The retrospective longitudinal data of height measured annually from 6 to 17 years old were studied in 439 boys and 483 girls aged between 18 and 22 years old (group I). Retrospective longitudinal growth data from 300 boys and 270 girls under the age of 6 years were also investigated (group II). Plotting these data on a graph, an individual growth curve was drawn by eye fitting technique, height at every three months of age was graphically obtained and height velocity over a whole year was calculated in each case. The average age at peak height velocity (PHV) during adolescence was 13.05±0.94 years in boys and 11.05±1.05 years in girls. The mean PHV of 135 boys ans 148 girls who had PHV at the average age of PHV (subjects with average growth tempo) was 9.9±1.5 and 8.3±1.0 cm/yr. respectively.
The mean height curves of children in group II and children with average growth tempo in group I were drawn and both curves were connected smoothly at the age of 6 years in each sex. The mean height velocity curves of both groups were also smoothly connected at the age of 6 3/12 in each sex as well. Finally the smoothed standard curves for height and height velocity for clinical use were produced for each sex.