俯卧撑中前臂旋转对上肢肌肉电活动的影响

Effects from forearm-rotation during push-up on muscle electric activities of upper-limb

目的分析俯卧撑中前臂旋转对上肢肌肉电活动的影响。方法采集10个对象在前臂内旋90°(IR90),中立位(NEU)和外旋90°(ER90)三个支撑位下肱三头肌长头和外侧头、三角肌前部和中部、胸大肌和肱二头肌的肌电信号,计算肌电信号的均方根值,并作归一化处理,运用单因素方差分析法比较不同支撑位下肌电信号的差异。同时,对一个周期内肌电信号进行包络线分析。结果从IR90到ER90,肱三头肌长头信号无显著变化,肱三头肌外侧头和三角肌中部信号逐渐减小,而三角肌前部、胸大肌和肱二头肌则逐渐增大。另外,包络分析结果显示了3种不同类型的肌电信号曲线。结论不同前臂转动支撑位对肌肉电活动产生影响,而对各肌肉的影响程度和方式并不相同。

Objective To analyze forearm-rotational effects on muscle electric activities of upper-limb during push-up. Method The EMG of long and lateral heads of biceps brachii, antedor and medius deltoid, pectoralis major and biceps brachii for ten subjects during push-ups at three forearm rotations of internally rotated 90°（IR90）, hand-neutral （NEU）, and externally90° （ER90） was collected. The root mean square （RMS） values of EMG were calculated and normalized. To determine whether there has any difference between the EMG from the three positions, a One-Way ANOVA with factor rotational position was conducted on the normalized RMS values. The EMG profiles through a cycle were also displayed. Result From IR90 to ER90, there was no significant difference for the long head of biceps brachii, but a decrease for the lateral head of biceps brachii and medius deltoid, and an increase for anterior deltoid, pectoralis major and biceps brachii were found. The EMG profiles showed three patterns. Conclusions There were differences of electric activities for the muscles during push-ups at various forearm positions. However, these changes or effects did not occur in the same way for the six muscles.