ABSTRACT
Objective To analyze the impact of soldiers’ single-leg landing with load carriage on knee joint, and investigate its relationship with muscle strength, so as to provide references for daily load carriage training. Methods A total of 12 soldiers were required to perform single-leg landing from the 30 cm height without load carriage and with 15 kg load carriage,respectively.The kinematic and kinetic parameters were collected using Vicon motion capture system and AMTI force platform. The surface electromyography (sEMG) of anterior and posterior thigh muscles were also collected simultaneously, and the isokinetic strength during knee flexion and extension was tested. Results Compared with landing without load carriage, knee flexion angle and joint reaction force significantly increased during landing with 15 kg load carriage (P0.05). There was a significant negative correlation between peak moment of knee extension and vertical ground reaction force during single-leg landing without load carriage (P0.05). Conclusions Knee flexion angle and joint reaction force significantly increase during single-leg landing with 15 kg load carriage, the activation of anterior and posterior thigh muscles can relieved the ground reaction force during landing, and muscle strength plays some role in preventing landing injury.
ABSTRACT
Objective To evaluate the influence of different load carriages during military walking on the gait of lower limbs. Methods In a randomized cross-over design, 15 healthy young males were asked to perform self-paced walking with a normal uniform under a load carriage of 0 kg, 7.5 kg, 27 kg, and 50 kg for four times. The kinematics parameters of the pelvis, knee, and ankle were evaluated by the Vicon motion capture system and AMTI force plates. Results With increasing load carriage, the stride frequency relatively improved, whereas the stride reduced and the speed was maintained on the whole. The peak left/right hip flexion and extension angle and peak knee adduction angle were obviously affected by the load carriage, whereas the movement magnitudes could be maintained. The peak varus angle of the left ankle and peak valgus angle of the right ankle were also affected. The peak force and moment of the left/right knee and ankle increased. Conclusions With increasing load carriage, overall, the movement magnitudes of lower limb joints were maintained under the given loads, whereas the lower limb loads were increased, which could increase the potential risk of lower limb injuries.