Effect of backpack weight on postural angles in preadolescent children

Background: Carrying heavy backpacks could cause a wide spectrum of pain related musculoskeletal disorders and postural dysfunctions. Objective: To determine the changes in various postural angles with different backpack weights in preadolescent children. Design: Cross-sectional. Participants: Healthy male school-children (n=200), mean (SD) age: 12.5 (0.5) years, from high schools in Mangalore, India. Measurements: Bodyweight and height were measured using a forceplate and stadiometer, respectively. From the weight recorded, 5%, 10%, 15%, 20%, and 25% of the bodyweight were calculated and implemented as their respective backpack loads. The Image Tool version 3.0, digitizing software was used for analyzing photographs to determine craniovertebral (CV), head on neck (HON), head and neck on trunk (HNOT), trunk and lower limb angles. Postural angles were compared with no backpack and with backpacks weighing 5% to 25% of the subject's bodyweight. Results: The CV angle changed significantly after 15% of backpack load (P 0.05). The HON and HNOT angles changed significantly after 10% of backpack load (P <0.05). The trunk and lower limb angle also changed significantly after 5% of backpack load (P <0.05). Conclusions: Carrying a backpack weighing 15% of body weight change all the postural angles in preadolescent children.