Diurnal variation in height and the reliability of height measurements using stretched and unstretched techniques in the evaluation of short-term growth

Abstract

Diurnal variation in stature is one potentially significant source of error in the evaluation of short-term growth. In order to assess the pattern of diurnal variation in height during a 12-h period, the standing height of two healthy prepubertal male siblings, 7 and 11 years of age, was measured by stretched and unstretched techniques five times a day at 3-h intervals over 8 consecutive days. The major loss of height occurred during the first 3h after rising when the mean stretched height decreased by 0.94cm (unstretched 1.03cm). The maximal height loss was achieved by 1500 hours when the mean stretched height had decreased by 1.44cm (unstretched 1.41cm) from that recorded in the morning. Over the next 6h there was a significant (p