太极拳白鹤亮翅对下肢肌电活动的影响

EMG characteristics of lower extremities during movement of white crane spreads its wings in Tai Chi Quan

目的通过对比太极拳初学者和太极拳运动员白鹤亮翅动作关节角度活动变化、压力中心(center of pres-sure,COP)变化和肌肉活动特点,分析运动员是如何通过肌肉活动控制其白鹤亮翅的姿势平衡。方法太极拳运动员和初学者分两组各10人。记录太极白鹤亮翅动作时双下肢10块骨骼肌表面肌电图、双下肢3大关节的二维角运动和COP在侧方和前后的移位。每次试验8 s完成,重复5次。统计处理后,做肌电运动和平衡分析;其中肌电数据做标准化处理,并比较太极拳运动员和初学者的异同。结果运动员组支撑腿胫骨前肌、股二头肌、臀中肌)的肌电活动表现为显著高于初学者同侧腿骨骼肌的肌电活动;运动员组虚步腿的腓肠肌和股直肌的肌电活动显著高于初学组同侧同名肌。运动员组下肢3大关节最大平均活动角度比初学组大,支撑腿髋关节显著高于初学组同侧同关节。运动员组COP前后方向位移显著小于初学组。结论运动员可以通过肌肉活动的增强对抗COP的移位,保持姿势平衡稳定,而初学者COP前后移位失控时并没表现出积极的肌肉活动。初步解释了太极拳练习能提高人体下肢肌肉力量和平衡控制能力的原因。

Objective To analyze how the athletes control postural balance through observing their joint angular motion change,center of pressure （COP） change and EMG activities of lower extremities for both athletes and beginners when performing the movement of white crane spreads its wings in Tai Chi Quan. Methods Twenty subjects were divided into 2 groups as l0 athletes and lO beginners of Tai Chi Quan in each. When performing the movement of white crane spreads its wings, their EMG activities of 10 skeletal muscles, two-dimensional an- gular motion of 3 large joints in bilateral lower extremities, and COP displacements in lateral and anterior-posterior directions were recorded. Each performing trial took 8 seconds and repeated 5 times. All data were statistically processed for EMG, motion and balance analysis, and the EMG data were normalized to compare the differences between the athletes and beginners of Tai Chi Quan. Results The EMG activities of tibialis anterior（Ta）, biceps femur（ bF）, gluteus medium（Gm） in support leg of athletes were significantly greater than those of the ipsilateral muscles in support leg of beginners, and the same was the EMG activities of gastrocnemius （G） and rectus fe- mur（rF） in virtual leg of athletes compared with the beginners. The maximal average angular motion of 3 large joints and the coxa joint motion of support leg in athletes were both significantly greater than that in beginners, but the anterior-posterior COP displacement in athletes was significantly smaller than that in beginners. Conclusions When performing the movement of white crane spreads its wings in Tai Chi Quan, athletes could oppose the COP change by enhancing muscle activities to maintain the postural balance, while beginners couldn＇ t makesuch active muscle activities against the uncontrolled anterior-posterior COP displacement. This may preliminarily explain the reason why Tai Chi Quan exercise can improve the muscle strength in lower extremities and enhance the ability of postural control.