THE EFFECTS OF LOADINGS AND SUSPENSIONS OF THREE BOOK BACKPACKS ON STATIC AND DYNAMIC POSTURE OF YOUTHS

Abstract

The purpose of this study was to investigate the effects of different loadings and types of suspension of backpacks on static standing and dynamic walking on the treadmill of youth aged 10–15 years. Twelve subjects (mean age: 12.66 +/−1.96 SD) were filmed in the sagittal plane by a 60 Hz camera. Three different loading conditions (0%, 10%, 20% BW) and three different types of backpack suspensions: traditional (TBP), modified suspension (MBP), and new suspension design backpacks (NBP) were randomly assigned to the participants and tested. Head (HA) and trunk angles (TA) in the sagittal plane were analyzed for both static and dynamic walking postures. In dynamic walking, HA and TA were analyzed during heel strike (HS), midstance (MS), and toe-off (TO). Repeated measures ANOVA revealed no significant differences of HA and TA between the types of backpack suspensions; however, HA and TA on different loading conditions significantly increased from 0% to 10% and from 10% to 20% BW in static standing. In the dynamic posture, HA did not show any significant differences across loading conditions and across backpack suspensions. Meanwhile, TA significantly increased from 0 to 10 and 10 to 20% BW. TA of TBP was lesser than MBP and NBP at 0% BW condition, but it was significantly greater than TA of MBP and NBP at 10 and 20% BW conditions. This may indicate that the suspension system of backpacks can reduce the forward lean of the trunk in the dynamic posture while carrying a load more than 10% BW. Supported by ZeroG Products.