Objective To study the effect of the physical activity on the anaerobic exercise capacity,the Wingate test is taken to compare the anaerobic capacity between physically active students and sedentary students，and the naerobic fatigue characteristics of lower limb muscle groups are analyzed by surface electromyography (sEMG) signals.Methods We recruited 38 college male students，19 sedentary students and 19 physically active students，to perform the Wingate test on a bicycle ergometer.The differences in peak power output (PP),mean power output (MP),and anaerobic fatigue index (AFI) were compared between the two groups.The selection criteria was that the physically active students participated exercises more than 4 times a week and more than 30min a time,whereas the sedentary students participated exercises less than 3 times a week.The sEMG signals from rectus femoris,vastus medialis,vastus lateralis,biceps femoris long head were recorded during the Wingate tests.sEMG signals were analyzed by a wavelet transform method.Results  The physically active students reached significantly higher PP and MP than sedentary students (P <0.05).The sEMG mean power frequency (MPF) from the four muscles decreased during the Wingate tests,and the decline of MPF were steeper for the physically active students than for the sedentary students.The EMG intensity showed different trends for the two groups of students.The anaerobic exercise capacity was closely related to the fast-twitch fiber.Conclusions The physically active students show significantly higher anaerobic capacity than the sedentary students.The anaerobic capacity is closely related to the fast-twitch fibers.Our results suggest that regular physical activities can increase the area of the fast-twitch fibers,which in turn increase muscle power output and speed.