Mechanical behaviour of leg extensor muscles in male and female sprinters

Leg extensor muscle characteristics, running speed and serum testosterone wewre studied in sixteen males and twelve female sprinters. The rise of center of gravity was measured during squat jumps executed without (SJ) and with extra loads (SJ(bm)), counter movement jump (CMJ) and continuous jumping (CJ) for 5 s. Nine females and nine males performed also half-squat exercises with extra loads ranging from 50% to 200% of the subject’s body mass (bm). Average mechanical power (P), force (F) and velocity (v) were calculated and measured during half-squat exercises using the Ergopower ®. Total serum testosterone (TT) was determined in venous blood. In women, 60 in dash, SJ, CMJ and CJ performances were significantly lower (P<0,001) than men. Gender differences were not found in F during half-squat exercises and in SJ(bm). Women demonstrated significantly higher ratios CMJ:SJ and CJ:SJ than men. With loads 50-100% of bm men demonstrated greater v and P than women. It was suggested that high testosterone level in men might be a factor ensured superiority in explosive power and speed, but not in muscle strength adjusted to body mass.