| Summary: | 碩士 === 國立臺北教育大學 === 體育學系碩士班 === 101 === Purpose: The purpose of this study is to analyze the kinematics, kinetic and myoelectric parameters changes while the middle-aged and elders perform stoops, semi-squats, deep squats and normal squats. Subjects: This study chose 12 healthy middle-aged and elders without any medical history of lower-limb diseases in the past year. Methods: A Mega Speed MS30K high-speed camera(100Hz), an AMTI force plate (1000Hz) and a Biovision myoelectric system (1000Hz) which are synchronized to capture the movement of squatting. This study used the Kwon3D tools to analysis the kinematics parameters. The original signals from the force plate were processed by DASY Lab6.0 analysis software and were standardized by body weight (B.W) to obtain ground reaction force and impulse. The original signals of EMG form lower limb muscles were processed by DASY Lab 6.0 software. After the integration analysis to get the integration EMG (IEMG), divided by the time of a total squat cycle to obtain the average EMG, this experiment proceeded to use the max value of EMG signals in a squat cycle to get standardized data. The resulting data were processed by SPSS 17 for Windows and analyzed with one-way ANOVA (α＝.05). Result：1. The study indicates that there exists significant changes in the angle of the trunk forward lean, hip joints, knee joints, and ankle joint(P<.05), demonstrating that there is a tendency that the deeper the squatting is, the more enlarged the angle of the lower limb joint is. This comes to increase the vertical displacement of center of gravity, prolongs the time of performing a squat, and gather the max speed of center of gravity. 2. The study indicates that there exists significant changes in the peak force of vertical ground reaction(p<.05), accompanied by greater impulse and ALF. 3. The study indicates that there exists significant changes in the average EMG signal amplitude from Rectus femoris, Biceps femoris long head, Tibialis anterior, Gastrocnemius lateral head while different types of squatting are performed(P<.05). 4. The variation of medial-lateral displacement of center of pressure is significantly greater in normal squats than in the other three(p< .05). Conclusion: After analyses and discussions, this study has found that the middle-aged and elders’ lower limb muscles are not robust enough to catch up with the increasing speed of squatting movement. In addition, longer reaction time and delayed recruitment of muscles, result in the middle-aged and elders’ slow initial velocity of bodily movement and being more liable to fall down. When squatting, the body gravity center has to be adjusted by all lower limb joints concerned and is there by balanced. The deeper the squats go, the angle of the trunk forward lean, all the joints concerned, the displacement of center of gravity, and the lower limb muscle will work together to deal with various circumstances. In view of this, deep squats have greater influence on the middle-aged and elders’ bodily control. It is recommended when the middle-aged and elders squat, it is better to reduce the change joint angles or prolong the time of squatting and avoid body swaying to diminish the ALF and increase movement stability.
Key words: stoops, semi-squats, deep squats, joint angles, EMG
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