不同负荷运动中下肢肌表面肌电图的变化

背景：尝试应用曲线拟合分析方法对表面肌电图进行分析和研究国内外尚处于起步阶段，将其应用于功率自行车运动至疲劳的研究鲜见报道。目的：探讨功率自行车不同负荷运动中下肢肌中值频率值的变化特征和规律，分析肌肉疲劳拟合曲线的特点及其影响肌肉疲劳的相关因素。方法：受试者为苏州大学体育学院8名男性青年，利用MONARK功率自行车，对受试者在不同负荷以及不同踏蹬频率下进行测试至疲劳，同时对股直肌、股外侧肌、股内侧肌、胫骨前肌、腓肠肌内侧头和腓肠肌外侧头进行表面肌电信号的采集与记录。分析中值频率指标的变化，并用minitab.15统计软件，按照在F检验的统计学差异有非常显著性意义（P〈0．001）的前提下，选取判定系数序最大，偏差的平方和最小的原则，对实验结果进行曲线优度拟合。结果与结论：①功率自行车150W运动时，肌纤维的募集形式由运动初始快肌纤维募集数量逐渐增多向慢肌纤维募集比例增高转变。②功率自行车300W运动时，肌纤维的募集形式从运动初期的快肌纤维募集为主逐渐向慢肌纤维募集比例增高转变。③功率自行车150W运动时，肌肉疲劳的拟合曲线均为三次项曲线，提示影响肌肉疲劳的主要因素有3个。300W运动时，肌肉疲劳的拟合曲线均为二次项曲线，提示影响肌肉疲劳的主要因素有2个。

Surface electromyogram of the lower limb muscle during different load movements

BACKGROUND： To analyze surface electromyogram data using curve fitting analysis method is still in its infancy, which is rarely reported in the research of power bicycle induced fatigue. OBJECTIVE： To explore the changes and rules of median frequency of the lower limbs induced by power bicycles under different toad, and to analyze the changes of the relevant indicators of surface electromyogram and characteristics of muscle fatigue fitting curves. METHODS： Eight young men from Physical Education School of Soochow University were enrolled as subjects. All subjects were subjected to different load and different pedaling frequency exercises usingMONARK power bicycle until they felt fatigue. At the same time, surface electromyogram signals of the rectus femoris, vastus lateralis, vastus medialis, tibialis anterior muscle, gastrocnemius medial head and lateral gastrocnemius head were collected and recorded. The data were analyzed using minitab.15 statistical software R2 was determined according to the F test （extremely significant statistical difference, P 〈 0.001）, and then the experimental results were analyzed using the curve fitting method. RESULTS AND CONCLUSION： （1） Under the 150 W power bicycle movement, the muscle fatigue increased with time and then trended to decrease. （2） Under the 300 W power bicycle movement, the muscle fatigue decreased with time, then showed an increasing trend and finally decreased with time. （3） Under the 150 W power bicycle movement, the fitting curve was a three-item curve, indicating there were three main factors affecting muscle fatigue. However, under the 300 W power bicycle movement, the fitting curve was a two-item curve, indicating there were two main influential factors for muscle fatigue.