Thirty men were tested for isokinetic knee strength using Cybex II+ at velocity of 90°/sec. In set one, the subjects were tested with fixing the non esting leg at 90° and the testing session consisted of one-legged isokinetic extension exercise test and flexion exercise test. In extension exercise condition, three maximal isokinetic extensions were done with performing isometric contractions of the extensors of non-testing leg in regard to the isokinetic testing legs(reciprocal mode), and then three maximal isokinetic extensions were done with contractions of the flexors of non-testing leg(concurrent mode). In flexion exercise condition, three maximal flexions in a concurrent mode and a reciprocal mode, respectively were also performed. We measured peak torque(PT) of the extensors and flexors of the testing leg and recorded myoelectrical signals from the knee muscles of the non-testing leg. PT of the knee extensors and flexors of the testing leg were of significantly higher value at reciprocally induced action of the non-testing leg(p<0.001). The mean root mean square(RMS) values recorded from the muscles of non-testing leg were of significantly higher value at reciprocal mode also(p<0.01). In set two, the testing was done in two different isokinetic extension-flexion knee testing conditions. For the first condition, testing was done with a bar in front of the ankle joint of the non-testing leg, thus limiting extension movement of the leg as is the usual testing method at present. For the second condition, the non-testing leg was fixed at 90° flexion and the non-testing leg was induced to contract reciprocally in regard to the isokinetic testing legs. PT of extensors of the second condition showed a significantly higher value compare to the first condition(p<0.001).

By fixing non-testing leg and making it to contract in a reciprocal manner with the testing leg, we can eliminate the shifting of non-testing leg and prevent the possible decrement in strength due to a bilateral deficit, and get an additional isometric exercise effect on non-testing leg.