Effects of exercise combined with whole body vibration in patients with patellofemoral pain syndrome: a randomised-controlled clinical trial

Background: Patellofemoral pain is a prevalent condition in the general population, especially in women, and produces functional impairment in patients. Therapeutic exercise is considered an essential part of the conservative management. The use of vibration platforms may help improve strength and function and reduce pain in patients with knee disorders. The aim of this investigation was to determine the effects of adding whole body vibration (vertical, vibration frequency of 40 Hz, with an amplitude from 2 to 4 mm) to an exercise protocol for pain and disability in adults with patellofemoral pain. Methods: A randomised clinical trial was designed, where 50 subjects were randomly distributed into either an exercise group plus whole body vibration or a control group. Pain, knee function (self-reported questionnaire) and range of motion and lower limb functionality were assessed at baseline and at 4 weeks. The experimental group performed 12 supervised sessions of hip, knee and core strengthening exercises on a vibration platform 3 times per week during 4 weeks. The control group followed the same protocol but without vibration stimuli. Differences in outcome measures were explored using an analysis of the variance of 2 repeated measures. Effect sizes were estimated using Square Eta (eta(2)). Significant level was set alP < 0.05. Results: Statistically significant differences were found after intervention in favour of the experimental group in the between-groups comparison and in the interaction of the experimental group before and after treatment in terms of pain perception (P = 0.000; eta(2) = 0.63) and function outcomes scores (P = 0.000; eta(2) 0.39 and 0.51 for lower limb functional scale and Kujala scores respectively). Conclusion: A 4-week whole body vibration exercise programme reduces pain level intensity and improves lower limb functionality in patellofemoral pain patients and is more effective than exercise alone in improving pain and function in the short-term.