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Shin-Yi Lin C, Howells J, Rutkove S, Nandedkar S, Neuwirth C, Noto YI, Shahrizaila N, Whittaker RG, Bostock H, Burke D, Tankisi H. Neurophysiological and imaging biomarkers of lower motor neuron dysfunction in motor neuron diseases/amyotrophic lateral sclerosis: IFCN handbook chapter. Clin Neurophysiol 2024; 162:91-120. [PMID: 38603949 DOI: 10.1016/j.clinph.2024.03.015] [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: 10/03/2023] [Revised: 02/07/2024] [Accepted: 03/12/2024] [Indexed: 04/13/2024]
Abstract
This chapter discusses comprehensive neurophysiological biomarkers utilised in motor neuron disease (MND) and, in particular, its commonest form, amyotrophic lateral sclerosis (ALS). These encompass the conventional techniques including nerve conduction studies (NCS), needle and high-density surface electromyography (EMG) and H-reflex studies as well as novel techniques. In the last two decades, new methods of assessing the loss of motor units in a muscle have been developed, that are more convenient than earlier methods of motor unit number estimation (MUNE),and may use either electrical stimulation (e.g. MScanFit MUNE) or voluntary activation (MUNIX). Electrical impedance myography (EIM) is another novel approach for the evaluation that relies upon the application and measurement of high-frequency, low-intensity electrical current. Nerve excitability techniques (NET) also provide insights into the function of an axon and reflect the changes in resting membrane potential, ion channel dysfunction and the structural integrity of the axon and myelin sheath. Furthermore, imaging ultrasound techniques as well as magnetic resonance imaging are capable of detecting the constituents of morphological changes in the nerve and muscle. The chapter provides a critical description of the ability of each technique to provide neurophysiological insight into the complex pathophysiology of MND/ALS. However, it is important to recognise the strengths and limitations of each approach in order to clarify utility. These neurophysiological biomarkers have demonstrated reliability, specificity and provide additional information to validate and assess lower motor neuron dysfunction. Their use has expanded the knowledge about MND/ALS and enhanced our understanding of the relationship between motor units, axons, reflexes and other neural circuits in relation to clinical features of patients with MND/ALS at different stages of the disease. Taken together, the ultimate goal is to aid early diagnosis, distinguish potential disease mimics, monitor and stage disease progression, quantify response to treatment and develop potential therapeutic interventions.
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Affiliation(s)
- Cindy Shin-Yi Lin
- Faculty of Medicine and Health, Central Clinical School, Brain and Mind Centre, University of Sydney, Sydney 2006, Australia.
| | - James Howells
- Central Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Seward Rutkove
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Sanjeev Nandedkar
- Natus Medical Inc, Middleton, Wisconsin, USA and Medical College of Wisconsin, Milwaukee, WI, USA
| | - Christoph Neuwirth
- Neuromuscular Diseases Unit/ALS Clinic, Kantonsspital, St. Gallen, Switzerland
| | - Yu-Ichi Noto
- Department of Neurology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Nortina Shahrizaila
- Division of Neurology, Department of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Roger G Whittaker
- Newcastle University Translational and Clinical Research Institute (NUTCRI), Newcastle University., Newcastle Upon Tyne, United Kingdom
| | - Hugh Bostock
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, WC1N 3BG, London, United Kingdom
| | - David Burke
- Central Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Hatice Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital and Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
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Tulimieri DT, Semrau JA. Aging increases proprioceptive error for a broad range of movement speed and distance estimates in the upper limb. Front Hum Neurosci 2023; 17:1217105. [PMID: 37886690 PMCID: PMC10598783 DOI: 10.3389/fnhum.2023.1217105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 09/22/2023] [Indexed: 10/28/2023] Open
Abstract
Previous work has identified age-related declines in proprioception within a narrow range of limb movements. It is unclear whether these declines are consistent across a broad range of movement characteristics that more closely represent daily living. Here we aim to characterize upper limb error in younger and older adults across a range of movement speeds and distances. The objective of this study was to determine how proprioceptive matching accuracy changes as a function of movement speed and distance, as well as understand the effects of aging on these accuracies. We used an upper limb robotic test of proprioception to vary the speed and distance of movement in two groups: younger (n = 20, 24.25 ± 3.34 years) and older adults (n = 21, 63 ± 10.74 years). The robot moved one arm and the participant was instructed to mirror-match the movement with their opposite arm. Participants matched seven different movement speeds (0.1-0.4 m/s) and five distances (7.5-17.5 cm) over 350 trials. Spatial (e.g., End Point Error) and temporal (e.g., Peak Speed Ratio) outcomes were used to quantify proprioceptive accuracy. Regardless of the speed or distance of movement, we found that older controls had significantly reduced proprioceptive matching accuracy compared to younger control participants (p ≤ 0.05). When movement speed was varied, we observed that errors in proprioceptive matching estimates of spatial and temporal measures were significantly higher for older adults for all but the slowest tested speed (0.1 m/s) for the majority of parameters. When movement distance was varied, we observed that errors in proprioceptive matching estimates were significantly higher for all distances, except for the longest distance (17.5 cm) for older adults compared to younger adults. We found that the magnitude of proprioceptive matching errors was dependent on the characteristics of the reference movement, and that these errors scaled increasingly with age. Our results suggest that aging significantly negatively impacts proprioceptive matching accuracy and that proprioceptive matching errors made by both groups lies along a continuum that depends on movement characteristics and that these errors are amplified due to the typical aging process.
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Affiliation(s)
- Duncan Thibodeau Tulimieri
- Biomechanics and Movement Science (BIOMS), University of Delaware, Newark, DE, United States
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, United States
| | - Jennifer A. Semrau
- Biomechanics and Movement Science (BIOMS), University of Delaware, Newark, DE, United States
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, United States
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
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Beausejour JP, Bohlen P, Harmon KK, Girts RM, Pagan JI, Hahs-Vaughn DL, Herda TJ, Stock MS. A comparison of techniques for verifying the accuracy of precision decomposition-derived relationships between motor unit firing rates and recruitment thresholds from surface EMG signals. Exp Brain Res 2023; 241:2547-2560. [PMID: 37707570 DOI: 10.1007/s00221-023-06694-7] [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: 03/15/2023] [Accepted: 08/21/2023] [Indexed: 09/15/2023]
Abstract
Approaches for validating motor unit firing times following surface electromyographic (EMG) signal decomposition with the precision decomposition III (PDIII) algorithm have not been agreed upon. Two approaches have been common: (1) "reconstruct-and-test" and (2) spike-triggered averaging (STA). We sought to compare motor unit results following the application of these approaches. Surface EMG signals were recorded from the vastus lateralis of 13 young males performing trapezoidal, isometric knee extensions at 50% and 80% of maximum voluntary contraction (MVC) force. The PDIII algorithm was used to quantify motor unit firing rates. Motor units were excluded using eight combinations of the reconstruct-and-test approach with accuracy thresholds of 0, 90, 91, and 92% with and without STA. The mean firing rate versus recruitment threshold relationship was minimally affected by STA. At 80% MVC, slopes acquired at the 0% accuracy threshold were significantly greater (i.e., less negative) than when 91% (p = .010) and 92% (p = .030) accuracy thresholds were applied. The application of STA has minimal influence on surface EMG signal decomposition results. Stringent reconstruct-and-test accuracy thresholds influence motor unit-derived relationships at high forces, perhaps explained through the increased presence of large motor unit action potentials. Investigators using the PDIII algorithm can expect negligible changes in motor unit-derived linear regression relationships with the application of secondary validation procedures.
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Affiliation(s)
- Jonathan P Beausejour
- Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL, 32816-2205, USA
- School of Kinesiology and Rehabilitation Sciences, University of Central Florida, Orlando, FL, USA
| | - Paul Bohlen
- Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL, 32816-2205, USA
- School of Kinesiology and Rehabilitation Sciences, University of Central Florida, Orlando, FL, USA
| | - Kylie K Harmon
- Department of Exercise Science, Syracuse University, Syracuse, NY, USA
| | - Ryan M Girts
- Department of Natural and Health Sciences, Pfeiffer University, Misenheimer, NC, USA
| | - Jason I Pagan
- Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL, 32816-2205, USA
- School of Kinesiology and Rehabilitation Sciences, University of Central Florida, Orlando, FL, USA
| | - Debbie L Hahs-Vaughn
- College of Community Innovation and Education, University of Central Florida, Orlando, FL, USA
| | - Trent J Herda
- Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, USA
| | - Matt S Stock
- Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL, 32816-2205, USA.
- School of Kinesiology and Rehabilitation Sciences, University of Central Florida, Orlando, FL, USA.
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Taylor JA, Greenhaff PL, Bartlett DB, Jackson TA, Duggal NA, Lord JM. Multisystem physiological perspective of human frailty and its modulation by physical activity. Physiol Rev 2023; 103:1137-1191. [PMID: 36239451 PMCID: PMC9886361 DOI: 10.1152/physrev.00037.2021] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
"Frailty" is a term used to refer to a state characterized by enhanced vulnerability to, and impaired recovery from, stressors compared with a nonfrail state, which is increasingly viewed as a loss of resilience. With increasing life expectancy and the associated rise in years spent with physical frailty, there is a need to understand the clinical and physiological features of frailty and the factors driving it. We describe the clinical definitions of age-related frailty and their limitations in allowing us to understand the pathogenesis of this prevalent condition. Given that age-related frailty manifests in the form of functional declines such as poor balance, falls, and immobility, as an alternative we view frailty from a physiological viewpoint and describe what is known of the organ-based components of frailty, including adiposity, the brain, and neuromuscular, skeletal muscle, immune, and cardiovascular systems, as individual systems and as components in multisystem dysregulation. By doing so we aim to highlight current understanding of the physiological phenotype of frailty and reveal key knowledge gaps and potential mechanistic drivers of the trajectory to frailty. We also review the studies in humans that have intervened with exercise to reduce frailty. We conclude that more longitudinal and interventional clinical studies are required in older adults. Such observational studies should interrogate the progression from a nonfrail to a frail state, assessing individual elements of frailty to produce a deep physiological phenotype of the syndrome. The findings will identify mechanistic drivers of frailty and allow targeted interventions to diminish frailty progression.
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Affiliation(s)
- Joseph A Taylor
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom
| | - Paul L Greenhaff
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom.,NIHR Nottingham Biomedical Research Centre, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom
| | - David B Bartlett
- Division of Medical Oncology, Department of Medicine, Duke University, Durham, North Carolina.,Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Thomas A Jackson
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Institute of Inflammation and Ageing, https://ror.org/03angcq70University of Birmingham, Birmingham, United Kingdom
| | - Niharika A Duggal
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Institute of Inflammation and Ageing, https://ror.org/03angcq70University of Birmingham, Birmingham, United Kingdom
| | - Janet M Lord
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Institute of Inflammation and Ageing, https://ror.org/03angcq70University of Birmingham, Birmingham, United Kingdom.,NIHR Birmingham Biomedical Research Centre, University Hospital Birmingham and University of Birmingham, Birmingham, United Kingdom
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Bayram MB, Suviseshamuthu ES, Plow EB, Forrest GF, Yue GH. Aging-induced alterations in EEG spectral power associated with graded force motor tasks. Exp Brain Res 2023; 241:905-915. [PMID: 36808464 PMCID: PMC10037673 DOI: 10.1007/s00221-023-06572-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 02/12/2023] [Indexed: 02/23/2023]
Abstract
BACKGROUND It has been demonstrated that in young and healthy individuals, there is a strong association between the amplitude of EEG-derived motor activity-related cortical potential or EEG spectral power (ESP) and voluntary muscle force. This association suggests that the motor-related ESP may serve as an index of central nervous system function in controlling voluntary muscle activation Therefore, it may potentially be used as an objective marker to track changes in functional neuroplasticity due to neurological disorders, aging, and following rehabilitation therapies. To this end, the relationship between the band-specific ESP-combined spectral power of EEG oscillatory and aperiodic (noise) components-and voluntary elbow flexion (EF) force has been analyzed in elder and young individuals. METHODS 20 young (22.6 ± 0.87 year) and 28 elderly (74.79 ± 1.37 year) participants performed EF contractions at 20%, 50%, and 80% of maximum voluntary contraction (MVC) while high-density EEG signals were recorded. Both the absolute and relative ESPs were computed for the EEG frequency bands of interest. RESULTS The MVC force generated by the elderly was foreseeably lower than that of the young participants. Compared to young, the elderly cohort's (1) total ESP was significantly lower for the high (80% MVC) force task; (2) relative ESP in beta band was significantly elevated for the low and moderate (20% MVC and 50% MVC) force tasks; (3) absolute ESP failed to have a positive trend with force for EEG frequency bands of interest; and (4) beta-band relative ESP did not exhibit a significant decrease with increasing force levels. CONCLUSIONS As opposed to young subjects, the beta-band relative ESP in elderly did not significantly decrease with increasing EF force values. This observation suggests the use of beta-band relative ESP as a potential biomarker for age-related motor control degeneration.
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Affiliation(s)
- Mehmed Bugrahan Bayram
- Center for Mobility and Rehabilitation Engineering Research, Kessler Foundation, 1199 Pleasant Valley Way, West Orange, NJ, 07052, USA.
- Department of Biomedical Engineering, Acıbadem Mehmet Ali Aydınlar University, Istanbul, Türkiye.
- Department of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Rutgers University, 185 W South Orange Ave, Newark, NJ, 07103, USA.
| | - Easter S Suviseshamuthu
- Center for Mobility and Rehabilitation Engineering Research, Kessler Foundation, 1199 Pleasant Valley Way, West Orange, NJ, 07052, USA
- Department of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Rutgers University, 185 W South Orange Ave, Newark, NJ, 07103, USA
| | - Ela B Plow
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, 44195, USA
| | - Gail F Forrest
- Center for Mobility and Rehabilitation Engineering Research, Kessler Foundation, 1199 Pleasant Valley Way, West Orange, NJ, 07052, USA
- Department of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Rutgers University, 185 W South Orange Ave, Newark, NJ, 07103, USA
| | - Guang H Yue
- Center for Mobility and Rehabilitation Engineering Research, Kessler Foundation, 1199 Pleasant Valley Way, West Orange, NJ, 07052, USA
- Department of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Rutgers University, 185 W South Orange Ave, Newark, NJ, 07103, USA
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, 44195, USA
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6
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Chen M, Lu Z, Zong Y, Li X, Zhou P. A Novel Analysis of Compound Muscle Action Potential Scan: Staircase Function Fitting and StairFit Motor Unit Number Estimation. IEEE J Biomed Health Inform 2023; PP:1579-1587. [PMID: 37015542 PMCID: PMC10032645 DOI: 10.1109/jbhi.2022.3229211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Compound muscle action potential (CMAP) scan provides a detailed stimulus-response curve for examination of neuromuscular disease. The objective of the study is to develop a novel CMAP scan analysis to extract motor unit number estimation (MUNE) and other physiological or diagnostic information. A staircase function was used as the basic mathematical model of the CMAP scan. An optimal staircase function fitting model was estimated for each given number of motor units, and the fitting model with the minimum number of motor units that meets a predefined error requirement was accepted. This yields MUNE as well as the spike amplitude and activation threshold of each motor unit that contributes to the CMAP scan. The significance of the staircase function fit was confirmed using simulated CMAP scans with different motor unit number (20, 50, 100 and 150) and baseline noise (1 µV, 5 µV and 10 µV) inputs, in terms of MUNE performance, repeatability, and the test-retest reliability. For experimental data, the average MUNE of the first dorsal interosseous muscle derived from the staircase function fitting was 57.5 ± 26.9 for the tested spinal cord injury subjects, which was significantly lower than 101.2 ± 16.9, derived from the control group (p < 0.001). The staircase function fitting provides an appropriate approach to CMAP scan processing, yielding MUNE and other useful parameters for examination of motor unit loss and muscle fiber reinnervation.
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Affiliation(s)
- Maoqi Chen
- School of Rehabilitation Science and Engineering, University of Health and Rehabilitation Sciences, Qingdao, Shandong 266072, China
| | - Zhiyuan Lu
- School of Rehabilitation Science and Engineering, University of Health and Rehabilitation Sciences, Qingdao, Shandong 266072, China
| | - Ya Zong
- Department of Rehabilitation Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Xiaoyan Li
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI 53226 USA; Fischell Department of Bioengineering, University of Maryland at College Park, College Park, MD 20742 USA
| | - Ping Zhou
- School of Rehabilitation Science and Engineering, University of Health and Rehabilitation Sciences, Qingdao, Shandong 266072, China
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7
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Bromberg MB. Quantitative electrodiagnosis of the motor unit. HANDBOOK OF CLINICAL NEUROLOGY 2023; 195:271-286. [PMID: 37562872 DOI: 10.1016/b978-0-323-98818-6.00016-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Electromyography (EMG) focuses on assessment of the motor unit (MU), and a given muscle has several hundred MUs, each innervating hundreds of muscle fibers. Assessment is limited by the recording radius of electrodes, 1-2 fibers with single-fiber electrodes and 7-15 fibers with concentric or monopolar electrodes. Routine qualitative EMG studies rely on observing MUs in free-run mode and qualitatively estimating common metrics. In contrast, quantitative EMG (QEMG) applied to routine studies includes assessment of individual MUs by software available in modern EMG machines with extraction of discrete values for common metrics, and also derived metrics. This results in greater precision and statistical interpretation. Other QEMG techniques assess muscle fiber density within the MU and time variability at the neuromuscular junction. The interference pattern can also be assessed. The number of MUs innervating a muscle can be estimated. Advanced signal processing, called near-fiber EMG, allows for extraction of underlying muscle fiber contributions to MU waveforms. It is also possible to use QEMG to make statistical probabilities of the state of a muscle as to whether normal, myopathic, or neuropathic. Time to acquire QEMG data is minimal. QEMG is most useful in situations where pathology is uncertain.
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Affiliation(s)
- Mark B Bromberg
- Department of Neurology, University of Utah, Salt Lake City, UT, United States.
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Dideriksen J, Del Vecchio A. Adaptations in motor unit properties underlying changes in recruitment, rate coding, and maximum force. J Neurophysiol 2023; 129:235-246. [PMID: 36515411 DOI: 10.1152/jn.00222.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Changes in the discharge characteristics of motor units as well as in the maximum force-producing capacity of the muscle are observed following training, aging, and fatiguability. The ability to measure the adaptations in the neuromuscular properties underlying these changes experimentally, however, is limited. In this study we used a computational model to systematically investigate the effects of various neural and muscular adaptations on motor unit recruitment thresholds, average motor unit discharge rates in submaximal contractions, and maximum force. The primary focus was to identify candidate adaptations that can explain experimentally observed changes in motor unit discharge characteristics after 4 wk of strength training (Del Vecchio A, Casolo A, Negro F, Scorcelletti M, Bazzucchi I, Enoka R, Felici F, Farina D. J Physiol 597: 1873-1887, 2019). The simulation results indicated that multiple combinations of adaptations, likely involving an increase in maximum discharge rate across motor units, may occur after such training. On a more general level, we found that the magnitude of the adaptations scales linearly with the change in recruitment thresholds, discharge rates, and maximum force. In addition, the combination of multiple adaptations can be predicted as the linear sum of their individual effects. Together, this implies that the outcomes of the simulations can be generalized to predict the effect of any combination of neural and muscular adaptations. In this way, the study provides a tool for estimating potential underlying adaptations in neural and muscular properties to explain any change in commonly used measures of rate coding, recruitment, and maximum force.NEW & NOTEWORTHY Our ability to measure adaptations in neuromuscular properties in vivo is limited. Using a computational model, we quantify the effect of multiple neuromuscular adaptations on common measures of motor unit recruitment, rate coding, and force-producing capacity. Scaling and combining adaptations had a near-linear effect on these measures, indicating that the results can explain and predict neuromuscular adaptations in a wide range of conditions, including, but not limited to, strength training.
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Affiliation(s)
- Jakob Dideriksen
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Alessandro Del Vecchio
- Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
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Verschueren A, Palminha C, Delmont E, Attarian S. Changes in neuromuscular function in elders: Novel techniques for assessment of motor unit loss and motor unit remodeling with aging. Rev Neurol (Paris) 2022; 178:780-787. [PMID: 35863917 DOI: 10.1016/j.neurol.2022.03.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/08/2022] [Accepted: 03/08/2022] [Indexed: 11/24/2022]
Abstract
Functional muscle fiber denervation is a major contributor to the decline in physical function observed with aging and is now a recognized cause of sarcopenia, a muscle disorder characterized by progressive and generalized degenerative loss of skeletal muscle mass, quality, and strength. There is an interrelationship between muscle strength, motor unit (MU) number, and aging, which suggests that a portion of muscle weakness in seniors may be attributable to the loss of functional MUs. During normal aging, there is a time-related progression of MU loss, an adaptive sprouting followed by a maladaptive sprouting, and continuing recession of terminal Schwann cells leading to a reduced capacity for compensatory reinnervation in elders. In amyotrophic lateral sclerosis, increasing age at onset predicts worse survival ALS and it is possible that age-related depletion of the motor neuron pool may worsen motor neuron disease. MUNE methods are used to estimate the number of functional MU, data from MUNIX arguing for motor neuron loss with aging will be reviewed. Recently, a new MRI technique MU-MRI could be used to assess the MU recruitment or explore the activity of a single MU. This review presents published studies on the changes of neuromuscular function with aging, then focusing on these two novel techniques for assessment of MU loss and MU remodeling.
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Affiliation(s)
- A Verschueren
- Reference Centre for Neuromuscular Disorders and ALS, CHU La Timone, Aix-Marseille University, 264, rue Saint Pierre, 13005 Marseille, France.
| | - C Palminha
- Reference Centre for Neuromuscular Disorders and ALS, CHU La Timone, Aix-Marseille University, 264, rue Saint Pierre, 13005 Marseille, France
| | - E Delmont
- Reference Centre for Neuromuscular Disorders and ALS, CHU La Timone, Aix-Marseille University, 264, rue Saint Pierre, 13005 Marseille, France
| | - S Attarian
- Reference Centre for Neuromuscular Disorders and ALS, CHU La Timone, Aix-Marseille University, 264, rue Saint Pierre, 13005 Marseille, France
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Guo Y, Jones EJ, Inns TB, Ely IA, Stashuk DW, Wilkinson DJ, Smith K, Piasecki J, Phillips BE, Atherton PJ, Piasecki M. Neuromuscular recruitment strategies of the vastus lateralis according to sex. Acta Physiol (Oxf) 2022; 235:e13803. [PMID: 35184382 PMCID: PMC9286427 DOI: 10.1111/apha.13803] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 02/03/2022] [Accepted: 02/16/2022] [Indexed: 12/19/2022]
Abstract
AIM Despite males typically exhibiting greater muscle strength and fatigability than females, it remains unclear if there are sex-based differences in neuromuscular recruitment strategies e.g. recruitment and modulation of motor unit firing rate (MU FR) at normalized forces and during progressive increases in force. METHODS The study includes 29 healthy male and 31 healthy female participants (18-35 years). Intramuscular electromyography (iEMG) was used to record individual motor unit potentials (MUPs) and near-fibre MUPs from the vastus lateralis (VL) during 10% and 25% maximum isometric voluntary contractions (MVC), and spike-triggered averaging was used to obtain motor unit number estimates (MUNE) of the VL. RESULTS Males exhibited greater muscle strength (P < .001) and size (P < .001) than females, with no difference in force steadiness at 10% or 25% MVC. Females had 8.4% and 6.5% higher FR at 10% and 25% MVC, respectively (both P < .03), while the MUP area was 33% smaller in females at 10% MVC (P < .02) and 26% smaller at 25% MVC (P = .062). However, both sexes showed similar increases in MU size and FR when moving from low- to mid-level contractions. There were no sex differences in any near-fibre MUP parameters or in MUNE. CONCLUSION In the vastus lateralis, females produce muscle force via different neuromuscular recruitment strategies to males which is characterized by smaller MUs discharging at higher rates. However, similar strategies are employed to increase force production from low- to mid-level contractions. These findings of similar proportional increases between sexes support the use of mixed sex cohorts in studies of this nature.
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Affiliation(s)
- Yuxiao Guo
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Eleanor J. Jones
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Thomas B. Inns
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Isabel A. Ely
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Daniel W. Stashuk
- Department of Systems Design Engineering University of Waterloo Waterloo Ontario Canada
| | - Daniel J. Wilkinson
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Kenneth Smith
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Jessica Piasecki
- Musculoskeletal Physiology Research Group Sport, Health and Performance Enhancement Research Centre Nottingham Trent University Nottingham UK
| | - Bethan E. Phillips
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Philip J. Atherton
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Mathew Piasecki
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
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11
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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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12
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Paolucci T, Pezzi L, La Verde R, Latessa PM, Bellomo RG, Saggini R. The Focal Mechanical Vibration for Balance Improvement in Elderly - A Systematic Review. Clin Interv Aging 2021; 16:2009-2021. [PMID: 34880607 PMCID: PMC8648022 DOI: 10.2147/cia.s328638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 10/09/2021] [Indexed: 11/23/2022] Open
Abstract
Background Aging has been associated with the progressive depletion of lean mass, reductions in muscle strength and the coordination of the lower extremities, accompanied by decreased gait assurance and balance control. Also, less balance control favors falling which is the leading cause of injury among the elderly. The aim of this systematic review is to identify and evaluate existing evidence regarding the use of focused vibration (FV) to improve balance and reduce the risk of falling during the rehabilitation of elderly populations. Methods The PICO question is what are the effects of focal/segmental/local vibration training on the assessment of balance and the risk of falls among the elderly population? A thorough literature review was conducted between May 1, 2009, and June 30, 2019, for studies in English, randomized clinical trials, including crossover and prospective design studies with assessing balance and the risk of falls in elderly populations (age > 60 years). Results Eight articles (N = 8) satisfied the inclusion criteria and were considered, of which 6 are RTC, one cross-sectional study and one clinical study, for a total of 635 participants. A total of 6 different vibration devices were used, each of which was associated with different FV frequency and amplitude characteristics and different treatment protocols. Conclusion In conclusion, FV can be effective in decreasing the risk of falls and improving the assessment of balance, but more evidence is necessary considering the limits of the studies; however, it does look an important promise during rehabilitative treatment.
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Affiliation(s)
- Teresa Paolucci
- University G. d'Annunzio Chieti, Department of Medical and Oral Sciences and Biotechnologies, Chieti-Pescara, Italy
| | - Letizia Pezzi
- University G. d'Annunzio Chieti, Department of Medical and Oral Sciences and Biotechnologies, Chieti-Pescara, Italy
| | - Roberta La Verde
- S. Filippo Neri Hospital, Physical Medicine and Rehabilitation, "Sapienza" University, Rome, Italy
| | | | - Rosa Grazia Bellomo
- University of Study of Urbino Carlo Bo, Department of Biomolecular Sciences, Urbino, Italy
| | - Raoul Saggini
- University G. d'Annunzio Chieti, Department of Medical and Oral Sciences and Biotechnologies, Chieti-Pescara, Italy
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13
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Healthy Women and Men Do Not Show Differences in Tongue Strength and Regular Effort Saliva Swallows as Assessed by Piezo-Resistive Sensors: Results from a Reproducibility Study. Dysphagia 2021; 37:1217-1225. [PMID: 34779910 DOI: 10.1007/s00455-021-10381-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 10/30/2021] [Indexed: 10/19/2022]
Abstract
The aim of this study was to establish the reproducibility of tongue strength measurements in healthy women and men during maximum anterior isometric pressure (MAIP) and regular effort saliva swallows (RESS). In this cross-sectional study, 30 healthy young adults were required to push with the tip of the tongue on a piezo-resistive sensor glued to the hard palate, immediately above the central incisor line. Tongue pressures exerted on the sensor during MAIP and spontaneous RESS were recorded. Participants underwent a retest procedure within the same session to verify the reproducibility of measurements, as determined by intraclass correlation coefficient (ICC), standard error of measurement (SEM), and minimum detectable change (MDC). Complete data were obtained from 30 subjects (15 women, 15 men; mean age 31.4 ± 7.8 years; mean weight 61.3 ± 9.4 kg). Compared to women, men showed a trend for generating larger MAIP (p = 0.06; d = 0.71) and RESS (p = 0.07; d = 0.69). After normalizing to body weight, height, and body mass index (BMI), such trends disappeared. At retest, MAIP and RESS proved stable and highly reliable (all ICCs ≥ 0.93) in men and women but associated to moderate variability as for SEM and MDC, with MAIP estimates associated to smaller SEM and MDC (SEM ranging 7.4-14.2%; MDC 18.6-20.9%) than RESS (SEM ranging 20.4-38.5%; MDC 52.5-55.6%). Piezo-resistive pressure sensors allow clinicians and researchers to perform reproducible measurements of tongue muscle performance. However, if therapeutic interventions are administered, measurement variability in tongue performance should be considered when appraising their clinical efficacy, especially for those populations who display impaired performance and may not be capable to generate high and stable forces. No gender-based differences emerged in the motor tasks tested.
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14
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Lu W, Xiao W, Xie W, Fu X, Pan L, Jin H, Yu Y, Zhang Y, Li Y. The Role of Osteokines in Sarcopenia: Therapeutic Directions and Application Prospects. Front Cell Dev Biol 2021; 9:735374. [PMID: 34650980 PMCID: PMC8505767 DOI: 10.3389/fcell.2021.735374] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 09/07/2021] [Indexed: 12/14/2022] Open
Abstract
Sarcopenia is an age-related disease in which muscle mass, strength and function may decline with age or can be secondary to cachexia or malnutrition and can lead to weakness, falls and even death. With the increase in life expectancy, sarcopenia has become a major threat to the health of the elderly. Currently, our understanding of bone-muscle interactions is not limited to their mechanical coupling. Bone and muscle have been identified as secretory endocrine organs, and their interaction may affect the function of each. Both muscle-derived factors and osteokines can play a role in regulating muscle and bone metabolism via autocrine, paracrine and endocrine mechanisms. Herein, we comprehensively summarize the latest research progress on the effects of the osteokines FGF-23, IGF-1, RANKL and osteocalcin on muscle to explore whether these cytokines can be utilized to treat and prevent sarcopenia.
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Affiliation(s)
- Wenhao Lu
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Wenfeng Xiao
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Wenqing Xie
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Xin Fu
- Xiangya School of Medicine, Central South University, Changsha, China
| | - Linyuan Pan
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Hongfu Jin
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Yongle Yu
- Xiangya School of Medicine, Central South University, Changsha, China
| | - Yi Zhang
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Yusheng Li
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
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15
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Kirk EA, Gilmore KJ, Rice CL. Anconeus motor unit firing rates during isometric and muscle-shortening contractions comparing young and very old adults. J Neurophysiol 2021; 126:1122-1136. [PMID: 34495770 DOI: 10.1152/jn.00219.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
With effects of aging, voluntary neural drive to the muscle, measured as motor unit (MU) firing rate, is lower in older adults during sustained isometric contractions compared with young adults, but differences remain unknown during limb movements. Therefore, our purpose was to compare MU firing rates during both isometric and shortening contractions between two adult age groups. We analyzed intramuscular electromyography of single-MU recordings in the anconeus muscle of young (n = 8, 19-33 yr) and very old (n = 13, 78-93 yr) male adults during maximal voluntary contractions (MVCs). In sustained isometric and muscle-shortening contractions during limb movement, MU trains were linked with elbow joint kinematic parameters throughout the contraction time course. The older group was 33% weaker and 10% slower during movements than the young group (P < 0.01). In isometric contractions, median firing rates were 42% lower (P < 0.01) in the older group (18 Hz) compared with the young group (31 Hz), but during shortening contractions firing rates were higher for both age groups and not statistically different between groups. As a function of contraction time, firing rates at MU recruitment threshold were 39% lower in the older group, but the firing rate decrease was attenuated threefold throughout shortening contraction compared with the young group. At the single-MU level, age-related differences during isometric contractions (i.e., pre-movement initiation) do not remain constant throughout movement that comprises greater effects of muscle shortening. Results indicate that neural drive is task dependent and during movement in older adults it is decreased minimally.NEW & NOTEWORTHY Changes of neural drive to the muscle with adult aging, measured as motor unit firing rates during limb movements, are unknown. Throughout maximal voluntary efforts we found that, in comparison with young adults, firing rates were lower during isometric contraction in older adults but not different during elbow extension movements. Despite the older group being ∼33% weaker across contractions, their muscles can receive neural drive during movements that are similar to that of younger adults.
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Affiliation(s)
- Eric A Kirk
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Ontario, Canada
| | - Kevin J Gilmore
- Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Charles L Rice
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Ontario, Canada.,Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
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16
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Gabr RM, El Salmawy DA, Basheer MA, Khairy M, Elkholy SH. Relation between the severity of liver cirrhosis and neurological symptoms, nerve conduction study results, and motor unit number estimation. J Viral Hepat 2021; 28:1312-1318. [PMID: 34048134 DOI: 10.1111/jvh.13552] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 04/02/2021] [Accepted: 05/16/2021] [Indexed: 01/29/2023]
Abstract
Liver cirrhosis is a global health problem that can be associated with several neurological manifestations. We aimed to assessment of the relation between the severity of the liver cirrhosis and the neurological symptoms, nerve conduction studies (NCS), as well as detecting subclinical neuropathic affection using motor unit number estimation (MUNE) technique. This cross-sectional study was conducted on 56 cirrhotic patients and 61 age- and sex-matched healthy controls. Neurological manifestations, Child-Pugh classification, Model for End-Stage Liver Disease score, NCS and MUNE using a modified spike-triggered averaging technique were studied. Forty-five (80.3%) of the cirrhotic patients had neurological manifestations. Muscle cramps were the most frequently reported manifestation, followed by fatigue and then numbness. NCS abnormality was significantly related to the presence of neurological symptoms (p < 0.001) and not only to peripheral numbness. Only fatigue was significantly related to the lower MUNE values (p < 0.017). Child-Pugh classification progression was significantly related to the presence of fatigue and abnormal NCS results (p < 0.001); no similar relation was detected between the Child-Pugh classification and the MUNE value (p = 0.103). Higher MELD scores were significantly related to NCS abnormalities (p = 0.014) and negatively correlated, although not significantly, with the MUNE values (r = -0.246 and p = 0.067). The progression of liver cirrhosis was related to the presence of neurological manifestations and nerve conduction abnormalities. Nerve conduction abnormalities may be present even in the absence of clinical numbness. A decline in motor unit number could explain the pathophysiology of fatigue in cirrhotic patients.
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Affiliation(s)
- Reem M Gabr
- Clinical Neurophysiology Unit, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Dina A El Salmawy
- Clinical Neurophysiology Unit, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Mye A Basheer
- Clinical Neurophysiology Unit, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Marwa Khairy
- Endemic Medicine Department and Hepatology unit, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Saly H Elkholy
- Clinical Neurophysiology Unit, Faculty of Medicine, Cairo University, Cairo, Egypt
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17
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Allen MD, Dalton BH, Gilmore KJ, McNeil CJ, Doherty TJ, Rice CL, Power GA. Neuroprotective effects of exercise on the aging human neuromuscular system. Exp Gerontol 2021; 152:111465. [PMID: 34224847 DOI: 10.1016/j.exger.2021.111465] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 05/31/2021] [Accepted: 06/30/2021] [Indexed: 12/23/2022]
Abstract
Human biological aging from maturity to senescence is associated with a gradual loss of muscle mass and neuromuscular function. It is not until very old age (>80 years) however, that these changes often manifest into functional impairments. A driving factor underlying the age-related loss of muscle mass and function is the reduction in the number and quality of motor units (MUs). A MU consists of a single motoneuron, located either in the spinal cord or the brain stem, and all of the muscle fibres it innervates via its peripheral axon. Throughout the adult lifespan, MUs are slowly, but progressively lost. The compensatory process of collateral reinnervation attempts to recapture orphaned muscle fibres following the death of a motoneuron. Whereas this process helps mitigate loss of muscle mass during the latter decades of adult aging, the neuromuscular system has fewer and larger MUs, which have lower quality connections between the axon terminal and innervated muscle fibres. Whether this process of MU death and degradation can be attenuated with habitual physical activity has been a challenging question of great interest. This review focuses on age-related alterations of the human neuromuscular system, with an emphasis on the MU, and presents findings on the potential protective effects of lifelong physical activity. Although there is some discrepancy across studies of masters athletes, if one considers all experimental limitations as well as the available literature in animals, there is compelling evidence of a protective effect of chronic physical training on human MUs. Our tenet is that high-levels of physical activity can mitigate the natural trajectory of loss of quantity and quality of MUs in old age.
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Affiliation(s)
- Matti D Allen
- Department of Physical Medicine and Rehabilitation, School of Medicine, Faculty of Health Sciences, Queen's University, Kingston, ON K7L 4X3, Canada; School of Kinesiology and Health Studies, Faculty of Arts and Sciences, Queen's University, Kingston, ON K7L 4X3, Canada
| | - Brian H Dalton
- School of Health and Exercise Science, University of British Columbia, Kelowna, BC V1V 1V7, Canada
| | - Kevin J Gilmore
- Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Chris J McNeil
- School of Health and Exercise Science, University of British Columbia, Kelowna, BC V1V 1V7, Canada
| | - Timothy J Doherty
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada; Department of Physical Medicine and Rehabilitation, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada
| | - Charles L Rice
- School of Kinesiology, The University of Western Ontario, London, ON, Canada; Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada.
| | - Geoffrey A Power
- Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
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18
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Paolucci T, Agostini F, Bernetti A, Paoloni M, Mangone M, Santilli V, Pezzi L, Bellomo RG, Saggini R. Integration of focal vibration and intra-articular oxygen-ozone therapy in rehabilitation of painful knee osteoarthritis. J Int Med Res 2021; 49:300060520986705. [PMID: 33641438 PMCID: PMC7923992 DOI: 10.1177/0300060520986705] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVE To examine the pain-reducing effects of intra-articular oxygen-ozone (O2O3) injections and mechanical focal vibration (mFV) versus O2O3 injections alone in patients with knee osteoarthritis. METHODS Patients with chronic pain (>6 weeks) due to knee osteoarthritis (II-III on the Kellgren-Lawrence scale) were consecutively enrolled and divided into two groups: O2O3 (n = 25) and O2O3-mFV (n = 24). The visual analog scale (VAS), Knee Injury and Osteoarthritis Outcome Score (KOOS), and Medical Research Council (MRC) Manual Muscle Testing scale were administered at baseline (before treatment), after 3 weeks of treatment, and 1 month after the end of treatment. Patients received three once-weekly intra-articular injections of O2O3 into the knee (20 mL O3, 20 μg/mL). The O2O3-mFV group also underwent nine sessions of mFV (three sessions per week). RESULTS The VAS score, KOOS, and MRC score were significantly better in the O2O3-mFV than O2O3 group. The within-group analysis showed that all scores improved over time compared with baseline and were maintained even 1 month after treatment. No adverse events occurred. CONCLUSION An integrated rehabilitation protocol involving O2O3 injections and mFV for 3 weeks reduces pain, increases autonomy in daily life activities, and strengthens the quadriceps femoris.
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Affiliation(s)
- Teresa Paolucci
- Physical Medicine and Rehabilitation, Department of Medical, Oral and Biotechnological Sciences, G. d'Annunzio University of Chieti-Pescara, Chieti, Italy
| | - Francesco Agostini
- Department of Anatomical and Histological Sciences, Legal Medicine and Orthopedics, Sapienza University of Rome, Rome, Italy
| | - Andrea Bernetti
- Department of Anatomical and Histological Sciences, Legal Medicine and Orthopedics, Sapienza University of Rome, Rome, Italy
| | - Marco Paoloni
- Department of Anatomical and Histological Sciences, Legal Medicine and Orthopedics, Sapienza University of Rome, Rome, Italy
| | - Massimiliano Mangone
- Department of Anatomical and Histological Sciences, Legal Medicine and Orthopedics, Sapienza University of Rome, Rome, Italy
| | - Valter Santilli
- Department of Anatomical and Histological Sciences, Legal Medicine and Orthopedics, Sapienza University of Rome, Rome, Italy
| | - Letizia Pezzi
- Physical Medicine and Rehabilitation, Department of Medical, Oral and Biotechnological Sciences, G. d'Annunzio University of Chieti-Pescara, Chieti, Italy
| | - Rosa Grazia Bellomo
- Department of Biomolecular Sciences, University of Study of Urbino Carlo Bo, Urbino, Italy
| | - Raoul Saggini
- Physical Medicine and Rehabilitation, Department of Medical, Oral and Biotechnological Sciences, G. d'Annunzio University of Chieti-Pescara, Chieti, Italy.,IRCCS Centro Neurolesi "Bonino Pulejo," Messina, Italy
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19
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Kirk EA, Christie AD, Knight CA, Rice CL. Motor unit firing rates during constant isometric contraction: establishing and comparing an age-related pattern among muscles. J Appl Physiol (1985) 2021; 130:1903-1914. [PMID: 33914656 DOI: 10.1152/japplphysiol.01047.2020] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Motor unit (MU) firing rates (FRs) are lower in aged adults, compared with young, at relative voluntary contraction intensities. However, from a variety of independent studies of disparate muscles, the age-related degree of difference in FR among muscles is unclear. Using a standardized statistical approach with data derived from primary studies, we quantified differences in FRs across several muscles between younger and older adults. The data set included 12 different muscles in young (18-35 yr) and older adults (62-93 yr) from 18 published and one unpublished study. Experiments recorded single MU activity from intramuscular electromyography during constant isometric contraction at different (step-like) voluntary intensities. For each muscle, FR ranges and FR variance explained by voluntary contraction intensity were determined using bootstrapping. Dissimilarity of FR variance among muscles was calculated by Euclidean distances. There were threefold differences in the absolute frequency of FR ranges across muscles in the young (soleus 8-16 and superior trapezius 20-49 Hz), but in the old, FR ranges were more similar and lower for nine out of 12 muscles. In contrast, the explained FR variance from voluntary contraction intensity in the older group had 1.6-fold greater dissimilarity among muscles than the young (P < 0.001), with FR variance differences being muscle dependent. Therefore, differences between muscle FR ranges were not explained by how FRs scale to changes in voluntary contraction intensity within each muscle. Instead, FRs were muscle dependent but were more dissimilar among muscles in the older group in their responsiveness to voluntary contraction intensity.NEW & NOTEWORTHY The mean frequency of motor unit firing rates were compared systematically among several muscles and between young and older adults from new and published data sets. Firing rates among muscles were lower and more similar during voluntary isometric contraction in older than younger adults. Firing rate responses from voluntary contraction intensity were muscle dependent and more dissimilar among muscles in the older than young adults.
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Affiliation(s)
- Eric A Kirk
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Canada
| | - Anita D Christie
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Canada
| | - Christopher A Knight
- Department of Kinesiology and Applied Physiology, College of Health Sciences, University of Delaware, Newark, Delaware
| | - Charles L Rice
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Canada.,Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada
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20
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Jin H, Xie W, Hu P, Tang K, Wang X, Wu Y, He M, Yu D, Li Y. The role of melatonin in sarcopenia: Advances and application prospects. Exp Gerontol 2021; 149:111319. [PMID: 33753178 DOI: 10.1016/j.exger.2021.111319] [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: 01/31/2021] [Revised: 03/04/2021] [Accepted: 03/16/2021] [Indexed: 12/24/2022]
Abstract
Sarcopenia is an age-related disease that has gradually become a serious health problem for elderly individuals. It not only greatly increases the risk of falls, weakness, and disability but also reduces the ability of patients to take care of themselves. Sarcopenia can directly affect the quality of life and disease prognosis of elderly individuals. However, drug interventions for this disease are lacking. Melatonin is a biological hormone produced by the body that has good free radical scavenging effects, antioxidant effects and other effects. It was originally used as a sleep aid and is now being used for an increasing number of new indications. Its effect on sarcopenia has also begun to attract attention. It is currently known that it can protect the mitochondria of skeletal muscle cells, maintain the number of muscle fibres, partially reverse the pathological changes of ageing muscle tissue, and increase muscle strength in patients with sarcopenia. A large number of microRNAs are expressed during cell ageing, that in turn provides a biological background to age-related diseases, like sarcopenia. Increasing studies have found an interaction between melatonin and miRNAs, suggesting that melatonin can be used in the treatment of sarcopenia. The increased expression of inflammation-associated miRNA-483 in elderly patients may be the basis for the age-dependent decrease in melatonin secretion,that may play a role in the morbidity of sarcopenia. Melatonin is closely related to sarcopenia. It has a wide range of effects on sarcopenia and has good application prospects for the prevention and treatment of sarcopenia.
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Affiliation(s)
- Hongfu Jin
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Wenqing Xie
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Peiwu Hu
- Department of Scientific Research, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Kun Tang
- Discipline Construction Office, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Xiuhua Wang
- Xiang Ya Nursing School, The Central South University, Changsha, China
| | - Yuxiang Wu
- School of Kinesiology, Jianghan University, Wuhan 430056, China
| | - Miao He
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Dengjie Yu
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Yusheng Li
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China.
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21
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Birkbeck MG, Blamire AM, Whittaker RG, Sayer AA, Dodds RM. The role of novel motor unit magnetic resonance imaging to investigate motor unit activity in ageing skeletal muscle. J Cachexia Sarcopenia Muscle 2021; 12:17-29. [PMID: 33354940 PMCID: PMC7890268 DOI: 10.1002/jcsm.12655] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 10/27/2020] [Accepted: 11/05/2020] [Indexed: 12/14/2022] Open
Abstract
Sarcopenia is a progressive and generalized disease, more common in older adults, which manifests as a loss of muscle strength and mass. The pathophysiology of sarcopenia is still poorly understood with many mechanisms suggested. Age associated changes to the neuromuscular architecture, including motor units and their constituent muscle fibres, represent one such mechanism. Electromyography can be used to distinguish between different myopathies and produce counts of motor units. Evidence from electromyography studies suggests that with age, there is a loss of motor units, increases to the sizes of remaining units, and changes to their activity patterns. However, electromyography is invasive, can be uncomfortable, does not reveal the exact spatial position of motor units within muscle and is difficult to perform in deep muscles. We present a novel diffusion-weighted magnetic resonance imaging technique called 'motor unit magnetic resonance imaging (MUMRI)'. MUMRI aims to improve our understanding of the changes to the neuromuscular system associated with ageing, sarcopenia and other neuromuscular diseases. To date, we have demonstrated that MUMRI can be used to detect statistically significant differences in fasciculation rate of motor units between (n = 4) patients with amyotrophic lateral sclerosis (mean age ± SD: 53 ± 15) and a group of (n = 4) healthy controls (38 ± 7). Patients had significantly higher rates of fasciculation compared with healthy controls (mean = 99.1/min, range = 25.7-161.0 in patients vs. 7.7/min, range = 4.3-9.7 in controls; P < 0.05. MUMRI has detected differences in size, shape, and distribution of single human motor units between (n = 5) young healthy volunteers (29 ± 2.2) and (n = 5) healthy older volunteers (65.6 ± 14.8). The maximum size of motor unit territories in the older group was 12.4 ± 3.3 mm and 9.7 ± 2.7 mm in the young group; P < 0.05. MUMRI is an entirely non-invasive tool, which can be used to detect physiological and pathological changes to motor units in neuromuscular diseases. MUMRI also has the potential to be used as an intermediate outcome measure in sarcopenia trials.
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Affiliation(s)
- Matthew G Birkbeck
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK.,NIHR Newcastle Biomedical Research Centre, Newcastle upon Tyne Hospitals NHS Foundation Trust, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,Northern Medical Physics and Clinical Engineering, Freeman Hospital, Newcastle upon Tyne NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Andrew M Blamire
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Roger G Whittaker
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Avan Aihie Sayer
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK.,NIHR Newcastle Biomedical Research Centre, Newcastle upon Tyne Hospitals NHS Foundation Trust, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Richard M Dodds
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK.,NIHR Newcastle Biomedical Research Centre, Newcastle upon Tyne Hospitals NHS Foundation Trust, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
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22
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Anton SD, Cruz-Almeida Y, Singh A, Alpert J, Bensadon B, Cabrera M, Clark DJ, Ebner NC, Esser KA, Fillingim RB, Goicolea SM, Han SM, Kallas H, Johnson A, Leeuwenburgh C, Liu AC, Manini TM, Marsiske M, Moore F, Qiu P, Mankowski RT, Mardini M, McLaren C, Ranka S, Rashidi P, Saini S, Sibille KT, Someya S, Wohlgemuth S, Tucker C, Xiao R, Pahor M. Innovations in Geroscience to enhance mobility in older adults. Exp Gerontol 2020; 142:111123. [PMID: 33191210 PMCID: PMC7581361 DOI: 10.1016/j.exger.2020.111123] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 10/15/2020] [Accepted: 10/16/2020] [Indexed: 02/07/2023]
Abstract
Aging is the primary risk factor for functional decline; thus, understanding and preventing disability among older adults has emerged as an important public health challenge of the 21st century. The science of gerontology - or geroscience - has the practical purpose of "adding life to the years." The overall goal of geroscience is to increase healthspan, which refers to extending the portion of the lifespan in which the individual experiences enjoyment, satisfaction, and wellness. An important facet of this goal is preserving mobility, defined as the ability to move independently. Despite this clear purpose, this has proven to be a challenging endeavor as mobility and function in later life are influenced by a complex interaction of factors across multiple domains. Moreover, findings over the past decade have highlighted the complexity of walking and how targeting multiple systems, including the brain and sensory organs, as well as the environment in which a person lives, can have a dramatic effect on an older person's mobility and function. For these reasons, behavioral interventions that incorporate complex walking tasks and other activities of daily living appear to be especially helpful for improving mobility function. Other pharmaceutical interventions, such as oxytocin, and complementary and alternative interventions, such as massage therapy, may enhance physical function both through direct effects on biological mechanisms related to mobility, as well as indirectly through modulation of cognitive and socioemotional processes. Thus, the purpose of the present review is to describe evolving interventional approaches to enhance mobility and maintain healthspan in the growing population of older adults in the United States and countries throughout the world. Such interventions are likely to be greatly assisted by technological advances and the widespread adoption of virtual communications during and after the COVID-19 era.
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Affiliation(s)
- Stephen D Anton
- University of Florida, Department of Aging and Geriatric Research, 2004 Mowry Road, Gainesville, FL 32611, United States.
| | - Yenisel Cruz-Almeida
- University of Florida, Department of Community Dentistry and Behavioral Science, 1329 SW Archer Road, Gainesville, FL 32610, United States.
| | - Arashdeep Singh
- University of Florida, Department of Pharmacodynamics, College of Pharmacy, 1345 Center Drive, Gainesville, FL 32610, United States.
| | - Jordan Alpert
- University of Florida, College of Journalism and Communications, Gainesville, FL 32610, United States.
| | - Benjamin Bensadon
- University of Florida, Department of Aging and Geriatric Research, 2004 Mowry Road, Gainesville, FL 32611, United States.
| | - Melanie Cabrera
- University of Florida, Department of Aging and Geriatric Research, 2004 Mowry Road, Gainesville, FL 32611, United States.
| | - David J Clark
- University of Florida, Department of Aging and Geriatric Research, 2004 Mowry Road, Gainesville, FL 32611, United States.
| | - Natalie C Ebner
- University of Florida, Department of Psychology, 945 Center Drive, Gainesville, FL 32611, United States.
| | - Karyn A Esser
- University of Florida, Department of Physiology and Functional Genomics, 1345 Center Drive, Gainesville, FL, United States.
| | - Roger B Fillingim
- University of Florida, Department of Community Dentistry and Behavioral Science, 1329 SW Archer Road, Gainesville, FL 32610, United States.
| | - Soamy Montesino Goicolea
- University of Florida, Department of Community Dentistry and Behavioral Science, 1329 SW Archer Road, Gainesville, FL 32610, United States.
| | - Sung Min Han
- University of Florida, Department of Aging and Geriatric Research, 2004 Mowry Road, Gainesville, FL 32611, United States.
| | - Henrique Kallas
- University of Florida, Department of Aging and Geriatric Research, 2004 Mowry Road, Gainesville, FL 32611, United States.
| | - Alisa Johnson
- University of Florida, Department of Aging and Geriatric Research, 2004 Mowry Road, Gainesville, FL 32611, United States.
| | - Christiaan Leeuwenburgh
- University of Florida, Department of Aging and Geriatric Research, 2004 Mowry Road, Gainesville, FL 32611, United States.
| | - Andrew C Liu
- University of Florida, Department of Physiology and Functional Genomics, 1345 Center Drive, Gainesville, FL, United States.
| | - Todd M Manini
- University of Florida, Department of Aging and Geriatric Research, 2004 Mowry Road, Gainesville, FL 32611, United States.
| | - Michael Marsiske
- University of Florida, Department of Clinical & Health Psychology, 1225 Center Drive, Gainesville, FL 32610, United States.
| | - Frederick Moore
- University of Florida, Department of Surgery, Gainesville, FL 32610, United States.
| | - Peihua Qiu
- University of Florida, Department of Biostatistics, Gainesville, FL 32611, United States.
| | - Robert T Mankowski
- University of Florida, Department of Aging and Geriatric Research, 2004 Mowry Road, Gainesville, FL 32611, United States.
| | - Mamoun Mardini
- University of Florida, Department of Aging and Geriatric Research, 2004 Mowry Road, Gainesville, FL 32611, United States.
| | - Christian McLaren
- University of Florida, Department of Aging and Geriatric Research, 2004 Mowry Road, Gainesville, FL 32611, United States.
| | - Sanjay Ranka
- University of Florida, Department of Computer & Information Science & Engineering, Gainesville, FL 32611, United States.
| | - Parisa Rashidi
- University of Florida, Department of Biomedical Engineering. P.O. Box 116131. Gainesville, FL 32610, United States.
| | - Sunil Saini
- University of Florida, Department of Aging and Geriatric Research, 2004 Mowry Road, Gainesville, FL 32611, United States.
| | - Kimberly T Sibille
- University of Florida, Department of Aging and Geriatric Research, 2004 Mowry Road, Gainesville, FL 32611, United States.
| | - Shinichi Someya
- University of Florida, Department of Aging and Geriatric Research, 2004 Mowry Road, Gainesville, FL 32611, United States.
| | - Stephanie Wohlgemuth
- University of Florida, Department of Aging and Geriatric Research, 2004 Mowry Road, Gainesville, FL 32611, United States.
| | - Carolyn Tucker
- University of Florida, Department of Psychology, 945 Center Drive, Gainesville, FL 32611, United States.
| | - Rui Xiao
- University of Florida, Department of Aging and Geriatric Research, 2004 Mowry Road, Gainesville, FL 32611, United States.
| | - Marco Pahor
- University of Florida, Department of Aging and Geriatric Research, 2004 Mowry Road, Gainesville, FL 32611, United States.
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Assessment of age-related differences in decomposition-based quantitative EMG in the intrinsic hand muscles: A multivariate approach. Clin Neurophysiol 2020; 131:2192-2199. [DOI: 10.1016/j.clinph.2020.06.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 05/06/2020] [Accepted: 06/02/2020] [Indexed: 01/17/2023]
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Higashihara M, Menon P, van den Bos M, Pavey N, Vucic S. Reproducibility of motor unit number index and MScanFit motor unit number estimation across intrinsic hand muscles. Muscle Nerve 2020; 62:192-200. [PMID: 32077117 DOI: 10.1002/mus.26839] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 02/09/2020] [Accepted: 02/15/2020] [Indexed: 12/12/2022]
Abstract
INTRODUCTION We sought to evaluate the reproducibility of the motor unit number index (MUNIX) and MScanFit motor unit number estimation (MScan) when recording was performed over intrinsic hand muscles. METHODS The compound muscle action potential (CMAP) amplitude, MUNIX, and MScan were measured from the abductor pollicis brevis (APB), first dorsal interosseous (FDI), and abductor digit minimi (ADM) muscles from 15 healthy volunteers on three different occasions. RESULTS The reproducibility of CMAP amplitudes was excellent, with intraclass correlation coefficients (ICC) of 0.86 (APB), 0.90 (FDI), and 0.96 (ADM). Motor unit number index (ICCAPB 0.73, ICCFDI 0.85, ICCADM 0.85) and MScan (ICCAPB 0.86, ICCFDI 0.83, ICCADM 0.81) were highly reproducible across the three muscles. There were no significant correlations between MUNIX and MScan coefficients of variation (CV) and CMAP amplitude CVs. DISCUSSION Reproducibility of MUNIX and MScan was not significantly different across the intrinsic hand muscles and was independent of CMAP amplitude variability.
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Affiliation(s)
- Mana Higashihara
- Westmead Clinical School, University of Sydney, Westmead, New South Wales, Australia
| | - Parvathi Menon
- Westmead Clinical School, University of Sydney, Westmead, New South Wales, Australia
| | - Mehdi van den Bos
- Westmead Clinical School, University of Sydney, Westmead, New South Wales, Australia
| | - Nathan Pavey
- Westmead Clinical School, University of Sydney, Westmead, New South Wales, Australia
| | - Steve Vucic
- Westmead Clinical School, University of Sydney, Westmead, New South Wales, Australia
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25
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Hara K, Tohara H, Namiki C, Yamaguchi K, Chantaramanee A, Kobayashi K, Saito T, Nakagawa K, Okumura T, Yoshimi K, Nakane A, Furuya J, Minakuchi S. Relationship between displacement of the masseter muscle during biting and masseter muscle quality and bite force in healthy elderly persons. J Oral Rehabil 2020; 47:441-448. [DOI: 10.1111/joor.12915] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 11/01/2019] [Accepted: 11/20/2019] [Indexed: 12/26/2022]
Affiliation(s)
- Koji Hara
- Department of Gerodontology Division of Gerontology and Gerodontology Tokyo Medical and Dental University Tokyo Japan
| | - Haruka Tohara
- Department of Gerodontology Division of Gerontology and Gerodontology Tokyo Medical and Dental University Tokyo Japan
| | - Chizuru Namiki
- Department of Gerodontology Division of Gerontology and Gerodontology Tokyo Medical and Dental University Tokyo Japan
| | - Kohei Yamaguchi
- Department of Gerodontology Division of Gerontology and Gerodontology Tokyo Medical and Dental University Tokyo Japan
| | - Ariya Chantaramanee
- Department of Gerodontology Division of Gerontology and Gerodontology Tokyo Medical and Dental University Tokyo Japan
| | | | | | - Kazuharu Nakagawa
- Department of Gerodontology Division of Gerontology and Gerodontology Tokyo Medical and Dental University Tokyo Japan
| | - Takuma Okumura
- Department of Gerodontology Division of Gerontology and Gerodontology Tokyo Medical and Dental University Tokyo Japan
| | - Kanako Yoshimi
- Department of Gerodontology Division of Gerontology and Gerodontology Tokyo Medical and Dental University Tokyo Japan
| | - Ayako Nakane
- Department of Gerodontology Division of Gerontology and Gerodontology Tokyo Medical and Dental University Tokyo Japan
| | - Junichi Furuya
- Graduate School of Medical and Dental Sciences Oral Health Sciences for Community Welfare Tokyo Medical and Dental University Tokyo Japan
| | - Shunsuke Minakuchi
- Department of Gerodontology Division of Gerontology and Gerodontology Tokyo Medical and Dental University Tokyo Japan
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Zhang X, Chan FK, Parthasarathy T, Gazzola M. Modeling and simulation of complex dynamic musculoskeletal architectures. Nat Commun 2019; 10:4825. [PMID: 31645555 PMCID: PMC6811595 DOI: 10.1038/s41467-019-12759-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 09/24/2019] [Indexed: 01/19/2023] Open
Abstract
Natural creatures, from fish and cephalopods to snakes and birds, combine neural control, sensory feedback and compliant mechanics to effectively operate across dynamic, uncertain environments. In order to facilitate the understanding of the biophysical mechanisms at play and to streamline their potential use in engineering applications, we present here a versatile numerical approach to the simulation of musculoskeletal architectures. It relies on the assembly of heterogenous, active and passive Cosserat rods into dynamic structures that model bones, tendons, ligaments, fibers and muscle connectivity. We demonstrate its utility in a range of problems involving biological and soft robotic scenarios across scales and environments: from the engineering of millimeter-long bio-hybrid robots to the synthesis and reconstruction of complex musculoskeletal systems. The versatility of this methodology offers a framework to aid forward and inverse bioengineering designs as well as fundamental discovery in the functioning of living organisms.
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Affiliation(s)
- Xiaotian Zhang
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Fan Kiat Chan
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Tejaswin Parthasarathy
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Mattia Gazzola
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
- National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
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Kirk EA, Gilmore KJ, Stashuk DW, Doherty TJ, Rice CL. Human motor unit characteristics of the superior trapezius muscle with age-related comparisons. J Neurophysiol 2019; 122:823-832. [PMID: 31242057 PMCID: PMC6734412 DOI: 10.1152/jn.00138.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 06/06/2019] [Accepted: 06/22/2019] [Indexed: 12/13/2022] Open
Abstract
Current understanding of human motor unit (MU) control and aging is mostly derived from hand and limb muscles that have spinal motor neuron innervations. The aim here was to characterize and test whether a muscle with a shared innervation supply from brainstem and spinal MU populations would demonstrate similar age-related adaptations as those reported for other muscles. In humans, the superior trapezius (ST) muscle acts to elevate and stabilize the scapula and has primary efferent supply from the spinal accessory nerve (cranial nerve XI) located in the brainstem. We compared electrophysiological properties obtained from intramuscular and surface recordings between 10 young (22-33 yr) and 10 old (77-88 yr) men at a range of voluntary isometric contraction intensities (from 15 to 100% of maximal efforts). The old group was 41% weaker with 43% lower MU discharge frequencies compared with the young (47.2 ± 9.6 Hz young and 26.7 ± 5.8 Hz old, P < 0.05) during maximal efforts. There was no difference in MU number estimation between age groups (228 ± 105 young and 209 ± 89 old, P = 0.33). Furthermore, there were no differences in needle detected near fiber (NF) stability parameters of jitter or jiggle. The old group had lower amplitude and smaller area of the stimulated compound muscle action potential and smaller NF MU potential area with higher NF counts. Thus, despite age-related ST weakness and lower MU discharge rates, there was minimal evidence of MU loss or compensatory reinnervation.NEW & NOTEWORTHY The human superior trapezius (ST) has shared spinal and brainstem motor neuron innervation providing a unique model to explore the impact of aging on motor unit (MU) properties. Although the ST showed higher MU discharge rates compared with most spinally innervated muscles, voluntary strength and mean MU rates were lower in old compared with young at all contraction intensities. There was no age-related difference in MU number estimates with minimal electrophysiological evidence of collateral reinnervation.
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Affiliation(s)
- Eric A Kirk
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Ontario, Canada
| | - Kevin J Gilmore
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Ontario, Canada
| | - Daniel W Stashuk
- Department of Systems Design Engineering, University of Waterloo, Ontario, Canada
| | - Timothy J Doherty
- Department of Clinical Neurological Sciences, The University of Western Ontario, London, Ontario, Canada
- Department of Physical Medicine and Rehabilitation, The University of Western Ontario, London, Ontario, Canada
| | - Charles L Rice
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Ontario, Canada
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, Ontario, Canada
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Piasecki M, Ireland A, Piasecki J, Degens H, Stashuk DW, Swiecicka A, Rutter MK, Jones DA, McPhee JS. Long-Term Endurance and Power Training May Facilitate Motor Unit Size Expansion to Compensate for Declining Motor Unit Numbers in Older Age. Front Physiol 2019; 10:449. [PMID: 31080415 PMCID: PMC6497749 DOI: 10.3389/fphys.2019.00449] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 04/01/2019] [Indexed: 11/15/2022] Open
Abstract
The evidence concerning the effects of exercise in older age on motor unit (MU) numbers, muscle fiber denervation and reinnervation cycles is inconclusive and it remains unknown whether any effects are dependent on the type of exercise undertaken or are localized to highly used muscles. MU characteristics of the vastus lateralis (VL) were assessed using surface and intramuscular electromyography in eighty-five participants, divided into sub groups based on age (young, old) and athletic discipline (control, endurance, power). In a separate study of the biceps brachii (BB), the same characteristics were compared in the favored and non-favored arms in eleven masters tennis players. Muscle size was assessed using MRI and ultrasound. In the VL, the CSA was greater in young compared to old, and power athletes had the largest CSA within their age groups. Motor unit potential (MUP) size was larger in all old compared to young (p < 0.001), with interaction contrasts showing this age-related difference was greater for endurance and power athletes than controls, and MUP size was greater in old athletes compared to old controls. In the BB, thickness did not differ between favored and non-favored arms (p = 0.575), but MUP size was larger in the favored arm (p < 0.001). Long-term athletic training does not prevent age-related loss of muscle size in the VL or BB, regardless of athletic discipline, but may facilitate more successful axonal sprouting and reinnervation of denervated fibers. These effects may be localized to muscles most involved in the exercise.
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Affiliation(s)
- M. Piasecki
- Clinical, Metabolic and Molecular Physiology, MRC-ARUK Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, University of Nottingham, Nottingham, United Kingdom
| | - A. Ireland
- School of Healthcare Science, Manchester Metropolitan University, Manchester, United Kingdom
| | - J. Piasecki
- Musculoskeletal Physiology Research Group, Sport, Health and Performance Enhancement Research Centre, School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
| | - H. Degens
- School of Healthcare Science, Manchester Metropolitan University, Manchester, United Kingdom
- Institute of Sport Science and Innovations, Lithuanian Sports University, Kaunas, Lithuania
| | - D. W. Stashuk
- Department of Systems Design Engineering, University of Waterloo, Waterloo, ON, Canada
| | - A. Swiecicka
- Division of Diabetes, Endocrinology and Gastroenterology, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - M. K. Rutter
- Division of Diabetes, Endocrinology and Gastroenterology, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
- Manchester Diabetes Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - D. A. Jones
- School of Healthcare Science, Manchester Metropolitan University, Manchester, United Kingdom
| | - J. S. McPhee
- Department of Sport and Exercise Sciences, Musculoskeletal Science and Sports Medicine Research Centre, Manchester Metropolitan University, Manchester, United Kingdom
- Department of Physiology, University of Padova, Padova, Italy
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McArdle A, Pollock N, Staunton CA, Jackson MJ. Aberrant redox signalling and stress response in age-related muscle decline: Role in inter- and intra-cellular signalling. Free Radic Biol Med 2019; 132:50-57. [PMID: 30508577 PMCID: PMC6709668 DOI: 10.1016/j.freeradbiomed.2018.11.038] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 11/29/2018] [Accepted: 11/29/2018] [Indexed: 12/22/2022]
Abstract
Age-associated frailty is predominantly due to loss of muscle mass and function. The loss of muscle mass is also associated with a greater loss of muscle strength, suggesting that the remaining muscle fibres are weaker than those of adults. The mechanisms by which muscle is lost with age are unclear, but in this review we aim to pull together various strands of evidence to explain how muscle contractions support proteostasis in non-muscle tissues, particularly focussed on the production and potential transfer of Heat Shock Proteins (HSPs) and how this may fail during ageing, Furthermore we will identify logical approaches, based on this hypothesis, by which muscle loss in ageing may be reduced. Skeletal muscle generates superoxide and nitric oxide at rest and this generation is increased by contractile activity. In adults, this increased generation of reactive oxygen and nitrogen species (RONS) activate redox-sensitive transcription factors such as nuclear factor κB (NFκB), activator protein-1 (AP1) and heat shock factor 1 (HSF1), resulting in increases in cytoprotective proteins such as the superoxide dismutases, catalase and heat shock proteins that prevent oxidative damage to tissues and facilitate remodelling and proteostasis in both an intra- and inter-cellular manner. During ageing, the ability of skeletal muscle from aged organisms to respond to an increase in ROS generation by increased expression of cytoprotective proteins through activation of redox-sensitive transcription factors is severely attenuated. This age-related lack of physiological adaptations to the ROS induced by contractile activity appears to contribute to a loss of ROS homeostasis, increased oxidative damage and age-related dysfunction in skeletal muscle and potentially other tissues.
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Affiliation(s)
- Anne McArdle
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Institute of Ageing and Chronic Disease, University of Liverpool, L7 8TX, United Kingdom.
| | - Natalie Pollock
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Institute of Ageing and Chronic Disease, University of Liverpool, L7 8TX, United Kingdom
| | - Caroline A Staunton
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Institute of Ageing and Chronic Disease, University of Liverpool, L7 8TX, United Kingdom
| | - Malcolm J Jackson
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Institute of Ageing and Chronic Disease, University of Liverpool, L7 8TX, United Kingdom
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Raghavan M, Fee D, Barkhaus PE. Generation and propagation of the action potential. ACTA ACUST UNITED AC 2019; 160:3-22. [DOI: 10.1016/b978-0-444-64032-1.00001-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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31
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Higashihara M, Menon P, van den Bos M, Geevasinga N, Vucic S. Reproducibility of motor unit number index and multiple point stimulation motor unit number estimation in controls. Muscle Nerve 2018; 58:660-664. [PMID: 30194855 DOI: 10.1002/mus.26339] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2018] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Reproducibility of the multiple point stimulation motor unit number estimation (MPS-MUNE) technique was compared with the recently developed motor unit number index (MUNIX) technique. METHODS MPS-MUNE and MUNIX were performed on 15 healthy subjects at 3 different time-points by the same examiner. Reproducibility was analyzed using intraclass correlation coefficient (ICC) and coefficient of variation (CV). RESULTS ICC values for MUNIX and MPS-MUNE were excellent across 3 tests (0.80 and 0.77, respectively), although CV values were significantly lower for MUNIX than MPS-MUNE (P < 0.01). In addition, test-retest reproducibility was better for MUNIX, a finding largely attributable to poor reproducibility of the single motor unit action potential area. MUNIX (R = -0.48, P < 0.05) and MPS-MUNE (R = -0.53, P < 0.05) were significantly correlated with age. DISCUSSION MUNIX demonstrated better intrarater reproducibility and may be a more reliable neurophysiological biomarker than MPS-MUNE. Muscle Nerve 58: 660-664, 2018.
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Affiliation(s)
- Mana Higashihara
- Department of Neurology, Westmead Hospital, Sydney, New South Wales, Australia
| | - Parvathi Menon
- Westmead Clinical School, Cnr. Hawkesbury and Darcy Road, University of Sydney, New South Wales, 2145, Australia
| | - Mehdi van den Bos
- Westmead Clinical School, Cnr. Hawkesbury and Darcy Road, University of Sydney, New South Wales, 2145, Australia
| | - Nimeshan Geevasinga
- Westmead Clinical School, Cnr. Hawkesbury and Darcy Road, University of Sydney, New South Wales, 2145, Australia
| | - Steve Vucic
- Westmead Clinical School, Cnr. Hawkesbury and Darcy Road, University of Sydney, New South Wales, 2145, Australia
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de Carvalho M, Barkhaus PE, Nandedkar SD, Swash M. Motor unit number estimation (MUNE): Where are we now? Clin Neurophysiol 2018; 129:1507-1516. [DOI: 10.1016/j.clinph.2018.04.748] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 03/31/2018] [Accepted: 04/29/2018] [Indexed: 12/13/2022]
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Impact of Aging on Endurance and Neuromuscular Physical Performance: The Role of Vascular Senescence. Sports Med 2018; 47:583-598. [PMID: 27459861 DOI: 10.1007/s40279-016-0596-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The portion of society aged ≥60 years is the fastest growing population in the Western hemisphere. Aging is associated with numerous changes to systemic physiology that affect physical function and performance. We present a narrative review of the literature aimed at discussing the age-related changes in various metrics of physical performance (exercise economy, anaerobic threshold, peak oxygen uptake, muscle strength, and power). It also explores aging exercise physiology as it relates to global physical performance. Finally, this review examines the vascular contributions to aging exercise physiology. Numerous studies have shown that older adults exhibit substantial reductions in physical performance. The process of decline in endurance capacity is particularly insidious over the age of 60 years and varies considerably as a function of sex, task specificity, and individual training status. Starting at the age of 50 years, aging also implicates an impressive deterioration of neuromuscular function, affecting muscle strength and power. Muscle atrophy, together with minor deficits in the structure and function of the nervous system and/or impairments in intrinsic muscle quality, plays an important role in the development of neuromotor senescence. Large artery stiffness increases as a function of age, thus triggering subsequent changes in pulsatile hemodynamics and systemic endothelial dysfunction. For this reason, we propose that vascular senescence has a negative impact on cerebral, cardiac, and neuromuscular structure and function, detrimentally affecting physical performance.
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DeForest BA, Winslow J, Thomas CK. Improved motor unit number estimate when motor unit alternation is addressed. J Appl Physiol (1985) 2018; 125:1131-1140. [PMID: 29771606 DOI: 10.1152/japplphysiol.00910.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Motor unit number estimation (MUNE) is important for determining motoneuron survival with age or in conditions such as amyotrophic lateral sclerosis or spinal cord injury. The original incremental method and approaches that were introduced to minimize alternation (e.g., multiple-point stimulation) are most commonly used, but one must accept the limitation that alternation of motor units may still inflate the estimate. Alternation occurs because axon thresholds are probabilistic and overlap for different axons; therefore, different combination of motor units may respond at a given stimulus intensity. Our aims were to quantify motor unit alternation systematically in the thenar muscles of 35 healthy adults by digital subtraction of EMG and force, and to compare MUNE with and without alternation. Alternation was prevalent, with one to nine occurrences in the first 7 to 11 steps in EMG in 34 of 35 muscles. It occurred in the first 3 steps in EMG in 49% of muscles. This alternation resulted in fewer units than steps in EMG (3 to 10 units at step 7 to 11). Accounting for alternation using digital subtraction reduced MUNE by up to 50%, day-to-day, and between-participant variability in MUNE. These results highlight the need to quantify alternation to improve the reliability and precision of motor unit number estimates, which will allow for detection of smaller changes in motoneuron survival with age, various health conditions, and/or due to an intervention. NEW & NOTEWORTHY Motor unit alternation was quantified systematically for the first time, addressing a major limitation of motor unit number estimates. Accounting for alternation decreased motor unit number estimates, and improved the reliability and precision of the motor unit number estimate, which will allow smaller, clinically relevant changes in motoneuron survival to be detected.
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Affiliation(s)
| | - Jeffrey Winslow
- The Miami Project to Cure Paralysis, University of Miami, Florida
| | - Christine K Thomas
- The Miami Project to Cure Paralysis, University of Miami, Florida.,Department of Neurological Surgery, University of Miami, Florida.,Department of Physiology and Biophysics, University of Miami, Florida
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Ni M, Signorile JF. High-Speed Resistance Training Modifies Load-Velocity and Load-Power Relationships in Parkinson's Disease. J Strength Cond Res 2018; 31:2866-2875. [PMID: 27893480 DOI: 10.1519/jsc.0000000000001730] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Muscle power is a major neuromuscular factor affecting motor function and independence in patients with Parkinson's disease (PD), and it is commonly targeted using high-speed exercise. This study examined the changes in velocities (Vpp) and percent loads (%1RMpp) at peak power and load-velocity (L-V) and load-power (L-P) relationships, resulting from resistance training because of exercise choice and loading in older patients with PD. Fourteen older adults with mild to moderate PD participated in a 12-week randomized controlled power training trial. Changes in L-V and L-P relationships for the biceps curl, chest press, leg press, hip abduction, and seated calf were assessed using pneumatic resistance machines at loads ranging from 30 through 90% of subjects' 1 repetition maximum for each exercise. Significant increases in Vpp were seen for biceps curl, leg press, hip abduction, and seated calf and decreases in %1RMpp were noted for biceps curl and hip abduction. Additionally, unique patterns of change were seen in these relationships across exercises, with biceps curl, chest press, and leg press showing the greatest shifts at the lower load end of the loading spectrum, and hip abduction and seated calf showing greatest responses at the higher end. The patterns of change in L-V and L-P relationships provide evidence for the unique responses of the specific muscle groups and joints to the exercises evaluated and offer a framework for more exacting exercise prescriptions in patients with PD.
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Affiliation(s)
- Meng Ni
- 1Department of PM&R, Harvard Medical School, Boston, Massachusetts; 2Department of Kinesiology and Sport Sciences, Laboratory of Neuromuscular Research and Active Aging, University of Miami, Coral Gables, Florida; and 3Miller School of Medicine, Center on Aging, University of Miami, Miami, Florida
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Piasecki M, Ireland A, Piasecki J, Stashuk DW, Swiecicka A, Rutter MK, Jones DA, McPhee JS. Failure to expand the motor unit size to compensate for declining motor unit numbers distinguishes sarcopenic from non-sarcopenic older men. J Physiol 2018. [PMID: 29527694 PMCID: PMC5924831 DOI: 10.1113/jp275520] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Key points The age‐related loss of muscle mass is related to the loss of innervating motor neurons and denervation of muscle fibres. Not all denervated muscle fibres are degraded; some may be reinnervated by an adjacent surviving neuron, which expands the innervating motor unit proportional to the numbers of fibres rescued. Enlarged motor units have larger motor unit potentials when measured using electrophysiological techniques. We recorded much larger motor unit potentials in relatively healthy older men compared to young men, but the older men with the smallest muscles (sarcopenia) had smaller motor unit potentials than healthy older men. These findings suggest that healthy older men reinnervate large numbers of muscle fibres to compensate for declining motor neuron numbers, but a failure to do so contributes to muscle loss in sarcopenic men.
Abstract Sarcopenia results from the progressive loss of skeletal muscle mass and reduced function in older age. It is likely to be associated with the well‐documented reduction of motor unit numbers innervating limb muscles and the increase in size of surviving motor units via reinnervation of denervated fibres. However, no evidence exists to confirm the extent of motor unit remodelling in sarcopenic individuals. The aim of the present study was to compare motor unit size and number between young (n = 48), non‐sarcopenic old (n = 13), pre‐sarcopenic (n = 53) and sarcopenic (n = 29) men. Motor unit potentials (MUPs) were isolated from intramuscular and surface EMG recordings. The motor unit numbers were reduced in all groups of old compared with young men (all P < 0.001). MUPs were higher in non‐sarcopenic and pre‐sarcopenic men compared with young men (P = 0.039 and 0.001 respectively), but not in the vastus lateralis of sarcopenic old (P = 0.485). The results suggest that extensive motor unit remodelling occurs relatively early during ageing, exceeds the loss of muscle mass and precedes sarcopenia. Reinnervation of denervated muscle fibres probably expands the motor unit size in the non‐sarcopenic and pre‐sarcopenic old, but not in the sarcopenic old. These findings suggest that a failure to expand the motor unit size distinguishes sarcopenic from pre‐sarcopenic muscles. The age‐related loss of muscle mass is related to the loss of innervating motor neurons and denervation of muscle fibres. Not all denervated muscle fibres are degraded; some may be reinnervated by an adjacent surviving neuron, which expands the innervating motor unit proportional to the numbers of fibres rescued. Enlarged motor units have larger motor unit potentials when measured using electrophysiological techniques. We recorded much larger motor unit potentials in relatively healthy older men compared to young men, but the older men with the smallest muscles (sarcopenia) had smaller motor unit potentials than healthy older men. These findings suggest that healthy older men reinnervate large numbers of muscle fibres to compensate for declining motor neuron numbers, but a failure to do so contributes to muscle loss in sarcopenic men.
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Affiliation(s)
- M Piasecki
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
| | - A Ireland
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
| | - J Piasecki
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
| | - D W Stashuk
- Department of Systems Design Engineering, University of Waterloo, Ontario, N2L 3G1, Canada
| | - A Swiecicka
- Andrology Research Unit, Cardiovascular, Metabolic and Nutritional Sciences Domain, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - M K Rutter
- Andrology Research Unit, Cardiovascular, Metabolic and Nutritional Sciences Domain, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.,Manchester Diabetes Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - D A Jones
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
| | - J S McPhee
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
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The reliability of methods to estimate the number and size of human motor units and their use with large limb muscles. Eur J Appl Physiol 2018; 118:767-775. [PMID: 29356950 PMCID: PMC5843678 DOI: 10.1007/s00421-018-3811-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 01/17/2018] [Indexed: 01/25/2023]
Abstract
Purpose Current methods for estimating muscle motor unit (MU) number provide values which are remarkably similar for muscles of widely differing size, probably because surface electrodes sample from similar and relatively small volumes in each muscle. We have evaluated an alternative means of estimating MU number that takes into account differences in muscle size. Methods Intramuscular motor unit potentials (MUPs) were recorded and muscle cross-sectional area (CSA) was measured using MRI to provide a motor unit number estimate (iMUNE). This was compared to the traditional MUNE method, using compound muscle action potentials (CMAP) and surface motor unit potentials (sMUPs) recorded using surface electrodes. Data were collected from proximal and distal regions of the vastus lateralis (VL) in young and old men while test–retest reliability was evaluated with VL, tibialis anterior and biceps brachii. Results MUPs, sMUPs and CMAPs were highly reliable (r = 0.84–0.91). The traditional MUNE, based on surface recordings, did not differ between proximal and distal sites of the VL despite the proximal CSA being twice the distal CSA. iMUNE, however, gave values that differed between young and old and were proportional to the muscle size. Conclusion When evaluating the contribution that MU loss makes to muscle atrophy, such as in disease or ageing, it is important to have a method such as iMUNE, which takes into account any differences in total muscle size.
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Piasecki M, Ireland A, Coulson J, Stashuk DW, Hamilton-Wright A, Swiecicka A, Rutter MK, McPhee JS, Jones DA. Motor unit number estimates and neuromuscular transmission in the tibialis anterior of master athletes: evidence that athletic older people are not spared from age-related motor unit remodeling. Physiol Rep 2017; 4:4/19/e12987. [PMID: 27694526 PMCID: PMC5064139 DOI: 10.14814/phy2.12987] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Accepted: 09/06/2016] [Indexed: 11/24/2022] Open
Abstract
Muscle motor unit numbers decrease markedly in old age, while remaining motor units are enlarged and can have reduced neuromuscular junction transmission stability. However, it is possible that regular intense physical activity throughout life can attenuate this remodeling. The aim of this study was to compare the number, size, and neuromuscular junction transmission stability of tibialis anterior (TA) motor units in healthy young and older men with those of exceptionally active master runners. The distribution of motor unit potential (MUP) size was determined from intramuscular electromyographic signals recorded in healthy male Young (mean ± SD, 26 ± 5 years), Old (71 ± 4 years) and Master Athletes (69 ± 3 years). Relative differences between groups in numbers of motor units was assessed using two methods, one comparing MUP size and muscle cross-sectional area (CSA) determined with MRI, the other comparing surface recorded MUPs with maximal compound muscle action potentials and commonly known as a "motor unit number estimate (MUNE)". Near fiber (NF) jiggle was measured to assess neuromuscular junction transmission stability. TA CSA did not differ between groups. MUNE values for the Old and Master Athletes were 45% and 40%, respectively, of the Young. Intramuscular MUPs of Old and Master Athletes were 43% and 56% larger than Young. NF jiggle was slightly higher in the Master Athletes, with no difference between Young and Old. These results show substantial and similar motor unit loss and remodeling in Master Athletes and Old individuals compared with Young, which suggests that lifelong training does not attenuate the age-related loss of motor units.
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Affiliation(s)
- Mathew Piasecki
- School of Healthcare Science, Manchester Metropolitan University, Manchester, UK
| | - Alex Ireland
- School of Healthcare Science, Manchester Metropolitan University, Manchester, UK
| | - Jessica Coulson
- School of Healthcare Science, Manchester Metropolitan University, Manchester, UK
| | - Dan W Stashuk
- Department of Systems Design Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Andrew Hamilton-Wright
- Mathematics and Computer Science, Mount Allison University, Sackville, New Brunswick, Canada
| | - Agnieszka Swiecicka
- Andrology Research Unit, Cardiovascular, Metabolic and Nutritional Sciences Domain, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Martin K Rutter
- Manchester Diabetes Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - Jamie S McPhee
- School of Healthcare Science, Manchester Metropolitan University, Manchester, UK
| | - David A Jones
- School of Healthcare Science, Manchester Metropolitan University, Manchester, UK
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Vasilaki A, Richardson A, Van Remmen H, Brooks SV, Larkin L, McArdle A, Jackson MJ. Role of nerve-muscle interactions and reactive oxygen species in regulation of muscle proteostasis with ageing. J Physiol 2017; 595:6409-6415. [PMID: 28792061 PMCID: PMC5638895 DOI: 10.1113/jp274336] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 08/02/2017] [Indexed: 12/24/2022] Open
Abstract
Skeletal muscle ageing is characterised by atrophy, a deficit in specific force generation, increased susceptibility to injury, and incomplete recovery after severe damage. The hypothesis that increased generation of reactive oxygen species (ROS) in vivo plays a key role in the ageing process has been extensively studied, but remains controversial. Skeletal muscle generates ROS at rest and during exercise. ROS can cause oxidative damage particularly to proteins. Indeed, products of oxidative damage accumulate in skeletal muscle during ageing and the ability of muscle cells to respond to increased ROS becomes defective. The aim of this review is to examine the evidence that ROS manipulation in peripheral nerves and/or muscle modifies mechanisms of proteostasis in skeletal muscle and plays a key role in initiating sarcopenia.
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Affiliation(s)
- Aphrodite Vasilaki
- Department of Musculoskeletal Biology, MRC Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Arlan Richardson
- Department of Geriatric Medicine and the Reynolds Oklahoma Center on Aging, Oklahoma University Health Science Center, Oklahoma City, OK, USA.,Oklahoma City VA Medical Center, Oklahoma City, OK, USA
| | - Holly Van Remmen
- Oklahoma City VA Medical Center, Oklahoma City, OK, USA.,Aging and Metabolism Division, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Susan V Brooks
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Lisa Larkin
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Anne McArdle
- Department of Musculoskeletal Biology, MRC Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Malcolm J Jackson
- Department of Musculoskeletal Biology, MRC Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
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Kiewiet H, Bulsink VE, Beugels F, Koopman HFJM. The co-contraction index of the upper limb for young and old adult cyclists. ACCIDENT; ANALYSIS AND PREVENTION 2017; 105:95-101. [PMID: 27174374 DOI: 10.1016/j.aap.2016.04.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 03/27/2016] [Accepted: 04/27/2016] [Indexed: 06/05/2023]
Abstract
Bicycling is a popular and convenient means of transportation amongst the elderly in the Netherlands. However, the uptake of the electric bicycle resulted in an increase of single-sided bicycle accidents amongst the elderly (Veiligheid, 2010). Since elderly are prone to severe injuries, bicycle stability is currently a popular research topic. Three main balance strategies have been proposed in former studies: steering as the primary balance strategy and trunk -and lateral knee movement as secondary balance strategies (Moore et al., 2011; Cain, 2013). Since steering is the primary strategy for bicycle stability, the stiffness of the arms plays an important role in active stability during cycling. It has been shown that the arm stiffness of a passive rider is an important factor on the stability of a bicycle (Doria and Tognazzo, 2014). In the study presented here, the co-contraction index (CCI) of the upper limb for young and old adult cyclist is studied. Data is collected during experiments based on the setup described in (Kiewiet et al., 2014), wherein contact forces, muscle activities and motions of the rider and bicycle are measured for 15 young adult (mean±sd: 25.3±2.8 yrs) and 15 old adult (mean±sd: 58.1±2.1 yrs) subjects during unperturbed and perturbed cycling. The arm stiffness is defined as a co-contraction ratio between muscle activity of the m. Biceps Brachii and m. Triceps Lateralis. Results suggest that older adult cyclists use more co-contraction of their arm muscles during cycling, compared to young cyclists. The inter-subject variability of the found CCI was higher for the old adult subject group, compared to the young group. The results support the initial hypothesis that the increase in co-contraction of the upper limb for older cyclists is higher during perturbed cycling compared to unperturbed cycling than for younger cyclists. The findings might give direction towards solutions for increasing the safety and stability for elderly cyclists.
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Affiliation(s)
- H Kiewiet
- Department of Engineering Technology, Laboratory of Design, Production and Management, University of Twente, Enschede, The Netherlands.
| | - V E Bulsink
- Department of Engineering Technology, Laboratory of Biomechanical Engineering, University of Twente, Enschede, The Netherlands
| | - F Beugels
- Department of Engineering Technology, Laboratory of Biomechanical Engineering, University of Twente, Enschede, The Netherlands
| | - H F J M Koopman
- Department of Engineering Technology, Laboratory of Biomechanical Engineering, University of Twente, Enschede, The Netherlands
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The role of attenuated redox and heat shock protein responses in the age-related decline in skeletal muscle mass and function. Essays Biochem 2017; 61:339-348. [PMID: 28698308 DOI: 10.1042/ebc20160088] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 04/29/2017] [Accepted: 05/11/2017] [Indexed: 11/17/2022]
Abstract
The loss of muscle mass and weakness that accompanies ageing is a major contributor to physical frailty and loss of independence in older people. A failure of muscle to adapt to physiological stresses such as exercise is seen with ageing and disruption of redox regulated processes and stress responses are recognized to play important roles in theses deficits. The role of redox regulation in control of specific stress responses, including the generation of heat shock proteins (HSPs) by muscle appears to be particularly important and affected by ageing. Transgenic and knockout studies in experimental models in which redox and HSP responses were modified have demonstrated the importance of these processes in maintenance of muscle mass and function during ageing. New data also indicate the potential of these processes to interact with and influence ageing in other tissues. In particular the roles of redox signalling and HSPs in regulation of inflammatory pathways appears important in their impact on organismal ageing. This review will briefly indicate the importance of this area and demonstrate how an understanding of the manner in which redox and stress responses interact and how they may be controlled offers considerable promise as an approach to ameliorate the major functional consequences of ageing of skeletal muscle (and potentially other tissues) in man.
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McKinnon NB, Connelly DM, Rice CL, Hunter SW, Doherty TJ. Neuromuscular contributions to the age-related reduction in muscle power: Mechanisms and potential role of high velocity power training. Ageing Res Rev 2017; 35:147-154. [PMID: 27697547 DOI: 10.1016/j.arr.2016.09.003] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 08/15/2016] [Accepted: 09/26/2016] [Indexed: 01/21/2023]
Abstract
Although much of the literature on neuromuscular changes with aging has focused on loss of muscle mass and isometric strength, deficits in muscle power are more pronounced with aging and may be a more sensitive measure of neuromuscular degeneration. This review aims to identify the adaptations to the neuromuscular system with aging, with specific emphasis on changes that result in decreased muscle power. We discuss how these changes in neuromuscular performance can affect mobility, and ultimately contribute to an increased risk for falls in older adults. Finally, we evaluate the literature regarding high-velocity muscle power training (PT), and its potential advantages over conventional strength training for improving functional performance and mitigating fall risk in older adults.
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Jackson MJ, McArdle A. Role of reactive oxygen species in age-related neuromuscular deficits. J Physiol 2016; 594:1979-88. [PMID: 26870901 DOI: 10.1113/jp270564] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 01/06/2016] [Indexed: 01/06/2023] Open
Abstract
Although it is now clear that reactive oxygen species (ROS) are not the key determinants of longevity, a number of studies have highlighted the key role that these species play in age-related diseases and more generally in determining individual health span. Age-related loss of skeletal muscle mass and function is a key contributor to physical frailty in older individuals and our current understanding of the key areas in which ROS contribute to age-related deficits in muscle is through defective redox signalling and key roles in maintenance of neuromuscular integrity. This topical review will describe how ROS stimulate adaptations to contractile activity in muscle that include up-regulation of short-term stress responses, an increase in mitochondrial biogenesis and an increase in some catabolic processes. These adaptations occur through stimulation of redox-regulated processes that lead to the activation of transcription factors such as NF-κB, AP-1 and HSF1 which mediate changes in gene expression. They are attenuated during ageing and this appears to occur through an age-related increase in mitochondrial hydrogen peroxide production. The potential for redox-mediated cross-talk between motor neurons and muscle is also described to illustrate how ROS released from muscle fibres during exercise may help maintain the integrity of axons and how the degenerative changes in neuromuscular structure that occur with ageing may contribute to mitochondrial ROS generation in skeletal muscle fibres.
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Affiliation(s)
- Malcolm J Jackson
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L69 3GA, UK
| | - Anne McArdle
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L69 3GA, UK
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Potiaumpai M, Gandia K, Rautray A, Prendergast T, Signorile JF. Optimal Loads for Power Differ by Exercise in Older Adults. J Strength Cond Res 2016; 30:2703-12. [PMID: 27386964 DOI: 10.1519/jsc.0000000000001549] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Potiaumpai, M, Gandia, K, Rautray, A, Prendergast, T, and Signorile, JF. Optimal loads for power differ by exercise in older adults. J Strength Cond Res 30(10): 2703-2712, 2016-Power training in older adults has been shown to increase muscle strength, power, and physical function, and decrease the risk of falls and related injuries. Although there are clear indications that optimal loads for power vary due to biomechanical factors, no studies have attempted to determine the optimal loads for specific exercises used to improve muscle power. Using the load that maximizes power output for individual exercises can maximize power gains, improve training efficiency, and augment gains in physical function. Seventy community-dwelling older adults (age = 70.5 ± 5.7 years) participated in strength and power testing during 2 sessions, each lasting for 1.5 hours. Participants were tested on 6 different pneumatic resistance machines to determine their one repetition maximum (1RM) and power. Power testing was performed at loads between 30 and 90% of each participant's 1RM. For the chest press and seated row, the optimal load range was between 40 and 60% 1RM, with peak power at 50% (p < 0.001) for both machines. The LAT pull-down optimal load range was between 30 and 50%, with peak power occurring at 40% (p < 0.001). The leg curl and leg press optimal load range was between 50 and 70%, with peak power occurring at 60% (p < 0.001). Peak power for the calf raise occurred at 60% (p < 0.001). We conclude that different exercise movements require the use of different optimal load ranges to maximize muscle power in older persons.
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Affiliation(s)
- Melanie Potiaumpai
- 1Laboratory of Neuromuscular Research and Active Aging, Department of Kinesiology and Sports Sciences, University of Miami, Coral Gables, Florida; and 2Center on Aging, Miller School of Medicine, University of Miami, Miami, Florida
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Vasilaki A, Pollock N, Giakoumaki I, Goljanek-Whysall K, Sakellariou GK, Pearson T, Kayani A, Jackson MJ, McArdle A. The effect of lengthening contractions on neuromuscular junction structure in adult and old mice. AGE (DORDRECHT, NETHERLANDS) 2016; 38:259-272. [PMID: 27470432 PMCID: PMC5061675 DOI: 10.1007/s11357-016-9937-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 07/14/2016] [Indexed: 06/06/2023]
Abstract
Skeletal muscles of old mice demonstrate a profound inability to regenerate fully following damage. Such a failure could be catastrophic to older individuals where muscle loss is already evident. Degeneration and regeneration of muscle fibres following contraction-induced injury in adult and old mice are well characterised, but little is known about the accompanying changes in motor neurons and neuromuscular junctions (NMJs) following this form of injury although defective re-innervation of muscle following contraction-induced damage has been proposed to play a role in sarcopenia. This study visualised and quantified structural changes to motor neurons and NMJs in Extensor digitorum longus (EDL) muscles of adult and old Thy1-YFP transgenic mice during regeneration following contraction-induced muscle damage. Data demonstrated that the damaging contraction protocol resulted in substantial initial disruption to NMJs in muscles of adult mice, which was reversed entirely within 28 days following damage. In contrast, in quiescent muscles of old mice, ∼15 % of muscle fibres were denervated and ∼80 % of NMJs showed disruption. This proportion of denervated and partially denervated fibres remained unchanged following recovery from contraction-induced damage in muscles of old mice although ∼25 % of muscle fibres were completely lost by 28 days post-contractions. Thus, in old mice, the failure to restore full muscle force generation that occurs following damage does not appear to be due to any further deficit in the percentage of disrupted NMJs, but appears to be due, at least in part, to the complete loss of muscle fibres following damage.
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Affiliation(s)
- Aphrodite Vasilaki
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Natalie Pollock
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Ifigeneia Giakoumaki
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Katarzyna Goljanek-Whysall
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Giorgos K Sakellariou
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Timothy Pearson
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Anna Kayani
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Malcolm J Jackson
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Anne McArdle
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK.
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46
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Wu R, Delahunt E, Ditroilo M, Lowery M, De Vito G. Effects of age and sex on neuromuscular-mechanical determinants of muscle strength. AGE (DORDRECHT, NETHERLANDS) 2016; 38:57. [PMID: 27189591 PMCID: PMC5005921 DOI: 10.1007/s11357-016-9921-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 05/08/2016] [Indexed: 05/20/2023]
Abstract
The aim of this study was to concurrently assess the effect of age on neuromuscular and mechanical properties in 24 young (23.6 ± 3.7 years) and 20 older (66.5 ± 3.8 years) healthy males and females. Maximal strength of knee extensors (KE) and flexors (KF), contractile rate of torque development (RTD) and neural activation of agonist-antagonist muscles (surface EMG) were examined during maximal voluntary isometric contraction (MVIC). Tissue stiffness (i.e. musculo-articular stiffness (MAS) and muscle stiffness (MS)) was examined via the free-oscillation technique, whereas muscle architecture (MA) of the vastus lateralis and subcutaneous fat were measured by ultrasonography. Males exhibited a greater age-related decline for KE (47.4 %) and KF (53.1 %) MVIC, and RTD (60.4 %) when compared to females (32.9, 42.6 and 34.0 %, respectively). Neural activation of agonist muscles during KE MVIC falls markedly with ageing; however, no age and sex effects were observed in the antagonist co-activation. MAS and MS were lower in elderly compared with young participants and in females compared with males. Regarding MA, main effects for age (young 23.0 ± 3.3 vs older 19.5 ± 2.0 mm) and sex (males 22.4 ± 3.5 vs females 20.4 ± 2.7 mm) were detected in muscle thickness. For fascicle length, there was an effect of age (young 104.6 ± 8.8 vs older 89.8 ± 10.5 mm), while for pennation angle, there was an effect of sex (males 13.3 ± 2.4 vs females 11.5 ± 1.7°). These findings suggest that both neuromuscular and mechanical declines are important contributors to the age-related loss of muscle strength/function but with some peculiar sex-related differences.
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Affiliation(s)
- Rui Wu
- School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Republic of Ireland.
| | - Eamonn Delahunt
- School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Republic of Ireland
- Institute for Sport and Health, University College Dublin, Dublin, Republic of Ireland
| | - Massimiliano Ditroilo
- School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Republic of Ireland
- Institute for Sport and Health, University College Dublin, Dublin, Republic of Ireland
| | - Madeleine Lowery
- School of Electrical, Electronic and Communications Engineering, University College Dublin, Dublin, Republic of Ireland
| | - Giuseppe De Vito
- School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Republic of Ireland
- Institute for Sport and Health, University College Dublin, Dublin, Republic of Ireland
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47
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Goljanek-Whysall K, Iwanejko LA, Vasilaki A, Pekovic-Vaughan V, McDonagh B. Ageing in relation to skeletal muscle dysfunction: redox homoeostasis to regulation of gene expression. Mamm Genome 2016; 27:341-57. [PMID: 27215643 PMCID: PMC4935741 DOI: 10.1007/s00335-016-9643-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/05/2016] [Indexed: 12/17/2022]
Abstract
Ageing is associated with a progressive loss of skeletal muscle mass, quality and function—sarcopenia, associated with reduced independence and quality of life in older generations. A better understanding of the mechanisms, both genetic and epigenetic, underlying this process would help develop therapeutic interventions to prevent, slow down or reverse muscle wasting associated with ageing. Currently, exercise is the only known effective intervention to delay the progression of sarcopenia. The cellular responses that occur in muscle fibres following exercise provide valuable clues to the molecular mechanisms regulating muscle homoeostasis and potentially the progression of sarcopenia. Redox signalling, as a result of endogenous generation of ROS/RNS in response to muscle contractions, has been identified as a crucial regulator for the adaptive responses to exercise, highlighting the redox environment as a potentially core therapeutic approach to maintain muscle homoeostasis during ageing. Further novel and attractive candidates include the manipulation of microRNA expression. MicroRNAs are potent gene regulators involved in the control of healthy and disease-associated biological processes and their therapeutic potential has been researched in the context of various disorders, including ageing-associated muscle wasting. Finally, we discuss the impact of the circadian clock on the regulation of gene expression in skeletal muscle and whether disruption of the peripheral muscle clock affects sarcopenia and altered responses to exercise. Interventions that include modifying altered redox signalling with age and incorporating genetic mechanisms such as circadian- and microRNA-based gene regulation, may offer potential effective treatments against age-associated sarcopenia.
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Affiliation(s)
- Katarzyna Goljanek-Whysall
- MRC-Arthritis Research UK Centre for Integrated research into Musculoskeletal Ageing (CIMA), Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8XL, UK.
| | - Lesley A Iwanejko
- MRC-Arthritis Research UK Centre for Integrated research into Musculoskeletal Ageing (CIMA), Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8XL, UK
| | - Aphrodite Vasilaki
- MRC-Arthritis Research UK Centre for Integrated research into Musculoskeletal Ageing (CIMA), Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8XL, UK
| | - Vanja Pekovic-Vaughan
- MRC-Arthritis Research UK Centre for Integrated research into Musculoskeletal Ageing (CIMA), Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8XL, UK
| | - Brian McDonagh
- MRC-Arthritis Research UK Centre for Integrated research into Musculoskeletal Ageing (CIMA), Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8XL, UK.
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48
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Rygiel KA, Picard M, Turnbull DM. The ageing neuromuscular system and sarcopenia: a mitochondrial perspective. J Physiol 2016; 594:4499-512. [PMID: 26921061 PMCID: PMC4983621 DOI: 10.1113/jp271212] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 12/14/2015] [Indexed: 12/15/2022] Open
Abstract
Skeletal muscles undergo structural and functional decline with ageing, culminating in sarcopenia. The underlying neuromuscular mechanisms have been the subject of intense investigation, revealing mitochondrial abnormalities as potential culprits within both nerve and muscle cells. Implicated mechanisms involve impaired mitochondrial dynamics, reduced organelle biogenesis and quality control via mitophagy, accumulation of mitochondrial DNA (mtDNA) damage and respiratory chain defect, metabolic disturbance, pro-apoptotic signalling, and oxidative stress. This article provides an overview of the cellular mechanisms whereby mitochondria may promote maladaptive changes within motor neurons, the neuromuscular junction (NMJ) and muscle fibres. Lifelong physical activity, which promotes mitochondrial health across tissues, is emerging as an effective countermeasure for sarcopenia.
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Affiliation(s)
- Karolina A Rygiel
- Newcastle University Centre for Ageing and Vitality, Newcastle upon Tyne, UK.,Wellcome Trust Centre for Mitochondrial Research, Newcastle upon Tyne, UK
| | - Martin Picard
- Division of Behavioral Medicine, Department of Psychiatry, College of Physicians and Surgeons, Columbia University, Columbia University Medical Center, New York, NY, USA
| | - Doug M Turnbull
- Newcastle University Centre for Ageing and Vitality, Newcastle upon Tyne, UK.,Wellcome Trust Centre for Mitochondrial Research, Newcastle upon Tyne, UK
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49
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Jackson MJ. Reactive oxygen species in sarcopenia: Should we focus on excess oxidative damage or defective redox signalling? Mol Aspects Med 2016; 50:33-40. [PMID: 27161871 DOI: 10.1016/j.mam.2016.05.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 05/03/2016] [Indexed: 12/17/2022]
Abstract
Physical frailty in the elderly is driven by loss of muscle mass and function and hence preventing this is the key to reduction in age-related physical frailty. Our current understanding of the key areas in which ROS contribute to age-related deficits in muscle is through increased oxidative damage to cell constituents and/or through induction of defective redox signalling. Recent data have argued against a primary role for ROS as a regulator of longevity, but studies have persistently indicated that aspects of the aging phenotype and age-related disorders may be mediated by ROS. There is increasing interest in the effects of defective redox signalling in aging and some studies now indicate that this process may be important in reducing the integrity of the aging neuromuscular system. Understanding how redox-signalling pathways are altered by aging and the causes of the defective redox homeostasis seen in aging muscle provides opportunities to identify targeted interventions with the potential to slow or prevent age-related neuromuscular decline with a consequent improvement in quality of life for older people.
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Affiliation(s)
- Malcolm J Jackson
- MRC-Arthritis Research UK Centre for Integrated research into Musculoskeletal Ageing (CIMA), Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L69 3GA, UK.
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50
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Power GA, Allen MD, Gilmore KJ, Stashuk DW, Doherty TJ, Hepple RT, Taivassalo T, Rice CL. Motor unit number and transmission stability in octogenarian world class athletes: Can age-related deficits be outrun? J Appl Physiol (1985) 2016; 121:1013-1020. [PMID: 27013605 DOI: 10.1152/japplphysiol.00149.2016] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 03/18/2016] [Indexed: 11/22/2022] Open
Abstract
Our group has shown a greater number of functioning motor units (MU) in a cohort of highly active older (∼65 yr) masters runners relative to age-matched controls. Because of the precipitous loss in the number of functioning MUs in the eighth and ninth decades of life it is unknown whether older world class octogenarian masters athletes (MA) would also have greater numbers of functioning MUs compared with age-matched controls. We measured MU numbers and neuromuscular transmission stability in the tibialis anterior of world champion MAs (∼80 yr) and compared the values with healthy age-matched controls (∼80 yr). Decomposition-enhanced spike-triggered averaging was used to collect surface and intramuscular electromyography signals during dorsiflexion at ∼25% of maximum voluntary isometric contraction. Near fiber (NF) MU potential analysis was used to assess neuromuscular transmission stability. For the MAs compared with age-matched controls, the amount of excitable muscle mass (compound muscle action potential) was 14% greater (P < 0.05), there was a trend (P = 0.07) toward a 27% smaller surface-detected MU potential representative of less collateral reinnervation, and 28% more functioning MUs (P < 0.05). Additionally, the MAs had greater MU neuromuscular stability than the controls, as indicated by lower NF jitter and jiggle values (P < 0.05). These results demonstrate that high-performing octogenarians better maintain neuromuscular stability of the MU and mitigate the loss of MUs associated with aging well into the later decades of life during which time the loss of muscle mass and strength becomes functionally relevant. Future studies may identify the concomitant roles genetics and exercise play in neuroprotection.
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Affiliation(s)
- Geoffrey A Power
- Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph Ontario, Canada;
| | - Matti D Allen
- School of Medicine and School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Kevin J Gilmore
- Faculty of Health Sciences, School of Kinesiology, Canadian Centre for Activity and Aging, The University of Western Ontario, Ontario, Canada
| | - Daniel W Stashuk
- Department of Systems Design Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Timothy J Doherty
- Faculty of Health Sciences, School of Kinesiology, Canadian Centre for Activity and Aging, The University of Western Ontario, Ontario, Canada.,Department of Physical Medicine and Rehabilitation, The University of Western Ontario, London, Ontario, Canada
| | - Russell T Hepple
- Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada.,Department of Medicine, McGill University, Montreal, Quebec, Canada.,Meakins Christie Laboratories, McGill University, Montreal, Quebec, Canada; and
| | - Tanja Taivassalo
- Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada
| | - Charles L Rice
- Faculty of Health Sciences, School of Kinesiology, Canadian Centre for Activity and Aging, The University of Western Ontario, Ontario, Canada.,Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
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