Objective To study the variations in lower limb muscle strength and gait after long-distance load marching in soldiers and to investigate the effects of muscle fatigue of the lower limbs on the walking and running gait.Methods Fifteen male soldiers completed a 15 km march with a 17.5 kg load carriage.The isometric muscle strength of the hip,knee,and ankle joints under flexion and extension were tested.The walking and running gait parameters were collected with a Vicon motion capture system and AMTI force platform.Results After load marching,the peak moment of the hip decreased significantly(P＜0.05),the mean power of the right knee decreased significantly(P＜0.05),and the relative peak moment and mean power of the ankle plantar flexion decreased significantly(P＜0.05).During walking,the left hip flexion,knee flexion and extension,ankle dorsiflexion,and inversion angles(P＜0.05)decreased significantly in conjunction with a significant increase in the knee inversion angle(P＜0.05).Additionally,the moments of left hip flexion,knee flexion,ankle plantar flexion,and bilateral knee inversion(P＜0.05)decreased significantly,coupled with a significant increase in the moments of right hip extension and vertical ground reaction forces(P＜0.05).During running,the step frequency decreased significantly(P＜0.01),and the left step width increased(P＜0.05).Both left and right ankle dorsiflexion angles decreased significantly(P＜0.05),whereas the knee adduction angle increased significantly(P＜0.05).Additionally,the moment of bilateral hip flexion,left knee flexion,right ankle dorsiflexion,and knee adduction decreased significantly(P＜0.05),and the ground reaction force on the right side increased significantly(P＜0.05).Conclusions The lower limb muscle strength decreased after long-distance marching.This was particularly so in the hip joint.The hip drive mechanism was used in the walking gait after marching.However,knee hyperextension and valgus occurred owing to the decreased muscle strength.The ankle joint was used more frequently during running.This increased the risk of ankle injury.It is necessary to strengthen the hip and hamstring muscle groups to optimize the gait,increase the load capacity,and prevent injury.

Objective To study the variations in lower limb muscle strength and gait after long-distance load marching in soldiers and to investigate the effects of muscle fatigue of the lower limbs on the walking and running gait.Methods Fifteen male soldiers completed a 15 km march with a 17.5 kg load carriage.The isometric muscle strength of the hip,knee,and ankle joints under flexion and extension were tested.The walking and running gait parameters were collected with a Vicon motion capture system and AMTI force platform.Results After load marching,the peak moment of the hip decreased significantly(P＜0.05),the mean power of the right knee decreased significantly(P＜0.05),and the relative peak moment and mean power of the ankle plantar flexion decreased significantly(P＜0.05).During walking,the left hip flexion,knee flexion and extension,ankle dorsiflexion,and inversion angles(P＜0.05)decreased significantly in conjunction with a significant increase in the knee inversion angle(P＜0.05).Additionally,the moments of left hip flexion,knee flexion,ankle plantar flexion,and bilateral knee inversion(P＜0.05)decreased significantly,coupled with a significant increase in the moments of right hip extension and vertical ground reaction forces(P＜0.05).During running,the step frequency decreased significantly(P＜0.01),and the left step width increased(P＜0.05).Both left and right ankle dorsiflexion angles decreased significantly(P＜0.05),whereas the knee adduction angle increased significantly(P＜0.05).Additionally,the moment of bilateral hip flexion,left knee flexion,right ankle dorsiflexion,and knee adduction decreased significantly(P＜0.05),and the ground reaction force on the right side increased significantly(P＜0.05).Conclusions The lower limb muscle strength decreased after long-distance marching.This was particularly so in the hip joint.The hip drive mechanism was used in the walking gait after marching.However,knee hyperextension and valgus occurred owing to the decreased muscle strength.The ankle joint was used more frequently during running.This increased the risk of ankle injury.It is necessary to strengthen the hip and hamstring muscle groups to optimize the gait,increase the load capacity,and prevent injury.