Each sporting activity appears to require some distinctive motor functions. The purpose of this study was to establish referential isokinetic strength parameters in competitive judo athletes because no previous studies have examined trunk strength of judo athletes isokinetically and to test the hypothesis that the isokinetic strength parameters of competitive judo athletes, who are specifically trained with respect to trunk strength, are significantly different from those in another well-trained population (racing cyclists), who train very differently. Twenty-eight male top judo athletes and 34 top racing cyclists, all without back trouble, were tested by means of the Cybex Trunk Extension Flexion (TEF) unit and the Torso Rotation (TR) unit. This was done at four different speeds-30, 60, 90 and 120 degrees /set. The results of MANOVA showed that the judo athletes have statistically higher performance than cyclists (p < 0.05) on all of the isokinetic variables (ie., peak torque, best work repetition, and average power corrected for body weight) in trunk extension, flexion, left rotation, and right rotation. The ratios of flexion to extension and left rotation to right rotation were not significantly different between the cyclists and the judo athletes. The authors concluded that for clinical purposes, the ratios of flexion to extension and left rotation to right rotation may be of more importance than separate values as such. Research in this area is of utmost importance to provide a needed shift in emphasis from injury treatment to injury prevention. J Orthop Sports Phys Ther 1992;16(2):92-96.