A randomised clinical trial of the efficacy of drop squats or leg extension/leg curl exercises to treat clinically diagnosed jumper's knee in athletes: pilot study

Objectives-To compare the therapeutic effect of two different exercise prot ocols in athletes with jumper's knee. Methods-Randomised clinical trial comparing a 12 week programme of either d rop squat exercises or leg extension/leg curl exercises. Measurement was pe rformed at baseline and after six and 12 weeks. Primary outcome measures we re pain (visual analogue scale 1-10) and return to sport. Secondary outcome measures included quadriceps and hamstring moment of force using a Cybex I I isokinetic dynamometer at 30 degrees /second. Differences in pain respons e between the drop squat and leg extension/curl treatment groups were asses sed by 2 (group) x 3 (time) analysis of variance. Two by two contingency ta bles were used to test differences in rates of return to sport. Analysis of variance (2 (injured versus non-injured leg) x 2(group) x 3(time)) was als o used to determine differences for secondary outcome measures. Results-Over the 12 week intervention, pain diminished by 2.3 points (36%) in the leg extension/curl group and 3.2 points (57%) in the squat group. Th ere was a significant main effect of both exercise protocols on pain (p<0.0 1) with no interaction effect. Nine of 10 subjects in the drop squat group returned to sporting activity by 12 weeks, but five of those subjects still had low level pain. Six of nine of the leg extension/curl group returned t o sporting activity by 12 weeks and four patients had low level pain. There was no significant difference between groups in numbers returning to sport ing activity. There were no differences in the change in quadriceps or hams tring muscle moment of force between groups. Conclusions-Progressive drop squats and leg extension/curl exercises can re duce the pain of jumper's knee in a 12 week period and permit a high propor tion of patients to return to sport. Not all patients, however, return to s port by that time.