Abstract:Objective: To study effects of backpack gravity centre position on kinetics and kinematics of lower-extremity joints in parachuting landing and evaluate injuries. Methods: Seven participants performed parachuting landing with backpack gravity centre on three positions: low-back (position 1), upper-back (position 2) and abdomen (position 3). Results: The peak vertical ground reaction force with backpack on position 2 (14.77±1.63 bodyweight (BW)) was significantly lower (P<0.05) than that on position 1 (15.97±1.64BW). The joint moment on sagittal plane of hip with backpack on position 2 (2.12±0.58BW) was significantly higher (P<0.05) than that on position 1 (1.67±0.50BW) and position 3 (1.63±0.37BW). The joint energy absorption of hip with backpack on position 2 (1.75±0.58BW) was significantly higher (P<0.05) than that on position 1 (1.40±0.49BW). The angular displacement of hip on sagittal plane with backpack on position 2 (68.98±12.00deg) was significantly higher (P<0.05) than that on position 1 (60.11±8.24deg) and was significantly lower (P<0.05) than that position 3 (78.56±10.93deg). The angular velocity of hip on sagittal plane with backpack on position 2 (509.58±63.33deg/s) was significantly lower (P<0.05) than that on position 3 (673.05±33.13deg/s).Conclusions: Different positions of backpack gravity centre could significantly influence kinetics and kinematics of hip. Backpack gravity centre on upper-back position could decrease lower-extremity injuries. The results could provide evidences for evaluating backpack gravity centre and decreasing injuries in parachuting landing.