Relationship Between Skeletal Maturity and Body Composition in Boys Aged 9 ~12 Years

Song, Jong Kook; Yoo, Seung Hee; Jung, Nak Hee

Abstract

The aims of this study were to investigate the present status of skeletal maturation and to compare body composition parameters on the basis of the levels of skeletal maturity in boys aged 9 ~12 years. The subjects participated consisted of 258 elementary school boys. Anthropometric characteristics included body weight, height, sitting height, bone widths, circumferences, and skinfold thicknesses. Skeletal maturation was assessed by the Tanner -Whitehouse II method. Skeletal age was determined by RUS scores (radius, ulna, and short bones). Body composition variables were evaluated by bioelectrical impedance analysis (BIA Model 310). Means and standard deviations were calculated by descriptive statistics. To compare body composition variables among skeletal maturity groups one -way analysis of variance (ANOVA) was applied and Duncan's a posteriori tests. The results showed that RUS scores varied from 298.2 for 9 years to 482.6 for 12 years. TW2 -20 scores were 569.2 for 9 years, 628.8 for 10 years, 701.8 for 11 years, and 814.5 for 12 years. Skeletal ages were 9.7 for 9 years, 10.5 for 10 years, 11.7 for 11 years, and 13.6 for 12 years. It indicates that chronological age was lower than skeletal age in all age groups. Although no significant difference was found in 12 years for body composition according to the levels of skeletal maturity, in general advanced boys had higher body composition variables than retarded boys. In 9 years there were significant differences (p 0.05) among skeletal maturity groups for body mass index, WHR, and WTR. Also, differences were found in 10 years for percent body fat, fat -free mass, and body mass index. In 11 years advanced children (40.4 kg) have statistically significant (p 0.05) higher fat -free mass than retarded children (32.2 kg).