Subjects were evaluated prior to the 8-week intervention as well as following completion. Evaluations included measures of pain and swelling, a graded exercise test on a treadmill, a 50-foot test of walking time, a 6-minute test of walking distance, and a locomotion biomechanical analysis which analyzed spatio-temporal, kinematic, and kinetic variables. The exercise intervention consisted of twice-weekly 1-hour exercise sessions, set to music, with four phases: warm-up, aerobic exercise, recovery, and cool-down. Dance-based exercise included slow, rhythmic movements that involved all joints. The exercise protocol was developed and led by a physical fitness instructor in collaboration with an occupational and physical therapist. The intensity and length of the aerobics segment was gradually increased to accommodate increased tolerance and improved fitness levels. Target heart rate (HR) was set at 50% of maximal HR during the first 3 weeks of the program, then increased to 60% or 70% of maximal HR for most of the participants.