Biomechanical Analysis of Lower Limbs during Walking under Simulated Reduced Gravity / 医用生物力学

Objective To investigate the influence of gravity levels on lower limb motions during human walking. Methods A suspended microgravity simulation system was designed for the experiment. Kinetic parameters from lower limb joints of twelve volunteers during walking were measured by the motion capture system and 3D force plate under simulated Mars gravity (1/3 G), lunar gravity (1/6 G) and earth gravity (1 G). Results Under simulated Mars and lunar gravity, the ranges of motion (ROMs) of hip and knee joints in sagittal plane significantly decreased (P＜0.01) while the ROMs of ankle joints obviously increased (P＜0.05). The ROMs of hip, knee and ankle joints in sagittal plane under earth gravity were 45.2°, 67.7°, 32.5°, respectively, while the ROMs of hip, knee and ankle joints under lunar gravity were 25.1°, 50.8°, 42.4°, respectively. In addition, the force and torque of lower limb joints in sagittal plane under lower gravity also decreased significantly (P＜0.01). Conclusions The results obtained by this study were almost the same as the research findings obtained by using treadmill. Astronauts can use the treadmill and microgravity simulation system for walking exercises under lunar gravity on the earth.

Joint angles and muscle activations in the lower limb of young women during slope walking / 医用生物力学

Objective To illustrate the influences of walking speed and road slope on lower limb motions by quantitative analysis on the changes of joint angles and muscle activation. Method Five walking speeds and three road slopes were selected from slow to fast according to the related measurement. The gaits of 15 young women were measured using the motion capture system and the EMG signals of 8 major muscles in lower limbs were collected simultaneously. The mean joint angles of hip, knee and ankle in sagittal plane at different speeds and different slopes were calculated. The subject whose data was closest to the mean value could be easily found. Results The joint angles of the subject’s hip, knee and ankle in sagittal plane at different speeds and different slopes in a gait cycle were presented and the activation curves of the 8 major muscles during lower limb movements were obtained. Conclusions In each gait cycle, the curves of joint angles and muscle activations varied little with 5 different speeds, while curves for 3 different road slopes only showed similar tendencies but with different peaks.

Influence of jogging speed on lower limb joints and muscles of young women / 医用生物力学

Objective To study the effect of reasonable jogging speed on body shape and walking gait to make people acquire graceful posture through jogging. Method Five jogging speeds were selected according to related measurements. Kinematical data of subjects (15 young women volunteers) in jogging were measured by the motion capture system, while the EMG signals of 8 major muscles in lower limb were collected simultaneously. The mean angles of hip, knee and ankle joints in sagittal plane at different speeds were calculated. The subject whose data was closest to the mean value was chosen as the research subject and analyze the kinematical data. Results The angles of the subject's hip, knee and ankle joints in sagittal plane at different speeds in a gait cycle were presented, and activation curves of her 8 major muscles were obtained during lower limb movements. Relationships between the jogging speed, jogging stage, muscle activation and joint angle were described by the scoring method. Conclusions The range of joint angle and maximum of muscle activation don't change with jogging speed monotonously. The study provides a reference for young women to choose their own jogging speed.