SEQUENCE OF GROWTH SPURTS IN SPECIFIC DIMENSIONS IN ADOLESCENTS GROUPED BY SPORT ACTIVITY STATUS

Abstract

848 The sequence of growth spurts in 7 body dimensions was examined in 52 males and 49 females grouped by sport activity status: 21 males and 23 females were regularly training for sport (A), 31 males and 26 females were not active in sport (NA). Mean duration of training during adolescence was 4.4±1.8 years (yrs) in A males and 3.9±1.2 yrs in A females; NA males and females had school physical education but no systematic training in sport. The subjects were followed longitudinally from 11-18 years. Body dimensions included weight, stature, symphyseal height (lower segment length), upper segment length (stature minus symphyseal height), biacromial and bicristal breadths, and chest circumference. Growth curves were mathematically fitted to individual growth records using kernel regression to derive ages at peak velocity (AsPV) and peak velocities (PVs). Mean AsPV were used to define the average sequence of spurts by sport activity status within each sex; Kendall's rank order correlations were used to estimate agreement between sequences. AsPV for stature, upper segment length, and weight occur earlier in A than NA males (p<0.05), while PVs for biacromial and bicristal breadths are greater in A than NA females (p<0.05). Average sequences are similar in A males and females (r=.81, p=0.01), but not in NA males and females (r=.20, p=0.27). An explanation is not immediately apparent. Allowing for sport selection factors, regular training does not influence the timing of growth spurts. The findings related to sequence concordance may be related to timing per se. A males are earlier maturing (mean AsPV for stature, 13.1 yrs vs. 13.8 yrs), while mean AsPV for stature in A (12.0 yrs) and NA (11.8 yrs) females do not differ. Perhaps the earlier maturation of A males contributes to their sequence concordance with females.