The Total Ionic Status of Muscle During Intense Exercise

During intense exercise, the high rate of glycolysis results in a large accumulation of intracellular lactate (La-) and increased hydrogen ion concentration (H+]) (Spriet et al., 1985). High intracellular [H+] during heavy exercise has often been implicated as a cause of muscle fatigue. A number of loci for fatigue have been suggested: excitation-contraction coupling (Fabiato and Fabiato, 1978), control of glycolytic flux at the level of Phosphorylase (Chasiotis et al., 1983) and phosphofructokinase (Trivedi and Danforth, 1966) and impairment of ionic pumps and exchanges on the sarcoplasmic reticulum and sarcolemma (Nakamura and Schwartz, 1972).