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Ergonomics Mar 2024Muscle fatigue is a primary risk factor in developing musculoskeletal disorders, which affect up to 93% musicians, especially violinists. Devices providing dynamic...
Muscle fatigue is a primary risk factor in developing musculoskeletal disorders, which affect up to 93% musicians, especially violinists. Devices providing dynamic assistive support (DAS) to the violin-holding arm can lessen fatigue. The objective was to assess DAS effects on electromyography median frequency and joint kinematics during a fatiguing violin-playing task. Fifteen university-level and professional violinists were equipped with electromyography sensors and reflective markers to record upper-body muscle activity and kinematics. They played G scales with and without DAS until exhaustion. Paired -tests assessed DAS effects on delta (final-initial) electromyography median frequencies and joint kinematics. DAS prevented the median frequency decrease of left supraspinatus, superior trapezius, and right medial deltoid, and increases in trunk rotation, left-wrist abduction, and right arm-elevation plane. DAS effects on kinematics were marginal due to retention of musical performance despite fatigue. However, DAS reduced fatigue of several muscles, which is promising for injury prevention. Violinists are greatly affected by musculoskeletal disorders. Effects of a mobility assistive device on muscle fatigue during violin playing was investigated. The assistive technology slowed down the development of fatigue for three neck/shoulder muscles, making assisted musical performance a promising avenue to prevent violinists' injuries.
Topics: Humans; Muscle Fatigue; Deltoid Muscle; Electromyography; Musculoskeletal Diseases; Neck Muscles
PubMed: 37264800
DOI: 10.1080/00140139.2023.2221416 -
Human Movement Science Feb 2022Muscle fatigue is represented as a reduction in force production capability; however, fatigue does not necessarily result in performance impairments. As the distal upper...
Muscle fatigue is represented as a reduction in force production capability; however, fatigue does not necessarily result in performance impairments. As the distal upper limb serves as the end effector when interacting or manipulating objects, it is important to understand how muscle fatigue may impact motor functionality. The aim of this study was to systematically review the literature to identify how various aspects of motor performance of the distal upper limb are impaired following muscle fatigue. Four databases were searched using 23 search terms describing the distal upper limb, muscle fatigue, and various performance metrics. A total of 4561 articles were screened with a total of 28 articles extracted and critically appraised. Evidence extracted indicates that muscle fatigue results in unique impairments based on the type of motor performance being evaluated. Furthermore, much data suggests that muscle fatigue does not result in consistent, predictable performance impairments, particularly while performing submaximal tasks. Additionally, magnitude of fatigue does not directly correlate with reductions in performance outcomes at the hand and wrist. Fatiguing protocols used highlighted the importance of fatigue specificity. When fatiguing and performance tasks are similar, performance impairment is likely to be observed. The numerous muscles found in the hand and wrist, often considered redundant, play a critical role in maintaining task performance in the presence of muscle fatigue. The presence of motor abundance (e.g. multiple muscles with similar function) is shown to reduce the impairment in multiple performance metrics by compensating for reduced function of fatigued muscles. Continued exploration into various fatiguing protocols (i.e. maximal or submaximal) will provide greater insights into performance impairments in the distal upper limb.
Topics: Humans; Muscle Contraction; Muscle Fatigue; Muscle, Skeletal; Task Performance and Analysis; Upper Extremity; Wrist; Wrist Joint
PubMed: 34929434
DOI: 10.1016/j.humov.2021.102912 -
International Journal of Environmental... Nov 2022Manual materials handling (MMH) contributes to musculoskeletal disorders (MSDs) in the workplace. The development and recovery of muscle fatigue are essential in...
Manual materials handling (MMH) contributes to musculoskeletal disorders (MSDs) in the workplace. The development and recovery of muscle fatigue are essential in work/rest arrangements for MMH tasks. A pulling experiment, including a muscle fatigue test and a muscle fatigue recovery test, was conducted. In the muscle fatigue test, the participant performed a pulling task on a treadmill with a walking velocity of 1 km/h until they could no longer do so. The load was either 30 or 45 kg. The maximum endurance time () was recorded. The pull strength () of the participant both before and after the pulling task was measured. The subjective ratings of muscle fatigue after the pulling task were recorded. In the muscle fatigue recovery test, the participant took a rest after performing the pulling task. The participants reported their subjective ratings of muscle fatigue on the scale after taking a rest for a time period where = 1, 2,…, 6 min. The of the participant was then measured again. It was found that the load significantly affected the for pulling tasks. The load was insignificant to the decrease of the , but was significant to the decrease rate ( decrease per min) of the . The decrease rate for the 45 kg condition (30.8 ± 16.5 N/min) was significantly higher ( < 0.05) than that of the 30 kg condition (15.4 ± 5.5 N/min). The recovery time significantly affected the and . Two models were established to explore the development of muscle fatigue in pulling tasks. A model was constructed to describe the recovery of muscle force. A model was proposed to show the subjective ratings of recovery. These models are beneficial for determining the work/rest allowance for pulling tasks.
Topics: Humans; Muscle Fatigue; Muscle, Skeletal; Walking; Exercise Test; Workplace
PubMed: 36429882
DOI: 10.3390/ijerph192215159 -
International Journal of Environmental... Jan 2022Manual demolition tasks are heavy, physically demanding tasks that could cause muscle fatigue accumulation and lead to work-related musculoskeletal disorders (WMSDs)....
Manual demolition tasks are heavy, physically demanding tasks that could cause muscle fatigue accumulation and lead to work-related musculoskeletal disorders (WMSDs). Fatigue and recovery models of muscles are essential in understanding the accumulation and the reduction in muscle fatigue for forceful exertion tasks. This study aims to explore the onset of muscle fatigue under different work/rest arrangements during manual demolition tasks and the offset of fatigue over time after the tasks were performed. An experiment, including a muscle fatigue test and a muscle fatigue recovery test, was performed. Seventeen male adults without experience in demolition hammer operation were recruited as human participants. Two demolition hammers (large and small) were adopted. The push force was either 20 or 40 N. The posture mimicked that of a demolition task on a wall. In the muscle fatigue test, the muscle strength () before and after the demolition task, maximum endurance time (MET), and the Borg category-ratio-10 (CR-10) ratings of perceived exertion after the demolition task were measured. In the muscle fatigue recovery test, and CR-10 at times 1, 2, 3, 4, 5, and 6 min were recorded. Statistical analyses were performed to explore the influence of push force and the weight of the tool on , MET, and CR-10. Both muscle fatigue models and muscle fatigue recovery models were established and validated. The results showed that push force affected MET significantly ( < 0.05). The weight of the tool was significant ( < 0.05) only on the CR-10 rating after the first pull. During the muscle fatigue recovery test, the increase and the CR-10 decrease were both significant ( < 0.05) after one or more breaks. Models of MET and prediction were established to assess muscle fatigue recovery, respectively. The absolute (AD) and relative (RD) deviations of the MET model were 1.83 (±1.94) min and 34.80 (±31.48)%, respectively. The AD and RD of the model were 1.39 (±0.81) N and 1.9 (±1.2)%, respectively. These models are capable of predicting the progress and recovery of muscle fatigue, respectively, and may be adopted in work/rest arrangements for novice workers performing demolition tasks.
Topics: Adult; Electromyography; Humans; Male; Muscle Fatigue; Muscle Strength; Muscle, Skeletal; Muscles; Musculoskeletal Diseases; Posture
PubMed: 35055755
DOI: 10.3390/ijerph19020930 -
Experimental Physiology Dec 2021What is the central question of this review? Is exposure to a hot environment detrimental to neuromuscular performance? What is the main finding and what is its... (Review)
Review
NEW FINDINGS
What is the central question of this review? Is exposure to a hot environment detrimental to neuromuscular performance? What is the main finding and what is its importance? Elevating body temperature improves peak power during short-duration, high-intensity exercise but trades off with an accelerated rate of decay. Higher muscle temperatures and cross-bridge cycling rate resemble a shift in contractile characteristic to a faster phenotype. Prolonged moderate-intensity exercise capacity is impaired in a hot environment. Fatigue appears to combine a reduced drive from the CNS and increased cardiovascular strain to maintain skeletal muscle perfusion and thermoregulation.
ABSTRACT
The effect of thermal stress on human work capacity and neuromuscular function has been of interest to physiologists since the 19th century. The aim of the present review is to examine the impact of exposure to heat stress on neuromuscular performance. Exposure to heat stress during exercise is known to increase strain on the cardiovascular system owing to the competing demands of skeletal muscle perfusion and homeostatic thermoregulation. The effects of exposure to heat stress on the neuromuscular system are more complex, because in some circumstances an elevation in muscle temperature leads to an improvement in function, whereas in other circumstances an increase in temperature leads to a decrement in function that is a consequence of the mode, metabolic demand and duration of the exercise. The ability to sustain isometric tension is impaired with an elevated muscle temperature and so too is locomotor capacity over prolonged periods of time. In contrast, peak power production is enhanced by increasing muscle temperature but is achieved at the expense of maintaining power output, owing to a higher rate of decay in power production. The different effects on neuromuscular function at an elevated muscle temperature are explained, in part, by a higher rate of energy turnover. In addition, the effect of an elevated core temperature also appears to impair neuromuscular performance either owing to a reduced voluntary drive in motor unit recruitment or to a failure in muscle afferent feedback, or a combination of the two.
Topics: Body Temperature Regulation; Heat Stress Disorders; Heat-Shock Response; Hot Temperature; Humans; Muscle Contraction; Muscle Fatigue; Muscle, Skeletal
PubMed: 32608071
DOI: 10.1113/EP088191 -
Journal of Strength and Conditioning... Jun 2020Pinto, BL and McGill, SM. Voluntary muscle relaxation can mitigate fatigue and improve countermovement jump performance. J Strength Cond Res 34(6): 1525-1529, 2020-When... (Clinical Trial)
Clinical Trial
Pinto, BL and McGill, SM. Voluntary muscle relaxation can mitigate fatigue and improve countermovement jump performance. J Strength Cond Res 34(6): 1525-1529, 2020-When muscles contract, they create force and stiffness. Thus, muscle activation and relaxation must be strategically sequenced to coordinate and control movement, to enhance athletic variables such as speed and strength. However, research has favored investigation of muscle activation over relaxation. Athletes such as runners, swimmers, and boxers often shake their limbs to allow the muscle to oscillate freely, immediately before a bout. The purpose was to investigate whether shaking the lower limbs with the intention to voluntarily relax the muscles of the limb has an effect on countermovement jump (CMJ) performance. Subjects performed 10 maximal effort CMJs with 30 seconds of rest between each jump. During the rest period, they either performed the relaxation technique or control condition (standing still). Statistical significance was considered at p < 0.05. Subjects significantly improved jump height, compared with their first jump of the day, when performing the relaxation technique. To further investigate the mechanism of enhancement, subjects were grouped into responders and nonresponders. The responder group significantly decreased their jump height and concentric phase impulse (relative to the first jump) during the control condition compared with the nonresponder group, indicating fatigue. When performing the relaxation technique, the responder group improved their jump height and mitigated fatigue by significantly increasing their unweighting impulse and unweighting force. The relaxation technique improved CMJ performance, specifically in those that fatigue with consecutive bouts, by enhancing unweighting, that requires muscle relaxation, rather than propulsion that requires activation. This technique can be useful for training or competition.
Topics: Adult; Athletes; Athletic Performance; Humans; Male; Muscle Fatigue; Muscle Relaxation; Muscle Strength; Muscle, Skeletal; Rest; Running; Young Adult
PubMed: 31714458
DOI: 10.1519/JSC.0000000000003326 -
European Journal of Applied Physiology Mar 2021Performance in self-paced endurance exercises results from continuous fatigue symptom management. While it is suggested that perceived responses and neuromuscular... (Review)
Review
Performance in self-paced endurance exercises results from continuous fatigue symptom management. While it is suggested that perceived responses and neuromuscular fatigue development may determine variations in exercise intensity, it is uncertain how these fatigue components interact throughout the task. To address the fatigue development in self-paced endurance exercises, the following topics were addressed in the present review: (1) fatigue development during constant-load vs. self-paced endurance exercises; (2) central and peripheral fatigue and perceived exertion interconnections throughout the self-paced endurance exercises; and (3) future directions and recommendations. Based on the available literature, it is suggested (1) the work rate variations during a self-paced endurance exercise result in transitions between exercise intensity domains, directly impacting the end-exercise central and peripheral fatigue level when compared to constant-load exercise mode; (2) central and peripheral fatigue, as well as perceived exertion response contribute to exercise intensity regulation at the different stages of the trial. It seems that while neuromuscular fatigue development might be relevant at beginning of the trial, the perceived exertion might interfere in the remaining parts to achieve maximal values only at the finish line; (3) future studies should focus on the mechanisms underpinning fatigue components interactions throughout the task and its influence on exercise intensity variations.
Topics: Exercise; Humans; Mental Fatigue; Muscle Fatigue; Physical Endurance; Physical Exertion; Running
PubMed: 33389141
DOI: 10.1007/s00421-020-04549-5 -
Journal of Manipulative and... 2022The purpose of this study was to examine the effects of submaximal isometric neck muscle fatigue and manual therapy on wrist joint position sense (JPS) within healthy...
OBJECTIVE
The purpose of this study was to examine the effects of submaximal isometric neck muscle fatigue and manual therapy on wrist joint position sense (JPS) within healthy individuals and individuals with subclinical neck pain (SCNP).
METHODS
Twelve healthy participants and 12 participants with SCNP were recruited. Each group completed 2 sessions, with 48 hours between sessions. On day 1, both groups performed 2 wrist JPS tests using a robotic device. The tests were separated by a submaximal isometric fatigue protocol for the cervical extensor muscles (CEM). On day 2, both groups performed a wrist JPS test, followed by a cervical treatment consisting of manual therapy (SCNP) or neck rest (20 minutes, control group) and another wrist JPS test. Joint position sense was measured as the participant's ability to recreate a previously presented wrist angle. Each wrist JPS test included 12 targets, 6 into wrist flexion and 6 into wrist extension. Kinematic data from the robot established absolute, variability, and constant error.
RESULTS
Absolute error significantly decreased (P = .01) from baseline to post-fatigue in the SCNP group (baseline = 4.48 ± 1.58°; post-fatigue = 3.90 ± 1.45°) and increased in the control group (baseline = 3.12 ± 0.98°; post-fatigue = 3.81 ± 0.90°). The single session of manual cervical treatment significantly decreased absolute error in participants with SCNP (P = .004).
CONCLUSION
This study demonstrated that neck pain or fatigue can lead to altered afferent input to the central nervous system and can affect wrist JPS. Our findings demonstrate that acute wrist proprioception may be improved in individuals with SCNP by a single cervical manual therapy session.
Topics: Humans; Muscle Fatigue; Musculoskeletal Manipulations; Neck Pain; Proprioception; Wrist; Wrist Joint
PubMed: 35906104
DOI: 10.1016/j.jmpt.2022.06.002 -
Journal of Applied Physiology... Aug 2022The purpose was to investigate whether postactivation potentiation (PAP) mitigates power (i.e., torque × angular velocity) loss during dynamic fatiguing contractions...
The purpose was to investigate whether postactivation potentiation (PAP) mitigates power (i.e., torque × angular velocity) loss during dynamic fatiguing contractions and subsequent recovery by enhancing either muscle torque or angular velocity in human plantar flexors. In 12 participants, electrically stimulated (1, 10, and 50 Hz) dynamic contractions were done during a voluntary isotonic fatiguing protocol until a 75% loss in voluntary peak power, and throughout 30 min of recovery. At the initial portion of fatigue (20% decrease), power responses of evoked low frequencies (1 and 10 Hz) were enhanced due to PAP (156% and 137%, respectively, < 0.001), whereas voluntary maximal efforts were depressed due to fatiguing mechanisms. Following the fatiguing task, prolonged low-frequency force depression (PLFFD) was evident by reduced 10:50 Hz peak power ratios (21%-24%) from 3 min onward during the 30-min recovery ( < 0.005). Inducing PAP with maximal voluntary dynamic contractions during PLFFD enhanced the peak power responses of low frequencies (1 and 10 Hz) by 128%-160%, < 0.01. This PAP response mitigated the effects of PLFFD as the 1:50 ( < 0.05) and 10:50 ( > 0.4) Hz peak power ratios were greater or not different from the prefatigue (baseline) values. In addition, PAP enhanced peak torque more than peak angular velocity during both baseline and fatigue measurements ( < 0.03). These results indicate that PAP can ameliorate PLFFD acutely when evaluated during concentric isotonic contractions and that peak torque is enhanced to a greater degree compared with peak angular velocity at baseline and in a fatigued state. Postactivation potentiation (PAP) enhanced stimulated low frequencies (1 and 10 Hz) during muscle fatigue development when assessed with power (torque × angular velocity) in a voluntary isotonic fatiguing task. Following the task during 30 min of recovery, prolonged low-frequency force depression (PLFFD) was evident, and inducing PAP with brief maximal contractions during this state ameliorated the effects of PLFFD. PAP enhanced peak torque more than peak angular velocity during both baseline and fatiguing conditions.
Topics: Animals; Electric Stimulation; Fishes; Humans; Isometric Contraction; Isotonic Contraction; Muscle Contraction; Muscle Fatigue; Muscle, Skeletal; Torque
PubMed: 35796610
DOI: 10.1152/japplphysiol.00214.2022 -
Acta of Bioengineering and Biomechanics 2023This study was aimed at investigating the joint regulations and body sway after general muscle fatigue during tasks that involve both static and dynamic balance. This...
This study was aimed at investigating the joint regulations and body sway after general muscle fatigue during tasks that involve both static and dynamic balance. This cross-sectional study used motion analysis to ascertain the kinematic changes in twelve healthy young individuals before and after running-induced fatigue. Six linear and nonlinear stability metrics were calculated to assess the whole body and joint-related variations. Significant instabilities were observed in the hip and specifically in the knee mechanisms and the whole body during the static condition. Velocity path length and approximate entropy for knee ( p = 0.019, p = 0.027) and hip ( p = 0.016, p = 0.042) were significantly greater after fatigue. These parameters for the whole body center of mass were also higher after fatigue ( p = 0.013, p = 0.013). General muscle fatigue did not significantly affect the ankle during static and dynamic standing ( p > 0.05). Dynamic standing did not reveal the effects of fatigue either on local joint regulations or on the whole body except for the nonlinear metrics of the proximal joints. The knee and hip were adversely affected by fatigue while the ankle strove to compensate for the fatigue-induced instability.
Topics: Humans; Muscle Fatigue; Cross-Sectional Studies; Hip Joint; Lower Extremity; Muscle, Skeletal; Ankle Joint; Postural Balance
PubMed: 38314530
DOI: No ID Found