Comparative Effects of Blood Flow Restriction Resistance Training Versus Blood Flow Restriction Cycling on Pain, Quadriceps Strength, and Functional Outcomes in Athletes With Patellofemoral Pain

This randomized controlled trial compares blood flow restriction (BFR) resistance training (leg press and seated knee extension at 30% 1RM) versus BFR cycling (stationary cycling at low resistance) in 60 athletes (aged 18-40 years) diagnosed with patellofemoral pain syndrome. Both interventions are delivered over 8 weeks (3 sessions/week) with a pneumatic cuff set at 80% limb occlusion pressure. Primary outcomes include pain intensity (NPRS), quadriceps strength (handheld dynamometer), and functional ability (Kujala Anterior Knee Pain Scale), assessed at baseline and post-intervention.

Inclusion Criteria: 1. Male and female athletes aged 18-40 years 2. Clinically diagnosed with patellofemoral pain syndrome 3. Anterior or retropatellar knee pain of at least 3 months duration 4. Pain provoked by at least two functional activities (e.g., squatting, stair climbing, running, prolonged sitting) 5. Willingness to participate and provide written informed consent Exclusion Criteria: 1. History of knee surgery or significant knee trauma in the past 6 months 2. Presence of ligament, meniscal, or cartilage injuries 3. Neurological, vascular, or systemic inflammatory conditions 4. Contraindications to BFR training (e.g., deep vein thrombosis, uncontrolled hypertension) 5. Pregnancy