Skeletal Muscle Fiber Type, Fiber Size, and Capillary Supply in Elite Soccer Players

Abstract

This study determined the fiber type composition, the fiber size, and the capillary characteristics of the vastus lateralis muscle in 11 young, elite, male soccer players and 8 sedentary male, age-matched controls. There were no significant differences (P < 0.05) in the fiber type percentages and fiber diameter between the soccer players and controls; however, all fiber types tended to be larger in the soccer players. The soccer players possessed a greater capillary supply; this was characterized by a significantly greater mean number of capillaries surrounding each fiber (5.7 ± 0.9 vs. 4.9 ± 0.4), a significantly larger capillary density (282.7 ±42.0 vs. 220.8 ±38.1), and a significantly higher capillary to fiber ratio (2.2 ± 0.6 vs 1.7 ± 0.1). The results indicate that soccer may be an appropriate stimulus for simultaneous adaptation to endurance and high intensity exercise.

Key words

Adaptation - endurance training - exercise - sprint training