Papers by Keyword: Postural Balance Control

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Authors: Hyeon Ki Choi, Jae Hoon Jeong, Sung Ho Hwang, Hyeon Chang Choi, Won Hak Cho
Abstract: We recognized EMG signal patterns of lower limb muscles by using neural networks and performed feature evaluation during the recovery of postural balance of human body. Surface electrodes were attached to lower limb and EMG signals were collected during the balance recovery process from a perturbation without permitting compensatory stepping. A waist pulling system was used to apply transient perturbations in five horizontal directions. The EMG signals of fifty repetitions of five motions were analyzed for ten subjects. Twenty features were extracted from EMG signals of one event. Feature evaluation was also performed by using DB (Davies-Bouldin) index. By using neural networks, EMG signals were classified into five categories, such as forward perturbation, backward perturbation, lateral perturbation and two oblique perturbations. As results, motions were recognized with mean success rates of 75 percent. With the neural networks classifier of this study, the EMG patterns of lower limb muscles during the recovery of postural balance can be classified with high accuracy of recognition.
Authors: Hyeon Ki Choi, Min Jwa Seo, Ja Choon Koo, Hyeon Chang Choi, Won Hak Cho
Abstract: We assessed the effects of muscle forces on ankle joint kinetics during postural balance control of human boy. Nine male subjects (mean age of 25.8 yrs) participated in the experiment. An ankle joint model assumed ball and socket joint was used, which was capable of three dimensional rotations. A six-camera VICON system was used for motion analysis. Waist pulling system and force platform were adopted for forward sway and GRF (ground reaction force) measurement. We used linear optimization programs to calculate the variation of muscle forces and angular displacements of shank and foot segments. With the experimental data and linear programs, we could calculate joint reaction forces, and bone-on-bone forces. The results presented in this study give us the insights to understand the roles of lower limb muscles during postural balance control and ankle injury mechanism.
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