Impact of Load Carriage on Gait and Muscle Activity

The amount of loads carried in backpacks by school children has been increasing over the last two decades raising concerns among medical practitioners and parents about the possible detrimental effects prolonged heavy load carriage can have on the musculoskeletal system. Previous studies have indicated that loads higher than 15% of body weight affect the gait and trunk posture of children and can cause long term musculoskeletal problems. It has been reported in many countries that due to the structure of the curriculum, children usually carry loads as high as 22-25% of their body weight. Therefore, it is important that ergonomic backpacks be designed in order to alleviate the musculoskeletal stress. The present study investigated whether it was better to place the loads high up or low down on the back. Three different load amounts 10%, 15% and 20% body weight loads were carried on two locations (high and low) on the back. Kinematic, kinetic, temporal, spatial and muscle activity data at the lower and upper back muscles was collected and studied.