摘要
Abstract
BACKGROUND: The balance and control of the human body depend on the coordination between the vestibular system of the inner ear, the proprioceptors and the visual system, as well as the central nervous system. However, it is unclear about the muscle stiffness regulation and motion control strategy for the lower limbs by the changes in neural control and sensory integration caused by visual deprivation (the eyes are blindfolded). OBJECTIVE: To compare the difference of muscle stiffness regulation and electromyography changes of the lower limbs during descending stairs in children and adolescents with the eyes blindfolded or not, and then to reveal the regulatory effects of visual sense on neuromuscular control and muscle stiffness regulation in adolescents. METHODS: Twenty adolescents with normal vision were randomly divided into blindfolded group and unblindfolded group (n=10 per group). The two groups of subjects were required to descend stairs from three different heights (20, 30, 40 cm) and do their best to perform a squat jump after landing. All subjects were asked to repeat the above-mentioned action thrice, and the data for the most natural actions were analyzed. Vision-based motion imaging analysis system, JP6 060 3 D force-plate, and 8-channel wireless surface electromyography testing system were utilized to test the kinematic (landed knee and ankle joint angles), kinetic (joint stiffness and stiffness of the lower limbs), and electromyography parameters (rectus femoris, biceps femoris, tibialis anterior, gastrocnemius) of the subjects during descending stairs. All the data were processed using SPSS17.0 software. RESULTS AND CONCLUSION: (1) During landing from three different heights, the knee and ankle joint angles of the blindfolded group were significantly larger than those of the unblindfolded group. At the moment of the appearance of the peak reacting force during landing, the knee joint angle of the blindfolded group was smaller than that of the unblindfolded group. Furthermore, the intergroup difference in the ankle joint angle was related to the height of the stair. (2) The first peak vertical force and its relative mean value during landing from different heights were significantly higher in the unblindfolded group compared to the blindfolded group, and both parameters significantly increased with the height increase. (3) During landing from different heights, the stiffness values of the knee joints and lower limbs in the unblindfolded group were significantly higher than those in the blindfolded group, and the stiffness values in the two groups were significantly increased with the height increase. (4) At the moment of pre-landing from different heights, the electromyography activities of the biceps femoris, tibialis anterior, gastrocnemius in the unblindfolded group were significantly higher than those in the blindfolded group, whereas during the buffer period, the electromyography activities of the rectus femoris, biceps femoris, tibialis anterior, gastrocnemius were significantly lower in the blindfolded group than in the unblindfolded group. (5) In conclusion, during descending stairs from different heights, visual deprivation (no visual feedback) reduces the capabilities of identification and environmental observation. The lack of vision may result in a significant decline in the performance of related movements, and thus the central nervous system cannot receive information, thereby impacting the implementation of the action.关键词
蒙眼状况/刚度调节/运动学/动力学/肌电/组织构建/姿势控制/蹲踞跳/组织构建Key words
Kinesiology, Applied/Kinetics/Electromyography/Tissue Engineering分类
医药卫生
