Effects of Selective Training on the Vastus Medialis Oblique in Patients with Patellofemoral Pain Syndrome

Objective: To evaluate the effects of electromyographic (EMG) biofeedback training and patellar taping targeted – interventions forthe vastus medialis oblique (VMO)—on pain, function, muscle strength, the VMO-to-vastus lateralis (VL) EMG activity ratio, andonset timing differences in patients with patellofemoral pain syndrome (PFPS). Design: Randomized controlled trial. Methods: Thirty-seven female patients with PFPS were randomly assigned to one of three groups: EMG biofeedback (n=13),patellar taping (n=12), and control (n=12). All participants engaged in conventional quadriceps strengthening exercises for sixweeks. Additionally, the two intervention groups received selective VMO training through either EMG biofeedback or patellartaping. Outcome measures included the visual analog scale, anterior knee pain scale (AKPS), lower extremity functional scale,maximal voluntary contraction, VMO/VL EMG activity ratio, and VMO–VL onset timing difference during stair ascent anddescent. Assessments occurred before and after the intervention. Results: All groups displayed significant within-group improvements in pain, function, and muscle strength (p<0.05). Post-intervention, the patellar taping group exhibitedsignificantly higher AKPS scores compared to the control group. During stairascent, the VMO/VL activity ratio significantly increased in both the EMG biofeedback and patellar taping groups. No significantbetween-group differences were found observed onset timing, although reductions in onset delay were noted across all groups. Conclusions: Selective VMO training using either EMG biofeedback or patellar taping enhanced the VMO/VL activation ratioduring stair ascent. When combined with conventional strengthening exercises, these strategies effectively rectify muscularimbalances and improve function in individuals with PFPS.