Skeletal muscle enzyme alterations after sprint and endurance training.

Specifically designed programs of sprint and endurance running were used to determine how different types of training affect enzyme activities in selected energy metabolism pathways. Three types of rat skeletal muscle were studied. After 8 wk of training, small but significant decreases in lactate dehydrogenase activity (15%) were found in the soleus and white vastus lateralis muscles of the sprint animals. Decreased levels of phosphoglucomutase and lactate dehydrogenase (approx. 20%) of the white vastus lateralis muscles of the endurance group were observed at the same time. By 16 wk of training, fumarase activity increased approximately twofold in the white vastus muscles and 45% in the soleus and plantaris muscles of the endurance group. Similarly, increased fumarase activity (42%) was seen in the soleus muscles of the sprint group. In all muscles, phosphoglucomutase and lactate dehydrogenase activities generally were lower in the endurance animals than in the control animals. No significant differences were found between the sprint and endurance groups at either or sixteen weeks of training. These results suggest that similar enzyme adaptations occur over time with both types of training.