Influence of load and carrying methods on gait phase and ground reactions in children's stair walking.

The study investigated the effects of carrying methods and loads on gait phase and ground reaction force during stair ascent and descent in children. The carrying methods that were examined included the backpack and one-strap athletic bag. The load weights included 0%, 10%, 15%, and 20% of body weight. Thirteen school children aged 12.21 +/- 0.98 years were recruited as subjects. A Novel Pedar System was used to record and analyze the insole pressure during stair walking with different loads. The load that caused a significant increase in the peak force in each bag and stair mode was 15% of body weight, except for stair ascent carrying the athletic bag, where the load was 10% of body weight. The maximum peak force that was induced by this load in stair descent was 1.25 times that in descent with no load, 1.89 times that in ascent with the same load, and 2.19 times that in ascent with no load. The force-to-time ratio in descent was about three times that in ascent.