Relative fat distribution: Relationship to skeletal maturation, growth status, and motor fitness of boys 8-11 years of age.

Skeletal maturia (Tanner-Whitehouse II [TW II]), growth status, and motor fitness were compared in boys having high and low trunk/extremity skinfold ratios (T/E ratio). The T/E ratio was based on the sums of the subscapular and midaxillary, and the triceps and medial calf skinfolds. The sample included 80 boys, age 8 through 11 years, who represented the highest and lowest quartiles of the distribution of the T/E ratio (10 boys per quartile in each age group). Chronological and skeletal ages did not differ between boys in the highest and lowest quartiles, with the exception of the 10-year-old sample in the highest quartile, in whom skeletal age was significantly advanced. Boys in the highest quartile tended to be slightly taller, but especially heavier and fatter (sum of four skinfolds). They thus had a higher body mass index (BMI), which was elevated in part due to increased muscle mass as reflected in a larger estimated midarm muscle circumference. In contrast, boys in the lowest quartile tended to perform better, both absolutely and per unit body mass, in the three motor tests (run, jump, throw), while there were no consistent differences in absolute strength. However, boys in the lowest quartile tended to be stronger and to perform better per unit body mass. The results thus suggest that more centrally distributed subcutaneous fat may have a negative effect on the motor fitness of children, and this effect is mediated in part through excess fatness. © 1994 Wiley-Liss, Inc.