EXERCISE PERFORMANCE AND MAGNETIC-RESONANCE IMAGING-DETERMINED THIGH MUSCLE VOLUME IN CHILDREN

This study examined the relationships between thigh muscle volume (TMV ) and aerobic and anaerobic performance in children. A total of 32 chi ldren, 16 boys and 16 girls, aged 9.9 (0.3) years completed a treadmil l running test to exhaustion for the determination of peak oxygen upta ke (peak (V) over dotO(2))) and a Wingate Anaerobic Test (WAnT) for th e determination of peak power (PP) and mean power (MP). The volume of the right thigh muscle was determined using magnetic resonance imaging . TMV was not significantly different in boys and girls [2.39 (0.29) 1 vs 2.18 (0.38) 1, P > 0.05]. Peak (V) over dotO(2) and MP were signif icantly higher in boys than girls (P < 0.01) whether expressed in abso lute, mass-related or allometrically scaled terms. Absolute PP was not significantly different in boys and girls but mass-related and allome trically scaled values were higher in boys (P < 0.01). TMV was correla ted with absolute peak (V) over dot O-2, PP and MP in both sexes (r = 0.52-0.89, P < 0.01). In boys, mass-related PP was correlated with TMV (r = 0.53, P < 0.01), and in girls mass-related peak (V) over dotO(2) was correlated with TMV (r = -0.61, P < 0.01). However, in neither se x were allometrically scaled peak (V) over dotO(2), PP or MP correlate d with TMV (P > 0.05). There were no significant differences between b oys and girls in terms of peak (V) over dotO(2), PP or MP when express ed in a ratio to TMV or allometrically scaled TMV. In conclusion, this study has demonstrated that, when body size is appropriately accounte d for using allometric scaling, TMV is unrelated to indices of aerobic and anaerobic power in 10-year-old children. Furthermore, there appea r to be no qualitative differences in the muscle function of boys and girls in respect of aerobic and anaerobic function.