SEMG Signal Changes On Lower Limb Musculus Fatigue During Cycling Exercise Process

Objective:To analysis and research the changes of the relevant indicators of surface EMG,to explore the changes of the rules and the Characteristics of different load and different frequencies power of bicycles in the lower limb muscle movements ;by goodness value curve fitting of iEMG, MF, obtain the general formula, to explore the nature of the fatigue curve fitting, and then analyzes the main factors affect the fatigue.Methods:1.The subjects is 8 young men come from Suzhou university PE college , all subjects do sports by different frequencies power of in the MONARK power bike ,every minute increments 20W, to maintain speed 60r/min.Every exercise program ended when the subjects are unable to maintain the provisions speed and get fatigue .Using surface electromyography technology, real-time monitoring and recording the whole surface of lower limb muscle EMG by iEMG and MF changes.With minitab.15 statistical software, according to the F test is extremely significant statistical difference (P <0.001) under the premise of selecting the largest coefficient of determination R2, the square and the smallest deviation principle, the experimental results were curve fit.Results:1.150W of Power Bicycle ,different pedaling frequency of movement, the iEMG increased with the exercise time; 300W-40r and 300W-60r power cycling, the lower limb muscle iEMG first risethen and then decreased;300W-80r power cycling, the lower limb muscle iEMG decreased with exercise time; incremental exercise, the lower limb muscle iEMG increased with exercise time.2.150W of Power Bicycle, different pedaling frequency of movement, The MF increased with the movement time and then decreased trend; 300W of different pedaling frequency of movement, the MF decreased with the movement time; incremental exercise, the MF showing a trend of increased and then decreased with the time3.There are significant or very significant difference (P <0.05 or P <0.01) between Bicycle-150W different frequency of exercise of each group iEMG and the MF, but 300W showed no significant difference (P> 0.05).4.150W of power cycling movement, iEMG and MF indicators are the best three fitting curve, the curve fitting equation: Y = b0+b1x+b2x2+b3x3.The iEMG and MF of bicycle 300W movement indicators fitting equation: Y = b0 + b1x + b2x2.Conclusion:1.150W of Bicycle Power movement, the number of muscle fibers are increased with exercise time.2.300W of power cycling movement, the number of muscle fibers are first increased and then reduction with exercise time.3.Incremental cycle exercise, the number of muscle fibers are increasing with the exercise time.4.150W of power cycling exercise, muscle fatigue curve fitting curve are three items, indicating that there are three main factors of muscle fatigue, and 300W movement, muscle fatigue are the quadratic curve fitting curve, suggesting that the muscle fatigue are two main factors.