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Sensors (Basel, Switzerland) Feb 2022The objective detection of muscle fatigue reports the moment at which a muscle fails to sustain the required force. Such a detection prevents any further injury to the...
The objective detection of muscle fatigue reports the moment at which a muscle fails to sustain the required force. Such a detection prevents any further injury to the muscle following fatigue. However, the objective detection of muscle fatigue still requires further investigation. This paper presents an algorithm that employs a new fatigue index for the objective detection of muscle fatigue using a double-step binary classifier. The proposed algorithm involves analyzing the acquired sEMG signals in both the time and frequency domains in a double-step investigation. The first step involves calculating the value of the integrated EMG (IEMG) to determine the continuous contraction of the muscle being investigated. It was found that the IEMG value continued to increase with prolonged muscle contraction and progressive fatigue. The second step involves differentiating between the high-frequency components (HFC) and low-frequency components (LFC) of the EMG, and calculating the fatigue index. Basically, the segmented EMG signal was filtered by two band-pass filters separately to produce two sub-signals, namely, a high-frequency sub-signal (HFSS) and a low-frequency sub-signal (LFSS). Then, the instantaneous mean amplitude (IMA) was calculated for the two sub-signals. The proposed algorithm indicates that the IMA of the HFSS tends to decrease during muscle fatigue, while the IMA of the LFSS tends to increase. The fatigue index represents the difference between the IMA values of the LFSS and HFSS, respectively. Muscle fatigue was found to be present and was objectively detected when the value of the proposed fatigue index was equal to or greater than zero. The proposed algorithm was tested on 75 EMG signals that were extracted from 75 middle deltoid muscles. The results show that the proposed algorithm had an accuracy of 94.66% in distinguishing between conditions of muscle fatigue and non-fatigue.
Topics: Algorithms; Electromyography; Muscle Contraction; Muscle Fatigue; Muscle, Skeletal
PubMed: 35271046
DOI: 10.3390/s22051900 -
Nutrients Aug 2010Alcohol consumption within elite sport has been continually reported both anecdotally within the media and quantitatively in the literature. The detrimental effects of... (Review)
Review
Alcohol consumption within elite sport has been continually reported both anecdotally within the media and quantitatively in the literature. The detrimental effects of alcohol on human physiology have been well documented, adversely influencing neural function, metabolism, cardiovascular physiology, thermoregulation and skeletal muscle myopathy. Remarkably, the downstream effects of alcohol consumption on exercise performance and recovery, has received less attention and as such is not well understood. The focus of this review is to identify the acute effects of alcohol on exercise performance and give a brief insight into explanatory factors.
Topics: Alcohol Drinking; Athletic Performance; Body Temperature Regulation; Central Nervous System Depressants; Dehydration; Ethanol; Exercise; Humans; Hypoglycemia; Muscle Fatigue; Muscle, Skeletal
PubMed: 22254055
DOI: 10.3390/nu2080781 -
International Journal of Environmental... Oct 2022Muscles are affected at the cellular level by exercised-induced fatigue, inducing changes in their stiffness. Examining muscle stiffness can improve the knowledge of...
Muscles are affected at the cellular level by exercised-induced fatigue, inducing changes in their stiffness. Examining muscle stiffness can improve the knowledge of various pathologic conditions, such as pain and injury. The objective of this study was to examine the stiffness of the medial gastrocnemius (MG) muscle and the lateral gastrocnemius (LG) muscle to determine the changes in stiffness, and to assess the differences in the stiffness between the MG and the LG, as affected by muscle fatigue measured using shear wave elastography (SWE) and a MyotonPRO after inducing muscle fatigue. A total of 35 healthy young adults participated in the study. The stiffness of the MG and the LG were assessed before and after a muscle fatigue protocol (MFP), which included three sets of 50 eccentric contractions of the calf muscles of the dominant leg, at rest, and at maximum voluntary contraction (MVC). The measurements were taken with SWE and the MyotonPRO simultaneously. Compared to baseline, the resting stiffness of the MG and the LG significantly increased immediately, 24 h, and 48 h after muscle fatigue ( < 0.05); however, during MVC, the stiffness of the MG decreased ( < 0.05) and that of the LG showed no change ( > 0.05). When the stiffness of the MG and the LG were compared before and after the MFP, changes in the stiffness of the MG were significantly greater than those in the LG ( < 0.05). This signifies that the MG was more affected by the exercise-induced muscle fatigue than was the LG. The assessment of musculoskeletal tissue and its characteristics, before and after eccentric exercise, is crucial in the prevention of overuse injuries associated with repeated exposure to both low and high levels of force.
Topics: Young Adult; Humans; Muscle Fatigue; Muscle, Skeletal; Elasticity Imaging Techniques; Leg; Exercise
PubMed: 36360770
DOI: 10.3390/ijerph192113891 -
Advances in Experimental Medicine and... 1995In conscious humans, fatiguing muscular contractions are accompanied by a decrease in the discharge rate of alpha motoneurons. The association between alpha motoneuron... (Review)
Review
In conscious humans, fatiguing muscular contractions are accompanied by a decrease in the discharge rate of alpha motoneurons. The association between alpha motoneuron discharge rate and the generation of force by skeletal muscle has been called "muscle wisdom" (Marsden et al., 1983). Its purpose is believed to ensure that central neural drive to skeletal muscle, which is fatigued, matches that needed to generate the required force. In addition, muscle wisdom may be one mechanism that functions either to decrease or to postpone central neural fatigue (Enoka & Stuart, 1992). Bigland-Ritchie and colleagues (1986) have suggested that a reflex arising from fatigued skeletal muscle is responsible, at least in part, for muscle wisdom. This chapter has two purposes. The first is to evaluate the evidence that a reflex arising from fatigued skeletal muscle causes muscle wisdom, and the second is to examine the discharge properties of muscle afferents to determine which ones are most likely to initiate reflexly this phenomenon.
Topics: Afferent Pathways; Animals; Humans; Motor Neurons; Muscle Contraction; Muscle Fatigue
PubMed: 8585456
DOI: 10.1007/978-1-4899-1016-5_21 -
Acta Paediatrica (Oslo, Norway : 1992) Nov 2003It has been shown at similar relative work rates that children have higher resistance to fatigue than adults during repeated bouts of high-intensity exercise. This... (Review)
Review
UNLABELLED
It has been shown at similar relative work rates that children have higher resistance to fatigue than adults during repeated bouts of high-intensity exercise. This age-related difference in fatigue resistance may be explained by factors including muscle mass, muscle morphology, energy metabolism and neuromuscular activation.
CONCLUSION
During high-intensity intermittent exercise, recovery periods play an important role in limiting fatigue. Age-related differences in fatigue resistance could also be explained by differences in the rates of resynthesis of some energetic substrates and the rates of removal of various muscle metabolites.
Topics: Age Factors; Exercise; Humans; Models, Biological; Muscle Fatigue; Muscle, Skeletal; Physical Endurance
PubMed: 14696843
DOI: No ID Found -
Acta Physiologica Scandinavica Mar 1998The efficiency of energy transduction is defined as the ratio of the work done by a muscle to the free energy change of the chemical processes driving contraction. Two... (Review)
Review
The efficiency of energy transduction is defined as the ratio of the work done by a muscle to the free energy change of the chemical processes driving contraction. Two examples of the experimental measurement of muscle efficiency are: (1) the classical method of Hill which measures the value during a steady state of shortening, (2) measuring the overall efficiency during a complete cycle of a sinusoidal process, which comes closer to the situation during natural locomotion. The reasons why fatigue might lower efficiency are the following. (1) The reduction in PCr concentration and increase in Pi and Cr concentration which are characteristic of fatigued muscle, reduce the free energy of PCr splitting. This will reduce the efficiency of the recovery process. It is not known whether the efficiency of the initial process is increased to compensate. (2) There is a general conflict between efficiency and power output when motor units are chosen for a task or when the timing of activation is decided. During fatigue more powerful units have to be used to achieve a task which is no longer within the scope of less powerful units. (3) The slowing of relaxation that is sometimes found with fatigue may make it impossible to achieve the short periods of activity required for optimum efficiency during rapid cyclical movements. A reason why fatigue might increase efficiency is that muscles are thought to be more efficient energy converters when not fully activated than when fully active. Full activation is often not achieved in muscle which is considerably fatigued. Available observations do not allow us to find where the balance between these factors lies. The conclusion is thus that experiments of both the types discussed here should be performed.
Topics: Animals; Energy Metabolism; Humans; Muscle Fatigue; Muscle, Skeletal
PubMed: 9578372
DOI: 10.1046/j.1365-201X.1998.0294e.x -
European Journal of Applied Physiology Nov 2023
Topics: Humans; Muscle Contraction; Muscle Fatigue; Muscle, Skeletal; Potassium
PubMed: 37728786
DOI: 10.1007/s00421-023-05313-1 -
Human Factors Mar 2022The purpose of this study was to evaluate localized muscle fatigue responses at three upper-extremity ergonomics threshold limit value (TLV) duty cycles.
OBJECTIVE
The purpose of this study was to evaluate localized muscle fatigue responses at three upper-extremity ergonomics threshold limit value (TLV) duty cycles.
BACKGROUND
Recently, a TLV equation was published to help mitigate excessive development of localized muscle fatigue in repetitive upper limb tasks. This equation predicts acceptable levels of maximal voluntary contraction (% MVC) for a given duty cycle (DC). Experimental validation of this TLV curve has not yet been reported, which can help guide utilization by practitioners.
METHOD
Eighteen participants performed intermittent isometric elbow flexion efforts, in three separate counter-balanced sessions, at workloads defined by the American Conference of Governmental Industrial Hygenists' (ACGIH) TLV equation: low DC (20% DC, 29.6% MVC), medium DC (40% DC, 19.7% MVC), and high DC (60% DC, 13.9% MVC). Targeted localized muscle fatigue (LMF) of the biceps brachii was tracked across numerous response variables, including decline in strength (MVC), electromyography (EMG) amplitude and mean power frequency (MnPF), and several psychophysical ratings.
RESULTS
At task completion, biceps MnPF and MVC (strength) were significantly different between each TLV workload, with the high DC condition eliciting the largest declines in MnPF and MVC.
CONCLUSION
Findings demonstrate that working at different DCs along the ACGIH TLV curve may not be equivalent in preventing excessive LMF. Higher DC workloads elicited a greater LMF response across several response variables.
APPLICATION
High DC work of the upper extremity should be avoided to mitigate excess LMF development. Current TLVs for repetitive upper-extremity work may overestimate acceptable relative contraction thresholds, particularly at higher duty cycles.
Topics: Electromyography; Ergonomics; Humans; Muscle Contraction; Muscle Fatigue; Muscle, Skeletal; Threshold Limit Values; Upper Extremity
PubMed: 32757794
DOI: 10.1177/0018720820940536 -
Gait & Posture Jun 2022
Topics: Fatigue; Gait; Humans; Isometric Contraction; Muscle Contraction; Muscle Fatigue; Muscle, Skeletal; Muscles; Posture; Torque
PubMed: 32950359
DOI: 10.1016/j.gaitpost.2020.09.011 -
Sensors (Basel, Switzerland) 2011Muscle fatigue is an established area of research and various types of muscle fatigue have been investigated in order to fully understand the condition. This paper gives... (Review)
Review
Muscle fatigue is an established area of research and various types of muscle fatigue have been investigated in order to fully understand the condition. This paper gives an overview of the various non-invasive techniques available for use in automated fatigue detection, such as mechanomyography, electromyography, near-infrared spectroscopy and ultrasound for both isometric and non-isometric contractions. Various signal analysis methods are compared by illustrating their applicability in real-time settings. This paper will be of interest to researchers who wish to select the most appropriate methodology for research on muscle fatigue detection or prediction, or for the development of devices that can be used in, e.g., sports scenarios to improve performance or prevent injury. To date, research on localised muscle fatigue focuses mainly on the clinical side. There is very little research carried out on the implementation of detecting/predicting fatigue using an autonomous system, although recent research on automating the process of localised muscle fatigue detection/prediction shows promising results.
Topics: Humans; Isometric Contraction; Muscle Contraction; Muscle Fatigue; Myography; Signal Processing, Computer-Assisted; Spectroscopy, Near-Infrared; Sports Medicine
PubMed: 22163810
DOI: 10.3390/s110403545