Impact of Tensor Fascia Lata Stretch on Vastus Medialis Obliqus Activity

Participants will have the assessed limb ready by shaving the hair on thigh and using alcohol swabs to clean the area from any residues.

For the VMO, a surface EMG electrode will be placed 4 cm superior and 4 cm medial to the supromedial boarder of patella at approximately 55 degrees to the long axis of the femur. As for the VL, the electrode will be placed 10 cm superior and 6-8 cm lateral to the superior lateral boarder of the patella and orientated 15 degrees to the vertical. All electrodes are self-adhesive (Figure 8) and will be connected to EMG sensors that will be attached and secured by double-sided tape.Each participant will perform three consecutive squats with 5 seconds interval break between each repetition. The squat depth will be kept at 50 degrees knee flexion. Mean muscle activity from three squat repetitions of VMO and VL is recorded and VMO:VL ratio is calculated. Afterward, each participant will perform the TFL stretch and repeat the three squats again.

Inclusion criteria

• Both genders.
• Body mass index (BMI) ranges from 18.5 to 29.9.
• Age ranges between 18 and 30 years old.
• Experience nontraumatic anterior knee pain.
• Pain with any two activities, including running, jumping, squatting, kneeling, stair ascent/descent or prolonged sitting.
• Having at least one positive PFPS clinical tests including, patellofemoral compression, patellofemoral gliding or resistive quadriceps setting

Exclusion criteria

• Coexisting pathology around the knee, including patellar subluxation or dislocation.
• Previous knee surgery.
• Suspicion of patellar tendinopathy, with strong consideration of pain localised to the patellar tendon.
• Patients didn't receive physiotherapy treatment or use of non-steroidal anti-inflammatory drugs for knee pain in the previous 3 months.
• Any neurological or rheumatic disorders
• Pain intensity more than 5 (based on visual analogue scale)
• Hip and ankle pathology.
• BMI more than 30%.
• Pregnancy.