Backpack Loads Have an Influence on Shoulder Height, Thoracic Kyphotic Angle, and Muscle Fatigue in Adults

다국어 초록 (Multilingual Abstract)

Purpose: This study examined the effects of backpack loads on the shoulder height, thoracic kyphotic angle, and muscle fatigue in healthy adults.
Methods: Fifty-six healthy adults participated in this study. The participants were divided into groups carrying backpacks weighing 0%, 10%, 15%, and 20% of their body weight. Each participant walked on a flat treadmill at 2.7 mi/h for 15 minutes. The changes in shoulder height (SH), thoracic kyphotic angle (TKA), and muscle fatigue according to the backpack loads were measured before and after treadmill walking.
Results: A pre-post comparison in SH revealed significant differences in all groups except for the 0% group (p<0.05). In TKA, there were no significant differences in all groups except for the 20% group (p>0.05). In muscle fatigue, significant differences were shown in the upper trapezius (UT), lower trapezius (LT), sternocleidomastoid (SCM), and serratus anterior (SA) of all groups except for the 0% group (p<0.05). In pectoralis major (PMa) muscle fatigue, significant differences were noted in the 15% and 20% groups (p>0.05). A comparison of pre-post changes in SH showed significant differences between the 0% and 20% groups (p<0.05), and there were no significant differences between all groups in TKA (p>0.05). In the UT muscle fatigue, significant differences were observed between 0% and 10%, 0% and 15%, and 0% and 20% groups (p<0.05), and the LT, SCM, SA, and PMa were similar all groups (p>0.05).
Conclusion: This study showed that SH, TKA, and muscle fatigue were affected by the different weights of backpacks. These results may provide guidelines for appropriate backpack weight and help prevent postural imbalances such as round shoulder posture.