ABSTRACT
Within the context of fatigue during exercise, two substances that have come to light as a result of a person's improved ability to determine their function during exercise are potassium and calcium. This chapter summarises the important functional roles of potassium and calcium, and discusses how disturbances in some of these functions during exercise could potentially contribute to fatigue. The chapter presents some arguments against extracellular potassium accumulation as a cause of fatigue during exercise. Chloride is another ion present in skeletal muscle that can exert a significant effect on potassium. The protective effect of acidosis on the force production of potassium depressed muscle has been shown using in vitro research. Calcium is the most abundant mineral in the body. Calcium release from the sarcoplasmic reticulum is delayed in a low muscle glycogen state, which may be related to localised adenosine triphosphate depletion.
