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Beausejour JP, Knowles KS, Wilson AT, Mangum LC, Hill EC, Hanney WJ, Wells AJ, Fukuda DH, Stout J, Stock MS. Innovations in the Assessment of Skeletal Muscle Health: A Glimpse into the Future. Int J Sports Med 2024; 45:659-671. [PMID: 38198822 DOI: 10.1055/a-2242-3226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Skeletal muscle is the largest organ system in the human body and plays critical roles in athletic performance, mobility, and disease pathogenesis. Despite growing recognition of its importance by major health organizations, significant knowledge gaps remain regarding skeletal muscle health and its crosstalk with nearly every physiological system. Relevant public health challenges like pain, injury, obesity, and sarcopenia underscore the need to accurately assess skeletal muscle health and function. Feasible, non-invasive techniques that reliably evaluate metrics including muscle pain, dynamic structure, contractility, circulatory function, body composition, and emerging biomarkers are imperative to unraveling the complexities of skeletal muscle. Our concise review highlights innovative or overlooked approaches for comprehensively assessing skeletal muscle in vivo. We summarize recent advances in leveraging dynamic ultrasound imaging, muscle echogenicity, tensiomyography, blood flow restriction protocols, molecular techniques, body composition, and pain assessments to gain novel insight into muscle physiology from cellular to whole-body perspectives. Continued development of precise, non-invasive tools to investigate skeletal muscle are critical in informing impactful discoveries in exercise and rehabilitation science.
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Affiliation(s)
- Jonathan P Beausejour
- Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, United States
| | - Kevan S Knowles
- Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, United States
| | - Abigail T Wilson
- Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, United States
| | - L Colby Mangum
- Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, United States
| | - Ethan C Hill
- Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, United States
| | - William J Hanney
- Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, United States
| | - Adam J Wells
- Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, United States
| | - David H Fukuda
- Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, United States
| | - JeffreyR Stout
- Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, United States
| | - Matt S Stock
- Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, United States
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Harmon KK, Girts RM, Rodriguez G, Beausejour JP, Pagan JI, Carr JC, Garcia J, Roberts MD, Hahs‐Vaughn DL, Stout JR, Fukuda DH, Stock MS. Combined action observation and mental imagery versus neuromuscular electrical stimulation as novel therapeutics during short-term knee immobilization. Exp Physiol 2024; 109:1145-1162. [PMID: 38687158 PMCID: PMC11215482 DOI: 10.1113/ep091827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 03/28/2024] [Indexed: 05/02/2024]
Abstract
Limb immobilization causes rapid declines in muscle strength and mass. Given the role of the nervous system in immobilization-induced weakness, targeted interventions may be able to preserve muscle strength, but not mass, and vice versa. The purpose of this study was to assess the effects of two distinct interventions during 1 week of knee joint immobilization on muscle strength (isometric and concentric isokinetic peak torque), mass (bioimpedance spectroscopy and ultrasonography), and neuromuscular function (transcranial magnetic stimulation and interpolated twitch technique). Thirty-nine healthy, college-aged adults (21 males, 18 females) were randomized into one of four groups: immobilization only (n = 9), immobilization + action observation/mental imagery (AOMI) (n = 10), immobilization + neuromuscular electrical stimulation (NMES) (n = 12), or control group (n = 8). The AOMI group performed daily video observation and mental imagery of knee extensions. The NMES group performed twice daily stimulation of the quadriceps femoris. Based on observed effect sizes, it appears that AOMI shows promise as a means of preserving voluntary strength, which may be modulated by neural adaptations. Strength increased from PRE to POST in the AOMI group, with +7.2% (Cohen's d = 1.018) increase in concentric isokinetic peak torque at 30°/s. However, NMES did not preserve muscle mass. Though preliminary, our findings highlight the specific nature of clinical interventions and suggest that muscle strength can be independently targeted during rehabilitation. This study was prospectively registered: ClinicalTrials.gov NCT05072652.
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Affiliation(s)
- Kylie K. Harmon
- Department of Exercise ScienceSyracuse UniversitySyracuseNew YorkUSA
| | - Ryan M. Girts
- Department of Natural and Health SciencesPfeiffer UniversityMisenheimerNorth CarolinaUSA
| | - Gabriela Rodriguez
- Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Rehabilitation SciencesUniversity of Central FloridaOrlandoFloridaUSA
| | - Jonathan P. Beausejour
- Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Rehabilitation SciencesUniversity of Central FloridaOrlandoFloridaUSA
| | - Jason I. Pagan
- Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Rehabilitation SciencesUniversity of Central FloridaOrlandoFloridaUSA
| | - Joshua C. Carr
- Department of KinesiologyTexas Christian UniversityFort WorthTexasUSA
- Department of Medical EducationAnne Burnett Marion School of Medicine at Texas Christian UniversityFort WorthTexasUSA
| | - Jeanette Garcia
- School of Sport SciencesWest Virginia UniversityMorgantownWest VirginiaUSA
| | | | - Debbie L. Hahs‐Vaughn
- Department of Learning Sciences and Educational ResearchUniversity of Central FloridaOrlandoFloridaUSA
| | - Jeffrey R. Stout
- Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Rehabilitation SciencesUniversity of Central FloridaOrlandoFloridaUSA
| | - David H. Fukuda
- Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Rehabilitation SciencesUniversity of Central FloridaOrlandoFloridaUSA
| | - Matt S. Stock
- Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Rehabilitation SciencesUniversity of Central FloridaOrlandoFloridaUSA
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Seo F, Clouette J, Huang Y, Potvin-Desrochers A, Lajeunesse H, Parent-L'Ecuyer F, Traversa C, Paquette C, Churchward-Venne TA. Changes in brain functional connectivity and muscle strength independent of elbow flexor atrophy following upper limb immobilization in young females. Exp Physiol 2024. [PMID: 38935545 DOI: 10.1113/ep091782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 06/11/2024] [Indexed: 06/29/2024]
Abstract
Muscle disuse induces a decline in muscle strength that exceeds the rate and magnitude of muscle atrophy, suggesting that factors beyond the muscle contribute to strength loss. The purpose of this study was to characterize changes in the brain and neuromuscular system in addition to muscle size following upper limb immobilization in young females. Using a within-participant, unilateral design, 12 females (age: 20.6 ± 2.1 years) underwent 14 days of upper arm immobilization using an elbow brace and sling. Bilateral measures of muscle strength (isometric and isokinetic dynamometry), muscle size (magnetic resonance imaging), voluntary muscle activation capacity, corticospinal excitability, cortical thickness and resting-state functional connectivity were collected before and after immobilization. Immobilization induced a significant decline in isometric elbow flexion (-21.3 ± 19.2%, interaction: P = 0.0440) and extension (-19.9 ± 15.7%, interaction: P = 0.0317) strength in the immobilized arm only. There was no significant effect of immobilization on elbow flexor cross-sectional area (CSA) (-1.2 ± 2.4%, interaction: P = 0.466), whereas elbow extensor CSA decreased (-2.9 ± 2.9%, interaction: P = 0.0177) in the immobilized arm. Immobilization did not differentially alter voluntary activation capacity, corticospinal excitability, or cortical thickness (P > 0.05); however, there were significant changes in the functional connectivity of brain regions related to movement planning and error detection (P < 0.05). This study reveals that elbow flexor strength loss can occur in the absence of significant elbow flexor muscle atrophy, and that the brain represents a site of functional adaptation in response to upper limb immobilization in young females.
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Affiliation(s)
- Freddie Seo
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada
| | - Julien Clouette
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada
| | - Yijia Huang
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada
| | - Alexandra Potvin-Desrochers
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada
- Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal, Montreal, QC, Canada
| | - Henri Lajeunesse
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada
| | | | - Claire Traversa
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada
| | - Caroline Paquette
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada
- Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal, Montreal, QC, Canada
| | - Tyler A Churchward-Venne
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada
- Division of Geriatric Medicine, McGill University, Montreal, QC, Canada
- Research Institute of the McGill University Health Centre, Montreal, QC, Canada
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Girts RM, Harmon KK, Rodriguez G, Beausejour JP, Pagan JI, Carr JC, Garcia J, Stout JR, Fukuda DH, Stock MS. Sex differences in muscle-quality recovery following one week of knee joint immobilization and subsequent retraining. Appl Physiol Nutr Metab 2024; 49:805-817. [PMID: 38382056 DOI: 10.1139/apnm-2023-0242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
This manuscript represents the second phase of a clinical trial designed to examine the effects of knee joint immobilization and retraining on muscle strength and mass. In Phase 2, we examined sex differences in the recovery of multiple indices of muscle quality after a resistance training-based rehabilitation program. Following 1 week of immobilization, 27 participants (16 males, 11 females) exhibiting weakness underwent twice weekly resistance training sessions designed to re-strengthen their left knee. Unilateral retraining sessions utilizing leg press, extension, and curl exercises were conducted until participants could reproduce their pre-immobilization knee extension isometric maximal voluntary contraction (MVC) peak torque. Post-immobilization, both sexes demonstrated impaired MVC peak torque (males = -10.8%, females = -15.2%), specific torque (-9.8% vs. -13.1%), echo intensity of the vastus lateralis (+6.9% vs. +5.9%) and rectus femoris (+5.9% vs. +2.1), and extracellular water/intracellular water ratio (+7.8% vs. +9.0%). The number of retraining sessions for peak torque to return to baseline for males (median = 1, mean = 2.13) versus females (median = 2, mean = 2.91) was not significantly different, though the disparity in recovery times may be clinically relevant. Following retraining, specific torque was the only muscle-quality indicator that improved along with MVC peak torque (males = 20.1%, females = 22.4%). Our findings indicate that measures of muscle quality demonstrate divergent recovery rates following immobilization, with muscle mass lagging behind improvements in strength. Greater immobilization-induced strength loss among females suggests that sex-specific rehabilitation efforts may be justified.
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Affiliation(s)
- Ryan M Girts
- Department of Natural and Health Sciences, Pfeiffer University, Misenheimer, NC, USA
| | - Kylie K Harmon
- Department of Exercise ScienceSyracuse University, Syracuse, NY, USA
| | - Gabriela Rodriguez
- Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Rehabilitation Sciences, University of Central Florida, Orlando, FL, USA
| | - Jonathan P Beausejour
- Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Rehabilitation Sciences, University of Central Florida, Orlando, FL, USA
| | - Jason I Pagan
- Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Rehabilitation Sciences, University of Central Florida, Orlando, FL, USA
| | - Joshua C Carr
- Department of Kinesiology, Texas Christian University, Fort Worth, TX, USA
- Department of Medical Education, Anne Burnett Marion School of Medicine at Texas Christian University, Fort Worth, TX, USA
| | - Jeanette Garcia
- School of Sport Sciences West Virginia University, Morgantown, WV, USA
| | - Jeffrey R Stout
- Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Rehabilitation Sciences, University of Central Florida, Orlando, FL, USA
| | - David H Fukuda
- Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Rehabilitation Sciences, University of Central Florida, Orlando, FL, USA
| | - Matt S Stock
- Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Rehabilitation Sciences, University of Central Florida, Orlando, FL, USA
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Sherman DA, Rush J, Stock MS, D. Ingersoll C, E. Norte G. Neural drive and motor unit characteristics after anterior cruciate ligament reconstruction: implications for quadriceps weakness. PeerJ 2023; 11:e16261. [PMID: 37818333 PMCID: PMC10561646 DOI: 10.7717/peerj.16261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 09/18/2023] [Indexed: 10/12/2023] Open
Abstract
Purpose The purpose of this investigation was to compare the quality of neural drive and recruited quadriceps motor units' (MU) action potential amplitude (MUAPAMP) and discharge rate (mean firing rate (MFR)) relative to recruitment threshold (RT) between individuals with anterior cruciate ligament reconstruction (ACLR) and controls. Methods Fourteen individuals with ACLR and 13 matched controls performed trapezoidal knee extensor contractions at 30%, 50%, 70%, and 100% of their maximal voluntary isometric contraction (MVIC). Decomposition electromyography (dEMG) and torque were recorded concurrently. The Hoffmann reflex (H-reflex) and central activation ratio (CAR) were acquired bilaterally to detail the proportion of MU pool available and volitionally activated. We examined MUAPAMP-RT and MFR-RT relationships with linear regression and extracted the regression line slope, y-intercept, and RT range for each contraction. Linear mixed effect modelling used to analyze the effect of group and limb on regression line slope and RT range. Results Individuals with ACLR demonstrated lower MVIC torque in the involved limb compared to uninvolved limb. There were no differences in H-reflex or CAR between groups or limbs. The ACLR involved limb demonstrated smaller mass-normalized RT range and slower MU firing rates at high contraction intensities (70% and 100% MVIC) compared to uninvolved and control limbs. The ACLR involved limb also demonstrated larger MU action potentials in the VM compared to the contralateral limb. These differences were largely attenuated with relative RT normalization. Conclusions These results suggest that persistent strength deficits following ACLR may be attributable to a diminished quadriceps motor neuron pool and inability to upregulate the firing rate of recruited MUs.
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Affiliation(s)
- David A. Sherman
- Live4 Physical Therapy and Wellness, Acton, Massachusetts, United States of America
- Chobanian & Avedisian School of Medicine, Boston University, Boston, Massachusetts, United States of America
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, United States of America
| | - Justin Rush
- Division of Physical Therapy, School of Rehabilitation and Communication Sciences, College of Health Sciences and Professions, Ohio University, Athens, Ohio, United States of America
| | - Matt S. Stock
- Cognition, Neuroplasticity, & Sarcopenia (CNS) Lab, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, United States of America
| | - Christopher D. Ingersoll
- College of Health Professions and Sciences, School of Kinesiology and Rehabilitation Sciences, University of Central Florida, Orlando, Florida, United States of America
| | - Grant E. Norte
- Cognition, Neuroplasticity, & Sarcopenia (CNS) Lab, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, United States of America
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6
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Preobrazenski N, Seigel J, Halliday S, Janssen I, McGlory C. Single-leg disuse decreases skeletal muscle strength, size, and power in uninjured adults: A systematic review and meta-analysis. J Cachexia Sarcopenia Muscle 2023; 14:684-696. [PMID: 36883219 PMCID: PMC10067508 DOI: 10.1002/jcsm.13201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 12/01/2022] [Accepted: 02/02/2023] [Indexed: 03/09/2023] Open
Abstract
We aimed to quantify declines from baseline in lower limb skeletal muscle size and strength of uninjured adults following single-leg disuse. We searched EMBASE, Medline, CINAHL, and CCRCT up to 30 January 2022. Studies were included in the systematic review if they (1) recruited uninjured participants; (2) were an original experimental study; (3) employed a single-leg disuse model; and (4) reported muscle strength, size, or power data following a period of single-leg disuse for at least one group without a countermeasure. Studies were excluded if they (1) did not meet all inclusion criteria; (2) were not in English; (3) reported previously published muscle strength, size, or power data; or (4) could not be sourced from two different libraries, repeated online searches, and the authors. We used the Cochrane Risk of Bias Assessment Tool to assess risk of bias. We then performed random-effects meta-analyses on studies reporting measures of leg extension strength and extensor size. Our search revealed 6548 studies, and 86 were included in our systematic review. Data from 35 and 20 studies were then included in the meta-analyses for measures of leg extensor strength and size, respectively (40 different studies). No meta-analysis for muscle power was performed due to insufficient homogenous data. Effect sizes (Hedges' gav ) with 95% confidence intervals for leg extensor strength were all durations = -0.80 [-0.92, -0.68] (n = 429 participants; n = 68 aged 40 years or older; n ≥ 78 females); ≤7 days of disuse = -0.57 [-0.75, -0.40] (n = 151); >7 days and ≤14 days = -0.93 [-1.12, -0.74] (n = 206); and >14 days = -0.95 [-1.20, -0.70] (n = 72). Effect sizes for measures of leg extensor size were all durations = -0.41 [-0.51, -0.31] (n = 233; n = 32 aged 40 years or older; n ≥ 42 females); ≤7 days = -0.26 [-0.36, -0.16] (n = 84); >7 days and ≤14 days = -0.49 [-0.67, -0.30] (n = 102); and >14 days = -0.52 [-0.74, -0.30] (n = 47). Decreases in leg extensor strength (cast: -0.94 [-1.30, -0.59] (n = 73); brace: -0.90 [-1.18, -0.63] (n = 106)) and size (cast: -0.61[-0.87, -0.35] (n = 41); brace: (-0.48 [-1.04, 0.07] (n = 41)) following 14 days of disuse did not differ for cast and brace disuse models. Single-leg disuse in adults resulted in a decline in leg extensor strength and size that reached a nadir beyond 14 days. Bracing and casting led to similar declines in leg extensor strength and size following 14 days of disuse. Studies including females and males and adults over 40 years of age are lacking.
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Affiliation(s)
| | - Joel Seigel
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Sandra Halliday
- Queen's University Library, Queen's University, Kingston, Ontario, Canada
| | - Ian Janssen
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Chris McGlory
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada.,Department of Medicine, Queen's University, Kingston, Ontario, Canada
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Mechanisms of Arthrogenic Muscle Inhibition. J Sport Rehabil 2021; 31:707-716. [PMID: 34470911 DOI: 10.1123/jsr.2020-0479] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 06/07/2021] [Accepted: 06/28/2021] [Indexed: 11/18/2022]
Abstract
CONTEXT Arthrogenic muscle inhibition (AMI) continues to be a limiting factor in joint rehabilitation as the inability to volitionally activate muscle significantly dampens recovery. New evidence acquired at higher brain centers and in clinical populations continues to reshape our perspective of what AMI is and how to treat it. This review aims to stimulate discussion about the far-reaching effects of AMI by exploring the interconnected pathways by which it evolves. OBJECTIVES To discuss how reflexive inhibition can lead to adaptations in brain activity, to illustrate how changes in descending motor pathways limit our ability to contract muscle following injury, and to summarize the emerging literature on the wide-reaching effects of AMI on other interconnected systems. DATA SOURCES The databases PubMed, SPORTDiscus, and Web of Science were searched for articles pertaining to AMI. Reference lists from appropriate articles were cross-referenced. CONCLUSION AMI is a sequential and cumulative neurological process that leads to complex clinical impairments. Originating with altered afferent information arising from an injured joint, patients experience changes in afferent information, reflexive muscle inhibition, deficiencies in somatosensation, neuroplastic compensations in higher brain centers, and ultimately decreased motor output to the muscle surrounding the joint. Other aspects of clinical function, like muscle structure and psychological responses to injury, are also impaired and influenced by AMI. Removing, or reducing, AMI should continue to be a focus of rehabilitation programs to assist in the optimization of health after joint injury.
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8
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Deschenes MR, Trebelhorn AM, High MC, Tufts HL, Oh J. Sensitivity of subcellular components of neuromuscular junctions to decreased neuromuscular activity. Synapse 2021; 75:e22220. [PMID: 34318955 DOI: 10.1002/syn.22220] [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: 02/04/2021] [Revised: 07/21/2021] [Accepted: 07/22/2021] [Indexed: 12/16/2022]
Abstract
Muscle unloading imparts subtotal disuse on the neuromuscular system resulting in reduced performance capacity. This loss of function, at least in part, can be attributed to disruptions at the neuromuscular junction (NMJ). However, research has failed to document morphological remodeling of the NMJ with short term muscle unloading. Here, rather than quantifying cellular components of the NMJ, we examined subcellular active zone responses to 2 weeks of unloading in male Wistar rats. It was revealed that in the plantaris, but not the soleus muscles, unloading elicited significant (P ≤ 0.05) decrements in active zone staining as measured by Bassoon, and calcium channel expression. It was also discovered that unloading decreased the area of calcium channels staining relative to active zone areas of staining suggesting potential interference in the ability of calcium influx to trigger the release of vesicles docked at the active zone. Post-synaptic adaptations of the motor endplate were not evident. This presynaptic subcellular size reduction was not associated with atrophy of the underlying plantaris muscle fibers, although atrophy of the weight-bearing soleus fibers, where no subcellular remodeling was evident, was noted. These results suggest that the active zone is highly sensitive to alterations in neuromuscular activity, and that morphological adaptation of excitatory and contractile components of the NMJ can occur independently of each other.
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Affiliation(s)
- Michael R Deschenes
- Department of Kinesiology & Health Sciences, College of William & Mary, Williamsburg, Virginia, USA.,Program in Neuroscience, College of William & Mary, Williamsburg, Virginia, USA
| | - Audrey M Trebelhorn
- Department of Kinesiology & Health Sciences, College of William & Mary, Williamsburg, Virginia, USA
| | - Madeline C High
- Department of Kinesiology & Health Sciences, College of William & Mary, Williamsburg, Virginia, USA
| | - Hannah L Tufts
- Program in Neuroscience, College of William & Mary, Williamsburg, Virginia, USA
| | - Jeongeun Oh
- Department of Kinesiology & Health Sciences, College of William & Mary, Williamsburg, Virginia, USA
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Harmon KK, Stout JR, Fukuda DH, Pabian PS, Rawson ES, Stock MS. The Application of Creatine Supplementation in Medical Rehabilitation. Nutrients 2021; 13:1825. [PMID: 34071875 PMCID: PMC8230227 DOI: 10.3390/nu13061825] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/17/2021] [Accepted: 05/26/2021] [Indexed: 02/07/2023] Open
Abstract
Numerous health conditions affecting the musculoskeletal, cardiopulmonary, and nervous systems can result in physical dysfunction, impaired performance, muscle weakness, and disuse-induced atrophy. Due to its well-documented anabolic potential, creatine monohydrate has been investigated as a supplemental agent to mitigate the loss of muscle mass and function in a variety of acute and chronic conditions. A review of the literature was conducted to assess the current state of knowledge regarding the effects of creatine supplementation on rehabilitation from immobilization and injury, neurodegenerative diseases, cardiopulmonary disease, and other muscular disorders. Several of the findings are encouraging, showcasing creatine's potential efficacy as a supplemental agent via preservation of muscle mass, strength, and physical function; however, the results are not consistent. For multiple diseases, only a few creatine studies with small sample sizes have been published, making it difficult to draw definitive conclusions. Rationale for discordant findings is further complicated by differences in disease pathologies, intervention protocols, creatine dosing and duration, and patient population. While creatine supplementation demonstrates promise as a therapeutic aid, more research is needed to fill gaps in knowledge within medical rehabilitation.
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Affiliation(s)
- Kylie K. Harmon
- Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, FL 32816, USA;
| | - Jeffrey R. Stout
- Physiology of Work and Exercise Response (POWER) Laboratory, Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, FL 32816, USA; (J.R.S.); (D.H.F.)
| | - David H. Fukuda
- Physiology of Work and Exercise Response (POWER) Laboratory, Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, FL 32816, USA; (J.R.S.); (D.H.F.)
| | - Patrick S. Pabian
- Musculoskeletal Research Laboratory, Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, FL 32816, USA;
| | - Eric S. Rawson
- Department of Health, Nutrition, and Exercise Science, Messiah University, Mechanicsburg, PA 17055, USA;
| | - Matt S. Stock
- Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, FL 32816, USA;
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10
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MacLennan RJ, Ogilvie D, McDorman J, Vargas E, Grusky AR, Kim Y, Garcia JM, Stock MS. The time course of neuromuscular impairment during short-term disuse in young women. Physiol Rep 2021; 9:e14677. [PMID: 33426809 PMCID: PMC7797948 DOI: 10.14814/phy2.14677] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 11/14/2020] [Indexed: 12/27/2022] Open
Abstract
Skeletal muscle disuse results in rapid functional declines. Previous studies have typically been at least 1 week in duration and focused on the responsiveness of men. Herein, we report the timeline of initial impairments in strength, voluntary activation (VA), and motor unit control during 2 weeks of knee joint immobilization. Thirteen women (mean age =21 years) underwent 2 weeks of left knee joint immobilization via ambulation on crutches and use of a brace. Participants visited the laboratory for testing on seven occasions (two familiarization visits, pretest, 48 and 72 h, 1 and 2 weeks). Knee extensor isometric and concentric isokinetic strength at two velocities (180 and 360 degrees⋅s-1 ), VA, and submaximal vastus lateralis motor unit activity were evaluated. Moderate-to-large decreases in isometric and concentric strength at 180 degrees⋅s-1 and VA were observed within 48 hours. Isometric strength continued to decline beyond 72 h, whereas other variables plateaued. The B-term of the motor unit mean firing rate versus action potential amplitude relationship demonstrated a moderate increase 1 week into immobilization, suggesting that greater firing rates were necessary to maintain pretest torque levels. Concentric strength at a velocity of 360 degrees s-1 was not affected. Decreases in knee extensor strength occur within a matter of days after immobilization, although the time course and magnitude vary among assessment methods. These changes are mediated by the nervous system's capacity to activate skeletal muscle. Clinically appropriate interventions which target nervous system plasticity should be implemented early to minimize the rapid functional impairments associated with disuse.
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Affiliation(s)
- Rob J MacLennan
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, OK, USA
| | - David Ogilvie
- School of Kinesiology & Physical Therapy, University of Central Florida, Orlando, FL, USA.,Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, USA
| | - John McDorman
- School of Kinesiology & Physical Therapy, University of Central Florida, Orlando, FL, USA.,Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, USA
| | - Ernest Vargas
- School of Kinesiology & Physical Therapy, University of Central Florida, Orlando, FL, USA.,Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, USA
| | - Arielle R Grusky
- School of Kinesiology & Physical Therapy, University of Central Florida, Orlando, FL, USA.,Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, USA
| | - Youngdeok Kim
- Department of Kinesiology and Health Sciences, Virginia Commonwealth University, Richmond, VA, USA
| | - Jeanette M Garcia
- Department of Health Sciences, University of Central Florida, Orlando, FL, USA
| | - Matt S Stock
- School of Kinesiology & Physical Therapy, University of Central Florida, Orlando, FL, USA.,Neuromuscular Plasticity Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, USA
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