Skeletal muscle profiles among elite long, middle, and short distance swimmers.

Skeletal muscle profiles of fiber composition and leg power and strength were obtained in 30 national caliber swimmers (20 males, 10 females). Subjects were classified into three groups based upon the distance of their primary events [long distance (LDS), middle distance (MDS), and short distance (SDS) swimmers]. Intergroup analyses showed that the LDS group had the highest values of percent Type I muscle fiber composition (percent Type I and percent Type I area), and the lowest values of leg power and strength values (vertical jump and torque-velocity relationships). In addition, when grouped by Type I fiber composition, subjects having greater than or equal to 50% Type I fibers had significantly lower vertical jump and torque values than those having less than 50% Type I fibers. Overall, the compositional and functional measurements were consistent with the specific metabolic and contractile demands of the different swim groups.