Biochemical adaptation as a response to exercise. 1. Effect of swimming on the levels of lactic dehydrogenase, malic dehydrogenase and phosphorylase in muscles of 8-, 11- and 15-week-old rats

Abstract

Male rats (Wistar strain) 8, 11 and 15 weeks old were exercised by swimming 30 min. daily for six 5-day weeks. The exercised animals gained significantly less weight than their control groups. Muscle assays revealed no differences in the levels of lactic dehydrogenase, malic dehydrogenase and phosphorylase, either between exercised or control groups or between the 3 different age groups. While other workers have shown that training enhances the metabolic activity of muscle, the constancy of enzyme levels reported here suggests that the adaptive response involves other controlling factors.