Dose-response effects of medical exercise therapy in patients with patellofemoral pain syndrome: a randomised controlled clinical trial

Objectives To evaluate two different therapeutic exercise regimens in patients with patellofemoral pain syndrome (PFPS). Design Multicentre, randomised controlled clinical trial. Setting Three primary healthcare physiotherapy clinics. Participants Forty-two patients with PFPS were assigned at random to an experimental group or a control group. Forty participants completed the study. Interventions Both groups received three treatments per week for 12 weeks. The experimental group received high-dose, high-repetition medical exercise therapy, and the control group received low-dose, low-repetition exercise therapy. The groups differed in terms of number of exercises, number of repetitions and sets, and time spent performing aerobic/global exercises. Main outcome measures Outcome parameters were pain (measured using a visual analogue scale) and function [measured using the step-down test and the modified Functional Index Questionnaire (FIQ)]. Results At baseline, there were no differences between the groups. After the interventions, there were statistically significant (P < 0.05) and clinically important differences between the groups for all outcome parameters, all in favour of the experimental group: -1.6 for mean pain [95% confidence interval (CI) -2.4 to -0.8], 6.5 for step-down test (95% CI 3.8 to 9.2) and 3.1 for FIQ (95% CI 1.2 to 5.0). Conclusion The results indicate that exercise therapy has a dose response effect on pain and functional outcomes in patients with PFPS. This indicates that high-dose, high-repetition medical exercise therapy is more efficacious than low-dose, low-repetition exercise therapy for this patient group. (c) 2012 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.