A longitudinal analysis of the growth of limb segments in adolescence.

The growth of upper and lower-limb segments of 96 adolescent boys and girls from the Royal Hospital School Longitudinal Study was analysed. Preece-Baines Model 1 curves were fitted to the longitudinal data to obtain, for each measurement, age at peak velocity and the magnitude of this velocity. Mean-constant peak velocities were between 1-0 and 2-5 cm/yr in all segments. They were in all cases greater than the values obtained from fitting the P-B curve to the cross-sectional means at successive ages. Boys had greater peak velocities than girls in all measurements (sex ratio 1-1 to 1-4). On average distal segments preceded more proximal segments in the ages at which peak velocity occurred. Considerable individual differences, however, occurred in the order for the upper limb segments. These differences seemed to be related to the individual's tempo of growth; late developers had a significantly different order to early developers.