Event-related difference in cross-sectional area of the gluteus maximus muscle in high-school athletes

This study investigated the cross-sectional area of the gluteus maximus muscle in high school athletes with reference to sex- and sport-related differences. The subjects were 269 male and female athletes (age 17.2±0.7 yr) majoring in 12 events: sprinting, long-distance, throwing events, volleyball, badminton, boating, canoeing, sailing, soccer, basketball, wrestling and judo. Thirty-six untrained high-school students also participated as controls. The muscle cross-sectional area (CSA) was determined from an axial magnetic resonance image using a slice level through the greater trochanter. Fat-free mass (FFM) was also measured by air-plethysmography, and the relationship between CSA and FFM was analyzed. The CSA and FFM showed a high correlation (r=0.80 for males and 0.71 for females) and there was no gender difference in the regression equation (CSA=3.92*FFM0.83 for the pooled data). The absolute CSA was larger in males than in females. The largest CSA was found in judo and throwing-event athletes of both genders, and the smallest in canoeing and long-distance athletes, whose CSA was comparable to that of the controls. However, when the CSA was divided according to FFM0.83 in order to control for body-size difference in sex and sports events, there was no significant difference in the value between genders. Moreover, although the body-size controlled value was the largest in badminton and sprint athletes of both genders, no significant event-related differences were found for males, and only canoeists showed a value that was less than that for badminton and sprint athletes among females. In conclusion, the development of the gluteus maximus appears to show a sport-specific difference among high school athletes; however, compared with thigh muscle groups suggested in previous studies, no sports-specific tendency was apparent when FFM was controlled for.