BACKGROUND:Skeletal muscle aging is associated with various chronic diseases.Exercise is considered an important means to delay this process,but the multimechanism regulation of exercise intervention strategies still requires in-depth exploration.OBJECTIVE:To systematically outline the main physiological changes in skeletal muscle aging and explore the multiple mechanisms by which exercise regulates these changes,thereby providing a theoretical basis for basic research and clinical applications.METHODS:By searching databases such as Web of Science,PubMed,Embase,CNKI,WanFang,and VIP,relevant literature from database inception to October 2024 was retrieved by the first author,including original research articles and reviews.The search terms were"skeletal muscle aging,sarcopenia,exercise regulation,physical activity,chronic inflammation,inflammaging,mitochondrial dysfunction,extracellular matrix fibrosis,lipid mediators,satellite cells"in English and Chinese.Literature was screened based on inclusion and exclusion criteria,and the included 95 articles underwent quality assessment and data extraction.RESULTS AND CONCLUSION:(1)The core manifestations of skeletal muscle aging are the decline in muscle mass,strength,and function,closely related to various physiological changes.The decreased protein synthesis capacity and accelerated degradation rate in muscles lead to muscle atrophy and functional decline.Additionally,dysfunction of satellite cells is considered a key factor in the reduced regenerative capacity of muscles.Mitochondrial dysfunction is another important factor leading to muscle fatigue and energy metabolism disorders,directly affecting the metabolic activity and endurance of skeletal muscles.Chronic inflammatory responses and extracellular matrix fibrosis further exacerbate muscle aging.These factors interact synergistically,collectively resulting in skeletal muscle degeneration.(2)Exercise is widely recognized as an important means to delay skeletal muscle aging.Exercise alleviates chronic low-grade inflammatory responses in skeletal muscle by regulating the immune system,increasing the secretion of anti-inflammatory factors,and inhibiting the expression of pro-inflammatory factors,thereby mitigating the damage of inflammation to muscles.Exercise also enhances mitochondrial biogenesis and function,improves the muscle's energy metabolism capacity,and consequently increases endurance and strength.Furthermore,exercise regulates lipid metabolism and the synthesis of lipid mediators,reduces fat accumulation and alleviates fat-induced inflammatory responses,thereby further protecting skeletal muscles.The mechanical stimulation from exercise promotes the remodeling of the extracellular matrix,reduces fibrosis occurrence,and improves muscle structure and function.Additionally,exercise activates satellite cells,enhancing the regenerative capacity of skeletal muscles,especially notable with strength training and high-intensity interval training.(3)Future research should include large-scale,multicenter clinical trials to evaluate the comprehensive effects of long-term exercise interventions on skeletal muscle aging.By analyzing data from genomics,metabolomics,and other fields,exploring individual differences in responses to exercise interventions can provide more precise theoretical bases for personalized exercise strategies.Besides exercise,the impacts of other interventions such as nutritional supplementation and pharmacological treatments on skeletal muscle aging should not be overlooked.Future studies can explore the combined use of exercise with these interventions to achieve more significant effects.

BACKGROUND:Skeletal muscle aging is associated with various chronic diseases.Exercise is considered an important means to delay this process,but the multimechanism regulation of exercise intervention strategies still requires in-depth exploration.OBJECTIVE:To systematically outline the main physiological changes in skeletal muscle aging and explore the multiple mechanisms by which exercise regulates these changes,thereby providing a theoretical basis for basic research and clinical applications.METHODS:By searching databases such as Web of Science,PubMed,Embase,CNKI,WanFang,and VIP,relevant literature from database inception to October 2024 was retrieved by the first author,including original research articles and reviews.The search terms were"skeletal muscle aging,sarcopenia,exercise regulation,physical activity,chronic inflammation,inflammaging,mitochondrial dysfunction,extracellular matrix fibrosis,lipid mediators,satellite cells"in English and Chinese.Literature was screened based on inclusion and exclusion criteria,and the included 95 articles underwent quality assessment and data extraction.RESULTS AND CONCLUSION:(1)The core manifestations of skeletal muscle aging are the decline in muscle mass,strength,and function,closely related to various physiological changes.The decreased protein synthesis capacity and accelerated degradation rate in muscles lead to muscle atrophy and functional decline.Additionally,dysfunction of satellite cells is considered a key factor in the reduced regenerative capacity of muscles.Mitochondrial dysfunction is another important factor leading to muscle fatigue and energy metabolism disorders,directly affecting the metabolic activity and endurance of skeletal muscles.Chronic inflammatory responses and extracellular matrix fibrosis further exacerbate muscle aging.These factors interact synergistically,collectively resulting in skeletal muscle degeneration.(2)Exercise is widely recognized as an important means to delay skeletal muscle aging.Exercise alleviates chronic low-grade inflammatory responses in skeletal muscle by regulating the immune system,increasing the secretion of anti-inflammatory factors,and inhibiting the expression of pro-inflammatory factors,thereby mitigating the damage of inflammation to muscles.Exercise also enhances mitochondrial biogenesis and function,improves the muscle's energy metabolism capacity,and consequently increases endurance and strength.Furthermore,exercise regulates lipid metabolism and the synthesis of lipid mediators,reduces fat accumulation and alleviates fat-induced inflammatory responses,thereby further protecting skeletal muscles.The mechanical stimulation from exercise promotes the remodeling of the extracellular matrix,reduces fibrosis occurrence,and improves muscle structure and function.Additionally,exercise activates satellite cells,enhancing the regenerative capacity of skeletal muscles,especially notable with strength training and high-intensity interval training.(3)Future research should include large-scale,multicenter clinical trials to evaluate the comprehensive effects of long-term exercise interventions on skeletal muscle aging.By analyzing data from genomics,metabolomics,and other fields,exploring individual differences in responses to exercise interventions can provide more precise theoretical bases for personalized exercise strategies.Besides exercise,the impacts of other interventions such as nutritional supplementation and pharmacological treatments on skeletal muscle aging should not be overlooked.Future studies can explore the combined use of exercise with these interventions to achieve more significant effects.

BACKGROUND:Muscle aging is closely related to various epigenetic changes,and exercise has a certain regulatory effect on these epigenetic changes.However,the specific mechanism is not fully understood. OBJECTIVE:To review the epigenetic mechanisms of skeletal muscle and how exercise can improve skeletal muscle aging and promote adaptive changes in muscle through these epigenetic mechanisms,aiming to provide a more comprehensive understanding of skeletal muscle aging and disease mechanisms. METHODS:During the period from June 1st to August 1st,2023,literature searches were conducted for relevant literature published from database inception to August 2023 in databases including Web of Science,PubMed,CNKI,WanFang,and VIP.The search terms used included"skeletal muscle,""muscle,""aging,""older adult,""aging,""exercise,""physical exercise,""epigenetic,"and"epigenetics"in Chinese as well as"skeletal muscle,muscle,aging,older adult,senescence,age,exercise,sports,physical activity,epigenetic,epigenetics"in English.Boolean logic operators were used to connect the search terms for retrieval,and corresponding strategies were developed.According to the predetermined inclusion and exclusion criteria,70 eligible articles were selected. RESULTS AND CONCLUSION:Epigenetics refers to the phenomenon where gene expression and function are regulated without changes in gene sequence,and epigenetic changes in skeletal muscle are an important field.The epigenetic mechanisms of skeletal muscle play an important role in muscle aging,mainly involving DNA methylation,histone modification,regulation of non-coding RNAs,chromatin remodeling,changes in mitochondrial function and expression changes of aging-related genes.Exercise significantly regulates the epigenetics of skeletal muscle,including promoting DNA methylation,muscle histone modification,regulating miRNA expression,and regulating lncRNA expression,regulating muscle factors(such as interleukin-6),regulating mitochondrial function(such as peroxisome proliferators-activated receptors γ co-activator 1α).Future studies are recommended for long-term,cross-diverse population-based exercise interventions;the application of multi-omics techniques such as proteomics and metabolomics;strengthening the understanding of epigenetic changes at the single-cell level;cross-species comparative studies as well as human clinical trials for the translation of animal model findings to humans;strategies for combining exercise and pharmacological interventions to assess their synergistic effects;and epigenetic studies of crosstalk interactions between skeletal muscle and different organs.

BACKGROUND:Central fatigue refers to the phenomenon where changes in the functions of the central nervous system lead to a decline in an individual's exercise capacity and an increase in the sense of fatigue.With the continuous development of sports science,the mechanisms of exercise-induced central fatigue have gradually become a research hotspot.Although a large number of studies have explored the roles of biological mechanisms such as neurotransmitters,energy metabolism,and neuroinflammation in central fatigue,the interactions of these mechanisms and their manifestations in different exercise scenarios are still not fully understood.OBJECTIVE:To explore various biological mechanisms of exercise-induced central fatigue,clarify the interactions of neurotransmitters,energy metabolism,neural network activities,neuroinflammation,and oxidative stress in the formation of fatigue,and thereby provide a new perspective for understanding central fatigue.METHODS:Web of Science,PubMed,CNKI,WanFang,and VIP databases were searched with search terms"central fatigue,neurophysiological basis,exercise,physical activity,neurotransmitters,serotonin,dopamine,glutamate,GABA,energy metabolism,astrocytes,neuroinflammation,oxidative stress,cortical activity,neural network activity,sport"in Chinese and English.Relevant literature published from the establishment of each database to August 2024 was retrieved,and finally 74 articles were included for review.RESULTS AND CONCLUSION:Exercise-induced central fatigue involves multiple complex biological mechanisms.The imbalance of neurotransmitters(such as serotonin,dopamine,glutamate,and γ-aminobutyric acid)is a key factor in central fatigue.In particular,the increase in serotonin is closely related to the enhancement of the sense of fatigue.The disorder of energy metabolism,especially the glycogen metabolism of astrocytes and the supply of lactic acid,plays an important role in the formation of fatigue during long-term exercise.Neuroinflammation and oxidative stress exacerbate the manifestations of central fatigue by affecting the release of neurotransmitters and the functions of neural networks.In addition,changes in the activities of neural networks,such as the decrease in the excitability of the cerebral cortex,directly affect exercise performance.Future studies should strengthen the comprehensive exploration of neurotransmitter,metabolic,and inflammatory pathways,conduct more human studies to verify the findings of animal experiments,explore the differences in the mechanisms of central fatigue under different exercise conditions(such as intensity,time,and environment),and study the potential of drug interventions or nutritional supplements based on neurotransmitter regulation in alleviating central fatigue.

BACKGROUND:Central fatigue refers to the phenomenon where changes in the functions of the central nervous system lead to a decline in an individual's exercise capacity and an increase in the sense of fatigue.With the continuous development of sports science,the mechanisms of exercise-induced central fatigue have gradually become a research hotspot.Although a large number of studies have explored the roles of biological mechanisms such as neurotransmitters,energy metabolism,and neuroinflammation in central fatigue,the interactions of these mechanisms and their manifestations in different exercise scenarios are still not fully understood.OBJECTIVE:To explore various biological mechanisms of exercise-induced central fatigue,clarify the interactions of neurotransmitters,energy metabolism,neural network activities,neuroinflammation,and oxidative stress in the formation of fatigue,and thereby provide a new perspective for understanding central fatigue.METHODS:Web of Science,PubMed,CNKI,WanFang,and VIP databases were searched with search terms"central fatigue,neurophysiological basis,exercise,physical activity,neurotransmitters,serotonin,dopamine,glutamate,GABA,energy metabolism,astrocytes,neuroinflammation,oxidative stress,cortical activity,neural network activity,sport"in Chinese and English.Relevant literature published from the establishment of each database to August 2024 was retrieved,and finally 74 articles were included for review.RESULTS AND CONCLUSION:Exercise-induced central fatigue involves multiple complex biological mechanisms.The imbalance of neurotransmitters(such as serotonin,dopamine,glutamate,and γ-aminobutyric acid)is a key factor in central fatigue.In particular,the increase in serotonin is closely related to the enhancement of the sense of fatigue.The disorder of energy metabolism,especially the glycogen metabolism of astrocytes and the supply of lactic acid,plays an important role in the formation of fatigue during long-term exercise.Neuroinflammation and oxidative stress exacerbate the manifestations of central fatigue by affecting the release of neurotransmitters and the functions of neural networks.In addition,changes in the activities of neural networks,such as the decrease in the excitability of the cerebral cortex,directly affect exercise performance.Future studies should strengthen the comprehensive exploration of neurotransmitter,metabolic,and inflammatory pathways,conduct more human studies to verify the findings of animal experiments,explore the differences in the mechanisms of central fatigue under different exercise conditions(such as intensity,time,and environment),and study the potential of drug interventions or nutritional supplements based on neurotransmitter regulation in alleviating central fatigue.

BACKGROUND:Satellite cells are a specific population of adult stem cells contained in skeletal muscle that promote the regenerative reconstruction of injured skeletal muscle,but their specific mechanisms are not well established. OBJECTIVE:To review the regulatory role of satellite cells during skeletal muscle regeneration and the mechanism of interaction between satellite cells and their ecological niche signals,aiming to provide new research ideas and perspectives based on the summary of existing knowledge. METHODS:Web of Science,PubMed,CNKI,WanFang,and VIP databases were searched for literature published between January 2002 and June 2022.English search terms were"muscle,skeletal muscle,muscle injury,stem cells,satellite cells,muscle repair".Chinese search terms were"skeletal muscle,skeletal muscle regeneration,skeletal muscle reconstruction,satellite cells,ecological niche".The 66 included papers were organized and analyzed. RESULTS AND CONCLUSION:(1)Satellite cells exist in skeletal muscle and contribute to both the formation of new muscle fibers after injury and the effective growth of existing adult muscle fibers.(2)After the activation of quiescent satellite cells in satellite cells,the steps of satellite cell proliferation,differentiation and fusion to form muscle fibers during skeletal muscle regeneration are influenced by their intrinsic regulatory effects of different mechanisms.(3)Satellite cells can interact with myofibers,extracellular matrix,skeletal muscle junctions,fibroblast progenitor cells,immune cells and endothelial cells in the ecological niche signal to promote satellite cell activation,proliferation and differentiation to achieve effective skeletal muscle regeneration.(4)Possible breakthroughs in future research include:the division pattern of satellite cells in the body;the mechanisms regulating satellite cell transfer;the specific timing of satellite cell differentiation or self-renewal in vivo;and the interaction mechanisms between satellite cells and skeletal muscle junctions.(5)This review may provide some theoretical reference values for the field of injury reconstruction of skeletal muscle and its innovation.

BACKGROUND:Sarcopenia is a chronic condition that leads to strength loss and functional decline,increasing the risk of frailty,disability,falls,and death in older adults.Blood flow restriction training can be effective in the treatment of sarcopenia,but a comprehensive review of its advantages,disadvantages,biological mechanisms,and application options is lacking. OBJECTIVE:To review the advantages,limitations,and biological mechanisms of blood flow restriction training interventions for sarcopenia and to give recommendations for application protocols based on current published evidence. METHODS:A search of major databases was conducted for literature published in the time frame up to February 2023.The search terms were"blood flow restriction training,KAATSU,elderly,sarcopenia,muscle"in English and Chinese.Finally,82 included papers were compiled and analyzed. RESULTS AND CONCLUSION:Blood flow restriction training as an intervention for sarcopenia has been effective in peripheral muscle groups,but there are limitations in its application.Blood flow restriction training is highly operational and safe.This training can improve muscle strength and physical performance,but there are potential risks,including adverse events on skeletal muscle,cardiovascular and endothelial cells.Therefore,blood flow restriction training needs to be performed under scientific guidance and further studies are needed to verify its efficacy in patients with sarcopenia.The biological mechanisms of blood flow restriction training intervention in sarcopenia may include:increasing muscle hypertrophy due to reactive muscle congestion,improving muscle protein synthesis capacity,inducing metabolic stress adaptation,promoting skeletal muscle growth and repair,activating vascular endothelial growth factor signaling pathway to promote angiogenesis,and promoting satellite cell proliferation.However,these specific roles and combined effects of these mechanisms need to be determined by more in-depth studies.Blood flow restriction training interventions for sarcopenia are mainly influenced by training and cuffs.To avoid adverse events,it is recommended that 20%to 50%1RM,20 to 75 repetitions,2 to 3 times per week,30-60 seconds interval between sessions,smaller size cuffs with a pressurization value≤140 mmHg for upper limb training,and larger size cuffs with a pressurization value≤180 mmHg for lower limb training,usually 50%to 80%of the pressure value in the completely occluded artery.However,more research is needed on the training frequency and interval between sessions in older adults,and further research is needed on the optimal choice of cuff pressurization values.

BACKGROUND:Satellite cells are myogenic stem cells located between the muscle fiber membrane and the basement membrane.However,a comprehensive review of the aging mechanisms of satellite cells and their potential mitigation strategies is still lacking.This gap in knowledge hinders the effective guidance for current strategies aimed at attenuating skeletal muscle aging. OBJECTIVE:To review the mechanisms of satellite cell aging in skeletal muscle and the relevant strategies for mitigating this aging process. METHODS:Major databases were searched up to May 2023,including Web of Science,PubMed,China National Knowledge Infrastructure(CNKI),WanFang Data,and VIP.Chinese and English search terms included"skeletal muscle,satellite cells,aging,mechanism,and solution strategy".After strict inclusion and exclusion criteria were applied,78 articles were finally included. RESULTS AND CONCLUSION:(1)Satellite cells,situated between the muscle fiber membrane and basement membrane,possess proliferative and differentiative potential.They usually remain in a quiescent state but become activated in response to muscle tissue stimuli,participating in processes of repair and restoration of normal tissue structure.Aging leads to a reduction in satellite cell numbers,resulting in symptoms such as muscle weakness and decreased endurance.(2)Mechanisms of satellite cell aging primarily involve diminished regenerative capacity,perturbed niche interactions with changing ecology,age-dependent loss,and heterogeneity changes.Reduced satellite cell numbers and activity due to aging lead to slower muscle regeneration and increased injury recovery time.Errors during differentiation may occur,resulting in decreased muscle quality and function deterioration.(3)Strategies for mitigating satellite cell aging encompass modulation of the receptor environment of intra-body satellite cells,peripheral interventions to promote satellite cell regeneration,construction of human muscle models,and exercise and nutritional interventions to induce satellite cell proliferation.These strategies hold promise in offering novel insights and methods for satellite cell regeneration and treatment of skeletal muscle diseases.(4)Future research should delve into the mechanisms of satellite cell aging,explore the interaction between satellite cells and their niches,investigate the relationship of satellite cells with the immune system and mitochondrial function,and develop human muscle models to enhance research depth and accuracy.

BACKGROUND:Sarcopenia is an age-related degenerative syndrome,and the relationship between mitochondrial autophagy and exercise in preventing and treating sarcopenia has been demonstrated.However,there is a lack of comprehensive reviews detailing the specific receptor proteins and signaling pathways involved in the role of exercise in sarcopenia prevention and treatment. OBJECTIVE:To comprehensively introduce the specific receptor proteins and signaling pathways related to mitochondrial autophagy and their role in the prevention and treatment of sarcopenia through exercise. METHODS:A literature search was conducted between February 1,2023,and April 1,2023,covering literature from database inception to April 2023.Databases included the Web of Science,PubMed,China National Knowledge Infrastructure(CNKI),WanFang Data,and VIP.Keywords used for the search included sarcopenia,muscle wasting,aging,elderly,mitochondria,mitochondrial function,proteins,pathways,and others.After strict inclusion and exclusion criteria,76 articles were ultimately included. RESULTS AND CONCLUSION:Sarcopenia is a disease characterized by a decline in muscle mass and function with age,and its pathogenesis involves neuro-muscular functional decline,chronic inflammation,acid-base imbalance,and mitochondrial dysfunction.Mitochondrial autophagy is an important process for clearing damaged mitochondria in cells,in which receptor proteins and signaling pathways are involved in the regulation of mitochondrial autophagy.Exercise can promote the occurrence of mitochondrial autophagy by regulating the activity of these receptor proteins and signaling pathways,thereby playing an important role in the prevention and treatment of sarcopenia.Exercise can induce mitochondrial autophagy in sarcopenia by upregulating AMPK,phosphorylating ULK1,and reducing mitochondrial energy,enhancing the expression of mitochondrial autophagy-related proteins associated with AMBRA1,and regulating the PINK1/Parkin pathway,to improve mitochondrial dysfunction caused by sarcopenia.In addition,exercise can activate the mTOR pathway to promote muscle growth and increase glucose uptake,thereby preventing and treating sarcopenia.Future studies are needed to further investigate the specific mechanisms and regulatory pathways of mitochondrial autophagy-related receptor proteins and signaling pathways in the prevention and treatment of sarcopenia by exercise,and to conduct more clinical trials in humans,thereby to promote further development in this field.

BACKGROUND:Parkinson's disease is a neurodegenerative disease,and its pathogenesis involves mitochondrial dysfunction.Exercise has a potential ameliorative effect on mitochondrial dysfunction related to Parkinson's disease,but there is no comprehensive review and in-depth analysis in this field. OBJECTIVE:To comprehensively review and analyze mitochondrial dysfunction related to Parkinson's disease and the potential ameliorative effect of exercise,thereby providing new ideas and methods for the treatment and prevention of Parkinson's disease. METHODS:We searched the Web of Science,PubMed,CNKI,WanFang,and VIP databases with the keywords of"mitochondria,mitochondrial function,mitochondrial disease,mitochondrial dysfunction,Parkinson's disease,Parkinson,exercise,physical activity,exercise training,exercise therapy,mitochondrial impairment,mitochondrial damage,mitochondrial defects"in Chinese and"mitochondria,Parkinson's disease,Parkinson disease,physical exercise,exercise,physical activity,mitochondrial dysfunction,mitochondrial damage,mitochondrial impairment,athletic training,exercise training,rehabilitation"in English.A total of 89 articles were included for review and analysis. RESLUTS AND CONCLUSION:Parkinson's disease is closely related to mitochondrial dysfunction,including mitochondrial biogenesis inhibition,reduced autophagy,increased apoptosis,abnormal elevation of Ca2+ concentration,and increased oxidative stress in Parkinson's disease patients.Exercise has a positive effect on mitochondrial dysfunction related to Parkinson's disease,by promoting mitochondrial biogenesisand autophagy,regulating mitochondrial morphology,altering the plasticity of the mitochondrial respiratory chain,and reducing oxidative stress,thus helping to improve the development and progression of Parkinson's disease.However,the detailed mechanism between mitochondrial dysfunction and the ameliorative effect of exercise is still not fully understood,and future clinical studies can be conducted to validate the results of animal models and gain insights into the benefits and mechanisms of exercise in patients with Parkinson's disease.