Longitudinal study of pubertal peak height velocity and related morphological and functional components in Brazilian children

The purpose of this study was to describe peak height velocity (PHV) characteristics and its relationship to morphological and functional developmental components in a select group of Brazilian children. The children (18 girls and 26 boys) were from a longitudinal study in Ilhabela, Sao Paulo, Brazil. Measurements, taken twice a year, included anthropometric parameters: weight, height, sitting height, seven skinfold thicknesses $(\Sigma$ of 7 skf), bone diameters and two circumferences, and physical fitness performance tests: vertical jump (VJ), vertical jump with (VJW) standing long jump (SBJ), hand grip strength (HG), shuttle-run (SR), and 50-meter run. The mean chronological age of the boys on the first measurement was 10.91 years $\pm$ 1.30 and the girls was 9.19 years $\pm$ 1.13. The mean period of follow-up for girls was 5.53 years $\pm$ 1.09 (range 3.5 to 8.0 years) and for boys 6.06 years $\pm$ 1.42 (range 4.0 to 8.5 years). PHV, estimated by the Preece-Baines Model I, occurred at an earlier age in girls than in boys (11.55 years and 13.99 years, respectively). The velocity at PHV was greater in boys (9.72 cm/year) than in girls (9.15 cm/year). PHV occurred before menarche (mean age = 12.67 years) in all girls. A significant correlation (p $<$.01) between age of PHV and age of menarche (r =.91) was also found. Polynomial regression demonstrated only linear, and linear and quadratic relationships between all variables and chronological age for individual subjects. Peak velocity for anthropometric and physical fitness variables, estimated by the increment method, and described in relation to the PHV showed for girls: a peak velocity close to PHV for body weight, HG, and SR, and for $\Sigma$ of 7 skf one year after PHV (coincidentally with menarche); while for the boys a peak velocity close to PHV for body weight, VJW and SBJ, and at PHV for VJ, HG, and 50 meter run.U of I OnlyETDs are only available to UIUC Users without author permissio