Differences in muscle thicknesses of male and female Japanese elite athletes / 体力科学

ABSTRACT

The pourpose of this study is to investigate the differences in muscle thickness between males and females of Japanese elite athletes. Subjects were 82 males and 65 females who were Japan candidates for the 1986 Asian and the 1988 Olympic Games 8 sports events, e, g., sprinters, middle and long distance runners, throwers, swimmers, gymnasts, volleyball players, basketball players, and oarsmen. Muscle thicknesses were measured by using B-scan ultrasound equipment with a 5 MHz transducer at the follwing sites forearm anterior, biceps, triceps, subsucapular, abdomen, quadriceps, hamstrings and posterior calf. In results, comparison in muscle thickness between males and females were made at upper extremity (forearm+biceps+triceps), trunk (subsucapular+ abdomen) and lower extremity (quadriceps+hamstrings+calf) . Males showed siginificantly higher values in muscle thickness than females at all sites, except for trunk of distance runners and lower extremity of volleyball players. Relative values of females to males in muscle thickness were 59-84% for upper extremity, 68-89% for trunk, 84-94% for lower extremity. At upper extremity and trunk, Males indicated significantly higher values in muscle thickness per body height (muscle thickness/Ht) execpt for distance runners. At lower extremity, however, there were no siginificant differences in muscle thickness/Ht at lower between males and females except for gymnasts. Relative values of females to males in muscle thickness/Ht were 66-94% for upper extremity, 72-99% for trunk and 89-100% for lower extremity. Males showed significantly higher values in upper/lower extremity ratio of muscle thickness than females, except for sprinters and distance runners. On the other hand, females had significantly higher values in lower/trunk ratio of muscle thickness than males, except for distance runners and gymnasts. These results indicate that the differences in muscle thickness between males and females exist remarkably at upper extremity and trunk commpared to lower extremity. These anatomical differences in the degree of muscle development may be refered to genetic and/or enviromental factors.