysiological and computational methods to accurately estimate the neural drive to muscles in humans in vivo. J Electromyogr Kinesiol 2024; 76:102873. [PMID: 38518426 DOI: 10.1016/j.jelekin.2024.102873] [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] [Indexed: 03/24/2024] Open
Abstract
The ultimate neural signal for muscle control is the neural drive sent from the spinal cord to muscles. This neural signal comprises the ensemble of action potentials discharged by the active spinal motoneurons, which is transmitted to the innervated muscle fibres to generate forces. Accurately estimating the neural drive to muscles in humans in vivo is challenging since it requires the identification of the activity of a sample of motor units (MUs) that is representative of the active MU population. Current electrophysiological recordings usually fail in this task by identifying small MU samples with over-representation of higher-threshold with respect to lower-threshold MUs. Here, we describe recent advances in electrophysiological methods that allow the identification of more representative samples of greater numbers of MUs than previously possible. This is obtained with large and very dense arrays of electromyographic electrodes. Moreover, recently developed computational methods of data augmentation further extend experimental MU samples to infer the activity of the full MU pool. In conclusion, the combination of new electrode technologies and computational modelling allows for an accurate estimate of the neural drive to muscles and opens new perspectives in the study of the neural control of movement and in neural interfacing.
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Affiliation(s)
| | - Andrew T M Phillips
- Department of Civil and Environmental Engineering, Imperial College London, UK
| | - Luca Modenese
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia.
| | - Dario Farina
- Department of Bioengineering, Imperial College London, UK.
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16
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Pereira HM, Keenan KG, Hunter SK. Influence of visual feedback and cognitive challenge on the age-related changes in force steadiness. Exp Brain Res 2024; 242:1411-1419. [PMID: 38613669 DOI: 10.1007/s00221-024-06831-w] [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: 11/19/2023] [Accepted: 04/05/2024] [Indexed: 04/15/2024]
Abstract
Force steadiness can be influenced by visual feedback as well as presence of a cognitive tasks and potentially differs with age and sex. This study determined the impact of altered visual feedback on force steadiness in the presence of a difficult cognitive challenge in young and older men and women. Forty-nine young (19-30 yr; 25 women, 24 men) and 25 older (60-85 yr; 15 women; 10 men) performed low force (5% of maximum) static contractions with the elbow flexor muscles in the presence and absence of a cognitive challenge (counting backwards by 13) either with low or high visual feedback gain. The cognitive challenge reduced force steadiness (increased force fluctuation amplitude) particularly in women (cognitive challenge × sex: P < 0.05) and older individuals (cognitive challenge × age: P < 0.05). Force steadiness improved with high-gain visual feedback compared with low-gain visual feedback (P < 0.01) for all groups (all interactions: P > 0.05). Manipulation of visual feedback had no influence on the reduced force steadiness in presence of the cognitive challenge for all groups (all P > 0.05). These findings indicate that older individuals and women have greater risk of impaired motor performance of the upper extremity if steadiness is required during a low-force static contraction. Manipulation of visual feedback had minimal effects on the reduced force steadiness in presence of a difficult cognitive challenge.
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Affiliation(s)
- Hugo M Pereira
- Department of Health and Exercise Science, University of Oklahoma, Norman, OK, USA.
| | - Kevin G Keenan
- Joseph J. Zilber College of Public Health, University of Wisconsin-Milwaukee, Milwaukee, USA
| | - Sandra K Hunter
- Exercise Science Program, Department of Physical Therapy, Marquette University, Milwaukee, USA
- Athletic and Human Performance Research Center, Marquette University, Milwaukee, USA
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17
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Oliveira JH, Santos P, Pezarat-Correia P, Vaz JR. Sleep deprivation increases the regularity of isometric torque fluctuations. Exp Brain Res 2024; 242:1037-1046. [PMID: 38451319 PMCID: PMC11078836 DOI: 10.1007/s00221-024-06810-1] [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: 09/05/2023] [Accepted: 02/18/2024] [Indexed: 03/08/2024]
Abstract
The regularity of the fluctuations present in torque signals represent the adaptability of the motor control. While previous research showed how it is affected by neuromuscular fatigue and ageing, the underlying mechanisms remain unclear. It is currently under debate whether these changes are explained by central or peripheral neuromuscular mechanisms. Here, we experimentally manipulated the sleep of thirteen young adults through a supervised 24 h-sleep deprivation protocol. This study aimed to investigate the effect of sleep deprivation on the regularity of torque fluctuations, and other standard torque-related outcomes (Peak Torque - PT - and Rate of Torque Development - RTD). The participants were asked to perform knee extension maximal voluntary contractions (MVC) and submaximal knee extensions at 40% of MVC for 30 s. PT and RTD were calculated from the MVC and the regularity of the torque fluctuations was determined on the submaximal task through Sample Entropy (SampEn). In addition, rate of perceived effort (RPE) was collected. We found no significant changes in PT and RTD. The regularity of torque fluctuations significantly increased (i.e., a decrease in SampEn) after 24 h-sleep deprivation (PRE = 1.76 ± 0.268, POS24 = 1.71 ± 0.306; p = 0.044). Importantly, we found a negative correlation between RPE and SampEn relative changes after sleep deprivation. This study brings new insights towards the understanding of the underlying mechanisms that explain changes in torque fluctuations, demonstrating that these changes are not limited to neuromuscular processes but are also likely to be affected by other domains, such as psychological profile, which can indirectly affect the neural drive to the muscles.
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Affiliation(s)
- João H Oliveira
- Neuromuscular Research Lab, Faculty of Human Kinetics, University of Lisbon, Lisbon, Portugal
- CIPER,Faculty of Human Kinetics, University of Lisbon, Lisbon, Portugal
| | - Paulo Santos
- Neuromuscular Research Lab, Faculty of Human Kinetics, University of Lisbon, Lisbon, Portugal
- CIPER,Faculty of Human Kinetics, University of Lisbon, Lisbon, Portugal
| | - Pedro Pezarat-Correia
- Neuromuscular Research Lab, Faculty of Human Kinetics, University of Lisbon, Lisbon, Portugal
- CIPER,Faculty of Human Kinetics, University of Lisbon, Lisbon, Portugal
| | - João R Vaz
- Egas Moniz Center for Interdisciplinary Research (CiiEM), Egas Moniz School of Health & Science, Almada, Portugal.
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18
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Yacoubi B, Christou EA. Rethinking force steadiness: a new perspective. J Appl Physiol (1985) 2024; 136:1260-1262. [PMID: 38299220 PMCID: PMC11368513 DOI: 10.1152/japplphysiol.00860.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/16/2024] [Accepted: 01/29/2024] [Indexed: 02/02/2024] Open
Affiliation(s)
- Basma Yacoubi
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, United States
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, United States
- Department of Neurology, Norman Fixel Institute of Neurological Disorders, University of Florida, Gainesville, Florida, United States
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19
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Leonardis JM, Senefeld JW. Integrative approach to understanding force (un)steadiness. J Appl Physiol (1985) 2024; 136:1269. [PMID: 38743397 DOI: 10.1152/japplphysiol.00204.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 03/21/2024] [Indexed: 05/16/2024] Open
Affiliation(s)
- Joshua M Leonardis
- Department of Health and Kinesiology, University of Illinois Urbana-Champaign, Urbana, Illinois, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois, United States
| | - Jonathon W Senefeld
- Department of Health and Kinesiology, University of Illinois Urbana-Champaign, Urbana, Illinois, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois, United States
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20
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Gaemelke T, Laustsen C, Feys P, Folkestad L, Andersen MS, Jørgensen NR, Jørgensen ML, Jespersen SN, Ringgaard S, Eskildsen SF, Dalgas U, Hvid LG. Effects of power training in older patients with multiple sclerosis on neurodegeneration, neuromuscular function, and physical function. A study protocol for the "power training in older multiple sclerosis patients (PoTOMS) randomized control trial. Contemp Clin Trials Commun 2024; 38:101279. [PMID: 38444875 PMCID: PMC10912361 DOI: 10.1016/j.conctc.2024.101279] [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: 10/23/2023] [Revised: 01/24/2024] [Accepted: 02/17/2024] [Indexed: 03/07/2024] Open
Abstract
Introduction Approximately one-third of all persons with multiple sclerosis (pwMS) are older, i.e., having an age ≥60 years. Whilst ageing and MS separately elicit deteriorating effects on brain morphology, neuromuscular function, and physical function, the combination of ageing and MS may pose a particular challenge. To counteract such detrimental changes, power training (i.e., a type of resistance exercise focusing on moderate-to-high loading at maximal intended movement velocity) presents itself as a viable and highly effective solution. Power training is known to positively impact physical function, neuromuscular function, as well as brain morphology. Existing evidence is promising but limited to young and middle-aged pwMS, with the effects of power training remaining to be elucidated in older pwMS. Methods The presented 'Power Training in Older MS patients (PoTOMS)' trial is a national, multi-center, parallel-group, randomized controlled trial. The trial compares 24 weeks of usual care(n = 30) to 24 weeks of usual care and power training (n = 30). The primary outcome is whole brain atrophy rate. The secondary outcomes include changes in brain micro and macro structures, neuromuscular function, physical function, cognitive function, bone health, and patient-reported outcomes. Ethics and dissemination The presented study is approved by The Regional Ethics Committee (reference number 1-10-72-222-20) and registered at the Danish Data Protection Agency (reference number 2016-051-000001). All study findings will be published in scientific peer-reviewed journals and presented at relevant scientific conferences independent of the results. The www.clinicaltrials.gov identifier is NCT04762342.
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Affiliation(s)
- Tobias Gaemelke
- Exercise Biology, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Christoffer Laustsen
- The MR Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Peter Feys
- REVAL, Rehabilitation Research Center, BIOMED, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Hasselt, Belgium
| | - Lars Folkestad
- Department of Endocrinology, Odense University Hospital and University of Southern Denmark, Odense, Denmark
| | | | - Niklas Rye Jørgensen
- Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Sune Nørhøj Jespersen
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
- Center of Functionally Integrative Neuroscience and MINDLab, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Steffen Ringgaard
- The MR Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Simon F. Eskildsen
- Center of Functionally Integrative Neuroscience and MINDLab, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Ulrik Dalgas
- Exercise Biology, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Lars G. Hvid
- Exercise Biology, Department of Public Health, Aarhus University, Aarhus, Denmark
- The Danish MS Hospitals, Ry and Haslev, Denmark
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21
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Labanca L, Tedeschi R, Mosca M, Benedetti MG. Individuals With Chronic Ankle Instability Show Abnormalities in Maximal and Submaximal Isometric Strength of the Knee Extensor and Flexor Muscles. Am J Sports Med 2024; 52:1328-1335. [PMID: 38459686 PMCID: PMC10986150 DOI: 10.1177/03635465241232090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 12/15/2023] [Indexed: 03/10/2024]
Abstract
BACKGROUND It has been shown that chronic ankle instability (CAI) leads to abnormalities in neuromuscular control of more proximal joints than the ankle. Although strength of the hip and the ankle muscles has been largely investigated providing concordant results, limited evidence with contrasting results has been reported regarding knee extensor and flexor muscles. PURPOSE To investigate maximal and submaximal isometric muscle strength in individuals with CAI. STUDY DESIGN Controlled laboratory study. METHODS Fifteen participants with unilateral CAI and 15 healthy matched controls were recruited. To quantify maximal strength, peak forces were recorded during a maximal isometric voluntary contraction of knee extensor and flexor muscles at 30° and 90° of knee flexion and normalized by the body weight of each participant. At both angles, submaximal isometric contractions at 20%, 50%, and 80% of the maximal voluntary isometric contraction were performed to analyze strength steadiness, in terms of coefficient of variation, and strength accuracy, in terms of absolute error. During all the assessments, knee extensor and flexor muscle activation was recorded by means of surface electromyography. RESULTS Knee flexor maximal isometric strength was significantly lower in the injured limb of individuals with CAI in comparison with healthy controls at both 30° (0.15 ± 0.05 vs 0.20 ± 0.05; P < .05) and 90° (0.14 ± 0.04 vs 0.18 ± 0.05; P < .05). Knee extensor and flexor steadiness was significantly lower (higher coefficient of variation) in both the injured and the noninjured limbs of individuals with CAI in comparison with healthy individuals at 90° and at 30° for knee flexor steadiness of the injured limb. Knee extensor and flexor accuracy was lower (higher absolute error) in both the injured and noninjured limbs of individuals with CAI in comparison with healthy individuals, mainly at 30°, while at 90° it was lower only in the injured limb. No differences between the 2 groups were found for maximal isometric strength of knee extensor muscles, as well as for muscle activations. CONCLUSION Individuals with CAI show abnormalities in maximal and submaximal isometric strength of knee flexor muscles, and submaximal strength of the knee extensor muscles. Further studies should deeply investigate mechanisms leading to these abnormalities. CLINICAL RELEVANCE Rehabilitation interventions should consider abnormalities of neuromuscular control affecting joints more proximal than the ankle in individuals with CAI. REGISTRATION NCT05273177 (ClinicalTrials.gov identifier).
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Affiliation(s)
- Luciana Labanca
- Physical Medicine and Rehabilitation Unit, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Roberto Tedeschi
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Massimiliano Mosca
- II Clinic of Orthopaedics and Traumatology, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Maria Grazia Benedetti
- Physical Medicine and Rehabilitation Unit, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
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22
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Yeung D, Negro F, Vujaklija I. Adaptive HD-sEMG decomposition: towards robust real-time decoding of neural drive. J Neural Eng 2024; 21:026012. [PMID: 38479007 DOI: 10.1088/1741-2552/ad33b0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 03/13/2024] [Indexed: 03/22/2024]
Abstract
Objective. Neural interfacing via decomposition of high-density surface electromyography (HD-sEMG) should be robust to signal non-stationarities incurred by changes in joint pose and contraction intensity.Approach. We present an adaptive real-time motor unit decoding algorithm and test it on HD-sEMG collected from the extensor carpi radialis brevis during isometric contractions over a range of wrist angles and contraction intensities. The performance of the algorithm was verified using high-confidence benchmark decompositions derived from concurrently recorded intramuscular electromyography.Main results. In trials where contraction conditions between the initialization and testing data differed, the adaptive decoding algorithm maintained significantly higher decoding accuracies when compared to static decoding methods.Significance. Using "gold standard" verification techniques, we demonstrate the limitations of filter re-use decoding methods and show the necessity of parameter adaptation to achieve robust neural decoding.
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Affiliation(s)
- Dennis Yeung
- Department of Electrical Engineering and Automation, Aalto University, Espoo, Finland
| | - Francesco Negro
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia, Italy
| | - Ivan Vujaklija
- Department of Electrical Engineering and Automation, Aalto University, Espoo, Finland
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Kim C, Wile DJ, Kraeutner SN, Larocque KA, Jakobi JM. Short term effects of contralateral tendon vibration on motor unit discharge rate variability and force steadiness in people with Parkinson's disease. Front Aging Neurosci 2024; 16:1301012. [PMID: 38529054 PMCID: PMC10962053 DOI: 10.3389/fnagi.2024.1301012] [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: 09/23/2023] [Accepted: 01/25/2024] [Indexed: 03/27/2024] Open
Abstract
Background Vibration of one limb affects motor performance of the contralateral limb, and this may have clinical implications for people with lateralized motor impairments through vibration-induced increase in cortical activation, descending neural drive, or spinal excitability. Objective The objective of this study was to evaluate the effects of acute biceps brachii tendon vibration on force steadiness and motor unit activity in the contralateral limb of persons with Parkinson's disease. Methods Ten participants with mild to moderate Parkinson's disease severity performed a ramp, hold and de-ramp isometric elbow flexion at 5% of maximum voluntary contraction with the more-affected arm while vibration was applied to the distal biceps brachii tendon on the contralateral, less-affected arm. Using intramuscular fine wire electrodes, 33 MUs in the biceps brachii were recorded across three conditions (baseline, vibration, and post-vibration). Motor unit recruitment & derecruitment thresholds, discharge rates & variability, and elbow flexion force steadiness were compared between conditions with and without vibration. Results Coefficient of variation of force and discharge rate variability decreased 37 and 17%, respectively in post-vibration compared with baseline and vibration conditions. Although the motor unit discharge rates did not differ between conditions the total number of motor units active at rest after de-ramp were fewer in the post-vibration condition. Conclusion Contralateral tendon vibration reduces MU discharge rate variability and enhances force control on the more affected side in persons with Parkinson's disease.
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Affiliation(s)
- Changki Kim
- Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada
- Healthy Exercise and Aging Laboratory, Aging in Place Research Cluster, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Daryl J. Wile
- Centre for Chronic Disease Prevention and Management, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Sarah N. Kraeutner
- Department of Psychology, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Kaylee A. Larocque
- Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Jennifer M. Jakobi
- Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada
- Healthy Exercise and Aging Laboratory, Aging in Place Research Cluster, University of British Columbia Okanagan, Kelowna, BC, Canada
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24
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Zambolin F, Duro Ocana P, Goulding R, Sanderson A, Venturelli M, Wood G, McPhee J, Parr JVV. The corticomuscular response to experimental pain via blood flow occlusion when applied to the ipsilateral and contralateral leg during an isometric force task. Psychophysiology 2024; 61:e14466. [PMID: 37872004 DOI: 10.1111/psyp.14466] [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: 04/24/2023] [Revised: 08/21/2023] [Accepted: 10/08/2023] [Indexed: 10/25/2023]
Abstract
Blood flow occlusion (BFO) has been previously used to investigate physiological responses to muscle ischemia, showing increased perceptual effort (RPE) and pain along with impaired neuromuscular performance. However, at present, it is unclear how BFO alters corticomuscular activities when either applied to the exercising or nonexercising musculature. The present study therefore set out to assess the corticomuscular response to these distinct BFO paradigms during an isometric contraction precision task. In a repeated measures design, fifteen participants (age = 27.00 ± 5.77) completed 15 isometric contractions across three experimental conditions; no occlusion (CNTRL), occlusion of the contralateral (i.e., nonexercising) limb (CON-OCC), and occlusion of the ipsilateral (i.e., exercising) limb (IPS-OCC). Measures of force, electroencephalographic (EEG), and electromyographic (EMG) were recorded during contractions. We observed that IPS-OCC broadly impaired force steadiness, elevated EMG of the vastus lateralis, and heightened RPE and pain. IPSI-OCC also significantly decreased corticomuscular coherence during the early phase of contraction and decreased EEG alpha activity across the sensorimotor and temporoparietal regions during the middle and late phases of contraction compared with CNTRL. By contrast, CON-OCC increased perceived levels of pain (but not RPE) and decreased EEG alpha activity across the prefrontal cortex during the middle and late phases of contraction, with no changes observed for EMG and force steadiness. Together, these findings highlight distinctive psychophysiological responses to experimental pain via BFO showing altered cortical activities (CON-OCC) and altered cortical, corticomuscular, and neuromuscular activities (IPS-OCC) when applied to the lower limbs during an isometric force precision task.
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Affiliation(s)
- F Zambolin
- Institute of Sport, Manchester Metropolitan University, Manchester, UK
- Department of Sport and Exercise Science, Manchester Metropolitan University, Manchester, UK
| | - P Duro Ocana
- Department of Life Science, Manchester Metropolitan University, Manchester, UK
| | - R Goulding
- Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - A Sanderson
- Institute of Sport, Manchester Metropolitan University, Manchester, UK
- Department of Sport and Exercise Science, Manchester Metropolitan University, Manchester, UK
| | - M Venturelli
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
| | - G Wood
- Institute of Sport, Manchester Metropolitan University, Manchester, UK
- Department of Sport and Exercise Science, Manchester Metropolitan University, Manchester, UK
| | - J McPhee
- Institute of Sport, Manchester Metropolitan University, Manchester, UK
- Department of Sport and Exercise Science, Manchester Metropolitan University, Manchester, UK
| | - J V V Parr
- Institute of Sport, Manchester Metropolitan University, Manchester, UK
- Department of Sport and Exercise Science, Manchester Metropolitan University, Manchester, UK
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25
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Marina M, Torrado P, Duchateau J, Baudry S. Neural Adjustments during Repeated Braking and Throttle Actions on a Motorcycle Setup. Int J Sports Med 2024; 45:125-133. [PMID: 38096909 DOI: 10.1055/a-2197-0967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
The aim of the study was to assess neuromuscular changes during an intermittent fatiguing task designed to replicate fundamental actions and ergonomics of road race motorcycling. Twenty-eight participants repeated a sequence of submaximal brake-pulling and gas throttle actions, interspaced by one maximal brake-pulling, until failure. During the submaximal brake-pulling actions performed at 30% MVC, force fluctuations, surface EMG, maximal M-wave (Mmax) and H-reflex were measured in the flexor digitorum superficialis. At the end of the task, the MVC force and associated EMG activity decreased (P<0.001) by 46% and 26%, respectively. During the task, force fluctuation and EMG activity increased gradually (106% and 61%, respectively) with respect to the pre-fatigue state (P≤0.029). The Mmax first phase did not change (P≥0.524), whereas the H-reflex amplitude, normalized to Mmax, increased (149%; P≤0.039). Noteworthy, the relative increase in H-reflex amplitude was correlated with the increase in EMG activity during the task (r=0.63; P<0.001). During the 10-min recovery, MVC force and EMG activity remained depressed (P≤0.05) whereas H-reflex amplitude and force fluctuation returned to pre-fatigue values. In conclusion, contrarily to other studies, our results bring forward that when mimicking motorcycling brake-pulling and gas throttle actions, supraspinal neural mechanisms primarily limit the duration of the performance.
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Affiliation(s)
- Michel Marina
- Research Group in Physical Activity and Health (GRAFAiS), Institut Nacional d'Educació Física de Catalunya (INEFC) - Universitat de Barcelona (UB), Barcelona, Spain
| | - Priscila Torrado
- Research Group in Physical Activity and Health (GRAFAiS), Institut Nacional d'Educació Física de Catalunya (INEFC) - Universitat de Barcelona (UB), Barcelona, Spain
| | - Jacques Duchateau
- Laboratory of Applied Biology, Research Unit in Applied Neurophysiology (LABNeuro), ULB Université Libre de Bruxelles, Bruxelles, Belgium
| | - Stephane Baudry
- Laboratory of Applied Biology, Research Unit in Applied Neurophysiology (LABNeuro), ULB Université Libre de Bruxelles, Bruxelles, Belgium
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26
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Petrovic I, Amiridis IG, Kannas T, Tsampalaki Z, Holobar A, Sahinis C, Kellis E, Stankovic D, Enoka RM. Footedness but not dominance influences force steadiness during isometric dorsiflexion in young men. J Electromyogr Kinesiol 2023; 73:102828. [PMID: 37782992 DOI: 10.1016/j.jelekin.2023.102828] [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: 06/14/2023] [Revised: 09/18/2023] [Accepted: 09/28/2023] [Indexed: 10/04/2023] Open
Abstract
The aim of the study was to assess the potential influence of footedness and dominance on maximal force, force fluctuations and neural drive during dorsiflexion. Fifteen left-footed (LF) and fifteen right-footed (RF) young adults performed 2 maximal voluntary contractions (MVC) and 3 steady submaximal isometric contractions at five target forces (5, 10, 20, 40 and 60% MVC) with the dorsiflexors of both legs. High-density electromyography (EMG) was used to record the discharge characteristics of motor units (MUs) of Tibialis Anterior. MVC force and EMG amplitude (root mean square) were similar between the two legs and groups (p > 0.05). Force fluctuations (Coefficient of Variation, CoV for force), mean discharge rate of MUs, discharge variability (CoV of interspike interval), and variability in neural drive (standard deviation of filtered cumulative spike train) were greater (p < 0.05) and the input-output gain of the MUs (ΔDR/ΔF) was lower (p < 0.05) for the LF relative to the RF group. The differences in force fluctuations during steady contractions with the dorsiflexors were associated with footedness but not with dominance. They reflect greater variability in motor neuron output, as suggested by coefficient of variation for interspike interval (independent input) and the standard deviation of the smoothed discharge times (common input).
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Affiliation(s)
- Ivana Petrovic
- Laboratory of Neuromechanics, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Greece; Faculty of Sport and Physical Education, University of Niš, Serbia
| | - Ioannis G Amiridis
- Laboratory of Neuromechanics, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Greece.
| | - Theodoros Kannas
- Laboratory of Neuromechanics, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Greece
| | - Zoi Tsampalaki
- Laboratory of Neuromechanics, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Greece
| | - Ales Holobar
- Faculty of Electrical Engineering and Computer Science, University of Maribor, Slovenia
| | - Chrysostomos Sahinis
- Laboratory of Neuromechanics, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Greece
| | - Eleftherios Kellis
- Laboratory of Neuromechanics, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Greece
| | - Daniel Stankovic
- Faculty of Sport and Physical Education, University of Niš, Serbia
| | - Roger M Enoka
- Department of Integrative Physiology, University of Colorado, Boulder, CO, USA
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Vila-Chã C, Bovolini A, Francisco C, Costa-Brito AR, Vaz C, Rua-Alonso M, de Paz JA, Vieira T, Mendonca GV. Acute effects of isotonic eccentric exercise on the neuromuscular function of knee extensors vary according to the motor task: impact on muscle strength profiles, proprioception and balance. Front Sports Act Living 2023; 5:1273152. [PMID: 38022776 PMCID: PMC10655025 DOI: 10.3389/fspor.2023.1273152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 10/18/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Eccentric exercise has often been reported to result in muscle damage, limiting the muscle potential to produce force. However, understanding whether these adverse consequences extend to a broader, functional level is of apparently less concern. In this study, we address this issue by investigating the acute and delayed effects of supramaximal isotonic eccentric exercise on neuromuscular function and motor performance of knee extensors during tasks involving a range of strength profiles, proprioception, and balance. Methods Fifteen healthy volunteers (23.2 ± 2.9 years old) performed a unilateral isotonic eccentric exercise of the knee extensors of their dominant lower limb (4 × 10 reps at 120% of one Repetition Maximum (1RM)). The maximum voluntary isometric contraction (MVC), rate of force development (RFD), force steadiness of the knee extensors, as well as knee joint position sense and mediolateral (MLI) and anteroposterior stability (API) of the dominant lower limb, were measured pre-, immediately, and 24 h after the eccentric exercise. The EMG amplitude of the vastus medialis (VM) and biceps femoris (BF) were concomitantly evaluated. Results MVC decreased by 17.9% immediately after exercise (P < 0.001) and remained reduced by 13.6% 24 h following exercise (P < 0.001). Maximum RFD decreased by 20.4% immediately after exercise (P < 0.001) and remained reduced by 15.5% at 24 h (P < 0.001). During the MVC, EMG amplitude of the VM increased immediately after exercise while decreasing during the RFD task. Both values returned to baseline 24 h after exercise. Compared to baseline, force steadiness during submaximal isometric tasks reduced immediately after exercise, and it was accompanied by an increase in the EMG amplitude of the VM. MLI and knee joint position sense were impaired immediately after isotonic eccentric exercise (P < 0.05). While MLI returned to baseline values 24 h later, the absolute error in the knee repositioning task did not. Discussion Impairments in force production tasks, particularly during fast contractions and in the knee joint position sense, persisted 24 h after maximal isotonic eccentric training, revealing that neuromuscular functional outputs were affected by muscle fatigue and muscle damage. Conversely, force fluctuation and stability during the balance tasks were only affected by muscle fatigue since fully recovered was observed 24 h following isotonic eccentric exercise.
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Affiliation(s)
- Carolina Vila-Chã
- Laboratory for the Assessment of Sports Performance, Physical Exercise and Health (Labmov), Polytechnic of Guarda, Guarda, Portugal
- Research Center in Sports Sciences, Health Sciences, and Human Development, Vila Real, Portugal
| | - Antonio Bovolini
- Laboratory for the Assessment of Sports Performance, Physical Exercise and Health (Labmov), Polytechnic of Guarda, Guarda, Portugal
- Research Center in Sports Sciences, Health Sciences, and Human Development, Vila Real, Portugal
| | - Cristiana Francisco
- Laboratory for the Assessment of Sports Performance, Physical Exercise and Health (Labmov), Polytechnic of Guarda, Guarda, Portugal
| | - Ana R. Costa-Brito
- Laboratory for the Assessment of Sports Performance, Physical Exercise and Health (Labmov), Polytechnic of Guarda, Guarda, Portugal
| | - Cláudia Vaz
- Laboratory for the Assessment of Sports Performance, Physical Exercise and Health (Labmov), Polytechnic of Guarda, Guarda, Portugal
| | - María Rua-Alonso
- Laboratory for the Assessment of Sports Performance, Physical Exercise and Health (Labmov), Polytechnic of Guarda, Guarda, Portugal
- Research Center in Sports Sciences, Health Sciences, and Human Development, Vila Real, Portugal
- Performance and Health Group, Department of Physical Education and Sport, Faculty of Sports Sciences and Physical Education, University of A Coruna, A Coruña, Spain
| | | | - Taian Vieira
- Laboratorio di Ingegneria del Sistema Neuromuscolare (LISiN), Dipartimento di Elettronica e Telecomunicazioni, Politecnico di Torino, Turin, Italy
- PoliToBIOMed Lab, Politecnico di Torino, Turin, Italy
| | - Goncalo V. Mendonca
- Neuromuscular Research Laboratory, Faculdade de Motricidade Humana, Universidade de Lisboa, Lisbon, Portugal
- Interdisciplinary Center for the Study of Human Performance (CIPER), Faculdade de Motricidade Humana, Universidade de Lisboa, Lisbon, Portugal
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28
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Levine J, Avrillon S, Farina D, Hug F, Pons JL. Two motor neuron synergies, invariant across ankle joint angles, activate the triceps surae during plantarflexion. J Physiol 2023; 601:4337-4354. [PMID: 37615253 PMCID: PMC10952824 DOI: 10.1113/jp284503] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Accepted: 08/10/2023] [Indexed: 08/25/2023] Open
Abstract
Recent studies have suggested that the nervous system generates movements by controlling groups of motor neurons (synergies) that do not always align with muscle anatomy. In this study, we determined whether these synergies are robust across tasks with different mechanical constraints. We identified motor neuron synergies using principal component analysis (PCA) and cross-correlations between smoothed discharge rates of motor neurons. In part 1, we used simulations to validate these methods. The results suggested that PCA can accurately identify the number of common inputs and their distribution across active motor neurons. Moreover, the results confirmed that cross-correlation can separate pairs of motor neurons that receive common inputs from those that do not receive common inputs. In part 2, 16 individuals performed plantarflexion at three ankle angles while we recorded EMG signals from the gastrocnemius lateralis (GL) and medialis (GM) and the soleus (SOL) with grids of surface electrodes. The PCA revealed two motor neuron synergies. These motor neuron synergies were relatively stable, with no significant differences in the distribution of motor neuron weights across ankle angles (P = 0.62). When the cross-correlation was calculated for pairs of motor units tracked across ankle angles, we observed that only 13.0% of pairs of motor units from GL and GM exhibited significant correlations of their smoothed discharge rates across angles, confirming the low level of common inputs between these muscles. Overall, these results highlight the modularity of movement control at the motor neuron level, suggesting a sensible reduction of computational resources for movement control. KEY POINTS: The CNS might generate movements by activating groups of motor neurons (synergies) with common inputs. We show here that two main sources of common inputs drive the motor neurons innervating the triceps surae muscles during isometric ankle plantarflexions. We report that the distribution of these common inputs is globally invariant despite changing the mechanical constraints of the tasks, i.e. the ankle angle. These results suggest the functional relevance of the modular organization of the CNS to control movements.
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Affiliation(s)
- Jackson Levine
- Legs + Walking LabShirley Ryan AbilityLabChicagoILUSA
- Department of Physical Medicine and RehabilitationFeinberg School of MedicineNorthwestern UniversityChicagoILUSA
- Department of Biomedical EngineeringMcCormick School of EngineeringNorthwestern UniversityChicagoILUSA
| | - Simon Avrillon
- Legs + Walking LabShirley Ryan AbilityLabChicagoILUSA
- Department of Physical Medicine and RehabilitationFeinberg School of MedicineNorthwestern UniversityChicagoILUSA
- Department of BioengineeringFaculty of Engineering, Imperial College LondonLondonUK
| | - Dario Farina
- Department of BioengineeringFaculty of Engineering, Imperial College LondonLondonUK
| | - François Hug
- Université Côte d'Azur, LAMHESSNiceFrance
- School of Biomedical SciencesThe University of QueenslandSt LuciaQueenslandAustralia
| | - José L. Pons
- Legs + Walking LabShirley Ryan AbilityLabChicagoILUSA
- Department of Physical Medicine and RehabilitationFeinberg School of MedicineNorthwestern UniversityChicagoILUSA
- Department of Biomedical EngineeringMcCormick School of EngineeringNorthwestern UniversityChicagoILUSA
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29
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Harrison S, Clark NC, Ansdell P, Pethick J. Sex differences in knee extensor torque control. J Electromyogr Kinesiol 2023; 72:102806. [PMID: 37566938 DOI: 10.1016/j.jelekin.2023.102806] [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: 02/20/2023] [Revised: 05/30/2023] [Accepted: 08/01/2023] [Indexed: 08/13/2023] Open
Abstract
There is currently equivocal evidence regarding sex-related differences in measures of muscle force and torque control. To that end, we investigated sex differences in knee extensor muscle torque control, using both magnitude- and complexity-based measures, across contraction intensities typical of activities of daily living. 50 participants (25 male, median age [and interquartile range] 23.0 [20.0-33.0]; 25 female, median age [and interquartile range] 21.0 [20.0-40.5]) performed a series of intermittent isometric knee extensor contractions at 10, 20 and 40% maximal voluntary contraction (MVC). Torque was measured in N·m and torque control was quantified according to the magnitude (standard deviation [SD], coefficient of variation [CV]) and complexity (approximate entropy [ApEn], detrended fluctuation analysis [DFA] α) of torque fluctuations. Males exhibited a significantly greater absolute magnitude (i.e., SD) of knee extensor torque fluctuations during contractions at 10% (P = 0.011), 20% (P = 0.002) and 40% MVC (P = 0.003), though no sex differences were evident when fluctuations were normalised to mean torque output (i.e., CV). Males exhibited significantly lower ApEn during contractions at 10% (P = 0.002) and 20% MVC (P = 0.024) and significantly greater DFA α during contractions at 10% (P = 0.003) and 20% MVC (P = 0.001). These data suggest sex differences in muscle torque control strategies and highlight the need to consider both the magnitude and complexity of torque fluctuations when examining sex differences in muscle force control.
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Affiliation(s)
- Savanna Harrison
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester, UK
| | - Nicholas C Clark
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester, UK
| | - Paul Ansdell
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle-upon-Tyne, UK
| | - Jamie Pethick
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester, UK.
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30
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Klawitter LA, Hackney KJ, Christensen BK, Hamm JM, Hanson M, McGrath R. Using Electronic Handgrip Dynamometry and Accelerometry to Examine Multiple Aspects of Handgrip Function in Master Endurance Athletes: A Pilot Study. J Strength Cond Res 2023; 37:1777-1782. [PMID: 37616535 DOI: 10.1519/jsc.0000000000004459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 10/19/2022] [Indexed: 08/26/2023]
Abstract
ABSTRACT Klawitter, LA, Hackney, KJ, Christensen, BK, Hamm, JM, Hanson, M, and McGrath, R. Using electronic handgrip dynamometry and accelerometry to examine multiple aspects of handgrip function in master endurance athletes: A Pilot Study. J Strength Cond Res 37(9): 1777-1782, 2023-Electronic handgrip dynamometry and accelerometry may provide novel opportunities to comprehensively measure muscle function for human performance, especially for master athletes. This investigation sought to determine the multivariate relationships between maximal strength, asymmetry, rate of force development, fatigability, submaximal force control, bimanual coordination, and neuromuscular steadiness to derive one or more handgrip principal components in master-aged endurance athletes. We included n = 31 cyclists and triathletes aged 35-70 years. Maximal strength, asymmetry, rate of force development, fatigability, submaximal force control, bimanual coordination, and neuromuscular steadiness were measured twice on each hand using electronic handgrip dynamometry and accelerometry. The highest performing measures were included in the analyses. A principal component analysis was conducted to derive a new collection of uncorrelated variables from the collected handgrip measurements. Principal components with eigenvalues >1.0 were kept, and individual measures with a factor loading of |>0.40| were retained in each principal component. There were 3 principal components retained with eigenvalues of 2.46, 1.31, and 1.17. The first principal component, "robust strength," contained maximal strength, rate of force development, submaximal force control, and neuromuscular steadiness. The second principal component, "bilateral synergy," contained asymmetry and bimanual coordination, whereas the third principal component, "muscle conditioning," contained fatigability. Principal components 1, 2, and 3 explained 44.0, 31.6, and 24.4% of the variance, respectively. Different dimensions of muscle function emerged from our findings, suggesting the potential of a muscle function battery. Further research examining how these measures are associated with appropriate human performance metrics and lower extremity correlates is warranted.
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Affiliation(s)
- Lukus A Klawitter
- Department of Health, Nutrition, and Exercise Sciences, North Dakota State University, Fargo, North Dakota
- School of Health and Human Performance, Northern Michigan University, Marquette, Michigan
| | - Kyle J Hackney
- Department of Health, Nutrition, and Exercise Sciences, North Dakota State University, Fargo, North Dakota
| | - Bryan K Christensen
- Department of Health, Nutrition, and Exercise Sciences, North Dakota State University, Fargo, North Dakota
| | - Jeremy M Hamm
- Department of Psychology, North Dakota State University, Fargo, North Dakota
| | - Matt Hanson
- Matt Hanson Racing, Castle Rock, Colorado; and
| | - Ryan McGrath
- Department of Health, Nutrition, and Exercise Sciences, North Dakota State University, Fargo, North Dakota
- Fargo VA Healthcare System, Fargo, North Dakota
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31
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Pethick J, Moran J, Behm DG. Prolonged static stretching increases the magnitude and decreases the complexity of knee extensor muscle force fluctuations. PLoS One 2023; 18:e0288167. [PMID: 37478104 PMCID: PMC10361527 DOI: 10.1371/journal.pone.0288167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 06/21/2023] [Indexed: 07/23/2023] Open
Abstract
Static stretching decreases maximal muscle force generation in a dose-response manner, but its effects on the generation of task-relevant and precise levels of submaximal force, i.e. force control, is unclear. We investigated the effect of acute static stretching on knee extensor force control, quantified according to both the magnitude and complexity of force fluctuations. Twelve healthy participants performed a series of isometric knee extensor maximal voluntary contractions (MVCs) and targeted intermittent submaximal contractions at 25, 50 and 75% MVC (3 x 6 seconds contraction separated by 4 seconds rest, with 60 seconds rest between each intensity) prior to, and immediately after, one of four continuous static stretch conditions: 1) no stretch; 2) 30-second stretch; 3) 60-second stretch; 4) 120-second stretch. The magnitude of force fluctuations was quantified using the standard deviation (SD) and coefficient of variation (CV), while the complexity of fluctuations was quantified using approximate entropy (ApEn) and detrended fluctuation analysis (DFA) α. These measures were calculated using the steadiest 5 seconds of the targeted submaximal contractions at each intensity (i.e., that with the lowest SD). Significant decreases in MVC were evident following the 30, 60 and 120-second stretch conditions (all P < 0.001), with a significant correlation observed between stretch duration and the magnitude of decrease in MVC (r = -0.58, P < 0.001). The 120-second stretch resulted in significant increases in SD at 50% MVC (P = 0.007) and CV at 50% (P = 0.009) and 75% MVC (P = 0.005), and a significant decrease in ApEn at 75% MVC (P < 0.001). These results indicate that the negative effects of prolonged static stretching extend beyond maximal force generation tasks to those involving generation of precise levels of force during moderate- to high-intensity submaximal contractions.
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Affiliation(s)
- Jamie Pethick
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester, Essex, United Kingdom
| | - Jason Moran
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester, Essex, United Kingdom
| | - David G Behm
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
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32
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Yunoki T, Zang K, Hatano K, Matsuura R, Ohtsuka Y. Relationship between disturbances of CO 2 homeostasis and force output characteristics during isometric knee extension. Respir Physiol Neurobiol 2023; 315:104119. [PMID: 37468055 DOI: 10.1016/j.resp.2023.104119] [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: 04/16/2023] [Revised: 06/30/2023] [Accepted: 07/14/2023] [Indexed: 07/21/2023]
Abstract
To determine whether disturbances of CO2 homeostasis alter force output characteristics of lower limb muscles, participants performed four isometric knee extension trials (MVC30%, 10s each with 20-s rest intervals) in three CO2 conditions (normocapnia [NORM], hypercapnia [HYPER], and hypocapnia [HYPO]). Respiratory frequency and tidal volume were matched between CO2 conditions. In each MVC30%, the participants exerted a constant force (30% of maximum voluntary contraction [MVC]). The force coefficient of variation (Fcv) during each MVC30% and MVC before and after the four MVC30% trials were measured. For the means of the four trials, Fcv was significantly lower in HYPER than in HYPO. However, within HYPER, a significant positive correlation was found between the increase in end-tidal CO2 partial pressure and the increase in Fcv. MVCs in NORM and HYPO decreased significantly over the four trials, while no such reduction was observed in HYPER. These results suggest that perturbed CO2 homeostasis influences the force output characteristics independently of breathing pattern variables.
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Affiliation(s)
- Takahiro Yunoki
- Department of Health and Physical Education, Graduate School of Education, Hokkaido University, Sapporo, Japan.
| | - Kejun Zang
- Department of Health and Physical Education, Graduate School of Education, Hokkaido University, Sapporo, Japan
| | - Kei Hatano
- Japan Institute of Sports Sciences, Japan
| | - Ryouta Matsuura
- Graduate School of Education, Joetsu University of Education, Japan
| | - Yoshinori Ohtsuka
- Department of Sports and Human Studies, Sapporo International University, Japan
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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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Petrović I, Amiridis IG, Holobar A, Trypidakis G, Sahinis C, Kannas T, Kellis E, Enoka RM. Alternating or Bilateral Exercise Training does not Influence Force Control during Single-Leg Submaximal Contractions with the Dorsiflexors. J Sports Sci Med 2023; 22:245-253. [PMID: 37293414 PMCID: PMC10244987 DOI: 10.52082/jssm.2023.245] [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: 02/07/2023] [Accepted: 04/26/2023] [Indexed: 06/10/2023]
Abstract
The aim of the study was to assess the influence of habitual training history on force steadiness and the discharge characteristics of motor units in tibialis anterior during submaximal isometric contractions. Fifteen athletes whose training emphasized alternating actions (11 runners and 4 cyclists) and fifteen athletes who relied on bilateral actions with leg muscles (7 volleyball players, 8 weight-lifters) performed 2 maximal voluntary contractions (MVC) with the dorsiflexors, and 3 steady contractions at 8 target forces (2.5%, 5%, 10%, 20%, 30%, 40%, 50% and 60% MVC). The discharge characteristics of motor units in tibialis anterior were recorded using high-density electromyography grids. The MVC force and the absolute (standard deviation) and normalized (coefficient of variation) amplitudes of the force fluctuations at all target forces were similar between groups. The coefficient of variation for force decreased progressively from 2.5% to 20% MVC force, then it plateaued until 60% MVC force. Mean discharge rate of the motor units in tibialis anterior was similar at all target forces between groups. The variability in discharge times (coefficient of variation for interspike interval) and the variability in neural drive (coefficient of variation of filtered cumulative spike train) was also similar for the two groups. These results indicate that athletes who have trained with either alternating or bilateral actions with leg muscles has similar effects on maximal force, force control, and variability in the independent and common synaptic input during a single-limb isometric task with the dorsiflexors.
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Affiliation(s)
- Ivana Petrović
- Laboratory of Neuromechanics, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Greece
- Faculty of Sport and Physical Education, University of Niš, Serbia
| | - Ioannis G Amiridis
- Laboratory of Neuromechanics, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Greece
| | - Ales Holobar
- Faculty of Electrical Engineering and Computer Science, University of Maribor, Slovenia
| | - Georgios Trypidakis
- Laboratory of Neuromechanics, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Greece
| | - Chrysostomos Sahinis
- Laboratory of Neuromechanics, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Greece
| | - Theodoros Kannas
- Laboratory of Neuromechanics, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Greece
| | - Eleftherios Kellis
- Laboratory of Neuromechanics, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Greece
| | - Roger M Enoka
- Department of Integrative Physiology, University of Colorado, Boulder, CO, USA
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Pereira HM, Hunter SK. Cognitive challenge as a probe to expose sex- and age-related differences during static contractions. Front Physiol 2023; 14:1166218. [PMID: 37260592 PMCID: PMC10227451 DOI: 10.3389/fphys.2023.1166218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 05/02/2023] [Indexed: 06/02/2023] Open
Abstract
Despite activities of daily living being frequently performed simultaneously with a cognitive task, motor function is often investigated in isolation, which can hinder the applicability of findings. This brief review presents evidence that 1) performing a cognitive challenge simultaneously with a motor task can negatively impact force steadiness and fatigability of limb muscles during a static contraction, 2) the negative impact on old adults (>65 years old), particularly older women is greater than young when a cognitive challenge is simultaneously performed with a static motor task, 3) age-related mechanisms potentially explain impairments in motor performance in the presence of a cognitive challenge, and 4) the mechanisms for the age-related decrements in motor performance can be distinct between men and women. These observations are highly relevant to the older adults, given the increased risk of accidents and injury when a motor task is performed with a high cognitive-demand task, especially in light of the expanding reliance on an aging workforce.
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Affiliation(s)
- Hugo M. Pereira
- Department of Health and Exercise Science, The University of Oklahoma, Norman, OK, United States
| | - Sandra K. Hunter
- Department of Physical Therapy, Marquette University, Milwaukee, WI, United States
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Choi YJ, Chalatzoglidis G, Trapezanidou M, Delmas S, Savva E, Yacoubi B, Arabatzi F, Christou EA. Adolescent boys who participate in sports exhibit similar ramp torque control with young men despite differences in strength and tendon characteristics. Eur J Appl Physiol 2023; 123:965-974. [PMID: 36607415 PMCID: PMC10718087 DOI: 10.1007/s00421-022-05130-y] [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: 04/18/2022] [Accepted: 12/26/2022] [Indexed: 01/07/2023]
Abstract
PURPOSE The goal of this paper was to determine if sports participation influences torque control differently for adolescent boys and young men during a slow ramp task. METHODS Twenty-one adolescent boys (11 athletes) and 31 young men (16 athletes) performed a slow ramp increase in plantar flexion torque from 0 to maximum. We quantified torque control as the coefficient of variation (CV) of torque during the ramp and quantified the Achilles tendon mechanical properties using ultrasonography. RESULTS Relative to adolescent boys, young men were taller, heavier, stronger, and had a longer and stiffer Achilles tendon. However, these characteristics were not different between athletes and non-athletes in adolescent boys. For the CV of torque, there was a significant interaction with sports participation, indicating that only adolescent boys who were non-athletes had greater variability than young men. The CV of torque of all participants was predicted from the maximum torque and torque oscillations from 1 to 2 Hz, whereas the CV of torque for adolescent boys was predicted only from torque oscillations from 1 to 2 Hz. CONCLUSION These findings suggested that adolescent boys who participate in sports exhibited lower torque variability during a slow ramp task, which was not explained by differences in Achilles tendon properties or strength.
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Affiliation(s)
- Yoon Jin Choi
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611-8205, USA
| | - George Chalatzoglidis
- Laboratory of Neuromechanics, Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Martha Trapezanidou
- Laboratory of Neuromechanics, Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Stefan Delmas
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611-8205, USA
| | - Evangelia Savva
- Laboratory of Neuromechanics, Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Basma Yacoubi
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611-8205, USA
| | - Fotini Arabatzi
- Laboratory of Neuromechanics, Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611-8205, USA.
- Department of Neurology, Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, USA.
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Goulding RP, Burnley M, Wüst RCI. How Priming Exercise Affects Oxygen Uptake Kinetics: From Underpinning Mechanisms to Endurance Performance. Sports Med 2023; 53:959-976. [PMID: 37010782 PMCID: PMC10115720 DOI: 10.1007/s40279-023-01832-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2023] [Indexed: 04/04/2023]
Abstract
The observation that prior heavy or severe-intensity exercise speeds overall oxygen uptake ([Formula: see text]O2) kinetics, termed the "priming effect", has garnered significant research attention and its underpinning mechanisms have been hotly debated. In the first part of this review, the evidence for and against (1) lactic acidosis, (2) increased muscle temperature, (3) O2 delivery, (4) altered motor unit recruitment patterns and (5) enhanced intracellular O2 utilisation in underpinning the priming effect is discussed. Lactic acidosis and increased muscle temperature are most likely not key determinants of the priming effect. Whilst priming increases muscle O2 delivery, many studies have demonstrated that an increased muscle O2 delivery is not a prerequisite for the priming effect. Motor unit recruitment patterns are altered by prior exercise, and these alterations are consistent with some of the observed changes in [Formula: see text]O2 kinetics in humans. Enhancements in intracellular O2 utilisation likely play a central role in mediating the priming effect, probably related to elevated mitochondrial calcium levels and parallel activation of mitochondrial enzymes at the onset of the second bout. In the latter portion of the review, the implications of priming on the parameters of the power-duration relationship are discussed. The effect of priming on subsequent endurance performance depends critically upon which phases of the [Formula: see text]O2 response are altered. A reduced [Formula: see text]O2 slow component or increased fundamental phase amplitude tend to increase the work performable above critical power (i.e. W´), whereas a reduction in the fundamental phase time constant following priming results in an increased critical power.
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Affiliation(s)
- Richie P Goulding
- Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands.
| | - Mark Burnley
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Rob C I Wüst
- Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
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Shi F, Rymer WZ, Son J. Ankle Joint Angle Influences Relative Torque Fluctuation during Isometric Plantar Flexion. Bioengineering (Basel) 2023; 10:bioengineering10030373. [PMID: 36978764 PMCID: PMC10045061 DOI: 10.3390/bioengineering10030373] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 03/09/2023] [Accepted: 03/13/2023] [Indexed: 03/30/2023] Open
Abstract
The purpose of this study was to investigate the influence of changes in muscle length on the torque fluctuations and on related oscillations in muscle activity during voluntary isometric contractions of ankle plantar flexor muscles. Eleven healthy individuals were asked to perform voluntary isometric contractions of ankle muscles at five different contraction intensities from 10% to 70% of maximum voluntary isometric contraction (MVIC) and at three different muscle lengths, implemented by changing the ankle joint angle (plantar flexion of 26°-shorter muscle length; plantar flexion of 10°-neutral muscle length; dorsiflexion of 3°-longer muscle length). Surface electromyogram (EMG) signals were recorded from the skin surface over the triceps surae muscles, and rectified-and-smoothed EMG (rsEMG) were estimated to assess the oscillations in muscle activity. The absolute torque fluctuations (quantified by the standard deviation) were significantly higher during moderate-to-high contractions at the longer muscle length. Absolute torque fluctuations were found to be a linear function of torque output regardless of muscle length. In contrast, the relative torque fluctuations (quantified by the coefficient of variation) were higher at the shorter muscle length. However, both absolute and relative oscillations in muscle activities remained relatively consistent at different ankle joint angles for all plantar flexors. These findings suggest that the torque steadiness may be affected by not only muscle activities, but also by muscle length-dependent mechanical properties. This study provides more insights that muscle mechanics should be considered when explaining the steadiness in force output.
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Affiliation(s)
- Fandi Shi
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL 60208, USA
- Shirley Ryan AbilityLab (Formerly the Rehabilitation Institute of Chicago), Chicago, IL 60611, USA
| | - William Zev Rymer
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL 60208, USA
- Shirley Ryan AbilityLab (Formerly the Rehabilitation Institute of Chicago), Chicago, IL 60611, USA
- Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Jongsang Son
- Department of Biomedical Engineering, Newark College of Engineering, New Jersey Institute of Technology, Newark, NJ 07102, USA
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Clark NC, Pethick J, Falla D. Measuring complexity of muscle force control: Theoretical principles and clinical relevance in musculoskeletal research and practice. Musculoskelet Sci Pract 2023; 64:102725. [PMID: 36773547 DOI: 10.1016/j.msksp.2023.102725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 01/18/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023]
Abstract
Musculoskeletal conditions affect bones, joints, and muscles of the locomotor system and are a leading cause of disability worldwide. This suggests that current musculoskeletal rehabilitation techniques fail to target the characteristics (e.g., physiological/physical/psychological) most influential for long-term musculoskeletal health. To identify whether a physiological characteristic is impaired, it must be measured. In neuromuscular control, traditional research approaches use magnitude-based measurements (e.g., peak force/standard deviation of force/coefficient of variation of force). However, magnitude-based measurements miss 'hidden information' regarding a physiological system's status across time. To better identify physiological characteristics that are clinically-important for long-term musculoskeletal health, other measurement approaches currently less applied in musculoskeletal research may be helpful. The purpose of this article is to present an introduction to technical and measurement principles for quantifying the 'complexity' of muscle force control as one representation of peripheral joint neuromuscular control. Complexity measurements are time-based and consider the irregular temporal structure of physiological signals. We review theoretical principles underlying measuring complexity of muscle force control and explain its clinical relevance for musculoskeletal scientists and clinicians. The principles include sensorimotor control of peripheral joints, muscle force signal construction and features, muscle force control measurement procedures, and variability and complexity variables. We propose the potential utility of measuring the complexity of muscle force control for diagnosing sensorimotor system impairment and prognosis following musculoskeletal disease or injury. This article will serve as an educational asset and a scientific resource that will inform future research directions to optimise rehabilitation for people with peripheral joint disease and injury.
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Affiliation(s)
- Nicholas C Clark
- School of Sport, Rehabilitation, and Exercise Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, CO4 3SQ, United Kingdom.
| | - Jamie Pethick
- School of Sport, Rehabilitation, and Exercise Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, CO4 3SQ, United Kingdom.
| | - Deborah Falla
- School of Sport, Exercise, and Rehabilitation Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
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Mear E, Gladwell V, Pethick J. Knee extensor force control as a predictor of dynamic balance in healthy adults. Gait Posture 2023; 100:230-235. [PMID: 36638669 DOI: 10.1016/j.gaitpost.2023.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 09/06/2022] [Accepted: 01/09/2023] [Indexed: 01/12/2023]
Abstract
BACKGROUND Previous research has demonstrated that force control in various muscles of the lower limb (measured according to the magnitude of force fluctuations) explains significant variance in static balance. Given the dynamic nature of many functional activities and sports, assessment of balance and its determinants under dynamic conditions is of importance. RESEARCH QUESTION Does muscle force control explain significant variance in dynamic balance, as measured using the Y balance test (YBT)? METHODS YBT performance and knee extensor muscle force control were measured in 28 healthy participants. The YBT involved stance on the right leg and attempting maximal reach with the left leg in the anterior, posteromedial, and posterolateral directions. Force control was assessed during isometric knee extension contractions of the right leg at 10%, 20% and 40% maximal voluntary contraction (MVC) and was quantified according to the magnitude (using the coefficient of variation [CV]), and the temporal structure (using sample entropy, SampEn; and detrended fluctuation analysis α), of force fluctuations. RESULTS Significant correlations were observed for YBT anterior reach and muscle force CV (r = -0.44, P = 0.02) and SampEn (r = 0.47, P = 0.012) during contractions at 40% MVC. A subsequent regression model demonstrated that muscle force CV and SampEn at 40% MVC significantly explained 54% of variance in YBT anterior reach. Significant correlations were also observed for YBT posteromedial reach and MVC (r = 0.39, P = 0.043) and muscle force CV during contractions at 40% MVC (r = -0.51, P = 0.006). The regression model demonstrated that MVC and muscle force CV at 40% MVC significantly explained 53.9% of variance in YBT posteromedial reach. SIGNIFICANCE These results are the first to indicate that a moderate amount of variance in dynamic balance can be explained by measures of isometric force control.
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Affiliation(s)
- Emily Mear
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Essex, UK
| | - Valerie Gladwell
- Institute of Health and Wellbeing, University of Suffolk, Suffolk, UK
| | - Jamie Pethick
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Essex, UK.
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Mackay-Phillips K, Orssatto LBR, Polman R, Van der Pols JC, Trajano GS. Effects of α-lactalbumin on strength, fatigue and psychological parameters: a randomised double-blind cross-over study. Eur J Appl Physiol 2023; 123:381-393. [PMID: 36443490 DOI: 10.1007/s00421-022-05103-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 11/16/2022] [Indexed: 11/30/2022]
Abstract
PURPOSE The neurotransmitter serotonin has a strong effect on behaviour and motor control. Regarding motor control, serotonin contributes to the development of fatigue and is also involved in the ability of motor neurones to operate across a large range of forces (gain control). The consumption of tryptophan-rich supplements (such as α-lactalbumin) is of interest because this amino acid is the only precursor for brain serotonin synthesis. Therefore, the purpose of this study was to determine the effects of α-lactalbumin supplementation on neuromuscular performance. METHODS Using a randomised double-blind cross-over design, 16 healthy participants performed plantar flexor and handgrip maximal voluntary contractions, a 30-s submaximal handgrip contraction, and a plantar flexor fatigue protocol before and 90 min after consuming either 40 g of α-lactalbumin, an isonitrogenous beverage (Zein) or an isocaloric beverage (corn-starch). Sleepiness, mood, and cognition were assessed to evaluate any psychological effects. RESULTS α-Lactalbumin decreased force steadiness by 25% during the sustained submaximal handgrip contraction (p < 0.01) and induced greater fatigue (15% reduction in total torque-time integral, p = 0.01) during the fatigue protocol. These effects were not observed for the other control beverages. No effects were found for maximal or explosive strength, or psychological measurements. CONCLUSIONS 40 g of α-lactalbumin increased handgrip force variability and reduced performance during fatiguing muscle contractions but did not influence brief maximal contractions or psychological parameters in healthy individuals. These findings support the hypothesis that the consumption of α-lactalbumin can increase motor neurone input-output gain and exacerbate central fatigue during sustained maximal exercise.
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Affiliation(s)
- Karen Mackay-Phillips
- School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology, 149 Victoria Park Rd, Kelvin Grove, Brisbane, QLD, 4059, Australia.
| | - Lucas B R Orssatto
- School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology, 149 Victoria Park Rd, Kelvin Grove, Brisbane, QLD, 4059, Australia
| | - Remco Polman
- Institute of Health and Wellbeing, Federation University, Berwick, Australia
| | - Jolieke C Van der Pols
- School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology, 149 Victoria Park Rd, Kelvin Grove, Brisbane, QLD, 4059, Australia
| | - Gabriel S Trajano
- School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology, 149 Victoria Park Rd, Kelvin Grove, Brisbane, QLD, 4059, Australia
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Bauer P, Gomes JS, Oliveira J, Santos P, Pezarat-Correia P, Vaz JR. Torque Regulation Is Influenced by the Nature of the Isometric Contraction. SENSORS (BASEL, SWITZERLAND) 2023; 23:726. [PMID: 36679523 PMCID: PMC9861772 DOI: 10.3390/s23020726] [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: 10/17/2022] [Revised: 12/07/2022] [Accepted: 01/03/2023] [Indexed: 06/17/2023]
Abstract
The present study aimed to investigate the effects of a continuous visual feedback and the isometric contraction nature on the complexity and variability of force. Thirteen healthy and young male adults performed three MVCs followed by three submaximal isometric force tasks at a target force of 40% of their MVC for 30 s, as follows: (i) push isometric task with visual feedback (Pvisual); (ii) hold isometric task with visual feedback (Hvisual); (iii) hold isometric task without visual feedback (Hnon-visual). Force complexity was evaluated through sample entropy (SampEn) of the force output. Force variability was analyzed through the coefficient of variation (CV). Results showed that differences were task-related, with Pvisual showing higher complexity (i.e., higher SampEn) and decreased variability (i.e., lower CV) when compared with the remaining tasks. Additionally, no significant differences were found between the two hold isometric force tasks (i.e., no influence of visual feedback). Our results are promising as we showed these two isometric tasks to induce different motor control strategies. Furthermore, we demonstrated that visual feedback's influence is also dependent on the type of isometric task. These findings should motivate researchers and physiologists to shift training paradigms and incorporate different force control evaluation tasks.
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Affiliation(s)
- Philipp Bauer
- Centro Interdisciplinar de Performance Humana (CIPER), Neuromuscular Research Lab, Faculty of Human Kinetics, University of Lisbon, 1495-751 Lisbon, Portugal
- Interdisciplinary Research Centre Egas Moniz (CiiEM), Egas Moniz School of Health & Science, 2829-511 Almada, Portugal
| | - João Sá Gomes
- Centro Interdisciplinar de Performance Humana (CIPER), Neuromuscular Research Lab, Faculty of Human Kinetics, University of Lisbon, 1495-751 Lisbon, Portugal
- Interdisciplinary Research Centre Egas Moniz (CiiEM), Egas Moniz School of Health & Science, 2829-511 Almada, Portugal
| | - João Oliveira
- Centro Interdisciplinar de Performance Humana (CIPER), Neuromuscular Research Lab, Faculty of Human Kinetics, University of Lisbon, 1495-751 Lisbon, Portugal
| | - Paulo Santos
- Centro Interdisciplinar de Performance Humana (CIPER), Neuromuscular Research Lab, Faculty of Human Kinetics, University of Lisbon, 1495-751 Lisbon, Portugal
| | - Pedro Pezarat-Correia
- Centro Interdisciplinar de Performance Humana (CIPER), Neuromuscular Research Lab, Faculty of Human Kinetics, University of Lisbon, 1495-751 Lisbon, Portugal
| | - João R. Vaz
- Centro Interdisciplinar de Performance Humana (CIPER), Neuromuscular Research Lab, Faculty of Human Kinetics, University of Lisbon, 1495-751 Lisbon, Portugal
- Interdisciplinary Research Centre Egas Moniz (CiiEM), Egas Moniz School of Health & Science, 2829-511 Almada, Portugal
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43
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Lower motor unit discharge rates in gastrocnemius lateralis, but not in gastrocnemius medialis or soleus, in runners with Achilles tendinopathy: a pilot study. Eur J Appl Physiol 2023; 123:633-643. [PMID: 36418751 PMCID: PMC9684880 DOI: 10.1007/s00421-022-05089-w] [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: 05/11/2022] [Accepted: 11/06/2022] [Indexed: 11/27/2022]
Abstract
OBJECTIVES Deficits in muscle performance could be a consequence of a reduced ability of a motor neuron to increase the rate in which it discharges. This study aimed to investigate motor unit (MU) discharge properties of each triceps surae muscle (TS) and TS torque steadiness during submaximal intensities in runners with Achilles tendinopathy (AT). METHODS We recruited runners with (n = 12) and without (n = 13) mid-portion AT. MU discharge rate was analysed for each of the TS muscles, using high-density surface electromyography during 10 and 20% isometric plantar flexor contractions. RESULTS MU mean discharge rate was lower in the gastrocnemius lateralis (GL) in AT compared to controls. In AT, GL MU mean discharge rate did not increase as torque increased from 10% peak torque, 8.24 pps (95% CI 7.08 to 9.41) to 20%, 8.52 pps (7.41 to 9.63, p = 0.540); however, in controls, MU discharge rate increased as torque increased from 10%, 8.39 pps (7.25-9.53) to 20%, 10.07 pps (8.89-11.25, p < 0.001). There were no between-group difference in gastrocnemius medialis (GM) or soleus (SOL) MU discharge rates. We found no between-group differences in coefficient of variation of MU discharge rate in any of the TS muscles nor in TS torque steadiness. CONCLUSION Our data demonstrate that runners with AT may have a lower neural drive to GL, failing to increase MU discharge rate to adjust for the increase in torque demand. Further research is needed to understand how interventions focussing on increasing neural drive to GL would affect muscle function in runners with AT.
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Cohen JW, Vieira TM, Ivanova TD, Garland SJ. Differential behavior of distinct motoneuron pools that innervate the triceps surae. J Neurophysiol 2023; 129:272-284. [PMID: 36475977 DOI: 10.1152/jn.00336.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
It has been shown that when humans lean in various directions, the central nervous system (CNS) recruits different motoneuron pools for task completion; common units that are active during different leaning directions, and unique units that are active in only one leaning direction. We used high-density surface electromyography (HD-sEMG) to examine if motor unit (MU) firing behavior was dependent on leaning direction, muscle (medial and lateral gastrocnemius; soleus), limits of stability, or whether a MU is considered common or unique. Fourteen healthy participants stood on a force platform and maintained their center of pressure in five different leaning directions. HD-sEMG recordings were decomposed into MU action potentials and the average firing rate (AFR), coefficient of variation (CoVISI), and firing intermittency were calculated on the MU spike trains. During the 30°-90° leaning directions both unique units and common units had higher firing rates (F = 31.31, P < 0.0001). However, the unique units achieved higher firing rates compared with the common units (mean estimate difference = 3.48 Hz, P < 0.0001). The CoVISI increased across directions for the unique units but not for the common units (F = 23.65, P < 0.0001). Finally, intermittent activation of MUs was dependent on the leaning direction (F = 11.15, P < 0.0001), with less intermittent activity occurring during diagonal and forward-leaning directions. These results provide evidence that the CNS can preferentially control separate motoneuron pools within the ankle plantarflexors during voluntary leaning tasks for the maintenance of standing balance.NEW & NOTEWORTHY In this study, we demonstrate that the different subpopulations of motor units within the three muscles comprising the ankle plantarflexors behave differently during multidirectional leaning. Our results suggest that the central nervous system has the capability to control distinct subpopulations of motor units to meet the force requirements necessary for leaning. This may allow for a precise, efficient, and flexible control strategy for the maintenance of standing balance.
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Affiliation(s)
- Joshua W Cohen
- School of Kinesiology, Western University, London, Ontario, Canada.,Collaborative Specialization in Musculoskeletal Health Research, Bone and Joint Institute, Western University, London, Ontario, Canada
| | - Taian M Vieira
- Laboratorio di Ingegneria del Sistema Neuromuscolare (LISiN), Dipartimento di Elettronica e Telecomunicazioni, Politecnico di Torino, Turin, Italy
| | - Tanya D Ivanova
- Physical Therapy, Faculty of Health Sciences, Western University, London, Ontario, Canada
| | - S Jayne Garland
- Physical Therapy, Faculty of Health Sciences, Western University, London, Ontario, Canada.,Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
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Hollman JH, Buenger NG, DeSautel SG, Chen VC, Koehler LR, Schilaty ND. Altered neuromuscular control in the vastus medialis following anterior cruciate ligament injury: A recurrence quantification analysis of electromyogram recruitment. Clin Biomech (Bristol, Avon) 2022; 100:105798. [PMID: 36244098 PMCID: PMC10958231 DOI: 10.1016/j.clinbiomech.2022.105798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/30/2022] [Accepted: 10/07/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND Neuromuscular deficits exist following anterior cruciate ligament (ACL) injury. To observe these deficits, we examined nonlinear characteristics of vastus medialis electromyography (EMG) signals during submaximal isometric knee extensor contractions. Our purpose was to examine if determinism and entropy in EMG signals reflected neuromuscular control deficits in individuals with ACL-deficient limbs. METHODS 24 participants (12 male, 12 female, mean age = 18.8 ± 3.1 years) with unilaterally injured ACLs and 25 age-similar healthy controls (11 male, 14 female, mean age = 18.8 ± 3.1 years) volunteered. Isometric knee extensions were tested at 10%, 25%, 35%, and 50% maximum voluntary contractions. Surface electrodes adhered over the vastus medialis captured EMG signals. EMG data were processed with recurrence quantification analyses. Specifically, determinism (an index of system predictability) and entropy (an index of system disorder) were calculated from recurrence plots. FINDINGS Determinism and entropy in EMG signals were lower in the injured than uninjured limb, and lower than that from healthy controls (P < .05). INTERPRETATION Vastus medialis EMG signals from the injured limb were less predictable and less complex than those from healthy limbs. The findings reflect impaired neuromuscular control in the injured limb's quadriceps and are consistent with a 'loss of complexity' hypothesis in physiologic signals emanating from pathologic states. Determinism and entropy in EMG signals may represent biomarkers of one's neuromuscular control system.
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Affiliation(s)
- John H Hollman
- Program in Physical Therapy, Mayo Clinic School of Health Sciences, Mayo Clinic College of Medicine and Science, Rochester, MN, USA; Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN, USA.
| | - Natalie G Buenger
- Program in Physical Therapy, Mayo Clinic School of Health Sciences, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
| | - Sarah G DeSautel
- Program in Physical Therapy, Mayo Clinic School of Health Sciences, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
| | - Vikki C Chen
- Program in Physical Therapy, Mayo Clinic School of Health Sciences, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
| | - Lauren R Koehler
- Program in Physical Therapy, Mayo Clinic School of Health Sciences, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
| | - Nathan D Schilaty
- Department of Neurosurgery & Brain Repair, University of South Florida, Tampa, FL, USA; Center for Neuromusculoskeletal Research, University of South Florida, Tampa, FL, USA
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Pethick J, Tallent J. The Neuromuscular Fatigue-Induced Loss of Muscle Force Control. Sports (Basel) 2022; 10:184. [PMID: 36422953 PMCID: PMC9694672 DOI: 10.3390/sports10110184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/14/2022] [Accepted: 11/17/2022] [Indexed: 11/22/2022] Open
Abstract
Neuromuscular fatigue is characterised not only by a reduction in the capacity to generate maximal muscle force, but also in the ability to control submaximal muscle forces, i.e., to generate task-relevant and precise levels of force. This decreased ability to control force is quantified according to a greater magnitude and lower complexity (temporal structure) of force fluctuations, which are indicative of decreased force steadiness and adaptability, respectively. The "loss of force control" is affected by the type of muscle contraction used in the fatiguing exercise, potentially differing between typical laboratory tests of fatigue (e.g., isometric contractions) and the contractions typical of everyday and sporting movements (e.g., dynamic concentric and eccentric contractions), and can be attenuated through the use of ergogenic aids. The loss of force control appears to relate to a fatigue-induced increase in common synaptic input to muscle, though the extent to which various mechanisms (afferent feedback, neuromodulatory pathways, cortical/reticulospinal pathways) contribute to this remains to be determined. Importantly, this fatigue-induced loss of force control could have important implications for task performance, as force control is correlated with performance in a range of tasks that are associated with activities of daily living, occupational duties, and sporting performance.
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Affiliation(s)
- Jamie Pethick
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester CO4 3SQ, UK
| | - Jamie Tallent
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester CO4 3SQ, UK
- Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne 3800, Australia
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Mear E, Gladwell VF, Pethick J. The Effect of Breaking Up Sedentary Time with Calisthenics on Neuromuscular Function: A Preliminary Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:14597. [PMID: 36361476 PMCID: PMC9653850 DOI: 10.3390/ijerph192114597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/02/2022] [Accepted: 11/04/2022] [Indexed: 06/16/2023]
Abstract
The ageing process results in reduced neuromuscular function. This alongside prolonged sedentary behaviour is associated with decreased muscle strength, force control and ability to maintain balance. Breaking up sedentary time with regular bouts of physical activity has numerous health benefits, though the effects on neuromuscular function are unknown. This study investigated the effect of breaking up sedentary time with calisthenic exercise on neuromuscular function. 17 healthy adults (33 ± 13.1 years), who spent ≥6 h/day sitting, were assigned to a four-week calisthenics intervention (n = 8) or control group (n = 9). The calisthenics intervention involved performing up to eight sets of exercises during the working day (09:00-17:00); with one set consisting of eight repetitions of five difference exercises (including squats and lunges). Before and immediately after the intervention, measures of knee extensor maximal voluntary contraction (MVC) and submaximal force control (measures of the magnitude and complexity of force fluctuations), and dynamic balance (Y balance test) were taken. The calisthenics intervention resulted in a significant increase in knee extensor MVC (p = 0.036), significant decreases in the standard deviation (p = 0.031) and coefficient of variation (p = 0.016) of knee extensor force fluctuations during contractions at 40% MVC, and a significant increase in Y balance test posterolateral reach with left leg stance (p = 0.046). These results suggest that breaking up sedentary time with calisthenics may be effective at increasing muscle strength, force steadiness and dynamic balance all of which might help reduce the effects of the ageing process.
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Affiliation(s)
- Emily Mear
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester CO4 3SQ, UK
| | | | - Jamie Pethick
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester CO4 3SQ, UK
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Tempo-controlled resistance training of the hip abductors and ankle dorsiflexors with light loads does not improve postural sway in older adults. Exp Brain Res 2022; 240:3049-3060. [PMID: 36227344 DOI: 10.1007/s00221-022-06477-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 09/30/2022] [Indexed: 11/04/2022]
Abstract
The force steadiness capabilities of the hip abductors and ankle dorsiflexors can explain a significant amount of the variance in postural sway during four types of standing balance tests. Control over balance, as well as force steadiness, generally worsens with aging, although the latter can be improved with unique training interventions. The purpose of our study was to assess how tempo-controlled, light-load resistance training of the hip abductors and ankle dorsiflexors influences performance in clinical movement tests, postural sway, muscle strength, and force steadiness in older adults. Participants (n = 28, 70 ± 7 years, 8 men) completed nine training sessions for either the hip abductors or ankle dorsiflexors in the nondominant leg. Training involved lifting a load equal to 15% of the maximal force achieved during an isometric contraction. Linear mixed-effects models revealed no changes (p > 0.05) in Sit-To-Stand test, Timed Up-and-Go test, maximal voluntary contraction (MVC) torque, or postural sway from before to after either training intervention. Only the dorsiflexor group significantly improved nondominant leg dorsiflexion force steadiness, but this did not translate to any other tasks. However, absolute and relative measures of MVC torque and force steadiness of the hip abductors and ankle dorsiflexors in the dominant and nondominant legs could predict sway-area rate in each of the four standing balance conditions. The responsiveness of leg muscles to light-load steadiness training in older adults appears to depend on the type of exercises performed during the intervention.
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People with chronic low back pain display spatial alterations in high-density surface EMG-torque oscillations. Sci Rep 2022; 12:15178. [PMID: 36071134 PMCID: PMC9452584 DOI: 10.1038/s41598-022-19516-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 08/30/2022] [Indexed: 11/08/2022] Open
Abstract
We quantified the relationship between spatial oscillations in surface electromyographic (sEMG) activity and trunk-extension torque in individuals with and without chronic low back pain (CLBP), during two submaximal isometric lumbar extension tasks at 20% and 50% of their maximal voluntary torque. High-density sEMG (HDsEMG) signals were recorded from the lumbar erector spinae (ES) with a 64-electrode grid, and torque signals were recorded with an isokinetic dynamometer. Coherence and cross-correlation analyses were applied between the filtered interference HDsEMG and torque signals for each submaximal contraction. Principal component analysis was used to reduce dimensionality of HDsEMG data and improve the HDsEMG-based torque estimation. sEMG-torque coherence was quantified in the δ(0–5 Hz) frequency bandwidth. Regional differences in sEMG-torque coherence were also evaluated by creating topographical coherence maps. sEMG-torque coherence in the δ band and sEMG-torque cross-correlation increased with the increase in torque in the controls but not in the CLBP group (p = 0.018, p = 0.030 respectively). As torque increased, the CLBP group increased sEMG-torque coherence in more cranial ES regions, while the opposite was observed for the controls (p = 0.043). Individuals with CLBP show reductions in sEMG-torque relationships possibly due to the use of compensatory strategies and regional adjustments of ES-sEMG oscillatory activity.
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Pethick J, Clark NC, Liew B. Alterations in peripheral joint muscle force control in adults with musculoskeletal disease, injury, surgery, or arthroplasty: A systematic review and meta-analysis. J Electromyogr Kinesiol 2022; 66:102696. [PMID: 35988532 DOI: 10.1016/j.jelekin.2022.102696] [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: 02/22/2022] [Revised: 06/23/2022] [Accepted: 08/10/2022] [Indexed: 10/15/2022] Open
Abstract
PURPOSE To systematically review and analyse whether musculoskeletal conditions affect peripheral joint muscle force control (i.e. magnitude and/or complexity of force fluctuations). METHODS A literature search was conducted using MEDLINE, CINAHL and SPORTDiscus databases (from inception-8th April 2021) for studies involving: 1) participants with musculoskeletal disease, injury, surgery, or arthroplasty in the peripheral joints of the upper/lower limb; 2) comparison with an unaffected control group or unaffected contralateral limb; and 3) measures of the magnitude and/or complexity of force fluctuations during targeted isometric contractions. The methodological quality of studies was evaluated using a modified Downs and Black Quality Index. Studies were combined using the standardized mean difference (SMD) in a random-effects model. RESULTS 14 studies (investigating 694 participants) were included in the meta-analysis. There was a significant effect of musculoskeletal conditions on peripheral joint muscle force coefficient of variation (CV; SMD = 0.19 [95 % CI 0.06, 0.32]), whereby individuals with musculoskeletal conditions exhibited greater CV than controls. Subgroup analyses revealed that CV was only greater: 1) when comparison was made between symptomatic and asymptomatic individuals (rather than between affected and contralateral limbs; SMD = 0.22 [95 % CI 0.07, 0.38]); 2) for conditions of the knee (SMD = 0.29 [95 % CI 0.14, 0.44]); and 3) for ACL injury post-surgery (SMD = 0.56 [95 % CI 0.36, 0.75]). CONCLUSION Musculoskeletal conditions result in an increase in peripheral joint muscle force CV, with this effect dependent on study design, peripheral joint, and surgical status. The greater force CV is indicative of decreased force steadiness and could have implications for long-term tissue health/day-to-day function.
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Affiliation(s)
- Jamie Pethick
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, UK.
| | - Nicholas C Clark
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, UK
| | - Bernard Liew
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, UK
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