Gait and posture responses to backpack load during level walking in children.

Eleven primary school boys aged between 9 and 10 years old completed carrying backpack loads of 0, 10, 15, and 20% of their body weight while level walking using natural cadence. Stride and temporal parameters, trunk lean angles and trunk motion range were analyzed. The results showed that both the backpack load and walking distance exerted no significant influence on stride and temporal parameters. However, when compared with the 0, 10 and 15% load conditions, the 20% load induced a significant increase (P<0.05) in trunk inclination. If trunk inclination is taken as the criteria to determine permissible backpack loads for children, those loads should not exceed 15% body weight. In addition, walking distance should be considered when permissible loads are determined.