Assessing the Impact of Backpack Design on Hikers Lumbar Extension and Centre of Pressure

Background: Heavy backpacks are carried by hikers for prolonged walking periods. Backpack designs impact a hiker’s biomechanics. Methods: We assessed the impact of different backpacks on lumbar extension (LE) and centre of pressure (COP) among hikers. Regular hikers (n=8; age = 23.4±1.9, years; weight = 85.1±7.9, kgs; height = 185.3±3.8, cm) who met the eligibility criteria attended testing sessions to test a traditional backpack (TBP) and a balance backpack (BBP), against a no backpack control (NBP) on three different gradient conditions (flat, 0°; incline, 12°; decline, -12°). Walking tests (1.1m/s) were performed on a force plate-embedded treadmill with a surrounding marker-based motion capture system. Multiple separate two-way ANOVA tests assessed the backpack effect on LE and COP. Results: Dunnett’s multiple comparison Post Hoc test revealed significant variance (p < 0.05) for TBP and an insignificant variance for BBP for LE values. A consistent degree of forward trunk lean across all conditions was observed, with a pronounced LE observed when using the TBP. Insignificant variance in the hiker’s COP between the NBP and BBP across all gradients was observed. Conclusions: This suggests that hikers using a BBP might find their walking posture quite like their normal gait kinematics in comparison to using a TBP.