There has been controversy in regard to the appropriateness of muscle strength testing and training in stroke subjects. Little has been reported in tne literature about the effect of muscle strengthening on the biomechanics of hemiparetic gait. The purpose of this study was to investigate the effects of an eight-week isokinetic training program on the biomechanics of the gait of subjects with hemiparesis secondary to stroke. Ten hemiparetic subjects, seven men and three women, 2 - 35 years post-stroke, and aged between 35 and 77 years (mean 62.3 ± 14.3) voluntarily participated in the study after signing an informed consent form. The following measures were taken prior to and after the training program:​ concentric isokinetic torque of the subjects’ affected and unaffected ankle, knee and hip muscles, gait measures (walking speed, and time and distance, kinematic, and kinetic variables), and H and stretch reflex properties. The isokinetic training of the affected lower limb consisted of eight weeks of three-times-weekly one hour sessions. All of the trained muscle groups had significant strength gains (p s 0.05). Walking speed and power generation capability of the affected ankle and hip muscles were improved significantly. Results of neurophysiological measures did not suggest any change in the level of spasticity, which was consistent with the results of clinical examination. The results of this study confirm the effectiveness of an isokinetic program in testing and training the weak muscles of hemiparetic subjects without increasing the spasticity. Increased capability of the affected side did not reduce the compensation by the unaffected side. The significant increase in walking speed after the program suggests that increased capabilities were used to achieve higher performance. Further research with a larger sample is recommended.