Literature on the comparative effectiveness of nonoperative treatments for patellofemoral pathologies has been limited. The purpose of this investigation was to study the effectiveness of selected static and isokinetic physical therapy rehabilitation programs for subjects with a clinical diagnosis of chondromalacia patella. Criteria employed to assess the effects of these therapeutic programs included measures of knee functional capacity as measured by the Cincinnati Rating System and traditional measures of leg strength and flexibility. Twenty-nine subjects were screened by an orthopaedic physician and assigned to a control (N = 9), static (N = 11), or isokinetic (N = 9) exercise group. Noncontrol subjects were administered a program of 12 treatments, three times a week, for four weeks by a registered physical therapist. Results of the ANCOVA for 17 pretest and posttest measures indicated that the static and isokinetic groups demonstrated significant (P < 0.05) functional improvements over the control group in walking, stair activity, running, jumping/twisting, and overall activity level as well as increased quadriceps strength and hamstring range of motion. No significant differences, however, were determined to exist between the static and isokinetic groups. The major implication of this investigation is that static and isokinetic treatment programs provide positive and comparable rehabilitation effects on the functional capacity of the knee joint for subjects with chondromalacia patella. Static therapy, however, appears to be most cost-effective. J Orthop Sports Phys Ther 1990;12(6):256-266.