This study compared the effects of patellar taping and electromyographic-biofeedback (EMG-BF) guided isometric quadriceps strengthening at different knee angles in patello-femoral pain syndrome (PFPS).

A total of 60 adult male athletes aged 18 to 45 years were recruited. Subjects will be included with the history of knee pain during activities such as descending and ascending stairs, squatting, and running, had positive J sign (lateral tilt of patella), and a sign of patellar malalignment on the radiograph. Individuals with a history of fracture around the knee, patella dislocation, knee deformity (e.g., genu varum), flexion contracture, ligaments/meniscal injuries, and osteoarthritis of the knee will be excluded from the study. The protocol was submitted to and approved by the ethical sub-committee of the College of applied medical science, Majmaah, Saudi Arabia (Ethics number: MUREC-Nov./COM-2O20/11-2). Participants were requested to sign a written informed consent form approved by the institution ethics committee.

Participants were randomly assigned to Group A (experimental group): electromyography biofeedback (EMG-BF) guided maximum voluntary isometric contraction exercise with patellar taping; Group B (control group): sham EMG-BF guided maximum voluntary isometric contraction without patellar taping. The outcome measure for this study will be the mean changes in maximum voluntary isometric contraction (MVIC) of the quadriceps muscle at different angles, pain intensity, single-leg triple hop test (SLTH), and functional status up to 6 weeks.

Inclusion Criteria:

• Knee pain during activities such as descending and ascending stairs, squatting, and running,
• Positive J sign (lateral tilt of patella),
• Sign of patellar malalignment on the radiograph

Exclusion Criteria:

• Fracture around the knee,
• Patella dislocation,
• Knee deformity (e.g., genu varum),
• Knee flexion contracture,
• Ligaments/meniscal injuries, and
• Osteoarthritis of the knee.

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