Body composition and sexual maturation in premenarcheal athletes and nonathletes

The purpose of this study was to compare premenarcheal athletes (A) and nonathletes (NA) in terms of body composition and sexual maturation and to discern the relationship between these variables. Percent body fat (%BF) was determined by the three-component system of Siri utilizing body density from hydrostatic weighing and total body water measured by deuterium oxide dilution. Sexual maturation was self-assessed using the system described by Marshall and Tanner. ANOVAs and polynomial regression analysis revealed that both the A (N = 73) and NA (N = 53) showed similar values and linear increases (P less than 0.001) in height (HT), weight (WT), breast (B) and pubic hair (PH) development from 7 to 15 yr but not in %BF (XA = 15.7 +/- 4.6; XNA = 20.5 +/- 6.4 (P less than 0.001]. The NA exhibited a quadratic curve (P less than 0.01) in %BF over age, while the A showed a negative linear relationship (P less than 0.001) with age. Scheffe post hoc tests revealed significant differences (P less than 0.03, A less than NA) at 11 and 12-15 yr. When %BF was compared to maturation, the A were found to have less fat (P less than 0.01) at stages 1 and 4 of PH and at stages 2, 3, and 4 of B. There were no significant differences between A and NA in the age at which B2, 3, or 4 or PH2, 3, or 4 occurred. Both groups exhibited similar and significant correlations between age, HT, WT, B, and PH development but not %BF.(ABSTRACT TRUNCATED AT 250 WORDS)