Influences of Different Stop Modes on Gait Stability of the Elderly Carrying Heavy Objects / 医用生物力学

ABSTRACT

Objective To analyze characteristics of muscle activity and changes of corresponding kinematic parameters of the lower limbs for the elderly carrying heavy objects under synchronous stop modes, and explore the effects of hand weight-bearing and stop modes on gait stability and body balance of the elderly. Methods The ankle, knee, hip joint angles and surface electromyography (EMG) signals of bilateral lower limbs were collected under the condition of emergency stop and planned stop by loading 0 kg, 2.5 kg on both hands and 5 kg on right hand. Results Under different weight-bearing modes, the ankle and hip angles of bilateral lower limbs were significantly different (P<0.05), while the knee angles did not change significantly, and different stop modes significantly affected the angle changes in each joint (P <0.001); the average EMG of tibia anterior muscle, lateral femoral muscle, and biceps femoris in braking leg showed higher muscle activity during emergency stop. Conclusions In order to cope with the instability caused by weight-bearing and emergency stop, the elderly will have a corresponding balance mechanism in the lower limbs. During an emergency stop, braking the tibialis anterior muscle of the leg requires a higher muscle activity level to control flexion angle of the ankle joint, thereby reducing amplitude of the ankle joint fluctuation. The single-handed load increases the muscle performance differences between the braking leg and trailing leg, resulting in the lateral instability.