The Effects of Backpacks of Different Structures with Different Loads on Shoulder to Back Pressure in Primary School Students

The main purpose of this study was to evaluate the difference between soft and hard backpacks in pressure transmission effect and decompression with increased load weight. mFLEX was used to measure shoulder to back pressure on 100 primary school students (male-female ratio 4:6) wearing different bag loads (equivalent to 5%, 10%, 15%, 20% and 25% of their body weights). Meanwhile, a comparative analysis test was done between backpacks of different structures (red backpack A with shoulder and back cushion design and regular yellow backpack B without shoulder and back cushion design). The conclusion is, along with the increase of backpack load, shoulder to back pressure value increased significantly, among them shoulder pressure value increased linearly, and back pressure value increased exponentially. Pressure values of the cushion bag (A) in three areas were all significantly larger than those of control bag (B). The results of the study are contrary to our hypothesis. Instead of effectively alleviating the concentration of pressure in three stress areas, left shoulder, right shoulder and lower back (LS, RS and LB), the buffer structure increases the pressure values. Therefore, in main pressure areas, we cannot simply rely on adding buffer structure to reduce the pressure generated by loading.