The comparison of common mechanisms in hip belt design of the backpack on the range of motion and coordination of trunk-pelvis rotation during walking

چکیده مقاله

This study aimed to compare common mechanisms in hip belt design on the range of motion and coordination of trunk pelvis rotation during walking. In this research, a total of 16 healthy subjects were examined. Three backpacks used in this study, include a movable frame, cross frame, and fixed hip belt. Pelvis and trunk range of motion were measured using the IMU system. All backpacks were carried with a 13 kg load that was inserted inside the backpack The IMU sensors were attached with special straps on the subject's trunk, pelvis, and thigh. Each subject walked 10 steps along the straight walkway. Pelvis and trunk range of motion in the horizontal plane, continuous relative phase (CRP), and variability in CRP were calculated. The repeated measure ANOVA was used for statistical comparisons and the Tukey Post hoc test was used for pair comparisons. The significance level was considered P ≤ 0.05 in all tests. The results indicated that the pelvis range of motion was reduced during gait with a fixed hip belt (P=0.002), however, there are no significant differences between pelvis rotation with cross frame and movable hip belts and normal gait (P>0.05). The results also showed that cross-frame hip belts reduced the trunk range of motion (P<0.05), however, movable hip belts and fixed hip belts don’t change the trunk range of motion (P>0.05). The results indicated that the trunk range of motion during gait with cross frame was significantly lower than normal gait (p<0.05), and the pelvic range of motion during gait with fixed hip belt was considerably lower than other conditions (p<0.05). The results of the study showed that movable hip belts and cross-frame hip belts were capable of increasing the pelvis' range of motion in the transverse plane. Based on the findings of this study, both movable and cross-frame hip belts enhance pelvis rotation and make the gait pattern more similar to normal. Consequently, backpacks with movable and cross-frame hip belts are safer for walking.