| Summary: | 碩士 === 中國文化大學 === 運動教練研究所 === 91 === Abstract
The purpose of this study was to analyze variance on the lower body muscular stiffness and EMG activity of contact and pre-contact between visually impaired students and healthy vision students on the process of movement for walking down stairs to identify the effects of eyesight for neuromuscular activation control and muscular stiffness adjustment.Ten normal vision students (age: 24.3±2.4 years; 171.5±4.6; mass: 65.9±8.0) and Ten visually impaired students (age: 23.2±2.4 years; 163.4±9.6; mass: 62.8±15.0) were asked to perform the stepdown walking from different heights:20, 30and 40㎝. AMTI force platform (sample rate: 1200Hz), Biovision system and Peak Performance high-speed camera (60Hz) were used synchronizely to record the ground reaction force, EMG signals and the video image of the movements Leg muscular stiffness was defined as: The ratio of ground reaction force at the transition from eccentric to concentric contraction and vertical displacement of center of gravity (Fmax/Lmax) during CMJ. The statistics is use two-way ANOVA and Independent-Samples T Test to determine the variances with alpha level of .05.
According to the results analyzed, we concluded that this phenomenon shows that the ability of stiffness regulation of the normal one is more efficient than that of impaired ones. i) During stepdown walking, the leg stiffness and the angular stiffness of visually impaired students as well as normal vision students (close-eye, open-eye). The the leg stiffness of CMJ for visually impaired students were less than normal students. There is a sign of increase of leg stiffness and angular stiffness as the escalation of altitude. ii) The myoelectric activities (EMG) of pre-contact for gastrocnemius lateral head of visually impaired students were smaller than those of normal ones. The myoelectric activities (EMG) of contact phase for rectus femoris , tibialis anterior and gastrocnemius lateral head of visually impaired students were smaller than those of normal ones. There is a sign of increase of IEMG as the escalation of altitude.
KEY WORDS: visually impaired student, leg stiffness, EMG, CMJ
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