Impact of tensor fascia lata stretch prior to squat on vastus medialis obliqus activity in patellofemoral pain syndrome: Pretest- posttest single group study.

Background: A prevailing cause of knee pain is the patellofemoral pain syndrome (PFPS) resulting from imbalance in the quadriceps components. Previous studies sought exercises that enhance vastus medialis obliquus (VMO) activation and the VMO to vastus lateralis (VL) ratio in PFPS patients. Purpose: This study tested if there is a difference in the muscle activity of the VMO and VL and VMO: VL ratio during standing and squat before and after tensor facia lata (TFL) stretch in PFPS patients. Methods: 37 PFPS patients participated in this study with age between 18 and 30 years. Participants performed three squat repetitions while the muscle activity of the VMO and VL was measured using electromyography (EMG) in standing and squat hold positions. They then completed a static stretch of the TFL in a side-lying position, holding the stretch for one minute and repeating it five times with 10-second intervals. Afterward, VMO and VL activity was remeasured, and the VMO:VL ratio was calculated before and after the TFL stretch. Results: No statistical differences were found in the VMO (r=0.08), VL activity (r=0.1), or VMO: VL ratio (r=0.21) while standing after the TFL stretch. A decrease in the VMO (r=0.52) and VL (r=0.47) activity occurred during the squat hold position, but the VMO: VL ratio (0.02) remained unchanged (p >0.05). Conclusion: The TFL stretch couldn’t enhance the VMO:VL ratio in PFPS patients. Further studies are needed to compare the results between both genders and study the effects of incorporating TFL stretch with VMO activation exercises.