CHANGES IN UPPER BODY AND ARM KINEMATICS WHILE CARRYING SYMMETRICAL AND ASSYMETRICAL BACKPACK LOADS

Christian Stanford¹, Peter Francis², Henry Chambers¹.

¹Motion Analysis Laboratory, Children’s Hospital, San Diego, California, USA. ²San Diego State University, San Diego, California, USA.

The effects of different backpack carrying techniques on posture were investigated in 10 adolescent females. Subjects walked with no load, while carrying 20% bodyweight (BW) in a backpack with both shoulder straps, and with 20% BW in a pack secured by one shoulder strap. Positions of skin markers attached to the trunk, pelvis, and upper extremities were recorded by a motion capture system. Mean angular positions and range of motion (ROM) for the trunk, pelvis, and shoulder were calculated. Results indicated that carrying 20% BW on both shoulders caused a significant increase in forward trunk inclination, a decrease in pelvic rotation, and changes in shoulder elevation and swing, relative to unloaded gait. When the backpack was supported by a single shoulder, numerous additional changes in posture were observed.