Comparison of the common mechanisms of the backpack pelvic belt on the coordination between the trunk and pelvis during walking

Abstract

Introduction: to carry items on long-distance trails and mountaineering, a backpack with a pelvic belt is one of the most important tools. Using a pelvic belt when carrying a backpack will properly distribute the load and spend minimal muscle energy, but will limit pelvic movements. So this study examines the comparison of common mechanisms in the design of the pelvic belt in the backpack on the coordination between segmentation of the trunk and pelvis during walking. Methodology: the test was conducted on 16 men with an average age of 21/88 ±93/1. The electromyography device was used to measure kinematic variables from the IMU sensor - based system and to examine muscle activity, as well as three types of backpacks (1 - Backpack with movable pelvic belt, 2-backpack with cross-frame in the back frame, 3-ordinary backpack). The participants carried the bags on a smooth, undivided surface with a load of 13 kg, and the data was stored. In data analysis phase, the continuous relative phase method (CRP) and its variability (VCRP) was calculated. Findings: The results showed a statistically significant difference between the different backpack modes in index CRP and VCRP. This significant difference was found in the CRP index of the trunk and pelvis between the state without backpack and the backpack 3 in the stance phase (P=0/03) and in the swing phase (P=0/02) during walking. There was also a significant difference in the VCRP index of the trunk and pelvis in the stance phase during walking between the state without backpack and backpack1 (P=0/01) and in the swing phase between the state without backpack and backpack2 (P=0/03) as well as between the state without backpack and backpack1 (P=0/04). Results: The cross-Frame Backpack is the best type of backpack because it tries to maintain anti-phase coordination between the two segments of the trunk and the pelvis by creating freedom of movement. It also shows increased alignment of the body's greater flexibility to adapt to new changes and conditions. Therefore, using the results of this study maintains people's health and helps a person carry heavy items for longer by reducing pressure.