AIM:To detect the muscle strength and endurance of healthy young people with different sport levels using isokinetic testing technique,so as to explore the characteristics of trunk muscle function. METHODS:①120 volunteer freshmen of Grade 2005 including 60 males and 60 females were selected from Capital Institute of Physical Education,and were divided into three groups:general group,physical training group and second-class athlete group(n =40,half male and female). Cybex6000 isokinetic testing system(U.S.A) was used. ②The muscle strength of flexors and extensors trunk muscle was measured at 60?/second and 120?/second and the endurance at 120?/second. ③Peak torque,flexors/extensors peak torque ratio,endurance ratio and recovery ratio were evaluated. RESULTS:①The peak torque values of male extensors in 3 groups were higher than those of flexors;with the increase in testing velocity,the peak torque value of extensor and flexors was decreased,especially the extensor. The peak torque value of general group was lower than that of physical training group and second class athlete group(P 0.05). The change in peak torque value of female extensor and flexors was the same to males. The flexors/extensors peak torque ratio at 60?/second and 120?/second of males was less than 1,but females more than 1. ②Under the same testing velocity,the endurance ratio and recovery ratio of extensor in 3 groups were higher than those of flexors. CONCLUSION:Compared with physical training students and second class athletes,significant decrease in the waist and back muscle strength and unbalance of extensor and flexors strength are found in general students. The muscle strength and endurance of extensor in students with different sport levels are inferior to those of flexors.