Changes in gait patterns in 10-year-old boys with increasing loads when walking on a treadmill.

This study examined the gait pattern, heart rate and blood pressure in children carrying school bags of 0 (as control), 10, 15 and 20% of their own body weight whilst walking on a treadmill. When compared to the 0% load condition, the 20% load condition induced a significant increase in trunk forward lean, double support and stance duration, and decreased trunk angular motion and swing duration and a prolonged blood pressure recovery time. The 15% load condition induced a significant increase in trunk forward lean and prolonged blood pressure recovery time. No significant difference was found in the measured parameters between the 10 and 0% load conditions. We concluded that back pack weight should not exceed 10% of body weight in 10-year-old boys.