Abstract

38 males and 22 females were administered a battery of exercise performances tests. Muscle biopsie were obtained from m. vastus lateralis for muscle fibre type composition and enzyme activities determination. Exercise performance, including V02 max, peak blood lactates, anaerobic power generation and muscle strength demonstrated that female subjects values were 60-80 of the male values even when corrected for lean body mass. Female subjects required almost twice the time to develop 70 of maximal leg force as compared to the males. Females demonstrated a faster muscle fibre composition (51 vs 44 fast twitch, FT) than the males yet muscle fibre composition was notpositive-ly related to exercise performance as it was in males. In spite of a higher FT-rich musculature, females evidenced lower activities for enzymes represen- tative of muscle contractility and glycogenolytic activity. The observations suggest that sexually mediated differences in neuromotoric control may exist affecting muscle force production, speed, and the accepted relationships between muscle fibre distribution and exercise performance. Verf.-Referat