Influence of School Backpack Load as a Variable Affecting Gait Kinematics among Seven-Year-Old Children.

This article investigates schoolchildren's ability to carry an additional load using a backpack (BP). According to scientific research, there is no precise limit to the maximum backpack load, which varies from 10% to 15% of body weight (BW). The purpose of this study was, therefore, to evaluate the influence of an additional external load carried using a backpack on gait kinematics among seven-year-old children in Poland, including assessment of the gender differences. The study was conducted among 26 (13 boys and 13 girls) primary school children aged seven years. The children walked at their preferred speed, under four conditions: with no load (0% BW) and with 10%, 15% and 20% BW. Spatiotemporal parameters were measured using the 2 m Footscan platform system and photocell Sectro timing system. The children walked more slowly under an additional load. Their step length and single support time decreased. Their base of support, step time and double support time increased. There was no significant effect on their stride length or gait cycle time. The gait kinematic changes were most evident between 10% BW and greater loading. The results highlight how children's gait is affected by carrying additional external loads, which should not exceed 10% BW. That limit is appropriate for both genders.