The goal of this study was to present a applicable basis for the muscular contraction mechanism of the human body by identifying the differences in the stretch-shortening cycle and shortening-stretch cycle in concentric and eccentric contraction according to muscular contraction types, through isokinetic analysis using Biodex. For this purpose, the experiments was conducted on flexion exercise of the elbow and knee joints by classifying them into a stretch-shortening cycle and shortening-stretch cycle in concentric and eccentric contraction at a three angular velocity of 60˚/sec, 180˚/sec, and 240˚/sec with 10 students at a physical education college. As a result of the experiment, I concluded as follows. First, As for the peak torque, peak torque/body weight, and total average power increased when the angle velocity was high. No differences were represented in the angle of peak torque. Second, the stretch-shortening cycle showed a higher peak torque, peak torque/body weight, and angle of peak torque than did the concentric contraction, according to exercise types. There were no big differences in total work and average power, but stretch -shortening cycle showed a bit higher than concentric contraction. From this conclusion, I found that the stretch-shortening cycle could bring about improvement in many aspects such as torque, total work, power, etc. than could the concentric contraction. Therefore, training with the stretch-shortening cycle method using the pre-stretch would be more effective.