Effects of training on muscle capillary pattern: intermittent vs continuous exercise.

The effects of two exercise regimens (intermittent and continuous endurance) on the fiber area, and capillarization of mice skeletal muscle (gastrocnemius) was studied. The training programs had a duration of 30 days, 5 days/week, and was performed on a motor-driven treadmill. The intermittent group performed the exercise at 16 m.min-1 with a slope of 5%. The continuous group performed the exercise at 16 m.min-1 with 0%. The fiber area and the capillarization was evaluated in the white portion of the gastrocnemius. A high degree of hypertrophy was observed, and a significant increase in the capillary density, capillary to fiber ratio, and in the number of capillaries sectioned obliquely and/or longitudinally was found. The results suggest that the endurance training, intermittent or continuous, induce cell hypertrophy, and an increase in capillarization especially, based on an alteration of the structural pattern.