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Scanning 2022In order to use the surface EMG signal to detect the muscle fatigue state, a research method of the muscle exercise fatigue intelligent scanning detection system based...
In order to use the surface EMG signal to detect the muscle fatigue state, a research method of the muscle exercise fatigue intelligent scanning detection system based on surface EMG was proposed, and the sEMG signal features of 10 subjects before and after fatigue were extracted. A time-varying parameter autoregressive model is established. By introducing the Legendre basis function, the parameter identification of the linear nonstationary process is transformed into the parameter identification of the linear time-invariant system. Combined with the correlation index, the optimal Legendre base function dimension of the time-varying system parameter estimation can be obtained, then the best model fitting effect can be obtained, and the time-invariant parameters are solved by the least square method. Using the rate of change of the first time-varying parameter (ARC1) of the autoregressive model before and after fatigue as an index to detect muscle fatigue sensitivity, a two-tailed test was used to compare the mean power frequency (MPF) and the median frequency (MF) with the rate of change. The results showed that the change rates of ARC1, MPF, and MF before and after fatigue were34.33% ± 2.5%, 68% + 2.03%, and 22.80% + 2.19%, which were 41% and 25%, respectively. The rate of change of ACR1 was significantly higher than that of MPF and MF ( < 0.05). When detecting muscle fatigue by sEMG signal, it has the advantages of short time and high sensitivity. It can be used for online real-time analysis of muscle fatigue, providing a potential analysis tool for limb muscle strain, rehabilitation, and ergonomics assessment.
Topics: Electromyography; Humans; Muscle Fatigue; Muscles
PubMed: 36101524
DOI: 10.1155/2022/9163978 -
Journal of Medical Systems Jan 2016Analysis of neuromuscular fatigue finds various applications ranging from clinical studies to biomechanics. Surface electromyography (sEMG) signals are widely used for...
Analysis of neuromuscular fatigue finds various applications ranging from clinical studies to biomechanics. Surface electromyography (sEMG) signals are widely used for these studies due to its non-invasiveness. During cyclic dynamic contractions, these signals are nonstationary and cyclostationary. In recent years, several nonstationary methods have been employed for the muscle fatigue analysis. However, cyclostationary based approach is not well established for the assessment of muscle fatigue. In this work, cyclostationarity associated with the biceps brachii muscle fatigue progression is analyzed using sEMG signals and Spectral Correlation Density (SCD) functions. Signals are recorded from fifty healthy adult volunteers during dynamic contractions under a prescribed protocol. These signals are preprocessed and are divided into three segments, namely, non-fatigue, first muscle discomfort and fatigue zones. Then SCD is estimated using fast Fourier transform accumulation method. Further, Cyclic Frequency Spectral Density (CFSD) is calculated from the SCD spectrum. Two features, namely, cyclic frequency spectral area (CFSA) and cyclic frequency spectral entropy (CFSE) are proposed to study the progression of muscle fatigue. Additionally, degree of cyclostationarity (DCS) is computed to quantify the amount of cyclostationarity present in the signals. Results show that there is a progressive increase in cyclostationary during the progression of muscle fatigue. CFSA shows an increasing trend in muscle fatiguing contraction. However, CFSE shows a decreasing trend. It is observed that when the muscle progresses from non-fatigue to fatigue condition, the mean DCS of fifty subjects increases from 0.016 to 0.99. All the extracted features found to be distinct and statistically significant in the three zones of muscle contraction (p < 0.05). It appears that these SCD features could be useful in the automated analysis of sEMG signals for different neuromuscular conditions.
Topics: Adult; Electromyography; Fourier Analysis; Humans; Muscle Fatigue; Muscle, Skeletal
PubMed: 26547848
DOI: 10.1007/s10916-015-0394-0 -
Physical Therapy Dec 2001Muscle fatigue is frequently defined as a temporary loss in force- or torque-generating ability because of recent, repetitive muscle contraction (1). The development of... (Review)
Review
Muscle fatigue is frequently defined as a temporary loss in force- or torque-generating ability because of recent, repetitive muscle contraction (1). The development of this temporary loss of force is a complex process and results from the failure of a number of processes, including motor unit recruitment and firing rate, chemical transmission across the neuromuscular junction, propagation of the action potential along the muscle membrane and T tubules, Ca2+ release from the sarcoplasmic reticulum (SR), Ca2+ binding to troponin C, and cross-bridge cycling (for detailed reviews, see Bigland-Ritchie and Woods(1), McLester(2), and Favero(3)). Muscle fatigue may limit the time a person can stand, the distance a person can ambulate, or the number of stairs a person can ascend or descend. In practical terms, however, we cannot know what actually leads to a decline in function for a given patient. For a phenomenon that may have profound clinical implications, muscle fatigue often receives inadequate attention in physiology textbooks, many of which contain a page or less of information on the entire topic (4-8). In addition, many textbooks report that muscle fatigue is mainly the result of a decrease in pH within the muscle cell due to a rise in hydrogen ion concentration ([H+]) resulting from anaerobic metabolism and the accumulation of lactic acid (6-8). Recent literature, however, contradicts this assertion (9-10). The purpose of this update, therefore, is to provide a brief review of the role of pH in the development of muscle fatigue.
Topics: Animals; Humans; Hydrogen-Ion Concentration; Muscle Fatigue; Muscle, Skeletal
PubMed: 11736624
DOI: No ID Found -
Revue Des Maladies Respiratoires Sep 2004
Review
Topics: Electric Stimulation; Electromagnetic Phenomena; Humans; Muscle Contraction; Muscle Fatigue; Respiratory Muscles; Work of Breathing
PubMed: 15536390
DOI: 10.1016/s0761-8425(04)71430-8 -
Applied Ergonomics Apr 2024Muscle fatigue monitoring, an important element in a fatigue risk management process, can help optimize work intensity and reduce risks for musculoskeletal injuries. An...
Muscle fatigue monitoring, an important element in a fatigue risk management process, can help optimize work intensity and reduce risks for musculoskeletal injuries. An experiment was conducted to determine whether myoelectric manifestations of muscle fatigue can reflect the pace of fatigue development associated with varying load intensity. Twenty male participants performed elbow flexion-extension movements with alternating hand loads (2 kg vs. 1 kg) for 16 min. The pace of fatigue in the biceps brachii in response to load variation was quantified by electromyographic (EMG) fatigue measures collected during the dynamic elbow flexion-extension movements and periodic submaximal isometric elbow flexion trials. The isometric and dynamic EMG measures, except for the amplitude of dynamic EMG, indicated fatigue development during the 2-kg isotonic movements and partial recovery with the 1 kg load. Study results suggest the potential of EMG measures for fatigue monitoring during dynamic work tasks with varying load intensity.
Topics: Male; Humans; Muscle Fatigue; Elbow; Electromyography; Muscle, Skeletal; Upper Extremity; Isometric Contraction
PubMed: 38160628
DOI: 10.1016/j.apergo.2023.104217 -
Medicine and Science in Sports and... Nov 2016: This paper highlights some key concepts related to fatigue and the seminal role of the 1981 Ciba Foundation Symposia "Human Muscle Fatigue: Physiological Mechanisms"... (Review)
Review
: This paper highlights some key concepts related to fatigue and the seminal role of the 1981 Ciba Foundation Symposia "Human Muscle Fatigue: Physiological Mechanisms" chaired by R.H.T. Edwards in consolidating key ideas that have moved the study of fatigue forward since that time. I also consider these concepts in their historical context via the pioneering work of the Italian physiologist and social activist Angelo Mosso in the late 1800s. Finally, fatigue as a multidimensional concept with implications beyond muscle physiology is considered.
Topics: Fatigue; Humans; Muscle Fatigue; Sports
PubMed: 27031741
DOI: 10.1249/MSS.0000000000000938 -
The Journal of Physiology Sep 2008During intense exercise or electrical stimulation of skeletal muscle the concentrations of several ions change simultaneously in interstitial, transverse tubular and... (Review)
Review
During intense exercise or electrical stimulation of skeletal muscle the concentrations of several ions change simultaneously in interstitial, transverse tubular and intracellular compartments. Consequently the functional effects of multiple ionic changes need to be considered together. A diminished transsarcolemmal K(+) gradient per se can reduce maximal force in non-fatigued muscle suggesting that K(+) causes fatigue. However, this effect requires extremely large, although physiological, K(+) shifts. In contrast, moderate elevations of extracellular [K(+)] ([K(+)](o)) potentiate submaximal contractions, enhance local blood flow and influence afferent feedback to assist exercise performance. Changed transsarcolemmal Na(+), Ca(2+), Cl(-) and H(+) gradients are insufficient by themselves to cause much fatigue but each ion can interact with K(+) effects. Lowered Na(+), Ca(2+) and Cl(-) gradients further impair force by modulating the peak tetanic force-[K(+)](o) and peak tetanic force-resting membrane potential relationships. In contrast, raised [Ca(2+)](o), acidosis and reduced Cl(-) conductance during late fatigue provide resistance against K(+)-induced force depression. The detrimental effects of K(+) are exacerbated by metabolic changes such as lowered [ATP](i), depleted carbohydrate, and possibly reactive oxygen species. We hypothesize that during high-intensity exercise a rundown of the transsarcolemmal K(+) gradient is the dominant cellular process around which interactions with other ions and metabolites occur, thereby contributing to fatigue.
Topics: Animals; Humans; Ions; Mice; Muscle Fatigue; Muscle, Skeletal
PubMed: 18591187
DOI: 10.1113/jphysiol.2008.155424 -
Journal of Neurophysiology Mar 2017Neuromuscular fatigue is due, in part, to central processes that involve failure of the nervous system to drive muscles maximally during exercise. A recent study by... (Review)
Review
Neuromuscular fatigue is due, in part, to central processes that involve failure of the nervous system to drive muscles maximally during exercise. A recent study by Abdelmoula, Baudry, and Duchateau ( 322: 94-103, 2016) showed that noninvasive brain stimulation can mitigate neuromuscular fatigue, however, does not rely on enhanced corticospinal excitability of the primary motor cortex. These findings are of high clinical importance because rehabilitative therapies are necessary to mitigate neuromuscular fatigue for patients with central nervous system disorders.
Topics: Humans; Motor Cortex; Muscle Contraction; Muscle Fatigue; Muscle, Skeletal; Transcranial Magnetic Stimulation
PubMed: 27440245
DOI: 10.1152/jn.00468.2016 -
Annals of the New York Academy of... Apr 2002
Topics: Animals; Mice; Muscle Contraction; Muscle Fatigue; Oculomotor Muscles
PubMed: 11960823
DOI: 10.1111/j.1749-6632.2002.tb02838.x -
Acta Physiologica Scandinavica Mar 1998A decline of isometric force production is one characteristic of skeletal muscle fatigue. In fatigue produced by repeated short tetani, this force decline can be divided... (Review)
Review
A decline of isometric force production is one characteristic of skeletal muscle fatigue. In fatigue produced by repeated short tetani, this force decline can be divided into two components: a reduction of the cross-bridges' ability to generate force, which comes early; and a reduction of the sarcoplasmic reticulum Ca2+ release, which develops late in fatigue. Acidification due to lactic acid accumulation has been considered as an important cause of the reduced cross-bridge force production. However, in mammalian muscle it has been shown that acidification has little effect on isometric force production at physiological temperatures. By exclusion, in mammalian muscle fatigue, the reduction of force due to impaired cross-bridge function would be caused by accumulation of inorganic phosphate ions, which results from phosphocreatine breakdown. The reduction of sarcoplasmic reticulum Ca2+ release in late fatigue correlates with a decline of ATP and we speculate that the reduced Ca2+ release is caused by a local increase of the ADP/ATP ratio in the triads.
Topics: Animals; Humans; Isometric Contraction; Muscle Fatigue; Muscle, Skeletal
PubMed: 9578370
DOI: 10.1046/j.1365-201X.1998.0301f.x