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Hayman O, Ansdell P, Angius L, Thomas K, Horsbrough L, Howatson G, Kidgell DJ, Škarabot J, Goodall S. Changes in motor unit behaviour across repeated bouts of eccentric exercise. Exp Physiol 2024. [PMID: 39226215 DOI: 10.1113/ep092070] [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: 05/29/2024] [Accepted: 08/13/2024] [Indexed: 09/05/2024]
Abstract
Unaccustomed eccentric exercise (EE) is protective against muscle damage following a subsequent bout of similar exercise. One hypothesis suggests the existence of an alteration in motor unit (MU) behaviour during the second bout, which might contribute to the adaptive response. Accordingly, the present study investigated MU changes during repeated bouts of EE. During two bouts of exercise where maximal lengthening dorsiflexion (10 repetitions × 10 sets) was performed 3 weeks apart, maximal voluntary isometric torque (MVIC) and MU behaviour (quantified using high-density electromyography; HDsEMG) were measured at baseline, during (after set 5), and post-EE. The HDsEMG signals were decomposed into individual MU discharge timings, and a subset were tracked across each time point. MVIC was reduced similarly in both bouts post-EE (Δ27 vs. 23%, P = 0.144), with a comparable amount of total work performed (∼1,300 J; P = 0.905). In total, 1,754 MUs were identified and the decline in MVIC was accompanied by a stepwise increase in discharge rate (∼13%; P < 0.001). A decrease in relative recruitment was found immediately after EE in Bout 1 versus baseline (∼16%; P < 0.01), along with reductions in derecruitment thresholds immediately after EE in Bout 2. The coefficient of variation of inter-spike intervals was lower in Bout 2 (∼15%; P < 0.001). Our data provide new information regarding a change in MU behaviour during the performance of a repeated bout of EE. Importantly, such changes in MU behaviour might contribute, at least in part, to the repeated bout phenomenon.
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Affiliation(s)
- Oliver Hayman
- Department of Sport, Exercise, & Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK
- School of Cardiovascular and Metabolic Health, BHF Glasgow Cardiovascular Research Center, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, UK
| | - Paul Ansdell
- Department of Sport, Exercise, & Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK
| | - Luca Angius
- Department of Sport, Exercise, & Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK
| | - Kevin Thomas
- Department of Sport, Exercise, & Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK
| | - Lauren Horsbrough
- Department of Sport, Exercise, & Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK
| | - Glyn Howatson
- Department of Sport, Exercise, & Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK
- Water Research Group, North West University, Potchefstroom, South Africa
| | - Dawson J Kidgell
- Monash Exercise Neuroplasticity Research Unit, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Australia
| | - Jakob Škarabot
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Stuart Goodall
- Department of Sport, Exercise, & Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK
- Physical Activity, Sport and Recreation Research Focus Area, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
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Valli G, Wu R, Minnock D, Sirago G, Annibalini G, Casolo A, Del Vecchio A, Toniolo L, Barbieri E, De Vito G. Can non-invasive motor unit analysis reveal distinct neural strategies of force production in young with uncomplicated type 1 diabetes? Eur J Appl Physiol 2024:10.1007/s00421-024-05595-z. [PMID: 39212731 DOI: 10.1007/s00421-024-05595-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2024] [Accepted: 08/23/2024] [Indexed: 09/04/2024]
Abstract
PURPOSE to investigate the early consequences of type 1 diabetes (T1D) on the neural strategies of muscle force production. METHODS motor unit (MU) activity was recorded from the vastus lateralis muscle with High-Density surface Electromyography during isometric knee extension at 20 and 40% of maximum voluntary contraction (MVC) in 8 T1D (4 males, 4 females, 30.5 ± 3.6 years) and 8 matched control (4 males, 4 females, 27.3 ± 5.9 years) participants. Muscle biopsies were also collected from vastus lateralis for fiber type analysis, including myosin heavy chain (MyHC) isoform content via protein and mRNA expression. RESULTS MVC was comparable between groups as well as MU conduction velocity, action potentials' amplitude and proportions of MyHC protein isoforms. Nonetheless, MU discharge rate, relative derecruitment thresholds and mRNA expression of MyHC isoform I were lower in T1D. CONCLUSIONS young people with uncomplicated T1D present a different neural control of muscle force production. Furthermore, differences are detectable non-invasively in absence of any functional manifestation (i.e., force production and fiber type distribution). These novel findings suggest that T1D has early consequences on the neuromuscular system and highlights the necessity of a better characterization of neural control in this population.
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Affiliation(s)
- Giacomo Valli
- Department of Biomedical Sciences, University of Padova, Padua, Italy
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | - Rui Wu
- School of Electrical and Electronic Engineering, University College Dublin, Belfield, Dublin 4, Ireland
| | - Dean Minnock
- School of Electrical and Electronic Engineering, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Giuseppe Sirago
- Department of Biomedical Sciences, University of Padova, Padua, Italy
- Institute of Sport Sciences and Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Giosuè Annibalini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Andrea Casolo
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Alessandro Del Vecchio
- Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander University, Erlangen, Germany
| | - Luana Toniolo
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Elena Barbieri
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Giuseppe De Vito
- Department of Biomedical Sciences, University of Padova, Padua, Italy
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Valli G, Sarto F, Casolo A, Del Vecchio A, Franchi MV, Narici MV, De Vito G. Lower limb suspension induces threshold-specific alterations of motor units properties that are reversed by active recovery. JOURNAL OF SPORT AND HEALTH SCIENCE 2024; 13:264-276. [PMID: 37331508 PMCID: PMC10980901 DOI: 10.1016/j.jshs.2023.06.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 03/17/2023] [Accepted: 05/16/2023] [Indexed: 06/20/2023]
Abstract
PURPOSE This study aimed to non-invasively test the hypothesis that (a) short-term lower limb unloading would induce changes in the neural control of force production (based on motor units (MUs) properties) in the vastus lateralis muscle and (b) possible changes are reversed by active recovery (AR). METHODS Ten young males underwent 10 days of unilateral lower limb suspension (ULLS) followed by 21 days of AR. During ULLS, participants walked exclusively on crutches with the dominant leg suspended in a slightly flexed position (15°-20°) and with the contralateral foot raised by an elevated shoe. The AR was based on resistance exercise (leg press and leg extension) and executed at 70% of each participant's 1 repetition maximum, 3 times/week. Maximal voluntary isometric contraction (MVC) of knee extensors and MUs properties of the vastus lateralis muscle were measured at baseline, after ULLS, and after AR. MUs were identified using high-density electromyography during trapezoidal isometric contractions at 10%, 25%, and 50% of the current MVC, and individual MUs were tracked across the 3 data collection points. RESULTS We identified 1428 unique MUs, and 270 of them (18.9%) were accurately tracked. After ULLS, MVC decreased by 29.77%, MUs absolute recruitment/derecruitment thresholds were reduced at all contraction intensities (with changes between the 2 variables strongly correlated), while discharge rate was reduced at 10% and 25% but not at 50% MVC. Impaired MVC and MUs properties fully recovered to baseline levels after AR. Similar changes were observed in the pool of total as well as tracked MUs. CONCLUSION Our novel results demonstrate, non-invasively, that 10 days of ULLS affected neural control predominantly by altering the discharge rate of lower-threshold but not of higher-threshold MUs, suggesting a preferential impact of disuse on motoneurons with a lower depolarization threshold. However, after 21 days of AR, the impaired MUs properties were fully restored to baseline levels, highlighting the plasticity of the components involved in neural control.
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Affiliation(s)
- Giacomo Valli
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy.
| | - Fabio Sarto
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy
| | - Andrea Casolo
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy
| | - Alessandro Del Vecchio
- Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander University, Erlangen-Nürnberg 91052, Germany
| | - Martino V Franchi
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy
| | - Marco V Narici
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy
| | - Giuseppe De Vito
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy
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Valli G, Ritsche P, Casolo A, Negro F, De Vito G. Tutorial: Analysis of central and peripheral motor unit properties from decomposed High-Density surface EMG signals with openhdemg. J Electromyogr Kinesiol 2024; 74:102850. [PMID: 38065045 DOI: 10.1016/j.jelekin.2023.102850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 10/05/2023] [Accepted: 11/28/2023] [Indexed: 01/29/2024] Open
Abstract
High-Density surface Electromyography (HD-sEMG) is the most established technique for the non-invasive analysis of single motor unit (MU) activity in humans. It provides the possibility to study the central properties (e.g., discharge rate) of large populations of MUs by analysis of their firing pattern. Additionally, by spike-triggered averaging, peripheral properties such as MUs conduction velocity can be estimated over adjacent regions of the muscles and single MUs can be tracked across different recording sessions. In this tutorial, we guide the reader through the investigation of MUs properties from decomposed HD-sEMG recordings by providing both the theoretical knowledge and practical tools necessary to perform the analyses. The practical application of this tutorial is based on openhdemg, a free and open-source community-based framework for the automated analysis of MUs properties built on Python 3 and composed of different modules for HD-sEMG data handling, visualisation, editing, and analysis. openhdemg is interfaceable with most of the available recording software, equipment or decomposition techniques, and all the built-in functions are easily adaptable to different experimental needs. The framework also includes a graphical user interface which enables users with limited coding skills to perform a robust and reliable analysis of MUs properties without coding.
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Affiliation(s)
- Giacomo Valli
- Department of Biomedical Sciences, University of Padova, Padova, Italy; Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy.
| | - Paul Ritsche
- Department of Sport, Exercise and Health, University of Basel, Basel, Switzerland.
| | - Andrea Casolo
- Department of Biomedical Sciences, University of Padova, Padova, Italy.
| | - Francesco Negro
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy.
| | - Giuseppe De Vito
- Department of Biomedical Sciences, University of Padova, Padova, Italy.
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de Assis RC, Celedonio RF, Valentim AB, Monteiro GR, da Silva AMH, Dantas ACP, Maia CSC. Influence of Anaerobic Exercise in Type 1 Diabetes Mellitus Biomarkers: ASystematic Review. Curr Diabetes Rev 2024; 20:e230124226018. [PMID: 38275039 DOI: 10.2174/0115733998274125231126111321] [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: 08/28/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 01/27/2024]
Abstract
AIM Physical exercise is part of the type 1 diabetes mellitus (T1DM) treatment. However, this practice is still neglected due to the wide variety of glycemic responses under the influence of anaerobic exercise. Therefore, this study aimed to investigate the influence of anaerobic exercise on biomarkers of T1DM. METHODS The systematic review was conducted on PubMed, Lilacs, and Embase, according to PRISMA. For this purpose, three groups of descriptors were used: Adults with T1DM, anaerobic physical exercise, and glycemic control. The search filter was set to human beings older than 18 years of age, longitudinal and cross-sectional studies, with studies published from 2000 to 2023 in English, Spanish, or Portuguese. Titles and abstracts were read independently by two reviewers, and then the articles were selected for this review. The Kappa coefficient was measured to evaluate the selection. RESULTS A total of 738 articles were identified, and five were selected to be part of the review after applying the steps of the procedure. Some benefits were observed in fatigue reduction, absence of diabetic ketoacidosis requiring hospitalization, and enhancement of glucose monitoring during exercise. In the anaerobic workouts of the groups with T1DM, glycemic mean values ranged from 124.5-185.0 mg/dl, and glycated hemoglobin records ranged from 6.7-8.1%. CONCLUSION Anaerobic exercise improved the biomarkers of T1DM, especially glycemic control, and the reduction of symptomatic hypoglycemic episodes. Anaerobic exercise can be performed by individuals with T1DM, suggesting an individualized training prescription and encouraging its practice associated with aerobic exercise.
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Zhang H, Jiang Q, Li A. The impact of resistance-based training programs on throwing performance and throwing-related injuries in baseball players: A systematic review. Heliyon 2023; 9:e22797. [PMID: 38125451 PMCID: PMC10731065 DOI: 10.1016/j.heliyon.2023.e22797] [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: 10/28/2023] [Revised: 11/17/2023] [Accepted: 11/20/2023] [Indexed: 12/23/2023] Open
Abstract
The aim of this systematic review is to assess the effects of structured resistance training programs on the throwing performance and injury risk of baseball players, irrespective of their age or sex. The literature search was carried out on 18/10/2023, utilizing databases that include PubMed, Scopus, and the Web of Science. Our inclusion criteria encompassed research involving baseball players of all ages and sex who had undergone resistance-based training interventions. For comparison, we considered active control groups, irrespective of their exposure to additional training programs. The outcomes under investigation were related to throwing performance (i.e., throwing velocity and accuracy) and injuries associated with throwing. In our review, we exclusively included studies with a two- or multi-arm design. We evaluated the risk of bias using the PEDro scale. Out of the initial pool of 509 studies, we carefully examined 27 full-text articles and ultimately selected and analyzed 16 studies for inclusion in our review. Out of the 12 studies that compared and presented the inferential statistics for the post-training effects of the experimental versus control groups, it was observed that 8 of these studies demonstrated a significantly more favorable impact of the experimental group on enhancing throwing velocity when compared to the control group. Out of the three studies that compared the experimental and control groups in terms of throwing accuracy, only one study showed a significant improvement in the experimental group compared to the control group after the intervention. In conclusion, this systematic review indicates that resistance-based training interventions appear to be effective in enhancing throwing velocity. However, the evidence regarding the efficacy of these interventions in improving throwing accuracy is less robust. It is worth noting that while some experimental conditions may lead to an increase in injury rates, there is limited data available on this aspect, with only a few studies reporting on this variable.
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Affiliation(s)
- HongBo Zhang
- Geely University of China, 641423, Chengdu, China
| | - Qiang Jiang
- Geely University of China, 641423, Chengdu, China
| | - Ang Li
- Geely University of China, 641423, Chengdu, China
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7
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Knowles KS, Parsowith EJ, Beausejour JP, Pagan JI, Hart JN. The non-invasive assessment of muscle fibre size: has the future arrived? J Physiol 2023; 601:3701-3702. [PMID: 37477293 DOI: 10.1113/jp285106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/22/2023] Open
Affiliation(s)
- Kevan S Knowles
- Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, USA
| | - Emily J Parsowith
- Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, USA
| | - Jonathan P Beausejour
- Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, USA
| | - Jason I Pagan
- Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, USA
| | - Jordan N Hart
- Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, USA
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Salmon OF, Housh TJ, Hill EC, Keller JL, Anders JPV, Johnson GO, Schmidt RJ, Smith CM. Changes in Neuromuscular Response Patterns After 4 Weeks of Leg Press Training During Isokinetic Leg Extensions. J Strength Cond Res 2023; 37:e405-e412. [PMID: 36525527 DOI: 10.1519/jsc.0000000000004418] [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: 09/16/2021] [Accepted: 09/19/2022] [Indexed: 08/20/2023]
Abstract
ABSTRACT Salmon, OF, Housh, TJ, Hill, EC, Keller, JL, Anders, JPV, Johnson, GO, Schmidt, RJ, and Smith, CM. Changes in neuromuscular response patterns after 4 weeks of leg press training during isokinetic leg extensions. J Strength Cond Res 37(7): e405-e412, 2023-The purpose of this study was to identify velocity-specific changes in electromyographic root mean square (EMG RMS), EMG frequency (EMG MPF), mechanomyographic RMS (MMG RMS), and MMG MPF during maximal unilateral isokinetic muscle actions performed at 60° and 240°·s -1 velocities within the right and left vastus lateralis (VL) after 4 weeks of dynamic constant external resistance (DCER) bilateral leg press training. Twelve resistance-trained men (age: mean ± SD = 21.4 ± 3.6 years) visited the laboratory 3d·wk -1 to perform resistance training consisting of 3 sets of 10 DCER leg presses. Four, three-way analysis of variance were performed to evaluate changes in neuromuscular responses (EMG RMS, EMG MPF, MMG RMS, and MMG MPF) from the right and left VL during 1 single-leg maximal isokinetic leg extension performed at 60° and 240°·s -1 before and after 4 weeks of DCER leg press training ( p < 0.05). The results indicated a 36% increase in EMG RMS for the right leg, as well as a 23% increase in MMG RMS and 10% decrease in MMG MPF after training, collapsed across velocity and leg. In addition, EMG RMS was 65% greater in the right leg than the left leg following training, whereas EMG MPF was 11% greater for the left leg than the right leg throughout training. Thus, 4 weeks of DCER leg press training provides sufficient stimuli to alter the neuromuscular activation process of the VL but not velocity-specific neuromuscular adaptations in trained males.
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Affiliation(s)
- Owen F Salmon
- Robbins College of Health and Human SciencesHuman & Environmental Physiology Laboratory, Department of Health, Human Performance and Recreation Baylor University Waco, Texas
| | - Terry J Housh
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Ethan C Hill
- School of Kinesiology & Physical Therapy, Division of Kinesiology, University of Central Florida, Orlando, Florida; and
| | - Joshua L Keller
- Integrated Laboratory of Exercise and Applied Physiology, Department of Health, Kinesiology, and Sport, College of Education and Professional Studies University of South Alabama, Mobile, Alabama
| | - John Paul V Anders
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Glen O Johnson
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Richard J Schmidt
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Cory M Smith
- Robbins College of Health and Human SciencesHuman & Environmental Physiology Laboratory, Department of Health, Human Performance and Recreation Baylor University Waco, Texas
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Morrison S, Newell KM. Strength training as a dynamical model of motor learning. J Sports Sci 2023:1-16. [PMID: 37270792 DOI: 10.1080/02640414.2023.2220177] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 05/22/2023] [Indexed: 06/06/2023]
Abstract
This paper outlines a framework for strength training as a dynamical model of perceptual-motor learning. We show, with emphasis on fixed-point attractor dynamics, that strength training can be mapped to the general dynamical principles of motor learning that arise from the constraints on action, including the distribution of practice/training. The time scales of the respective dynamics of performance change (increment and decrement) in discrete strength training and motor learning tasks reveal superposition of exponential functions in fixed-point dynamics, but distinctive attractor and parameter dynamics in oscillatory limit cycle and more continuous tasks, together with unique timescales to process influences (including practice, learning, strength, fitness, fatigue, warm-up decrement). Increments and decrements of strength can be viewed within a dynamical model of change in motor performance that reflects the integration of practice and training processes at multiple levels of learning and skill development.
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Affiliation(s)
- Steven Morrison
- School of Rehabilitation Sciences, Old Dominion University, Norfolk, VA, USA
| | - Karl M Newell
- Department of Kinesiology, University of Georgia, Athens, GA, USA
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10
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Borzuola R, Nuccio S, Scalia M, Parrella M, Del Vecchio A, Bazzucchi I, Felici F, Macaluso A. Adjustments in the motor unit discharge behavior following neuromuscular electrical stimulation compared to voluntary contractions. Front Physiol 2023; 14:1212453. [PMID: 37324379 PMCID: PMC10267458 DOI: 10.3389/fphys.2023.1212453] [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: 04/26/2023] [Accepted: 05/26/2023] [Indexed: 06/17/2023] Open
Abstract
Introduction: The application of neuromuscular electrical stimulation superimposed on voluntary muscle contractions (NMES+) has demonstrated a considerable potential to enhance or restore muscle function in both healthy and individuals with neurological or orthopedic disorders. Improvements in muscle strength and power have been commonly associated with specific neural adaptations. In this study, we investigated changes in the discharge characteristics of the tibialis anterior motor units, following three acute exercises consisting of NMES+, passive NMES and voluntary isometric contractions alone. Methods: Seventeen young participants participated in the study. High-density surface electromyography was used to record myoelectric activity in the tibialis anterior muscle during trapezoidal force trajectories involving isometric contractions of ankle dorsi flexors with target forces set at 35, 50% and 70% of maximal voluntary isometric contraction (MVIC). From decomposition of the electromyographic signal, motor unit discharge rate, recruitment and derecruitment thresholds were extracted and the input-output gain of the motoneuron pool was estimated. Results: Global discharge rate increased following the isometric condition compared to baseline at 35% MVIC while it increased after all experimental conditions at 50% MVIC target force. Interestingly, at 70% MVIC target force, only NMES + led to greater discharge rate compared to baseline. Recruitment threshold decreased after the isometric condition, although only at 50% MVIC. Input-output gain of the motoneurons of the tibialis anterior muscle was unaltered after the experimental conditions. Discussion: These results indicated that acute exercise involving NMES + induces an increase in motor unit discharge rate, particularly when higher forces are required. This reflects an enhanced neural drive to the muscle and might be strongly related to the distinctive motor fiber recruitment characterizing NMES+.
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Affiliation(s)
- Riccardo Borzuola
- Department of Movement, Human, and Health Sciences, University of Rome “Foro Italico”, Rome, Italy
| | - Stefano Nuccio
- Department of Movement, Human, and Health Sciences, University of Rome “Foro Italico”, Rome, Italy
| | - Martina Scalia
- Department of Movement, Human, and Health Sciences, University of Rome “Foro Italico”, Rome, Italy
| | - Martina Parrella
- Department of Movement, Human, and Health Sciences, University of Rome “Foro Italico”, Rome, Italy
| | - Alessandro Del Vecchio
- Department Artificial Intelligence in Biomedical Engineering, Faculty of Engineering, Zentralinstitut für Medizintechnik (ZIMT), Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Ilenia Bazzucchi
- Department of Movement, Human, and Health Sciences, University of Rome “Foro Italico”, Rome, Italy
| | - Francesco Felici
- Department of Movement, Human, and Health Sciences, University of Rome “Foro Italico”, Rome, Italy
| | - Andrea Macaluso
- Department of Movement, Human, and Health Sciences, University of Rome “Foro Italico”, Rome, Italy
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11
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Casolo A, Maeo S, Balshaw TG, Lanza MB, Martin NRW, Nuccio S, Moro T, Paoli A, Felici F, Maffulli N, Eskofier B, Kinfe TM, Folland JP, Farina D, Vecchio AD. Non-invasive estimation of muscle fibre size from high-density electromyography. J Physiol 2023; 601:1831-1850. [PMID: 36929484 DOI: 10.1113/jp284170] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 03/13/2023] [Indexed: 03/18/2023] Open
Abstract
Because of the biophysical relation between muscle fibre diameter and the propagation velocity of action potentials along the muscle fibres, motor unit conduction velocity could be a non-invasive index of muscle fibre size in humans. However, the relation between motor unit conduction velocity and fibre size has been only assessed indirectly in animal models and in human patients with invasive intramuscular EMG recordings, or it has been mathematically derived from computer simulations. By combining advanced non-invasive techniques to record motor unit activity in vivo, i.e. high-density surface EMG, with the gold standard technique for muscle tissue sampling, i.e. muscle biopsy, here we investigated the relation between the conduction velocity of populations of motor units identified from the biceps brachii muscle, and muscle fibre diameter. We demonstrate the possibility of predicting muscle fibre diameter (R2 = 0.66) and cross-sectional area (R2 = 0.65) from conduction velocity estimates with low systematic bias (∼2% and ∼4% respectively) and a relatively low margin of individual error (∼8% and ∼16%, respectively). The proposed neuromuscular interface opens new perspectives in the use of high-density EMG as a non-invasive tool to estimate muscle fibre size without the need of surgical biopsy sampling. The non-invasive nature of high-density surface EMG for the assessment of muscle fibre size may be useful in studies monitoring child development, ageing, space and exercise physiology, although the applicability and validity of the proposed methodology need to be more directly assessed in these specific populations by future studies. KEY POINTS: Because of the biophysical relation between muscle fibre size and the propagation velocity of action potentials along the sarcolemma, motor unit conduction velocity could represent a potential non-invasive candidate for estimating muscle fibre size in vivo. This relation has been previously assessed in animal models and humans with invasive techniques, or it has been mathematically derived from simulations. By combining high-density surface EMG with muscle biopsy, here we explored the relation between the conduction velocity of populations of motor units and muscle fibre size in healthy individuals. Our results confirmed that motor unit conduction velocity can be considered as a novel biomarker of fibre size, which can be adopted to predict muscle fibre diameter and cross-sectional area with low systematic bias and margin of individual error. The proposed neuromuscular interface opens new perspectives in the use of high-density EMG as a non-invasive tool to estimate muscle fibre size without the need of surgical biopsy sampling.
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Affiliation(s)
- Andrea Casolo
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Sumiaki Maeo
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
- School of Sport, Exercise & Health Sciences, Loughborough University, Loughborough, UK
| | - Thomas G Balshaw
- School of Sport, Exercise & Health Sciences, Loughborough University, Loughborough, UK
- Versus Arthritis Centre for Sport, Exercise and Osteoarthritis Research, Loughborough University, Leicestershire, UK
| | - Marcel B Lanza
- Department of Physical Therapy and Rehabilitation Science, University of Maryland, Baltimore, MD, USA
| | - Neil R W Martin
- Versus Arthritis Centre for Sport, Exercise and Osteoarthritis Research, Loughborough University, Leicestershire, UK
| | - Stefano Nuccio
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy
| | - Tatiana Moro
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Antonio Paoli
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Francesco Felici
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy
| | - Nicola Maffulli
- Department of Trauma and Orthopaedic Surgery, School Medicine, Surgery and Dentistry, University of Salerno, Salerno, Italy
- School of Pharmacy and Bioengineering, Keele University School of Medicine, Stoke on Trent, UK
- Queen Mary University of London, Barts and the London School of Medicine and Dentistry, Centre for Sports and Exercise Medicine, Mile End Hospital, London, UK
| | - Bjoern Eskofier
- Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Thomas M Kinfe
- Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Jonathan P Folland
- School of Sport, Exercise & Health Sciences, Loughborough University, Loughborough, UK
- Versus Arthritis Centre for Sport, Exercise and Osteoarthritis Research, Loughborough University, Leicestershire, UK
| | - Dario Farina
- Department of Bioengineering, Imperial College London, London, UK
| | - Alessandro Del Vecchio
- Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
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12
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Sánchez Pastor A, García-Sánchez C, Marquina Nieto M, de la Rubia A. Influence of Strength Training Variables on Neuromuscular and Morphological Adaptations in Prepubertal Children: A Systematic Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:4833. [PMID: 36981742 PMCID: PMC10049541 DOI: 10.3390/ijerph20064833] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/06/2023] [Accepted: 03/07/2023] [Indexed: 06/18/2023]
Abstract
Strength training in prepubertal children is one of the topics that has aroused the most interest and controversy among training professionals in recent years. Therefore, the aim of the present study was to analyze the available scientific evidence on the influence of strength training variables on morphological and/or neuromuscular adaptations in healthy prepubertal populations with no previous experience in this type of training according to the descriptive sample characteristics. According to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis, 22 studies were selected after a systematic search and selection process using four electronic databases: Google Scholar, PubMed, Scopus, and SPORT Discus. Furthermore, the internal validity of the studies included was assessed using the modified PEDro scale. The sample consisted of 604 prepubertal children (age, 10.02 ± 0.75 years), of whom 473 were boys and 131 were girls, with 104 strength training programs recorded. Strength training resulted in a significant increase in jumping (n = 29) and sprinting (n = 13) abilities. Moreover, muscle strength was increased in 100% of the cases. Morphologically, strength training resulted in a decrease in body fat percentage (n = 19) and an increase in lean body mass (n = 17). With regard to gender, increases in general sport skills and basic physical abilities were significant in males but not in females. Thus, the results are more heterogeneous in girls due to the small number of studies carried out. Therefore, this research provides practical applications for coaches to design and implement more effective training programs to maximize adaptations, enhance physical performance, and reduce injury risk.
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Affiliation(s)
- Alberto Sánchez Pastor
- Facultad de Ciencias de la Actividad Física y del Deporte, Universidad Politécnica de Madrid, Calle Martín Fierro 7, 28040 Madrid, Spain
| | - Carlos García-Sánchez
- Deporte y Entrenamiento Research Group, Departamento de Deportes, Facultad de Ciencias de la Actividad Física y del Deporte, Universidad Politécnica de Madrid, Calle Martín Fierro 7, 28040 Madrid, Spain
| | - Moisés Marquina Nieto
- Deporte y Entrenamiento Research Group, Departamento de Deportes, Facultad de Ciencias de la Actividad Física y del Deporte, Universidad Politécnica de Madrid, Calle Martín Fierro 7, 28040 Madrid, Spain
| | - Alfonso de la Rubia
- Deporte y Entrenamiento Research Group, Departamento de Deportes, Facultad de Ciencias de la Actividad Física y del Deporte, Universidad Politécnica de Madrid, Calle Martín Fierro 7, 28040 Madrid, Spain
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13
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Extracellular Vesicles in Regenerative Processes Associated with Muscle Injury Recovery of Professional Athletes Undergoing Sub Maximal Strength Rehabilitation. Int J Mol Sci 2022; 23:ijms232314913. [PMID: 36499243 PMCID: PMC9739739 DOI: 10.3390/ijms232314913] [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: 10/19/2022] [Revised: 11/21/2022] [Accepted: 11/25/2022] [Indexed: 11/30/2022] Open
Abstract
Platelet-rich plasma (PRP) has great potential in regenerative medicine. In addition to the well-known regenerative potential of secreted growth factors, extracellular vesicles (EVs) are emerging as potential key players in the regulation of tissue repair. However, little is known about their therapeutic potential as regenerative agents. In this study, we have identified and subtyped circulating EVs (platelet-, endothelial-, and leukocyte-derived EVs) in the peripheral blood of athletes recovering from recent muscular injuries and undergoing a submaximal strength rehabilitation program. We found a significant increase in circulating platelet-derived EVs at the end of the rehabilitation program. Moreover, EVs from PRP samples were isolated by fluorescence-activated cell sorting and analyzed by label-free proteomics. The proteomic analysis of PRP-EVs revealed that 32% of the identified proteins were associated to "defense and immunity", and altogether these proteins were involved in vesicle-mediated transport (GO: 0016192; FDR = 3.132 × 10-19), as well as in wound healing (GO: 0042060; FDR = 4.252 × 10-13) and in the events regulating such a process (GO: 0061041; FDR = 2.812 × 10-12). Altogether, these data suggest that platelet-derived EVs may significantly contribute to the regeneration potential of PRP preparations.
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14
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Gabriel DA. Teaching Essential EMG Theory to Kinesiologists and Physical Therapists Using Analogies Visual Descriptions, and Qualitative Analysis of Biophysical Concepts. SENSORS (BASEL, SWITZERLAND) 2022; 22:6555. [PMID: 36081014 PMCID: PMC9460425 DOI: 10.3390/s22176555] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/24/2022] [Accepted: 08/28/2022] [Indexed: 06/15/2023]
Abstract
Electromyography (EMG) is a multidisciplinary field that brings together allied health (kinesiology and physical therapy) and the engineering sciences (biomedical and electrical). Since the physical sciences are used in the measurement of a biological process, the presentation of the theoretical foundations of EMG is most conveniently conducted using math and physics. However, given the multidisciplinary nature of EMG, a course will most likely include students from diverse backgrounds, with varying levels of math and physics. This is a pedagogical paper that outlines an approach for teaching foundational concepts in EMG to kinesiologists and physical therapists that uses a combination of analogies, visual descriptions, and qualitative analysis of biophysical concepts to develop an intuitive understanding for those who are new to surface EMG. The approach focuses on muscle fiber action potentials (MFAPs), motor unit action potentials (MUAPs), and compound muscle action potentials (CMAPs) because changes in these waveforms are much easier to identify and describe in comparison to the surface EMG interference pattern (IP).
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Affiliation(s)
- David A Gabriel
- Electromyographic Kinesiology Laboratory, Faculty of Applied Health Sciences, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
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15
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Elgueta-Cancino E, Evans E, Martinez-Valdes E, Falla D. The Effect of Resistance Training on Motor Unit Firing Properties: A Systematic Review and Meta-Analysis. Front Physiol 2022; 13:817631. [PMID: 35295567 PMCID: PMC8918924 DOI: 10.3389/fphys.2022.817631] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 01/24/2022] [Indexed: 11/13/2022] Open
Abstract
While neural changes are thought to be responsible for early increases in strength following resistance training (RT), the exact changes in motor unit (MU) firing properties remain unclear. This review aims to synthesize the available evidence on the effect of RT on MU firing properties. MEDLINE (OVID interface), EMBASE (OVID interface), Web of Science (all databases), Cochrane Library, EBSCO CINAHL Plus, PubMed, and EBSCO SportDiscus were searched from inception until June 2021. Randomized controlled trials and non-randomized studies of interventions that compared RT to no intervention (control) were included. Two reviewers independently extracted data from each trial, assessed the risk of bias and rated the cumulative quality of evidence. Motor unit discharge rate (MUDR), motor unit recruitment threshold (MURT), motor unit discharge rate variability (MUDRV), MU discharge rate at recruitment vs. recruitment threshold relationship, and MU discharge rate vs. recruitment threshold relationship were assessed. Seven trials including 167 participants met the inclusion criteria. Meta-analysis (four studies) revealed that MUDR did not change significantly (P = 0.43), but with considerable heterogeneity likely to be present (I 2 = 91). Low to moderate evidence supports changes in MUDRV, MUDR at recruitment vs. recruitment threshold relationship, and the MUDR vs. recruitment threshold relationship. Overall, this systematic review revealed that there is a lack of high-quality evidence for the effect of RT on MU firing properties. Heterogeneity across studies undermines the quality of the evidence for multiple outcomes and affects the conclusions that can be drawn.
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Affiliation(s)
| | | | | | - Deborah Falla
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
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16
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Ackermans LL, Rabou J, Basrai M, Schweinlin A, Bischoff S, Cussenot O, Cancel-Tassin G, Renken R, Gómez E, Sánchez-González P, Rainoldi A, Boccia G, Reisinger K, Ten Bosch JA, Blokhuis TJ. Screening, Diagnosis and Monitoring of Sarcopenia: when to use which tool? Clin Nutr ESPEN 2022; 48:36-44. [DOI: 10.1016/j.clnesp.2022.01.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 11/18/2021] [Accepted: 01/23/2022] [Indexed: 10/19/2022]
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17
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Del Vecchio A, Casolo A, Dideriksen JL, Aagaard P, Felici F, Falla D, Farina D. Lack of increased rate of force development after strength training is explained by specific neural, not muscular, motor unit adaptations. J Appl Physiol (1985) 2021; 132:84-94. [PMID: 34792405 DOI: 10.1152/japplphysiol.00218.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
While maximal force increases following short-term isometric strength training, the rate of force development (RFD) may remain relatively unaffected. The underlying neural and muscular mechanisms during rapid contractions after strength training are largely unknown. Since strength training increases the neural drive to muscles, it may be hypothesized that there are distinct neural or muscular adaptations determining the change in RFD independently of an increase in maximal force. Therefore, we examined motor unit population data acquired from surface electromyography during the rapid generation of force before and after four weeks of strength training. We observed that strength training did not change the RFD because it did not influence the number of motor units recruited per second or their initial discharge rate during rapid contractions. While strength training did not change motoneuron behaviour in the force increase phase of rapid contractions, it increased the discharge rate of motoneurons (by ~4 spikes/s) when reaching the plateau phase (~150 ms) of the rapid contractions, determining an increase in maximal force production. Computer simulations with a motor unit model that included neural and muscular properties, closely matched the experimental observations and demonstrated that the lack of change in RFD following training is primarily mediated by an unchanged maximal recruitment speed of motoneurons. These results demonstrate that maximal force and contraction speed are determined by different adaptations in motoneuron behaviour following strength training and indicate that increases in the recruitment speed of motoneurons are required to evoke training-induced increases in RFD.
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Affiliation(s)
- Alessandro Del Vecchio
- Department of Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander University, Erlangen, Bavaria, Germany
| | - Andrea Casolo
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | | | - Per Aagaard
- Department of Sports Science and Clinical Biomechanics, Muscle Physiology and Biomechanics Research Unit, University of Southern Denmark, Odense, Denmark
| | - Francesco Felici
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Rome, Italy
| | - 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, United Kingdom
| | - Dario Farina
- Department of Bioengineering, Imperial College London, London, United Kingdom
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18
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Casolo A, Del Vecchio A, Balshaw TG, Maeo S, Lanza MB, Felici F, Folland JP, Farina D. Behavior of motor units during submaximal isometric contractions in chronically strength-trained individuals. J Appl Physiol (1985) 2021; 131:1584-1598. [PMID: 34617822 DOI: 10.1152/japplphysiol.00192.2021] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neural and morphological adaptations combine to underpin the enhanced muscle strength following prolonged exposure to strength training, although their relative importance remains unclear. We investigated the contribution of motor unit (MU) behavior and muscle size to submaximal force production in chronically strength-trained athletes (ST) versus untrained controls (UT). Sixteen ST (age: 22.9 ± 3.5 yr; training experience: 5.9 ± 3.5 yr) and 14 UT (age: 20.4 ± 2.3 yr) performed maximal voluntary isometric force (MViF) and ramp contractions (at 15%, 35%, 50%, and 70% MViF) with elbow flexors, whilst high-density surface electromyography (HDsEMG) was recorded from the biceps brachii (BB). Recruitment thresholds (RTs) and discharge rates (DRs) of MUs identified from the submaximal contractions were assessed. The neural drive-to-muscle gain was estimated from the relation between changes in force (ΔFORCE, i.e. muscle output) relative to changes in MU DR (ΔDR, i.e. neural input). BB maximum anatomical cross-sectional area (ACSAMAX) was also assessed by MRI. MViF (+64.8% vs. UT, P < 0.001) and BB ACSAMAX (+71.9%, P < 0.001) were higher in ST. Absolute MU RT was higher in ST (+62.6%, P < 0.001), but occurred at similar normalized forces. MU DR did not differ between groups at the same normalized forces. The absolute slope of the ΔFORCE - ΔDR relationship was higher in ST (+66.9%, P = 0.002), whereas it did not differ for normalized values. We observed similar MU behavior between ST athletes and UT controls. The greater absolute force-generating capacity of ST for the same neural input demonstrates that morphological, rather than neural, factors are the predominant mechanism for their enhanced force generation during submaximal efforts.NEW & NOTEWORTHY In this study, we observed that recruitment strategies and discharge characteristics of large populations of motor units identified from biceps brachii of strength-trained athletes were similar to those observed in untrained individuals during submaximal force tasks. We also found that for the same neural input, strength-trained athletes are able to produce greater absolute muscle forces (i.e., neural drive-to-muscle gain). This demonstrates that morphological factors are the predominant mechanism for the enhanced force generation during submaximal efforts.
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Affiliation(s)
- Andrea Casolo
- Department of Bioengineering, Imperial College London, London, United Kingdom.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Alessandro Del Vecchio
- Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Thomas G Balshaw
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, United Kingdom.,Versus Arthritis Centre for Sport, Exercise and Osteoarthritis Research, Loughborough University, Leicestershire, United Kingdom
| | - Sumiaki Maeo
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, United Kingdom.,College of Sport and Health Sciences, Ritsumeikan University, Kusatsu, Japan
| | - Marcel Bahia Lanza
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, United Kingdom.,Department of Physical Therapy and Rehabilitation Science, University of Maryland, Baltimore, Maryland
| | - Francesco Felici
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy
| | - Jonathan P Folland
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, United Kingdom.,Versus Arthritis Centre for Sport, Exercise and Osteoarthritis Research, Loughborough University, Leicestershire, United Kingdom
| | - Dario Farina
- Department of Bioengineering, Imperial College London, London, United Kingdom
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19
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Nuccio S, Del Vecchio A, Casolo A, Labanca L, Rocchi JE, Felici F, Macaluso A, Mariani PP, Falla D, Farina D, Sbriccoli P. Deficit in knee extension strength following anterior cruciate ligament reconstruction is explained by a reduced neural drive to the vasti muscles. J Physiol 2021; 599:5103-5120. [PMID: 34605556 DOI: 10.1113/jp282014] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 09/30/2021] [Indexed: 11/08/2022] Open
Abstract
The persistence of quadriceps weakness represents a major concern following anterior cruciate ligament reconstruction (ACLR). The underlying adaptations occurring in the activity of spinal motoneurons are still unexplored. This study examined the discharge patterns of large populations of motor units (MUs) in the vastus lateralis (VL) and vastus medialis muscles following ACLR. Nine ACLR individuals and 10 controls performed unilateral trapezoidal contractions of the knee extensor muscles at 35%, 50% and 70% of the maximal voluntary isometric force (MVIF). High-density surface electromyography (HDsEMG) was used to record the myoelectrical activity of the vasti muscles in both limbs. HDsEMG signals were decomposed with a convolutive blind source separation method and MU properties were extracted and compared between sides and groups. The ACLR group showed a lower MVIF on the reconstructed side compared to the contralateral side (28.1%; P < 0.001). This force deficit was accompanied by reduced MU discharge rates (∼21%; P < 0.05), lower absolute MU recruitment and derecruitment thresholds (∼22% and ∼22.5%, respectively; P < 0.05) and lower input-output gain of motoneurons (27.3%; P = 0.009). Deficits in MU discharge rates of the VL and in absolute recruitment and derecruitment thresholds of both vasti MUs were associated with deficits in MVIF (P < 0.05). A strong between-side correlation was found for MU discharge rates of the VL of ACLR individuals (P < 0.01). There were no significant between-group differences (P > 0.05). These results indicate that mid- to long-term strength deficits following ACLR may be attributable to a reduced neural drive to vasti muscles, with potential changes in excitatory and inhibitory synaptic inputs. KEY POINTS: Impaired expression and control of knee extension forces is common after anterior cruciate ligament reconstruction and is related to high risk of a second injury. To provide novel insights into the neural basis of this impairment, the discharge patterns of motor units in the vastus lateralis and vastus medialis were investigated during voluntary force contractions. There was lower knee extensor strength on the reconstructed side with respect to the contralateral side, which was explained by deficits in motor unit discharge rate and an altered motoneuronal input-output gain. Insufficient excitatory inputs to motoneurons and increased inhibitory afferent signals potentially contributed to these alterations. These results further our understanding of the neural underpinnings of quadriceps weakness following anterior cruciate ligament reconstruction and can help to develop effective rehabilitation protocols to regain muscle strength and reduce the risk of a second injury.
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Affiliation(s)
- Stefano Nuccio
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy
| | - Alessandro Del Vecchio
- Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander University, Erlangen, Germany
| | - Andrea Casolo
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Luciana Labanca
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy
| | | | - Francesco Felici
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy
| | - Andrea Macaluso
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy.,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
| | - Deborah Falla
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Dario Farina
- Department of Bioengineering, Imperial College London, London, UK
| | - Paola Sbriccoli
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy
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20
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Škarabot J, Balshaw TG, Maeo S, Massey GJ, Lanza MB, Maden-Wilkinson TM, Folland JP. Neural adaptations to long-term resistance training: evidence for the confounding effect of muscle size on the interpretation of surface electromyography. J Appl Physiol (1985) 2021; 131:702-715. [PMID: 34166110 DOI: 10.1152/japplphysiol.00094.2021] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study compared elbow flexor (EF; experiment 1) and knee extensor (KE; experiment 2) maximal compound action potential (Mmax) amplitude between long-term resistance trained (LTRT; n = 15 and n = 14, 6 ± 3 and 4 ± 1 yr of training) and untrained (UT; n = 14 and n = 49) men, and examined the effect of normalizing electromyography (EMG) during maximal voluntary torque (MVT) production to Mmax amplitude on differences between LTRT and UT. EMG was recorded from multiple sites and muscles of EF and KE, Mmax was evoked with percutaneous nerve stimulation, and muscle size was assessed with ultrasonography (thickness, EF) and magnetic resonance imaging (cross-sectional area, KE). Muscle-electrode distance (MED) was measured to account for the effect of adipose tissue on EMG and Mmax. LTRT displayed greater MVT (+66%-71%, P < 0.001), muscle size (+54%-56%, P < 0.001), and Mmax amplitudes (+29%-60%, P ≤ 0.010) even when corrected for MED (P ≤ 0.045). Mmax was associated with the size of both muscle groups (r ≥ 0.466, P ≤ 0.011). Compared with UT, LTRT had higher absolute voluntary EMG amplitude for the KE (P < 0.001), but not the EF (P = 0.195), and these differences/similarities were maintained after correction for MED; however, Mmax normalization resulted in no differences between LTRT and UT for any muscle and/or muscle group (P ≥ 0.652). The positive association between Mmax and muscle size, and no differences when accounting for peripheral electrophysiological properties (EMG/Mmax), indicates the greater absolute voluntary EMG amplitude of LTRT might be confounded by muscle morphology, rather than providing a discrete measure of central neural activity. This study therefore suggests limited agonist neural adaptation after LTRT.NEW & NOTEWORTHY In a large sample of long-term resistance-trained individuals, we showed greater maximal M-wave amplitude of the elbow flexors and knee extensors compared with untrained individuals, which appears to be at least partially mediated by differences in muscle size. The lack of group differences in voluntary EMG amplitude when normalized to maximal M-wave suggests that differences in muscle morphology might impair interpretation of voluntary EMG as an index of central neural activity.
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Affiliation(s)
- Jakob Škarabot
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, United Kingdom
| | - Thomas G Balshaw
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, United Kingdom.,Versus Arthritis Centre for Sport, Exercise and Osteoarthritis Research, Loughborough University, Leicestershire, United Kingdom
| | - Sumiaki Maeo
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, United Kingdom.,Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan
| | - Garry J Massey
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, United Kingdom.,School of Sport and Health Sciences, University of Exeter, Exeter, United Kingdom
| | - Marcel B Lanza
- Department of Physical Therapy and Rehabilitation, University of Maryland, Baltimore, Maryland
| | - Thomas M Maden-Wilkinson
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, United Kingdom.,Academy of Sport and Physical Activity, Faculty of Health and Wellbeing, Sheffield Hallam University, Sheffield, United Kingdom
| | - Jonathan P Folland
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, United Kingdom.,Versus Arthritis Centre for Sport, Exercise and Osteoarthritis Research, Loughborough University, Leicestershire, United Kingdom
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21
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Hortobágyi T, Granacher U, Fernandez-Del-Olmo M, Howatson G, Manca A, Deriu F, Taube W, Gruber M, Márquez G, Lundbye-Jensen J, Colomer-Poveda D. Functional relevance of resistance training-induced neuroplasticity in health and disease. Neurosci Biobehav Rev 2020; 122:79-91. [PMID: 33383071 DOI: 10.1016/j.neubiorev.2020.12.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 12/18/2020] [Accepted: 12/19/2020] [Indexed: 01/13/2023]
Abstract
Repetitive, monotonic, and effortful voluntary muscle contractions performed for just a few weeks, i.e., resistance training, can substantially increase maximal voluntary force in the practiced task and can also increase gross motor performance. The increase in motor performance is often accompanied by neuroplastic adaptations in the central nervous system. While historical data assigned functional relevance to such adaptations induced by resistance training, this claim has not yet been systematically and critically examined in the context of motor performance across the lifespan in health and disease. A review of muscle activation, brain and peripheral nerve stimulation, and imaging data revealed that increases in motor performance and neuroplasticity tend to be uncoupled, making a mechanistic link between neuroplasticity and motor performance inconclusive. We recommend new approaches, including causal mediation analytical and hypothesis-driven models to substantiate the functional relevance of resistance training-induced neuroplasticity in the improvements of gross motor function across the lifespan in health and disease.
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Affiliation(s)
- Tibor Hortobágyi
- Center for Human Movement Sciences, University of Groningen, University Medical CenterGroningen, Groningen, Netherlands.
| | - Urs Granacher
- Division of Training and Movement Sciences, Research Focus Cognition Sciences, University of Potsdam, Potsdam, Germany
| | - Miguel Fernandez-Del-Olmo
- Area of Sport Sciences, Faculty of Sports Sciences and Physical Education, Center for Sport Studies, King Juan Carlos University, Madrid, Spain
| | - Glyn Howatson
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle, UK; Water Research Group, North West University, Potchefstroom, South Africa
| | - Andrea Manca
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Franca Deriu
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Wolfgang Taube
- Department of Neurosciences and Movement Sciences, University of Fribourg, Fribourg, Switzerland
| | - Markus Gruber
- Human Performance Research Centre, Department of Sport Science, University of Konstanz, Konstanz, Germany
| | - Gonzalo Márquez
- Department of Physical Education and Sport, Faculty of Sports Sciences and Physical Education, University of A Coruña, A Coruña, Spain
| | - Jesper Lundbye-Jensen
- Movement & Neuroscience, Department of Nutrition, Exercise & Sports Department of Neuroscience, University of Copenhagenk, Faculty of Health Science, Universidad Isabel I, Burgos, Spain
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22
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Škarabot J, Brownstein CG, Casolo A, Del Vecchio A, Ansdell P. The knowns and unknowns of neural adaptations to resistance training. Eur J Appl Physiol 2020; 121:675-685. [PMID: 33355714 PMCID: PMC7892509 DOI: 10.1007/s00421-020-04567-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 11/18/2020] [Indexed: 12/22/2022]
Abstract
The initial increases in force production with resistance training are thought to be primarily underpinned by neural adaptations. This notion is firmly supported by evidence displaying motor unit adaptations following resistance training; however, the precise locus of neural adaptation remains elusive. The purpose of this review is to clarify and critically discuss the literature concerning the site(s) of putative neural adaptations to short-term resistance training. The proliferation of studies employing non-invasive stimulation techniques to investigate evoked responses have yielded variable results, but generally support the notion that resistance training alters intracortical inhibition. Nevertheless, methodological inconsistencies and the limitations of techniques, e.g. limited relation to behavioural outcomes and the inability to measure volitional muscle activity, preclude firm conclusions. Much of the literature has focused on the corticospinal tract; however, preliminary research in non-human primates suggests reticulospinal tract is a potential substrate for neural adaptations to resistance training, though human data is lacking due to methodological constraints. Recent advances in technology have provided substantial evidence of adaptations within a large motor unit population following resistance training. However, their activity represents the transformation of afferent and efferent inputs, making it challenging to establish the source of adaptation. Whilst much has been learned about the nature of neural adaptations to resistance training, the puzzle remains to be solved. Additional analyses of motoneuron firing during different training regimes or coupling with other methodologies (e.g., electroencephalography) may facilitate the estimation of the site(s) of neural adaptations to resistance training in the future.
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Affiliation(s)
- Jakob Škarabot
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Callum G Brownstein
- Laboratoire Interuniversitaire de Biologie de la Motricité, Université Jean Monnet Saint-Etienne, Université Lyon, Saint-Étienne, France
| | - Andrea Casolo
- Department of Bioengineering, Imperial College London, London, UK.,Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Alessandro Del Vecchio
- Department of Artificial Intelligence and Biomedical Engineering, Faculty of Engineering, Friedrich-Alexander University, Erlangen-Nurnberg, 91052, Erlangen, Germany
| | - Paul Ansdell
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK.
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23
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Šarabon N, Kozinc Ž. Effects of Resistance Exercise on Balance Ability: Systematic Review and Meta-Analysis of Randomized Controlled Trials. Life (Basel) 2020; 10:E284. [PMID: 33203156 PMCID: PMC7697352 DOI: 10.3390/life10110284] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/13/2020] [Accepted: 11/13/2020] [Indexed: 01/28/2023] Open
Abstract
With this systematic review, we explored whether resistance exercise (RE) could be used to improve balance in addition to muscular strength and power. Scientific databases were searched for randomized controlled trials that investigated the effects of RE on the performance of various balance tests. Studies were considered if they involved healthy participants of any age group. Thirteen studies were included in the meta-analysis. The results showed moderate to large improvements in balance ability following RE in older adults, as reflected in functional reach test (mean difference (MD): +4.22 cm, p < 0.001), single-leg standing test (MD: +1.9-37.6 s, p < 0.001) and timed-up-and-go test (MD: -0.55 s; p = 0.002). Moderate to large improvements following RE were seen in adults in star excursion balance test (MD: +4.09-5.17 cm; p = 0.001-0.020), but not for Y-balance test score (MD: +4.94%, p = 0.14). The results implicate that RE interventions may significantly improve balance ability in adults and older adults. Therefore, RE could be used to improve balance in these populations, while further studies are needed to investigate children populations. Performing RE alone could be a time-efficient compromise for individuals who are unwilling or unable to perform large volumes of exercise or different exercise modalities.
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Affiliation(s)
- Nejc Šarabon
- Faculty of Health Sciences, University of Primorska, 6310 Izola, Slovenia;
- Laboratory for Motor Control and Motor Behavior, S2P, Science to Practice, Ltd., 1000 Ljubljana, Slovenia
- InnoRenew CoE, 6310 Izola, Slovenia
- Andrej Marušič Institute, University of Primorska, 6000 Koper, Slovenia
| | - Žiga Kozinc
- Faculty of Health Sciences, University of Primorska, 6310 Izola, Slovenia;
- Andrej Marušič Institute, University of Primorska, 6000 Koper, Slovenia
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24
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Jenkins NDM, Rogers EM, Banks NF, Muddle TWD, Colquhoun RJ. Increases in motor unit action potential amplitudes are related to muscle hypertrophy following eight weeks of high-intensity exercise training in females. Eur J Sport Sci 2020; 21:1403-1413. [DOI: 10.1080/17461391.2020.1836262] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Nathaniel D. M. Jenkins
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, OK, USA
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, USA
| | - Emily. M. Rogers
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, OK, USA
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, USA
| | - Nile F. Banks
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, OK, USA
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, USA
| | - Tyler W. D. Muddle
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, OK, USA
| | - Ryan J. Colquhoun
- Department of Health, Kinesiology and Sport, University of South Alabama, Mobile, AL, USA
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25
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Nuccio S, Del Vecchio A, Casolo A, Labanca L, Rocchi JE, Felici F, Macaluso A, Mariani PP, Falla D, Farina D, Sbriccoli P. Muscle fiber conduction velocity in the vastus lateralis and medialis muscles of soccer players after ACL reconstruction. Scand J Med Sci Sports 2020; 30:1976-1984. [DOI: 10.1111/sms.13748] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/30/2020] [Accepted: 06/01/2020] [Indexed: 01/05/2023]
Affiliation(s)
- Stefano Nuccio
- Department of Movement, Human and Health Sciences University of Rome “Foro Italico” Rome Italy
- Department of Bioengineering Imperial College London London UK
| | | | - Andrea Casolo
- Department of Movement, Human and Health Sciences University of Rome “Foro Italico” Rome Italy
- Department of Bioengineering Imperial College London London UK
| | - Luciana Labanca
- Department of Movement, Human and Health Sciences University of Rome “Foro Italico” Rome Italy
| | - Jacopo Emanuele Rocchi
- Department of Movement, Human and Health Sciences University of Rome “Foro Italico” Rome Italy
- 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
| | - Andrea Macaluso
- Department of Movement, Human and Health Sciences University of Rome “Foro Italico” Rome Italy
- Villa Stuart Sport Clinic‐FIFA Medical Centre of Excellence Rome Italy
| | | | - Deborah Falla
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine) School of Sport, Exercise and Rehabilitation Sciences University of Birmingham Birmingham UK
| | - Dario Farina
- Department of Bioengineering Imperial College London London UK
| | - Paola Sbriccoli
- Department of Movement, Human and Health Sciences University of Rome “Foro Italico” Rome Italy
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26
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Casolo A, Nuccio S, Bazzucchi I, Felici F, Del Vecchio A. Reproducibility of muscle fibre conduction velocity during linearly increasing force contractions. J Electromyogr Kinesiol 2020; 53:102439. [PMID: 32563844 DOI: 10.1016/j.jelekin.2020.102439] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 05/14/2020] [Accepted: 06/06/2020] [Indexed: 12/13/2022] Open
Abstract
Muscle fibre conduction velocity (MFCV) is a basic physiological parameter biophysically related to the diameter of muscle fibres and properties of the sarcolemma. The aim of this study was to assess the intersession reproducibility of the relation between voluntary force and estimates of average muscle fibre conduction velocity (MFCV) from multichannel high-density surface electromyographic recordings (HDsEMG). Ten healthy men performed six linearly increasing isometric ankle dorsiflexions on two separate experimental sessions, 4 weeks apart. Each session involved the recordings of voluntary force during maximal isometric (MViF) and submaximal ramp contractions at 35-50-70% of MViF. Concurrently, the HDsEMG activity was detected from the tibialis anterior muscle and MFCV estimates were derived in 250-ms epochs. Absolute and relative reproducibility of MFCV initial value (intercept) and rate of change (regression slope) as a function of force were assessed by within-subject coefficient of correlation (CVw) and with intraclass correlation coefficient (ICC). MFCV was positively correlated with voluntary force (R2 = 0.75 ± 0.12) in all individuals and test conditions (P < 0.001). Average CVw for MFCV intercept and slope were of 2.6 ± 2.0% and 11.9 ± 3.2% and ICC values of 0.96 and 0.94, respectively. Overall, MFCV regression coefficients showed a high degree of intersession reproducibility in both absolute and relative terms. These results may have important practical implications in the tracking of training-induced neuromuscular changes and/or in the monitoring of the progress of neuromuscular disorders when a full sEMG signal decomposition is problematic or not possible.
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Affiliation(s)
- Andrea Casolo
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy; Department of Bioengineering, Imperial College London, SW7 2AZ London, UK
| | - Stefano Nuccio
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy; Department of Bioengineering, Imperial College London, SW7 2AZ London, UK
| | - Ilenia Bazzucchi
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy
| | - Francesco Felici
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy
| | - Alessandro Del Vecchio
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy; Department of Bioengineering, Imperial College London, SW7 2AZ London, UK.
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