MUSCLE PERFORMANCE AND ENZYMATIC ADAPTATIONS TO SPRINT INTERVAL TRAINING

Our purpose was to examine the effects of sprint interval training on muscle glycolytic and oxidative enzyme activity and exercise performan ce. Twelve healthy men (22 +/- 2 yr of age) underwent intense interval training on a cycle ergometer for 7 wk. Training consisted of 30-s ma ximum sprint efforts (Wingate protocol) interspersed by 2-4 min of rec overy, performed three times per week. The program began with four int ervals with 4 min of recovery per session in week 1 and progressed to 10 intervals with 2.5 min of recovery per session by week 7. Peak powe r output and total work over repeated maximal 30-s efforts and maximal oxygen consumption (V(over dot)2(max)) were measured before and after the training program. Needle biopsies were taken from vastus laterali s of nine subjects before and after the program and assayed for the ma ximal activity of hexokinase, total glycogen phosphorylase, phosphofru ctokinase, lactate dehydrogenase, citrate synthase, succinate dehydrog enase, malate dehydrogenase, and 3-hydroxyacyl-CoA dehydrogenase. The training program resulted in significant increases in peak power outpu t, total work over 30 s, and V(over dot)O-2max. Maximal enzyme activit y of hexokinase, phosphofructokinase, citrate synthase, succinate dehy drogenase, and malate dehydrogenase was also significantly (P < 0.05) higher after training. It was concluded that relatively brief but inte nse sprint training can result in an increase in both glycolytic and o xidative enzyme activity, maximum short-term power output, and V(over dot)O-2max.