The purpose of this study is to examine and analyze the kinematics effects of carrying the school backpack with four different weights on the parameters of gait cycle and posture of youngsters aged between 12 and 14.
The subjects (n =12) in this research were 12 volunteer, boys with the average age of 13.26±0.32 years and the average weight of 54.96±7.7 kg. The subjects carried backpacks with four different levels to their body weight (BW):
0% (control group), 7.25% (the average weight of backpacks used by subjects), 10%(5.5 kg) and 15% (8.3 kg) during a 200m course with natural pace, all in random order. The subjects gaits were cinematographed in both static and dynamic manners, with the speed of 60 frames per second. The “Win Analyzer” software was used to analyze the films on the basis of kinematics. The following results were obtained :1) comparing to 0% load condition, increase in weight of backpacks of youngsters by 10% or more induced a significant decrease in left and right stride length, an increase in stride frequency, increase in forward lean. of trunk and head in static and dynamic body posture. 2) No significant difference was found in the measures between 7.25 and 0% body weight. Based on the results, we advise that backpack weight of school youngsters aged between 12 and 14 shouldn’t be heavier than 7.25 to 10% of their body weight.
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