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Angius L, Del Vecchio A, Goodall S, Thomas K, Ansdell P, Atkinson E, Farina D, Howatson G. Supraspinal, spinal, and motor unit adjustments to fatiguing isometric contractions of the knee extensors at low and high submaximal intensities in males. J Appl Physiol (1985) 2024; 136:1546-1558. [PMID: 38695356 DOI: 10.1152/japplphysiol.00675.2023] [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: 09/22/2023] [Revised: 04/04/2024] [Accepted: 04/23/2024] [Indexed: 06/16/2024] Open
Abstract
Contraction intensity is a key factor determining the development of muscle fatigue, and it has been shown to induce distinct changes along the motor pathway. The role of cortical and spinal inputs that regulate motor unit (MU) behavior during fatiguing contractions is poorly understood. We studied the cortical, spinal, and neuromuscular response to sustained fatiguing isometric tasks performed at 20% and 70% of the maximum isometric voluntary contraction (MVC), together with MU behavior of knee extensors in healthy active males. Neuromuscular function was assessed before and after performance of both tasks. Cortical and spinal responses during exercise were measured via stimulation of the motor cortex and spinal cord. High-density electromyography was used to record individual MUs from the vastus lateralis (VL). Exercise at 70%MVC induced greater decline in MVC (P = 0.023) and potentiated twitch force compared with 20%MVC (P < 0.001), with no difference in voluntary activation (P = 0.514). Throughout exercise, corticospinal responses were greater during the 20%MVC task (P < 0.001), and spinal responses increased over time in both tasks (P ≤ 0.042). MU discharge rate increased similarly after both tasks (P ≤ 0.043), whereas recruitment and derecruitment thresholds were unaffected (P ≥ 0.295). These results suggest that increased excitability of cortical and spinal inputs might be responsible for the increase in MU discharge rate. The increase in evoked responses together with the higher MU discharge rate might be required to compensate for peripheral adjustments to sustain fatiguing contractions at different intensities.NEW & NOTEWORTHY Changes in central nervous system and muscle function occur in response to fatiguing exercise and are specific to exercise intensity. This study measured corticospinal, neuromuscular, and motor unit behavior to fatiguing isometric tasks performed at different intensities. Both tasks increased corticospinal excitability and motor unit discharge rate. Our findings suggest that these acute adjustments are required to compensate for the exercise-induced decrements in neuromuscular function caused by fatiguing tasks.
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Affiliation(s)
- Luca Angius
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Alessandro Del Vecchio
- Department of Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Stuart Goodall
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Kevin Thomas
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Paul Ansdell
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Elliot Atkinson
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Dario Farina
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Glyn Howatson
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
- Water Research Group, North-West University, Potchefstroom, South Africa
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Valenčič T, Ansdell P, Brownstein CG, Spillane PM, Holobar A, Škarabot J. Motor unit discharge rate modulation during isometric contractions to failure is intensity- and modality-dependent. J Physiol 2024; 602:2287-2314. [PMID: 38619366 DOI: 10.1113/jp286143] [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: 12/14/2023] [Accepted: 03/25/2024] [Indexed: 04/16/2024] Open
Abstract
The physiological mechanisms determining the progressive decline in the maximal muscle torque production capacity during isometric contractions to task failure are known to depend on task demands. Task-specificity of the associated adjustments in motor unit discharge rate (MUDR), however, remains unclear. This study examined MUDR adjustments during different submaximal isometric knee extension tasks to failure. Participants performed a sustained and an intermittent task at 20% and 50% of maximal voluntary torque (MVT), respectively (Experiment 1). High-density surface EMG signals were recorded from vastus lateralis (VL) and medialis (VM) and decomposed into individual MU discharge timings, with the identified MUs tracked from recruitment to task failure. MUDR was quantified and normalised to intervals of 10% of contraction time (CT). MUDR of both muscles exhibited distinct modulation patterns in each task. During the 20% MVT sustained task, MUDR decreased until ∼50% CT, after which it gradually returned to baseline. Conversely, during the 50% MVT intermittent task, MUDR remained stable until ∼40-50% CT, after which it started to continually increase until task failure. To explore the effect of contraction intensity on the observed patterns, VL and VM MUDR was quantified during sustained contractions at 30% and 50% MVT (Experiment 2). During the 30% MVT sustained task, MUDR remained stable until ∼80-90% CT in both muscles, after which it continually increased until task failure. During the 50% MVT sustained task the increase in MUDR occurred earlier, after ∼70-80% CT. Our results suggest that adjustments in MUDR during submaximal isometric contractions to failure are contraction modality- and intensity-dependent. KEY POINTS: During prolonged muscle contractions a constant motor output can be maintained by recruitment of additional motor units and adjustments in their discharge rate. Whilst contraction-induced decrements in neuromuscular function are known to depend on task demands, task-specificity of motor unit discharge behaviour adjustments is still unclear. In this study, we tracked and compared discharge activity of several concurrently active motor units in the vastii muscles during different submaximal isometric knee extension tasks to failure, including intermittent vs. sustained contraction modalities performed in the same intensity domain (Experiment 1), and two sustained contractions performed at different intensities (Experiment 2). During each task, motor units modulated their discharge rate in a distinct, biphasic manner, with the modulation pattern depending on contraction intensity and modality. These results provide insight into motoneuronal adjustments during contraction tasks posing different demands on the neuromuscular system.
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Affiliation(s)
- Tamara Valenčič
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Paul Ansdell
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle upon Tyne, UK
| | - Callum G Brownstein
- School of Biomedical, Nutritional and Sport Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Padraig M Spillane
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle upon Tyne, UK
| | - Aleš Holobar
- Faculty of Electrical Engineering and Computer Science, University of Maribor, Maribor, Slovenia
| | - Jakob Škarabot
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
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3
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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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Lim J, Lu L, Goonewardena K, Liu JZ, Tan Y. Assessment of Self-report, Palpation, and Surface Electromyography Dataset During Isometric Muscle Contraction. Sci Data 2024; 11:208. [PMID: 38360835 PMCID: PMC10869346 DOI: 10.1038/s41597-024-03030-8] [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: 07/12/2023] [Accepted: 01/31/2024] [Indexed: 02/17/2024] Open
Abstract
Measuring muscle fatigue involves assessing various components within the motor system. While subjective and sensor-based measures have been proposed, a comprehensive comparison of these assessment measures is currently lacking. This study aims to bridge this gap by utilizing three commonly used measures: participant self-reported perceived muscle fatigue scores, a sports physiotherapist's manual palpation-based muscle tightness scores, and surface electromyography sensors. Compensatory muscle fatigue occurs when one muscle group becomes fatigued, leading to the involvement and subsequent fatigue of other muscles as they compensate for the workload. The evaluation of compensatory muscle fatigue focuses on nine different upper body muscles selected by the sports physiotherapist. With a cohort of 30 male subjects, this study provides a valuable dataset for researchers and healthcare practitioners in sports science, rehabilitation, and human performance. It enables the exploration and comparison of diverse methods for evaluating different muscles in isometric contraction.
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Affiliation(s)
- Jihoon Lim
- Department of Mechanical Engineering, The University of Melbourne, Parkville, 3010, Australia
| | - Lei Lu
- Department of Engineering Science, University of Oxford, Oxford, OX1 2JD, UK
- Department of Population Health Sciences, King's College London, London, UK
| | | | - Jefferson Zhe Liu
- Department of Mechanical Engineering, The University of Melbourne, Parkville, 3010, Australia
| | - Ying Tan
- Department of Mechanical Engineering, The University of Melbourne, Parkville, 3010, Australia.
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5
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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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6
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Orssatto LBR, Blazevich AJ, Trajano GS. Ageing reduces persistent inward current contribution to motor neurone firing: Potential mechanisms and the role of exercise. J Physiol 2023; 601:3705-3716. [PMID: 37488952 DOI: 10.1113/jp284603] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 06/26/2023] [Indexed: 07/26/2023] Open
Abstract
Nervous system deterioration is a primary driver of age-related motor impairment. The motor neurones, which act as the interface between the central nervous system and the muscles, play a crucial role in amplifying excitatory synaptic input to produce the desired motor neuronal firing output. For this, they utilise their ability to generate persistent (long-lasting) depolarising currents that increase cell excitability, and both amplify and prolong the output activity of motor neurones for a given synaptic input. Modulation of these persistent inward currents (PICs) contributes to the motor neurones' capacities to attain the required firing frequencies and rapidly modulate them to competently complete most tasks. Thus, PICs are crucial for adequate movement generation. Impairments in intrinsic motor neurone properties can impact motor unit firing capacity, with convincing evidence indicating that the PIC contribution to motor neurone firing is reduced in older adults. Indeed, this could be an important mechanism underpinning the age-related reductions in strength and physical function. Furthermore, resistance training has emerged as a promising intervention to counteract age-associated PIC impairments, with changes in PICs being correlated with improvements in muscular strength and physical function after training. In this review, we present the current knowledge of the PIC magnitude decline during ageing and discuss whether reduced serotonergic and noradrenergic input onto the motor neurones, voltage-gated calcium channel dysfunction or inhibitory input impairments are candidates that: (i) explain age-related reductions in the PIC contribution to motor neurone firing and (ii) underpin the enhanced PIC contribution to motor neurone firing following resistance training in older adults.
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Affiliation(s)
- Lucas B R Orssatto
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Faculty of Health, Deakin University, Geelong, VIC, Australia
| | - Anthony J Blazevich
- School of Medical and Health Sciences, Centre for Human Performance, Edith Cowan University, Joondalup, WA, Australia
| | - Gabriel S Trajano
- School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, QLD, Australia
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7
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Hug F, Avrillon S, Sarcher A, Del Vecchio A, Farina D. Correlation networks of spinal motor neurons that innervate lower limb muscles during a multi-joint isometric task. J Physiol 2023; 601:3201-3219. [PMID: 35772071 DOI: 10.1113/jp283040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 06/22/2022] [Indexed: 11/08/2022] Open
Abstract
Movements are reportedly controlled through the combination of synergies that generate specific motor outputs by imposing an activation pattern on a group of muscles. To date, the smallest unit of analysis of these synergies has been the muscle through the measurement of its activation. However, the muscle is not the lowest neural level of movement control. In this human study (n = 10), we used a purely data-driven method grounded on graph theory to extract networks of motor neurons based on their correlated activity during an isometric multi-joint task. Specifically, high-density surface electromyography recordings from six lower limb muscles were decomposed into motor neurons spiking activity. We analysed these activities by identifying their common low-frequency components, from which networks of correlated activity to the motor neurons were derived and interpreted as networks of common synaptic inputs. The vast majority of the identified motor neurons shared common inputs with other motor neuron(s). In addition, groups of motor neurons were partly decoupled from their innervated muscle, such that motor neurons innervating the same muscle did not necessarily receive common inputs. Conversely, some motor neurons from different muscles-including distant muscles-received common inputs. The study supports the theory that movements are produced through the control of small numbers of groups of motor neurons via common inputs and that there is a partial mismatch between these groups of motor neurons and muscle anatomy. We provide a new neural framework for a deeper understanding of the structure of common inputs to motor neurons. KEY POINTS: A central and unresolved question is how spinal motor neurons are controlled to generate movement. We decoded the spiking activities of dozens of spinal motor neurons innervating six muscles during a multi-joint task, and we used a purely data-driven method grounded on graph theory to extract networks of motor neurons based on their correlated activity (considered as common input). The vast majority of the identified motor neurons shared common inputs with other motor neuron(s). Groups of motor neurons were partly decoupled from their innervated muscle, such that motor neurons innervating the same muscle did not necessarily receive common inputs. Conversely, some motor neurons from different muscles, including distant muscles, received common inputs. The study supports the theory that movement is produced through the control of groups of motor neurons via common inputs and that there is a partial mismatch between these groups of motor neurons and muscle anatomy.
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Affiliation(s)
- François Hug
- LAMHESS, Université Côte d'Azur, Nice, France
- Laboratory 'Movement, Interactions, Performance' (EA 4334), Nantes University, Nantes, France
- Institut Universitaire de France (IUF), Paris, France
| | - Simon Avrillon
- Legs + Walking AbilityLab, Shirley Ryan AbilityLab, Chicago, IL, USA
- Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, IL, USA
- Neuromechanics & Rehabilitation Technology Group, Department of Bioengineering, Faculty of Engineering, Imperial College London, London, UK
| | - Aurélie Sarcher
- Laboratory 'Movement, Interactions, Performance' (EA 4334), Nantes University, Nantes, France
| | - Alessandro Del Vecchio
- Neuromuscular Physiology and Neural Interfacing Group, Department of Artificial Intelligence in Biomedical Engineering, Faculty of Engineering, Erlangen-Nuremberg, Friedrich-Alexander University, Erlangen, Germany
| | - Dario Farina
- Neuromechanics & Rehabilitation Technology Group, Department of Bioengineering, Faculty of Engineering, Imperial College London, London, UK
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Farina D, Enoka RM. Evolution of surface electromyography: From muscle electrophysiology towards neural recording and interfacing. J Electromyogr Kinesiol 2023; 71:102796. [PMID: 37343466 DOI: 10.1016/j.jelekin.2023.102796] [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] [Indexed: 06/23/2023] Open
Abstract
Surface electromyography (EMG) comprises a recording of electrical activity from the body surface generated by muscle fibres during muscle contractions. Its characteristics depend on the fibre membrane potentials and the neural activation signal sent from the motor neurons to the muscles. EMG has been classically used as the primary investigation tool in kinesiology studies in a variety of applications. More recently, surface EMG techniques have evolved from single-channel methods to high-density systems with hundreds of electrodes. High-density EMG recordings can be deconvolved to estimate the discharge times of spinal motor neurons innervating the recorded muscles, with algorithms that have been developed and validated in the last two decades. Within limits and with some variability across muscles, these techniques provide a non-invasive method to study relatively large populations of motor neurons in humans. Surface EMG is thus evolving from a peripheral measure of muscle electrical activity towards a neural recording and neural interfacing signal. These advances in technology have had a major impact on our fundamental understanding of the neural control of movement and have exposed new perspectives in neurotechnologies. Here we provide an overview and perspective of modern EMG technology, as derived from past achievements, and its impact in neurophysiology and neural engineering.
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Affiliation(s)
- Dario Farina
- Department of Bioengineering, Imperial College London, United Kingdom.
| | - Roger M Enoka
- Department of Integrative Physiology, University of Colorado Boulder, CO, United States
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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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10
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Schilaty ND, McPherson AL, Nagai T, Bates NA. Arthrogenic muscle inhibition manifests in thigh musculature motor unit characteristics after anterior cruciate ligament injury. Eur J Sport Sci 2023; 23:840-850. [PMID: 35306977 PMCID: PMC9626399 DOI: 10.1080/17461391.2022.2056520] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Joint trauma induces a presynaptic reflex inhibition termed arthrogenic muscle inhibition (AMI) that prevents complete activation of muscles. Reduced motor unit (MU) output is a hypothesised mechanism for persistent strength deficits. The objective of this study was to determine MU characteristics of thigh musculature and determine how they change with anterior cruciate ligament (ACL) injury compared to healthy controls. A randomised protocol of knee flexion/extension isometric contractions (10-50% maximal voluntary isometric contraction) was performed for each leg with surface EMG 5-pin array electrodes placed on the vastus medialis, vastus lateralis, semitendinosus and biceps femoris. Longitudinal assessments for average rate coding, recruitment thresholds and MU action potentials were acquired at 6-month intervals. With exception of the vastus medialis, all thigh musculature of ACL-injured demonstrated smaller MU action potential peak-to-peak amplitude. For average rate coding, ACL-injured demonstrated lower coding rates than Controls for the quadriceps (p < .05) and higher rates than Controls for the hamstrings (p < .05). These MU characteristics were different from Controls after ACL reconstruction up to 12 months post-surgery, yet maximal strength increased during this time frame. As thigh MU characteristics are known across phases of ACL rehabilitation, future studies can assess these patterns of motor control and their potential to determine risk of re-injury. Further, future rehabilitation can target specific intervention programmes to restore motor control.HighlightsMotor unit strategies of arthrogenic muscle inhibition are characterised for the first time via decomposed EMG.Motor unit deficits of thigh musculature persist throughout all phases of ACL rehabilitation, even after return-to-sport.After ACL injury, motor unit sizes at similar recruitment thresholds were smaller than those of healthy controls.
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Affiliation(s)
- 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
- Department of Orthopedics, Mayo Clinic, Rochester, MN, USA
| | - April L. McPherson
- Department of Orthopedics, Mayo Clinic, Rochester, MN, USA
- United States Olympic & Paralympic Committee, Colorado Springs, CO, USA
| | - Takashi Nagai
- Department of Orthopedics, Mayo Clinic, Rochester, MN, USA
- United States Army Research Institute of Environmental Medicine, Natick, MA, USA
| | - Nathaniel A. Bates
- Department of Orthopedics, Mayo Clinic, Rochester, MN, USA
- Department of Orthopaedics, The Ohio State University, Columbus, OH, USA
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11
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Raikova R, Krutki P, Celichowski J. Skeletal muscle models composed of motor units: A review. J Electromyogr Kinesiol 2023; 70:102774. [PMID: 37099899 DOI: 10.1016/j.jelekin.2023.102774] [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: 11/28/2022] [Revised: 04/06/2023] [Accepted: 04/09/2023] [Indexed: 04/28/2023] Open
Abstract
The mathematical muscle models should include several aspects of muscle structure and physiology. First, muscle force is the sum of forces of multiple motor units (MUs), which have different contractile properties and play different roles in generating muscle force. Second, whole muscle activity is an effect of net excitatory inputs to a pool of motoneurons innervating the muscle, which have different excitability, influencing MU recruitment. In this review, we compare various methods for modeling MU twitch and tetanic forces and then discuss muscle models composed of different MU types and number. We first present four different analytical functions used for twitch modeling and show limitations related to the number of twitch describing parameters. We also show that a nonlinear summation of twitches should be considered in modeling tetanic contractions. We then compare different muscle models, most of which are variations of Fuglevand's model, adopting a common drive hypothesis and the size principle. We pay attention to integrating previously developed models into a consensus model based on physiological data from in vivo experiments on the rat medial gastrocnemius muscle and its respective motoneurons. Finally, we discuss the shortcomings of existing models and potential applications for studying MU synchronization, potentiation, and fatigue.
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Affiliation(s)
- Rositsa Raikova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Bulgaria.
| | - Piotr Krutki
- Department of Neurobiology, Poznan University of Physical Education, Poland
| | - Jan Celichowski
- Department of Neurobiology, Poznan University of Physical Education, Poland
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12
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Yokoyama H, Kaneko N, Sasaki A, Saito A, Nakazawa K. Firing behavior of single motor units of the tibialis anterior in human walking as non-invasively revealed by HDsEMG decomposition. J Neural Eng 2022; 19. [PMID: 36541453 DOI: 10.1088/1741-2552/aca71b] [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: 08/31/2022] [Accepted: 11/29/2022] [Indexed: 12/02/2022]
Abstract
Objective.Investigation of the firing behavior of motor units (MUs) provides essential neuromuscular control information because MUs are the smallest organizational component of the neuromuscular system. The MUs activated during human infants' leg movements and rodent locomotion, mainly controlled by the spinal central pattern generator (CPG), show highly synchronous firing. In addition to spinal CPGs, the cerebral cortex is involved in neuromuscular control during walking in human adults. Based on the difference in the neural control mechanisms of locomotion between rodent, human infants and adults, MU firing behavior during adult walking probably has some different features from the other populations. However, so far, the firing activity of MUs in human adult walking has been largely unknown due to technical issues.Approach.Recent technical advances allow noninvasive investigation of MU firing by high-density surface electromyogram (HDsEMG) decomposition. We investigated the MU firing behavior of the tibialis anterior (TA) muscle during walking at a slow speed by HDsEMG decomposition.Main results.We found recruitment threshold modulation of MU between walking and steady isometric contractions. Doublet firings, and gait phase-specific firings were also observed during walking. We also found high MU synchronization during walking over a wide range of frequencies, probably including cortical and spinal CPG-related components. The amount of MU synchronization was modulated between the gait phases and motor tasks. These results suggest that the central nervous system flexibly controls MU firing to generate appropriate force of TA during human walking.Significance.This study revealed the MU behavior during walking at a slow speed and demonstrated the feasibility of noninvasive investigation of MUs during dynamic locomotor tasks, which will open new frontiers for the study of neuromuscular systems in the fields of neuroscience and biomedical engineering.
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Affiliation(s)
- Hikaru Yokoyama
- Institute of Engineering, Tokyo University of Agriculture and Technology, Tokyo 184-8588, Japan.,Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan
| | - Naotsugu Kaneko
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan.,Japan Society for the Promotion of Science, Tokyo 102-0083, Japan.,Department of Neuropsychiatry, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Atsushi Sasaki
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan.,Japan Society for the Promotion of Science, Tokyo 102-0083, Japan.,Graduate School of Engineering Science, Department of Mechanical Science and Bioengineering, Osaka University, Osaka 560-8531, Japan
| | - Akira Saito
- Center for Health and Sports Science, Kyushu Sangyo University, Fukuoka 813-8503, Japan
| | - Kimitaka Nakazawa
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan
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13
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Muceli S, Poppendieck W, Holobar A, Gandevia S, Liebetanz D, Farina D. Blind identification of the spinal cord output in humans with high-density electrode arrays implanted in muscles. SCIENCE ADVANCES 2022; 8:eabo5040. [PMID: 36383647 PMCID: PMC9668292 DOI: 10.1126/sciadv.abo5040] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 10/20/2022] [Indexed: 06/16/2023]
Abstract
Invasive electromyography opened a new window to explore motoneuron behavior in vivo. However, the technique is limited by the small fraction of active motoneurons that can be concurrently detected, precluding a population analysis in natural tasks. Here, we developed a high-density intramuscular electrode for in vivo human recordings along with a fully automatic methodology that could detect the discharges of action potentials of up to 67 concurrently active motoneurons with 99% accuracy. These data revealed that motoneurons of the same pool receive common synaptic input at frequencies up to 75 Hz and that late-recruited motoneurons inhibit the discharges of those recruited earlier. These results constitute an important step in the population coding analysis of the human motor system in vivo.
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Affiliation(s)
- Silvia Muceli
- Department of Electrical Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | | | - Aleš Holobar
- Faculty of Electrical Engineering and Computer Science, University of Maribor, Maribor, Slovenia
| | - Simon Gandevia
- Neuroscience Research Australia and University of New South Wales, Randwick, Sydney, New South Wales, Australia
| | - David Liebetanz
- Department of Neurology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany
| | - Dario Farina
- Department of Bioengineering, Imperial College London, London, UK
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14
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Souza de Oliveira D, Casolo A, Balshaw TG, Maeo S, Lanza MB, Martin NRW, Maffulli N, Kinfe TM, Eskofier B, Folland JP, Farina D, Del Vecchio A. Neural decoding from surface high-density EMG signals: influence of anatomy and synchronization on the number of identified motor units. J Neural Eng 2022; 19. [PMID: 35853438 DOI: 10.1088/1741-2552/ac823d] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 07/19/2022] [Indexed: 11/11/2022]
Abstract
OBJECTIVE High-density surface electromyography (HD-sEMG) allows the reliable identification of individual motor unit (MU) action potentials. Despite the accuracy in decomposition, there is a large variability in the number of identified MUs across individuals and exerted forces. Here we present a systematic investigation of the anatomical and neural factors that determine this variability. APPROACH We investigated factors of influence on HD-sEMG decomposition, such as synchronization of MU discharges, distribution of MU territories, muscle-electrode distance (MED - subcutaneous adipose tissue thickness), maximum anatomical cross-sectional area (ACSAmax), and fiber CSA. For this purpose, we recorded HD-sEMG signals, ultrasound and, magnetic resonance images, and took a muscle biopsy from the biceps brachii muscle from 30 male participants drawn from two groups to ensure variability within the factors - untrained-controls (UT=14) and strength-trained individuals (ST=16). Participants performed isometric ramp contractions with elbow flexors (at 15, 35, 50 and 70% maximum voluntary torque - MVT). We assessed the correlation between the number of accurately detected MUs by HD-sEMG decomposition and each measured parameter, for each target force level. Multiple regression analysis was then applied. MAIN RESULTS ST subjects showed lower MED (UT=5.1±1.4 mm; ST=3.8±0.8 mm) and a greater number of identified motor units (UT:21.3±10.2 vs ST:29.2±11.8 MUs/subject across all force levels). The entire cohort showed a negative correlation between MED and the number of identified MUs at low forces (r= -0.6, p=0.002 at 15%MVT). Moreover, the number of identified MUs was positively correlated to the distribution of MU territories (r=0.56, p=0.01) and ACSAmax(r=0.48, p=0.03) at 15%MVT. By accounting for all anatomical parameters, we were able to partly predict the number of decomposed MUs at low but not at high forces. SIGNIFICANCE Our results confirmed the influence of subcutaneous tissue on the quality of HD-sEMG signals and demonstrated that MU spatial distribution and ACSAmaxare also relevant parameters of influence for current decomposition algorithms.
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Affiliation(s)
- Daniela Souza de Oliveira
- Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Henkestraße 91, Erlangen, 91052, GERMANY
| | - Andrea Casolo
- Department of Biomedical Sciences, University of Padua, Via Marzolo, 3, Padova, Veneto, 35131, ITALY
| | - Thomas G Balshaw
- School of Sport, Exercise and Health Sciences, Loughborough University, Epinal Way, Loughborough, LE11 3TU, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Sumiaki Maeo
- Faculty of Sport and Health Sciences, Ritsumeikan University, 1 Chome-1-1 Nojihigashi, Kusatsu, Shiga, 525-0058, JAPAN
| | - Marcel Bahia Lanza
- Physical Therapy and Rehabilitation Sciences, University of Maryland Baltimore, 100 penn street, BALTIMORE, Maryland, 21201, UNITED STATES
| | - Neil R W Martin
- School of Sport, Exercise and Health Sciences, Loughborough University, Epinal Way, Loughborough, LE11 3TU, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Nicola Maffulli
- School of Medicine and Surgery, University of Salerno, Via Giovanni Paolo II, 132, Fisciano, Campania, 84084, ITALY
| | - Thomas Mehari Kinfe
- Division of Functional Neurosurgery and Stereotaxy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schwabachanlage 6, Erlangen, 91054, GERMANY
| | - Bjoern Eskofier
- Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Carl-Thiersch-Straße 2b, Erlangen, 91052, GERMANY
| | - Jonathan P Folland
- School of Sport, Exercise and Health Sciences, Loughborough University, Epinal Way, Loughborough, Leicestershire, LE11 3TU, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Dario Farina
- Department of Bioengineering, Imperial College London, South Kensington, London, SW7 2AZ, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Alessandro Del Vecchio
- Artificial Intelligence in Biomedical engineering, Friedrich-Alexander-Universitat Erlangen-Nurnberg, Henkestrasse 91, 91052, Erlangen, Erlangen, Bavaria, 91052, GERMANY
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15
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Xie Z. Fatigue Monitoring and Recognition During Basketball Sports via Physiological Signal Analysis. INTERNATIONAL JOURNAL OF INFORMATION SYSTEM MODELING AND DESIGN 2022. [DOI: 10.4018/ijismd.313581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Fatigue is a feeling that appears after the human body undergoes excessive physical or mental work. The fatigue may reduce the ability to complete work. When sport fatigue occurs, the athlete's heart load continues to increase, muscles become sore, flexibility is reduced, thinking and judgment become slow, and the athlete is easily irritated. Thus, it is necessary to monitor the athlete's status during sports, such as playing basketball. Generally, the ion current in the body will change when the athlete suffers fatigue. That means the sport fatigue may cause changes in the bioelectric signals of the human body. This paper adopts bioelectric signals to analyze athlete status to prevent sport fatigue during basketball. The experiments on a basketball sport dataset demonstrate the effectiveness of the proposed method.
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Affiliation(s)
- Zhenhua Xie
- Jiyuan Vocational and Technical College, China
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16
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Schilaty ND, Savoldi F, Nasr Z, Weinshenker BG. Neuromotor control associates with muscle weakness observed with McArdle sign of multiple sclerosis. Ann Clin Transl Neurol 2022; 9:515-528. [PMID: 35289110 PMCID: PMC8994990 DOI: 10.1002/acn3.51526] [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: 12/07/2021] [Revised: 01/20/2022] [Accepted: 02/05/2022] [Indexed: 11/07/2022] Open
Abstract
OBJECTIVE Multiple Sclerosis (MS) is often accompanied by myelopathy, which may be associated with progressive worsening. A specific finding of MS-associated myelopathy is McArdle sign, wherein neck flexion is associated with prominent increased limb weakness relative to that detected with neck extension. In this study, we characterized neuromotor control properties of finger extensors in association with the McArdle sign. METHODS A custom-built device was utilized to monitor torque production of the wrist extensors with simultaneous recording of surface electromyography of the extensor digitorum. The electromyography was decomposed and analyzed via both linear and nominal regressions. RESULTS Linear regressions demonstrated a strong difference between groups for MS from healthy controls and other myelopathies for motor unit action potential amplitude and average firing rate (p < 0.001). Further, linear regression demonstrated good correlations of neuromotor variables to mechanical torque output (0.24 ≤ R2 ≤ 0.76). Nominal regression distinguished MS from healthy controls with an AUC of 0.87, specificity of 0.97, and sensitivity of 0.64. Nominal regression of MS from other myelopathies demonstrated an AUC of 0.88, specificity of 0.85, and sensitivity of 0.79. INTERPRETATION These data demonstrate the neuromotor control factors that largely determine muscle force production change with the observation of McArdle sign; these neuromotor control factors can differentiate MS from both healthy controls and other myelopathy conditions.
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Affiliation(s)
- Nathan D Schilaty
- Department of Neurosurgery & Brain Repair, University of South Florida, Tampa, Florida, USA.,Center for Neuromusculoskeletal Research, University of South Florida, Tampa, Florida, USA
| | - Filippo Savoldi
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
| | - Zahra Nasr
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
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17
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Kudina LP, Andreeva RE. Human motoneuron firing behavior and single motor unit F-wave. J Electromyogr Kinesiol 2022; 63:102641. [DOI: 10.1016/j.jelekin.2022.102641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 01/31/2022] [Accepted: 02/03/2022] [Indexed: 10/19/2022] Open
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18
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Favretto MA, Cossul S, Andreis FR, Nakamura LR, Ronsoni MF, Tesfaye S, Selvarajah D, Marques JLB. Alterations of tibialis anterior muscle activation pattern in subjects with type 2 diabetes and diabetic peripheral neuropathy. Biomed Phys Eng Express 2022; 8. [PMID: 34933285 DOI: 10.1088/2057-1976/ac455b] [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: 06/26/2021] [Accepted: 12/21/2021] [Indexed: 11/11/2022]
Abstract
Diabetic peripheral neuropathy (DPN) is associated with loss of motor units (MUs), which can cause changes in the activation pattern of muscle fibres. This study investigated the pattern of muscle activation using high-density surface electromyography (HD-sEMG) signals from subjects with type 2 diabetes mellitus (T2DM) and DPN. Thirty-five adults participated in the study: 12 healthy subjects (HV), 12 patients with T2DM without DPN (No-DPN) and 11 patients with T2DM with DPN (DPN). HD-sEMG signals were recorded in the tibialis anterior muscle during an isometric contraction of ankle dorsiflexion at 50% of the maximum voluntary isometric contraction (MVIC) during 30-s. The calculated HD-sEMG signals parameters were the normalised root mean square (RMS), normalised median frequency (MDF), coefficient of variation (CoV) and modified entropy (ME). The RMS increased significantly (p = 0.001) with time only for the DPN group, while the MDF decreased significantly (p < 0.01) with time for the three groups. Moreover, the ME was significantly lower (p = 0.005), and CoV was significantly higher (p = 0.003) for the DPN group than the HV group. Using HD-sEMG, we have demonstrated a reduction in the number of MU recruited by individuals with DPN. This study provides proof of concept for the clinical utility of this technique for identifying neuromuscular impairment caused by DPN.
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Affiliation(s)
- M A Favretto
- Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering, Federal University of Santa Catarina, Florianopolis, Santa Catarina, Brazil
| | - S Cossul
- Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering, Federal University of Santa Catarina, Florianopolis, Santa Catarina, Brazil
| | - F R Andreis
- Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - L R Nakamura
- Department of Informatics and Statistics, Federal University of Santa Catarina, Florianopolis, Santa Catarina, Brazil
| | - M F Ronsoni
- Department of Endocrinology and Metabolism, University Hospital, Federal University of Santa Catarina, Florianopolis, Santa Catarina, Brazil
| | - S Tesfaye
- Diabetes Research Department, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom
| | - D Selvarajah
- Department of Oncology and Human Metabolism, University of Sheffield, Sheffield, United Kingdom
| | - J L B Marques
- Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering, Federal University of Santa Catarina, Florianopolis, Santa Catarina, Brazil
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19
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Electrical Properties of Adult Mammalian Motoneurons. ADVANCES IN NEUROBIOLOGY 2022; 28:191-232. [PMID: 36066827 DOI: 10.1007/978-3-031-07167-6_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Motoneurons are the 'final common path' between the central nervous system (that intends, selects, commands, and organises movement) and muscles (that produce the behaviour). Motoneurons are not passive relays, but rather integrate synaptic activity to appropriately tune output (spike trains) and therefore the production of muscle force. In this chapter, we focus on studies of mammalian motoneurons, describing their heterogeneity whilst providing a brief historical account of motoneuron recording techniques. Next, we describe adult motoneurons in terms of their passive, transition, and active (repetitive firing) properties. We then discuss modulation of these properties by somatic (C-boutons) and dendritic (persistent inward currents) mechanisms. Finally, we briefly describe select studies of human motor unit physiology and relate them to findings from animal preparations discussed earlier in the chapter. This interphyletic approach to the study of motoneuron physiology is crucial to progress understanding of how these diverse neurons translate intention into behaviour.
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20
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Abstract
The purpose of our review was to compare the distribution of motor unit properties across human muscles of different sizes and recruitment ranges. Although motor units can be distinguished based on several different attributes, we focused on four key parameters that have a significant influence on the force produced by muscle during voluntary contractions: the number of motor units, average innervation number, the distributions of contractile characteristics, and discharge rates within motor unit pools. Despite relatively few publications on this topic, current data indicate that the most influential factor in the distribution of these motor unit properties between muscles is innervation number. Nonetheless, despite a fivefold difference in innervation number between a hand muscle (first dorsal interosseus) and a lower leg muscle (tibialis anterior), the general organization of their motor unit pools, and the range of discharge rates appear to be relatively similar. These observations provide foundational knowledge for studies on the control of movement and the changes that occur with aging and neurological disorders.
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Affiliation(s)
- Jacques Duchateau
- Laboratory of Applied Biology and Neurophysiology, ULB Neuroscience Institute, Université Libre de Bruxelles, Brussels, Belgium
| | - Roger M Enoka
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado
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21
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Orssatto LBR, Borg DN, Blazevich AJ, Sakugawa RL, Shield AJ, Trajano GS. Intrinsic motoneuron excitability is reduced in soleus and tibialis anterior of older adults. GeroScience 2021; 43:2719-2735. [PMID: 34716899 PMCID: PMC8556797 DOI: 10.1007/s11357-021-00478-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 10/18/2021] [Indexed: 12/19/2022] Open
Abstract
Age-related deterioration within both motoneuron and monoaminergic systems should theoretically reduce neuromodulation by weakening motoneuronal persistent inward current (PIC) amplitude. However, this assumption remains untested. Surface electromyographic signals were collected using two 32-channel electrode matrices placed on soleus and tibialis anterior of 25 older adults (70 ± 4 years) and 17 young adults (29 ± 5 years) to investigate motor unit discharge behaviors. Participants performed triangular-shaped plantar and dorsiflexion contractions to 20% of maximum torque at a rise-decline rate of 2%/s of each participant's maximal torque. Pairwise and composite paired-motor unit analyses were adopted to calculate delta frequency (ΔF), which has been used to differentiate between the effects of synaptic excitation and intrinsic motoneuronal properties and is assumed to be proportional to PIC amplitude. Soleus and tibialis anterior motor units in older adults had lower ΔFs calculated with either the pairwise [-0.99 and -1.46 pps; -35.4 and -33.5%, respectively] or composite (-1.18 and -2.28 pps; -32.1 and -45.2%, respectively) methods. Their motor units also had lower peak discharge rates (-2.14 and -2.03 pps; -19.7 and -13.9%, respectively) and recruitment thresholds (-1.50 and -2.06% of maximum, respectively) than young adults. These results demonstrate reduced intrinsic motoneuron excitability during low-force contractions in older adults, likely mediated by decreases in the amplitude of persistent inward currents. Our findings might be explained by deterioration in the motoneuron or monoaminergic systems and could contribute to the decline in motor function during aging; these assumptions should be explicitly tested in future investigations.
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Affiliation(s)
- Lucas B. R. Orssatto
- School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, Australia
| | - David N. Borg
- Menzies Health Institute Queensland, The Hopkins Centre, Griffith University, Brisbane, Australia
| | | | - Raphael L. Sakugawa
- Biomechanics Laboratory, Department of Physical Education, Federal University of Santa Catarina, Florianopolis, Brazil
| | - Anthony J. Shield
- School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, Australia
| | - Gabriel S. Trajano
- School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, Australia
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22
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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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23
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Reece TM, Arnold CE, Herda TJ. An examination of motor unit firing rates during steady torque of maximal efforts with either an explosive or slower rate of torque development. Exp Physiol 2021; 106:2517-2530. [PMID: 34676609 DOI: 10.1113/ep089808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 10/11/2021] [Indexed: 12/29/2022]
Abstract
NEW FINDINGS What is the central question of this study? The aim was to explore agonist and antagonist motor unit firing rates during maximal efforts performed with either an explosive or a slower rate of torque development. What is the main finding and its importance? The antagonist muscle presented a motor unit firing rate relationship similar to the agonist muscle. Additionally, the motor units of both muscles exhibited higher firing rates during explosive maximal contractions than during maximal contractions performed at a slower rate of torque development. These results could prove useful to future research analysing the effects of age, disease, resistance training and/or fatigue-related alterations to motor unit firing rates. ABSTRACT The primary purpose of the present study was to examine motor unit (MU) firing rates in agonist and antagonist muscles during periods of steady, maximal efforts using explosive and slower rates of torque development. A secondary purpose was to analyse the MU firing rate versus action potential amplitude relationships of the agonist and antagonist muscles during maximal efforts. Thirteen subjects (mean ± SD; age, 21.2 ± 3.6 years; mass 81.1 ± 21.3 kg; and stature, 177.1±9.9 cm) performed two maximal isometric trapezoid muscle actions of the elbow flexors that included either an explosive or a slower, linearly increasing rate (ramp) of torque development. Surface EMG signals of the biceps brachii (BB) and triceps brachii (TB) muscles were collected and decomposed into their constituent MU action potential trains. The MU firing rate versus action potential amplitude relationships of the BB (agonist) and TB (antagonist) muscles were analysed. Moderate to strong relationships (|r| ≥ 0.65) were present for the explosive and ramp contractions in the agonist and antagonist muscles. Firing rates of smaller and larger MUs were higher during the explosive [mean ± SD; agonist = 18.1 ± 6.9 pulses per second (pps), antagonist = 22.0±3.9 pps] than the ramp (agonist = 14.0 ± 5.1 pps, antagonist = 18.3 ± 4.4 pps) contractions for the agonist (P = 0.013) and antagonist muscles (P = 0.007). The antagonist muscle exhibits a similar MU firing rate versus action potential amplitude relationship to the agonist muscle at maximal efforts. Future research should investigate the effects of short-term resistance training on antagonist firing rates and the involvement of peripheral feedback on firing rates during maximal efforts performed at various rates of torque development.
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Affiliation(s)
- Tanner M Reece
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, Kansas, USA
| | - Catherine E Arnold
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, Kansas, USA
| | - Trent J Herda
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, Kansas, USA
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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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Parra ME, Miller JD, Sterczala AJ, Kelly MR, Herda TJ. The reliability of the slopes and y-intercepts of the motor unit firing times and action potential waveforms versus recruitment threshold relationships derived from surface electromyography signal decomposition. Eur J Appl Physiol 2021; 121:3389-3398. [PMID: 34477930 DOI: 10.1007/s00421-021-04790-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 08/12/2021] [Indexed: 11/24/2022]
Abstract
PURPOSE Changes in motor unit (MU) activity pre- to post-interventions is of high interest. However, there is minimal information regarding day-to-day changes or the reliability of measuring MU activity. This study examined the reliability of relationships calculated via the MU action potential (AP) trains derived from surface electromyography signal decomposition. A comparison between reliability statistics was made between MUAP trains verified with only the reconstruct-and-test versus verification including reconstruct-and-test with spike trigger average (STA) procedures. METHODS Twenty-one individuals performed isometric muscle actions at 50% of maximal voluntary contraction of the first dorsal interosseous on two separate visits. MUs included for reliability analyses initially met the > 90% accuracy from the reconstruct-and-test. STA was applied as an additional exclusionary procedure. Linear regressions were applied to the firing rate and AP amplitude versus recruitment threshold relationships with and without MUs that met the STA criteria. Reliability statistics were also performed on relationships that met a strict range of recruitment thresholds. Reliability was established with intraclass correlation coefficients (ICC) along with other traditional parameters. RESULTS The firing rate versus recruitment threshold relationships were reliable (ICC > 0.56) and improved (ICC > 0.84) when recruitment ranges were controlled. The slopes of the MUAP amplitude versus recruitment threshold relationships were reliable (ICC > 0.78) while the y-intercepts were reliable (ICC > 0.81) once corrections were made to combat negative scores. CONCLUSIONS Electromyographic signal decomposition without the secondary STA verification procedures can be used to detect intervention-related changes in neural drive with confidence when recorded MU recruitment thresholds are similar across days.
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Affiliation(s)
- Mandy E Parra
- School of Exercise and Sport Science, University of Mary Hardin-Baylor, Belton, TX, USA
| | - Jonathan D Miller
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, 1301 Sunnyside Avenue, Room 101BE, Lawrence, KS, 66045, USA
| | - Adam J Sterczala
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburg, Pittsburgh, PA, USA
| | - Melani R Kelly
- Human Performance Research Laboratory, Department of Exercise Science and Pre-Health Professions, Creighton University, Omaha, NE, USA
| | - Trent J Herda
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, 1301 Sunnyside Avenue, Room 101BE, Lawrence, KS, 66045, USA.
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Escriche-Escuder A, Cuesta-Vargas AI, Casaña J. Effect of a common exercise programme with an individualised progression criterion based on the measurement of neuromuscular capacity versus current best practice for lower limb tendinopathies (MaLaGa trial): a protocol for a randomised clinical trial. BMJ Open 2021; 11:e046729. [PMID: 34404699 PMCID: PMC8372811 DOI: 10.1136/bmjopen-2020-046729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
INTRODUCTION High-load resistance training has shown positive effects in pain and function in lower limb tendinopathies. However, some authors suggest that current exercise programmes produce an increase in tolerance to load and exercise in general but without fixing some existing issues in tendinopathy. This may indicate the need to include training aspects not currently taken into account in the current programmes. The main objective of this study will be to compare the effect of a common exercise protocol for the three predominant lower limb tendinopathies (Achilles, patellar and gluteal), based on an individualised control of the dose and training of specific aspects of the neuromuscular system versus the current best practice for each location. METHODS AND ANALYSIS This study will be conducted among people with mid-portion Achilles, patellar or gluteal tendinopathy. The participants allocated to the experimental group will perform a 14-week innovative common therapeutic exercise programme. Participants allocated to the control group will carry out a 14-week exercise programme based on the best current practice for each of the studied locations. The Victorian Institute of Sports Assessment questionnaire will be considered the primary outcome. Pain, central sensitisation, fear avoidance behaviour, quality of life, treatment satisfaction, lower-limb strength and function, and high-density electromyography profile will be evaluated as secondary outcomes. Outcomes will be assessed at baseline, 7 weeks, after the intervention (week 14), 26 weeks and 52 weeks. ETHICS AND DISSEMINATION The study has been approved by the Portal de Ética de la Investigación Biomédica de Andalucía Ethics Committee (1221-N-19). All participants will be informed about the purpose and content of the study and written informed consent will be completed. The results of this study will be published in a peer-reviewed journal and will be disseminated electronically and in print. TRIAL REGISTRATION NUMBER NCT03853122; Pre-results.
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Affiliation(s)
- Adrian Escriche-Escuder
- Department of Physiotherapy, University of Malaga, Malaga, Spain
- Grupo Clinimetría (F-14), Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain
| | - Antonio I Cuesta-Vargas
- Department of Physiotherapy, University of Malaga, Malaga, Spain
- Grupo Clinimetría (F-14), Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain
- Health, Queensland University Technology, Brisbane, Queensland, Australia
| | - Jose Casaña
- Department of Physiotherapy, University of Valencia, Valencia, Spain
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Evans V, Koh RGL, Duarte FCK, Linde L, Amiri M, Kumbhare D. A randomized double blinded placebo controlled study to evaluate motor unit abnormalities after experimentally induced sensitization using capsaicin. Sci Rep 2021; 11:13793. [PMID: 34215800 PMCID: PMC8253857 DOI: 10.1038/s41598-021-93188-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 06/17/2021] [Indexed: 12/02/2022] Open
Abstract
Central sensitization is a condition that represents a cascade of neurological adaptations, resulting in an amplification of nociceptive responses from noxious and non-noxious stimuli. However, whether this abnormality translates into motor output and more specifically, ventral horn abnormalities, needs to be further explored. Twenty healthy participants aged 20-70 were randomly allocated to topical capsaicin or a placebo topical cream which was applied onto their left upper back to induce a transient state of sensitization. Visual analogue scale (VAS) ratings of pain intensity and brush allodynia score (BAS) were used to determine the presence of pain and secondary allodynia. Surface electromyography (sEMG) and intramuscular electromyography (iEMG) were used to record motor unit activity from the upper trapezius and infraspinatus muscles before and twenty minutes after application of capsaicin/placebo. Motor unit recruitment and variability were analyzed in the sEMG and iEMG, respectively. An independent t-test and Kruskal-Wallis H test were performed on the data. The sEMG results demonstrated a shift in the motor unit recruitment pattern in the upper trapezius muscle, while the iEMG showed a change in motor unit variability after application of capsaicin. These results suggest that capsaicin-induced central sensitization may cause changes in ventral horn excitability outside of the targeted spinal cord segment, affecting efferent pathway outputs. This preclinical evidence may provide some explanation for the influence of central sensitization on changes in movement patterns that occur in patients who have pain encouraging of further clinical investigation.Clinical Trials registration number: NCT04361149; date of registration: 24-Apr-2020.
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Affiliation(s)
- Valerie Evans
- Toronto Rehabilitation Institute, University Health Network, Toronto, ON, Canada
- Department of Medicine, Institute of Biomaterials and Biomedical Engineering (IBBME), University of Toronto, 550 University Ave, Suite 7-131, Toronto, ON, M5G 2A2, Canada
| | - Ryan G L Koh
- Toronto Rehabilitation Institute, University Health Network, Toronto, ON, Canada
| | - Felipe C K Duarte
- Division of Research and Innovation, Canadian Memorial of Chiropractic College, Toronto, ON, Canada
| | - Lukas Linde
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Mohammadreza Amiri
- Toronto Rehabilitation Institute, University Health Network, Toronto, ON, Canada
| | - Dinesh Kumbhare
- Toronto Rehabilitation Institute, University Health Network, Toronto, ON, Canada.
- Department of Medicine, Institute of Biomaterials and Biomedical Engineering (IBBME), University of Toronto, 550 University Ave, Suite 7-131, Toronto, ON, M5G 2A2, Canada.
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of Toronto, Toronto, ON, Canada.
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Hug F, Avrillon S, Del Vecchio A, Casolo A, Ibanez J, Nuccio S, Rossato J, Holobar A, Farina D. Analysis of motor unit spike trains estimated from high-density surface electromyography is highly reliable across operators. J Electromyogr Kinesiol 2021; 58:102548. [PMID: 33838590 DOI: 10.1016/j.jelekin.2021.102548] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/23/2021] [Accepted: 03/23/2021] [Indexed: 12/25/2022] Open
Abstract
There is a growing interest in decomposing high-density surface electromyography (HDsEMG) into motor unit spike trains to improve knowledge on the neural control of muscle contraction. However, the reliability of decomposition approaches is sometimes questioned, especially because they require manual editing of the outputs. We aimed to assess the inter-operator reliability of the identification of motor unit spike trains. Eight operators with varying experience in HDsEMG decomposition were provided with the same data extracted using the convolutive kernel compensation method. They were asked to manually edit them following established procedures. Data included signals from three lower leg muscles and different submaximal intensities. After manual analysis, 126 ± 5 motor units were retained (range across operators: 119-134). A total of 3380 rate of agreement values were calculated (28 pairwise comparisons × 11 contractions/muscles × 4-28 motor units). The median rate of agreement value was 99.6%. Inter-operator reliability was excellent for both mean discharge rate and time at recruitment (intraclass correlation coefficient > 0.99). These results show that when provided with the same decomposed data and the same basic instructions, operators converge toward almost identical results. Our data have been made available so that they can be used for training new operators.
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Affiliation(s)
- François Hug
- Nantes University, Laboratory "Movement, Interactions, Performance" (EA 4334), Nantes, France; The University of Queensland, NHMRC Centre of Clinical Research Excellence in Spinal Pain, Injury and Health, School of Health and Rehabilitation Sciences, Brisbane, Australia; Institut Universitaire de France (IUF), Paris, France.
| | - Simon Avrillon
- Legs Walking AbilityLab, Shirley Ryan AbilityLab, Chicago, IL, USA; Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, IL, USA
| | - Alessandro Del Vecchio
- Department of Artificial Intelligence in Biomedical Engineering, Faculty of Engineering, Friedrich-Alexander University, Erlangen-Nuremberg, 91052 Erlangen, Germany
| | - Andrea Casolo
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Jaime Ibanez
- Department of Bioengineering, Faculty of Engineering, Imperial College London, UK; Department of Clinical and Movement Disorders, Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Stefano Nuccio
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Rome, Italy
| | - Julien Rossato
- Nantes University, Laboratory "Movement, Interactions, Performance" (EA 4334), Nantes, France
| | - Aleš Holobar
- Faculty of Electrical Engineering and Computer Science, University of Maribor, Slovenia
| | - Dario Farina
- Department of Bioengineering, Faculty of Engineering, Imperial College London, UK
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Enoka RM, Farina D. Force Steadiness: From Motor Units to Voluntary Actions. Physiology (Bethesda) 2021; 36:114-130. [DOI: 10.1152/physiol.00027.2020] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Voluntary actions are controlled by the synaptic inputs that are shared by pools of spinal motor neurons. The slow common oscillations in the discharge times of motor units due to these synaptic inputs are strongly correlated with the fluctuations in force during submaximal isometric contractions (force steadiness) and moderately associated with performance scores on some tests of motor function. However, there are key gaps in knowledge that limit the interpretation of differences in force steadiness.
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Affiliation(s)
- Roger M. Enoka
- Department of Integrative Physiology, University of Colorado Boulder, Colorado
| | - Dario Farina
- Department of Bioengineering, Faculty of Engineering, Imperial College London, London, United Kingdom
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Is the 'reverse onion skin' phenomenon more prevalent than we thought during intramuscular myoelectric recordings from low to maximal force outputs? Neurosci Lett 2020; 743:135583. [PMID: 33352279 DOI: 10.1016/j.neulet.2020.135583] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 12/10/2020] [Accepted: 12/14/2020] [Indexed: 11/21/2022]
Abstract
There are isolated instances in the literature that suggest the 'onion skin' phenomenon is not always present. That is, newly recruited high threshold motor units (MU) have higher discharge rates than previously recruited low threshold MUs. Therefore, the purpose of this paper was to investigate the presence of the 'onion skin' phenomenon in a large sample of intramuscular myoelectric recordings from low to maximal force outputs. Forty-eight participants performed rapid isometric dorsiflexion contractions at 20, 40, 60, 80 and 100 % MVC while intramuscular electrical activity was recorded. A bivariate frequency-distribution of the motor unit discharge rate and motor unit action potential peak-to-peak (P-P) amplitude was assessed. There was a significant difference in bivariate frequency-distribution across force levels (D's = 0.1083-0.3094, p's < 0.001). Newly recruited high threshold MUs did have lower discharge rates, but there was an increase in the presence of high threshold, large P-P amplitude MUs with higher discharge rates than lower threshold MUs (reverse onion skin) during the stable portion of the force output. The recruitment of high threshold MUs with higher discharge rates decreased the level of common drive from the cross-correlation (Rxy) = 0.79 at 20 % MVC to Rxy = 0.68 at 100 % MVC (p < 0.01), but it remained high. As the interference pattern becomes more complex with the recruitment of more motor units at higher force outputs, intramuscular electrodes may be more discriminating while recording motor unit activity leading to the identification of both the 'reverse onion skin' and 'onion skin' phenomenon being present.
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Felici F, Del Vecchio A. Surface Electromyography: What Limits Its Use in Exercise and Sport Physiology? Front Neurol 2020; 11:578504. [PMID: 33240204 PMCID: PMC7677519 DOI: 10.3389/fneur.2020.578504] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/21/2020] [Indexed: 12/31/2022] Open
Abstract
The aim of the present paper is to examine to what extent the application of surface electromyography (sEMG) in the field of exercise and, more in general, of human movement, is adopted by professionals on a regular basis. For this purpose, a brief history of the recent developments of modern sEMG techniques will be assessed and evaluated for a potential use in exercise physiology and clinical biomechanics. The idea is to understand what are the limitations that impede the translation of sEMG to applied fields such as exercise physiology. A cost/benefits evaluation will be drawn in order to understand possible causes that prevents sEMG from being routinely adopted. Among the possible causative factors, educational, economic and technical issues will be considered. Possible corrective interventions will be proposed. We will also give an overview of the parameters that can be extracted from the decomposition of the sHDEMG signals and how this can be related by professionals for assessing the health and disease of the neuromuscular system. We discuss how the decomposition of surface EMG signals might be adopted as a new non-invasive tool for assessing the status of the neuromuscular system. Recent evidences show that is possible to monitor the changes in neuromuscular function after training of longitudinally tracked populations of motoneurons, predict the maximal rate of force development by an individual via motoneuron interfacing, and identify possible causal relations between aging and the decrease in motor performance. These technologies will guide our understanding of motor control and provide a new window for the investigation of the underlying physiological processes determining force control, which is essential for the sport and exercise physiologist. We will also illustrate the challenges related to extraction of neuromuscular parameters from global EMG analysis (i.e., root-mean-square, and other global EMG metrics) and when the decomposition is needed. We posit that the main limitation in the application of sEMG techniques to the applied field is associated to problems in education and teaching, and that most of the novel technologies are not open source.
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Affiliation(s)
- Francesco Felici
- Department Motor, Human and Health Sciences, Rome University Foro Italico, Rome, Italy
| | - Alessandro Del Vecchio
- Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander University, Erlangen, Germany
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Martinez-Valdes E, Negro F, Falla D, Dideriksen JL, Heckman CJ, Farina D. Inability to increase the neural drive to muscle is associated with task failure during submaximal contractions. J Neurophysiol 2020; 124:1110-1121. [DOI: 10.1152/jn.00447.2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Motor unit firing and contractile properties during a submaximal contraction until failure were assessed with a new tracking technique. Two distinct phases in firing behavior were observed, which compensated for changes in twitch area and predicted time to failure. However, the late increase in firing rate was below the rates attained in the absence of fatigue, which points to an inability of the central nervous system to sufficiently increase the neural drive to muscle with fatigue.
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Affiliation(s)
- 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, United Kingdom
| | - Francesco Negro
- Department of Clinical and Experimental Sciences, Research Centre for Neuromuscular Function and Adapted Physical Activity “Teresa Camplani,” Università degli Studi di Brescia, Brescia, 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
| | - Jakob Lund Dideriksen
- Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - C. J. Heckman
- Department of Physiology, Northwestern University, Chicago, Illinois
| | - Dario Farina
- Department of Bioengineering, Imperial College London, Royal School of Mines, London, United Kingdom
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Senefeld JW, Singh-Peters LA, Kenno KA, Hunter SK, Jakobi JM. Greater fatigue resistance of dorsiflexor muscles in people with prediabetes than type 2 diabetes. J Electromyogr Kinesiol 2020; 54:102458. [PMID: 32896804 DOI: 10.1016/j.jelekin.2020.102458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 08/05/2020] [Accepted: 08/19/2020] [Indexed: 11/16/2022] Open
Abstract
Although exercise can prevent progression to T2D among people with prediabetes, little is known about fatigue during exercise in people with prediabetes compared to T2D. The purpose of the study was to compare the magnitude and mechanisms of fatigability of the ankle dorsiflexor muscles between people with prediabetes and T2D. Ten people with prediabetes (6 females, 51.7 ± 6.9 years) and fourteen with T2D (6 females, 52.6 ± 6.2 years) who were matched for age, body mass index and physical activity performed an intermittent (6 s contraction: 4 s relaxation) fatiguing task at 75% maximal voluntary contraction (MVC) with the dorsiflexors. Electrical stimulation was used to assess contractile properties of the dorsiflexor muscles before and after the fatiguing task. People with prediabetes had a longer time-to-task failure, i.e. greater fatigue resistance (7.9 ± 5.1 vs. 4.9 ± 2.5 min, P = 0.04), and slower rate of decline of the (potentiated) twitch amplitude (6.5 ± 3.1 vs. 16.5 ± 11.7%·min-1, P = 0.03) than people with T2D. Shorter time-to-task failure (i.e. greater fatigability) was associated with greater baseline MVC torque (r2 = 0.21, P = 0.02) and faster rate of decline of twitch amplitude (r2 = 0.39, P = 0.04). The ankle dorsiflexor muscles of males and females with prediabetes were more fatigue resistant than people with T2D, and fatigability was associated with contractile mechanisms.
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Affiliation(s)
- Jonathon W Senefeld
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA; Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
| | | | - Kenji A Kenno
- Department of Kinesiology, University of Windsor, Windsor, ON, Canada
| | - Sandra K Hunter
- Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
| | - Jennifer M Jakobi
- School of Health and Exercise Sciences, The University of British Columbia-Okanagan, Kelowna, BC, Canada.
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35
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Tutorial: Analysis of motor unit discharge characteristics from high-density surface EMG signals. J Electromyogr Kinesiol 2020; 53:102426. [DOI: 10.1016/j.jelekin.2020.102426] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Aagaard P, Bojsen-Møller J, Lundbye-Jensen J. Assessment of Neuroplasticity With Strength Training. Exerc Sport Sci Rev 2020; 48:151-162. [DOI: 10.1249/jes.0000000000000229] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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37
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Afsharipour B, Manzur N, Duchcherer J, Fenrich KF, Thompson CK, Negro F, Quinlan KA, Bennett DJ, Gorassini MA. Estimation of self-sustained activity produced by persistent inward currents using firing rate profiles of multiple motor units in humans. J Neurophysiol 2020; 124:63-85. [PMID: 32459555 DOI: 10.1152/jn.00194.2020] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Persistent inward calcium and sodium currents (IP) activated during motoneuron recruitment help synaptic inputs maintain self-sustained firing until derecruitment. Here, we estimate the contribution of the IP to self-sustained firing in human motoneurons of varying recruitment threshold by measuring the difference in synaptic input needed to maintain minimal firing once the IP is fully activated compared with the larger synaptic input required to initiate firing before full IP activation. Synaptic input to ≈20 dorsiflexor motoneurons simultaneously recorded during ramp contractions was estimated from firing profiles of motor units decomposed from high-density surface electromyography (EMG). To avoid errors introduced when using high-threshold units firing in their nonlinear range, we developed methods where the lowest threshold units firing linearly with force were used to construct a composite (control) unit firing rate profile to estimate synaptic input to higher threshold (test) units. The difference in the composite firing rate (synaptic input) at the time of test unit recruitment and derecruitment (ΔF = Frecruit - Fderecruit) was used to measure IP amplitude that sustained firing. Test units with recruitment thresholds 1-30% of maximum had similar ΔF values, which likely included both slow and fast motor units activated by small and large motoneurons, respectively. This suggests that the portion of the IP that sustains firing is similar across a wide range of motoneuron sizes.NEW & NOTEWORTHY A new method of estimating synaptic drive to multiple, simultaneously recorded motor units provides evidence that the portion of the depolarizing drive from persistent inward currents that contributes to self-sustained firing is similar across motoneurons of different sizes.
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Affiliation(s)
- Babak Afsharipour
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Nagib Manzur
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Jennifer Duchcherer
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Keith F Fenrich
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Christopher K Thompson
- Department of Health and Rehabilitation Sciences, Temple University, Philadelphia, Pennsylvania
| | - Francesco Negro
- Research Centre for Neuromuscular Function and Adapted Physical Activity "Teresa Camplani," Università degli Studi di Brescia, Brescia, Italy
| | - Katharina A Quinlan
- Department of Biomedical and Pharmaceutical Sciences and George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, Rhode Island
| | - David J Bennett
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Monica A Gorassini
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada
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38
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Herda TJ, Parra ME, Miller JD, Sterczala AJ, Kelly MR. Measuring the accuracies of motor unit firing times and action potential waveforms derived from surface electromyographic decomposition. J Electromyogr Kinesiol 2020; 52:102421. [PMID: 32353708 DOI: 10.1016/j.jelekin.2020.102421] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 04/09/2020] [Accepted: 04/09/2020] [Indexed: 11/25/2022] Open
Abstract
This study included spike trigger averaging (STA) procedures to examine the acceptability of the Precision Decomposition (PD) III derived motor unit action potential (MUAP) trains that met the >90% accuracy criteria from the reconstruct-and-test. MUs met the >90% accuracy criteria from the reconstruct-and-test with STA procedures then applied. Y-intercepts and slopes were calculated for the firing rate- and MUAP amplitude-recruitment threshold relationships. Gaussian noise (1% of the SD of the mean interspike interval) was added to the firing times with the changes in MUAPs quantified. A total of 455 MUs were decomposed with 155 MUs removed as a result of the reconstruct-and-test. Five additional MUs were excluded via the STA criteria. The MUAP waveforms deteriorated with the inclusion of Gaussian noise. There were differences in the derived action potentials amplitudes of higher-threshold MUs between the PD III algorithm and the STA procedure. There was excellent agreement among the slopes and y-intercepts between the relationships that included or excluded MUs that did not meet the STA criteria. There was good agreement between the MUAP amplitude-recruitment threshold relationships derived from the PD III and STA procedure. The addition of the STA procedures did not alter the MU-derived relationships.
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Affiliation(s)
- Trent J Herda
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, USA.
| | - Mandy E Parra
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, USA
| | - Jonathan D Miller
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, USA
| | - Adam J Sterczala
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburg, Pittsburgh, PA, USA
| | - Melani R Kelly
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, USA
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Hoshizaki T, Clancy EA, Gabriel DA, Green LA. The reliability of surface EMG derived motor unit variables. J Electromyogr Kinesiol 2020; 52:102419. [PMID: 32305018 DOI: 10.1016/j.jelekin.2020.102419] [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: 04/27/2019] [Revised: 03/28/2020] [Accepted: 04/01/2020] [Indexed: 11/16/2022] Open
Abstract
Motor unit (MU) recordings obtained from surface electromyography (sEMG) decomposition are used to investigate the neural control of muscle in response to interventions, but our understanding of the longer-term reliability of MU variables is limited. This study examined the reliability of MU variables in the flexor carpi radialis (FCR) and tibialis anterior (TA) over a three-month period. Forty college-aged participants completed isometric wrist flexion (n = 20) and dorsiflexion (n = 20). There were 3 maximal isometric voluntary contractions (MVC) and 3 ramp contractions to 60% of MVC on four separate sessions separated by a total of 13 weeks. Intraclass correlation coefficients (ICC) were calculated from a fully nested ANOVA model. Maximal force was highly reliable (ICC = 0.94-0.99). The ICC values ranged from 0.49 to 0.92 for the FCR MU variables and from 0.58 to 0.96 for the TA MU variables. All MU variables exhibited a high degree of stability of means across test session and consistency within subjects, with the exception of the number of MUs detected in the TA. Poor ICC values did not reflect poor reliability but rather, convergence towards a narrow range of physiologically normal values. Surface EMG decomposition of a large population of MUs showed no differences in common drive between FCR (0.273) and for the TA (0.267) across test sessions. Forty percent of the sampled MUs in both muscles had a common drive of 0.30 or greater, which provides indirect support for the validity of the decompositions. MU variables may be used to monitor adaptations to a longer-term intervention study.
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Affiliation(s)
| | | | | | - Lara A Green
- Brock University, St. Catharines, ON, Canada; Wilfrid Laurier University, Waterloo, ON, Canada.
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40
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Mallette MM, Cheung SS, Kumar RI, Hodges GJ, Holmes MWR, Gabriel DA. The effects of local forearm heating and cooling on motor unit properties during submaximal contractions. Exp Physiol 2020; 106:200-211. [DOI: 10.1113/ep088256] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 01/07/2020] [Indexed: 11/08/2022]
Affiliation(s)
- Matthew M. Mallette
- Department of Kinesiology and Physical Education Wilfrid Laurier University Waterloo Ontario Canada
- Department of Kinesiology Brock University St Catharines Ontario Canada
| | - Stephen S. Cheung
- Department of Kinesiology Brock University St Catharines Ontario Canada
| | - Robert I. Kumar
- Department of Kinesiology Brock University St Catharines Ontario Canada
| | - Gary J. Hodges
- Department of Kinesiology Brock University St Catharines Ontario Canada
| | | | - David A. Gabriel
- Department of Kinesiology Brock University St Catharines Ontario Canada
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41
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Kumar RI, Mallette MM, Cheung SS, Stashuk DW, Gabriel DA. A method for editing motor unit potential trains obtained by decomposition of surface electromyographic signals. J Electromyogr Kinesiol 2020; 50:102383. [DOI: 10.1016/j.jelekin.2019.102383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 12/04/2019] [Accepted: 12/23/2019] [Indexed: 12/13/2022] Open
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42
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Vecchio AD, Farina D. Interfacing the neural output of the spinal cord: robust and reliable longitudinal identification of motor neurons in humans. J Neural Eng 2019; 17:016003. [DOI: 10.1088/1741-2552/ab4d05] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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43
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Enoka RM. A primer on motor unit physiology. J Electromyogr Kinesiol 2019; 47:123-124. [DOI: 10.1016/j.jelekin.2019.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 05/01/2019] [Indexed: 10/26/2022] Open
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44
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Tomko PM, Colquhoun RJ, Banks NF, Magrini MA, Muddle TWD, Jenkins NDM. Maximal contraction methods influence the magnitude and reliability of global electromyographic signal characteristics. J Electromyogr Kinesiol 2019; 48:121-127. [PMID: 31344640 DOI: 10.1016/j.jelekin.2019.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 06/11/2019] [Accepted: 07/06/2019] [Indexed: 10/26/2022] Open
Abstract
OBJECTIVE The purpose was two-fold: (1) to examine differences in maximal voluntary isometric torque (MVIT) production, and electromyographic signal amplitude (EMGAMP) and mean power frequency (EMGMPF) values obtained during traditional (MVICTRAD), rapid (MVICRAPID), and ramp (MVICRAMP) maximal voluntary isometric contractions, and (2) to determine if there were differences in the reliability of MVIT, EMGAMP and EMGMPF among the three MVIC types. APPROACH Twenty-two young males and females completed MVICTRAD, MVICRAPID, and MVICRAMP muscle actions on two separate visits separated by 48 h. During all MVICs, MVIT and EMGAMP and EMGMPF of the vastus lateralis (VL) and rectus femoris (RF) were quantified. MAIN RESULTS MVIT was greater during MVICTRAD and MVICRAPID than during MVITRAMP (both p < 0.001). VL and RF EMGAMP were greater during MVICRAMP than during MVICRAPID (p = 0.02 and 0.004). For EMGMPF, there were no significant differences among MVIC types. Although all MVIC types generally resulted in reliable measurements of MVIT and EMGAMP, reliability was stronger for EMGMPF quantified during the MVICRAMP. SIGNIFICANCE Investigators may choose MVIC type based on preference or equipment availability. However, investigators should note that MVICRAMP contractions will likely yield the greatest EMGAMP values and more reliable measurements of VL and RF EMGMPF.
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Affiliation(s)
- Patrick M Tomko
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, United States
| | - Ryan J Colquhoun
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, United States
| | - Nile F Banks
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, United States
| | - Mitchel A Magrini
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, United States
| | - Tyler W D Muddle
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, United States
| | - Nathaniel D M Jenkins
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, United States.
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45
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DeFreitas JM. In regards to motor unit decomposition, are we caring about the right information? J Electromyogr Kinesiol 2019; 47:121-122. [PMID: 31078381 DOI: 10.1016/j.jelekin.2019.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 05/01/2019] [Indexed: 10/26/2022] Open
Affiliation(s)
- Jason M DeFreitas
- Applied Neuromuscular Physiology Lab, Oklahoma State University, Stillwater, OK 74078, USA.
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