ABSTRACT
Objective To study the changes of plantar pressure during backward walking, so as to explore its effects on balance ability of human gait. Methods Plantar pressure measurement system (Pedar-X pressure insoles) was used to collect the plantar pressure data from 10 subjects during forward walking and backward walking, respectively. The experiment was conducted on the treadmill, and the forward walking was set as the control group. According to the test conditions and intuitive feeling of test participants, 4 speed values (2.0, 2.5, 3.0, 3.5 km/h) were selected to carry out the experiment under two walking modes, respectively. The changes in parameters such as plantar pressure center trajectory, plantar pressure and foot-ground contact time under different speed were analyzed. Results Under two walking modes at different walking speed, subjects showed different plantar pressure during walking. During backward walking, the plantar pressure center transferred from the front foot to the heel and from inside to outside. Compared with forward walking, the plantar pressure during backward walking decreased significantly while the foot-ground contact time increased. Conclusions The study on pressure distribution during backward walking contributes to comprehensively understanding the mechanism of dynamic balance and provides a new perspective for related study on walking stability.
ABSTRACT
Objective To collect the kinematics and kinetics functional parameters of healthy human lower limbs during stair ascent and descent, so as to provide data for designing the gait trajectory and selecting the driving components of the exoskeleton walker to achieve the motion of stair climbing. Methods Common staircase as an experimental setup was designed, and the three-dimensional (3D) motion capture system and 3D force plate were used to simultaneously measure the ankle, knee, hip motion information during stair ascent and descent. The movement characteristics of the lower limb during stair climbing was analyzed by SPSS statistical software and Origin graphics software, and the functional parameters during stair ascent and decent were also compared and analyzed. Results The joint angle at the sagittal plane, joint moment variation with gait and activity limits in lower limbs of healthy youth during stair ascent and descent were obtained by the experiment. The ranges of motion in ankle，knee and hip joints during stair ascent were -10.66°-13.26°, 6.85°-88.92°, 1.31°-50.18°,while those during stair descent were -37.42°-27.18°,9.83°-95.53°,8.01°-31.62°.The maximum ankle, knee and hip joint moment during stair ascent and descent were 1.788, 1.121, 0.946 N•m/kg, respectively. Conclusions The gait parameters variation with gait and the joint range of motion in human lower limb were significantly different during stair ascent and descent. Separate design targeting at stair ascent or stair descent is required for gait planning of walking aids, and the selection of driving element should consider the maximum moment in each joint during stair ascent and descent.