Changes in dynamic stability, motor coordination and joint mechanics of the lower extremity during stair descent and performing phone task / 中国组织工程研究

ABSTRACT

BACKGROUND: The coupling and coordination control of the multi-link rigid body of human body is the key to stable walking. It is reported that the use of cell phones greatly increases the chance of falling down stairs when walking; however, it lacks the analysis of the dynamic stability, motion coordination and joint mechanics of the lower limbs when walking down stairs with cell phone intervention. OBJECTIVE: To investigate the effects of cell phone on coupling control strategy of the multi-link rigid body in lower extremity during stair descent. METHODS: Twenty healthy university students were recruited and conducted the stair descent under no-interference (single task) and cell phone (phone task) randomly. Using the method of synchronous acquisition of 3D kinematics and dynamics, the kinetic and kinematic data were synchronously collected to acquire the parameters of stair descent under both conditions. RESULTS AND CONCLUSION: (1) The intervention of phone task significantly reduced the dynamic stability in anterior-posterior/media-lateral direction, the first knee extension moment peak, the first dorsiflexion moment peak, the second hip flexion moment peak in sagittal plane during stance phase, and significantly increased the mean and standard deviation of hip-knee/knee-ankle relative phase angles during swing phase. (2) It is concluded that when the gait of human body changes from time to time, the coupling control ability of multi-link rigid bodies decreased and the risk of falling increased. (3) The intervention of phone task reduces the supporting moment of lower limbs in the supporting phase, reduces the stability of adjacent joint coordination control in the swinging phase, reduces the dynamic stability in front, back and inside directions, and increases the risk of falling.