Muscle fatigue: general understanding and treatment

Muscle fatigue is a common complaint in clinical practice. In humans, muscle fatigue can be defined as exercise-induced decrease in the ability to produce force. Here, to provide a general understanding and describe potential therapies for muscle fatigue, we summarize studies on muscle fatigue, including topics such as the sequence of events observed during force production, in vivo fatigue-site evaluation techniques, diagnostic markers and non-specific but effective treatments. Muscle fatigue after exercise is only partially understood and more research is needed to uncover its mechanisms and develop treatments. Xia Liu, Yang Sun and colleagues at the Second Military Medical University in Shanghai, reviewed current understanding of muscle fatigue. Published studies cover the sequence of events leading to fatigue, the techniques and biomarkers used for diagnosis and evaluation, and the effectiveness of therapies and supplements. Non-invasive techniques can assess muscle fatigue using electrical or magnetic stimulation of a muscle or other areas of the body that affect the muscle. Changes in nerve cell activity, blood flow and muscle metabolism alter the levels of biochemicals that could potentially be reliable biomarkers of muscle fatigue. The authors also review the claims and evidence for benefits of a wide range of chemical treatments and nutritional supplements.