Coupled effect of load weights and belt use on male shoulder pressure redistribution

Shoulder pressure redistribution is jointly affected by backpack loads and belt support. However, the combined effect of both factors has rarely been fully evaluated. Here, we studied the coupled effect of backpack loads and belt support on shoulder pressure redistribution. All twenty-eight healthy male subjects underwent eight loading conditions with both chest and hip belts fastened (CH) and unfastened (CON) in four conditions where the backpack weighed 7.5, 15, 22.5, and 30% of body weight (BW). Shoulder pressure distribution was quantified through a pressure-sensing vest mat. The results showed that using the hip belt and chest belt was effective in relieving the high pressure in the lateral clavicle and medial trapezius region and strengthening the load-bearing capacity of shoulder. However, the assistance in pressure relief of using belt was weakened when load increased to 30% BW. This study also showed that the belt use can be effective in improving pressure asymmetry on both sides.