This review highlights the critical role of controlled cellular calcium handling, particularly decreased sarcoplasmic reticulum calcium release, in the development of exercise-induced muscle fatigue to prevent cellular damage.
The contractile function of skeletal muscle declines during intense or prolonged physical exercise, that is, fatigue develops. Skeletal muscle fibers fatigue acutely during highly intense exercise when they have to rely on anaerobic metabolism. Early stages of fatigue involve impaired myofibrillar function, whereas decreased Ca 2 release from the sarcoplasmic reticulum (SR) becomes more important in later stages. SR Ca 2 release can also become reduced with more prolonged, lower intensity exercise, and it is then related to glycogen depletion. Increased reactive oxygen/nitrogen species can cause long-lasting impairments in SR Ca 2 release resulting in a prolonged force depression after exercise. In this article, we discuss molecular and cellular mechanisms of the above fatigue-induced changes, with special focus on multiple mechanisms to decrease SR Ca 2 release to avoid energy depletion and preserve muscle fiber integrity. We also discuss fatigue-related effects of exerciseinduced Ca 2 fluxes over the sarcolemma and between the cytoplasm and mitochondria.
Cheng et al. (Fri,) studied this question.