Anaerobic muscle enzyme changes after interval training.

In contrast to endurance training, little evidence is available concerning the effects of sprint-type training programs on the anaerobic metabolism of skeletal muscle. Four male subjects completed a mean of 16 training sessions consisting of eight 200-m runs at 90% of maximal speed, which were separated by 2-min rest periods. Before and after the 5-week training period, muscle biopsies were taken out of the lateral head of m. gastrocnemius and analyzed for the activities of phosphorylase, phosphofructokinase (PFK), glyceraldehyde phosphate dehydrogenase (GAPDH), lactate dehydrogenase (LDH), succinate dehydrogenase (SDH), and malate dehydrogenase (MDH). Following training there was a significant increase in the subjects' performance time in a treadmill test at a speed of 16 km/h speed and 15% grade. Significant increases were observed in the activities of phosphorylase, PFK, GAPDH, LDH, and MDH, whereas the 17.5% increase in SDH was not statistically significant. It is concluded that interval training with high intensity and a 1:4 work-rest ratio leads to increased activities of key enzymes involved in glycogenolysis and anaerobic glycolysis of skeletal muscle.