Abstract Purpose: To determine whether isokinetic training can improve the strength of the hemiparetic knee musculature, functional mobility, and physical activity and to evaluate its effect on spasticity in long-term stroke survivors. Design: Nonrandomized self-controlled trial. Subjects: A volunteer sample of 15 community-dwelling stroke survivors of at least 6 months. Intervention: A 6-week (3 days/week, 40 minutes/day) program consisting of warm-up, stretches, reciprocal knee extension and flexion isokinetic strengthening, and cool-down for the paretic limb. Main Outcome Measures: Peak isokinetic hamstring and quadriceps torque, quadriceps spasticity, gait velocity, timed Up and Go, timed stair climb, and the Human Activity Profile (HAP) scores were recorded at baseline, after training, and 4 weeks after training cessation (follow-up). Results: Paretic muscle strength improved after training ( p < .05) while tone remained consistent ( p > .87). Gait velocity increased after training ( p < .05) and at follow-up ( p < .05). Changes in stair climbing and timed Up and Go were not significant ( p > .37; p > .91), although subjects perceived gains in their physical abilities at follow-up ( p < .01). Conclusions: Gains in strength and gait velocity without concomitant increases in muscle tone are possible after a shortterm strengthening program for stroke survivors. The psychological benefit associated with physical activity is significant.