Abstract: Objective To study the influence of different positions in the isokinetic muscle test of knees by CON-TREX Biomechanical Test and Training System, so as to select the suitable conditions for forensic identification of muscle strength test. Methods Fifty-two healthy volunteers joined the isokinetic muscle strength test in unfixed and fixed position, respectively and in two kinds of angular speed （60°/s and 30°/s）. The differences of peak torque （PT） and peak torque angle （PTA） between bilateral knee flexor and extensor were statistically analyzed. Results In the unfixed position, under the two speed, there was statistically significant difference in PT between bilateral knee flexor and extensor（P<0.05）; while in the fixed position, under the two speed, there was no statistically significant difference （P>0.05）. In any kind of conditions, the PTA of bilateral knee flexor and extensor did not have statistically significant difference（P>0.05）. Conclusion The position of the subject influences the results of PT. So the position of subject in knees isokinetic muscle test should be regulated.

Key words:  forensic medicine, knee joint, isokinetic muscle strength, posture, function evaluation