Effects of carrying heavy backpacks on back muscles and range of motion of joints during level and inclined walking

Carrying a heavy backpack while walking is considered one of the most widespread tasks, especially by students, hikers, and the military. The effects of carrying it while level or inclined slope walking on the back muscles and joints' ranges of motion (ROM) have been investigated in this study. The study investigation, using surface electromyography (sEMG) and the XSENS Awinda motion capture system, focused on loads 12% of an individual's body weight, by assessing the activation patterns of muscles associated with locomotion and concentrating on spinal segments and lower extremity joints. While the combined effects of sloped walking and backpack loads are known to be physically demanding MATLAB facilitates comprehensive data analysis, and statistical significance is evaluated through a one-way analysis of variance (ANOVA) test. Results highlight a significant decrease in left and right erector spinae and multifidus muscles RMS, axial bending, and lateral bending of the thoracic and lumbar spine joints ROM, no significant differences were observed in the cervical thoracic segment or flexion-extension of the thoracic and lumbar regions. A significant decrease was observed in knee flexion extension and ankle dorsiflexion plantarflexion. However, a significant increase in hip flexion extension and internal external rotation was observed. In this study, we found no significant correlation between muscles and the range of motion of spinal joints without a backpack, while a moderate correlation emerged when individuals carried a backpack. These results suggest that external loads influence musculoskeletal interactions, emphasizing the importance of considering such factors in ergonomic and intervention strategies.