Patellofemoral Pain (PFP) is a common knee condition causing pain around the kneecap during activities like running or squatting. Limited ankle flexibility ("dorsiflexion" - how far participants can lift their toes toward the shin) may worsen PFP by altering leg movements. This study investigates whether adding ankle flexibility exercises to standard knee-strengthening programs improves outcomes for young adults with PFP. Active adults aged 18-30 with PFP and limited ankle flexibility (measured with a simple tool) are eligible, excluding those with prior knee/ankle surgeries, fractures, or conditions like arthritis. Sixty-four participants will be randomly assigned to either an Exercise + Ankle Training group (standard knee exercises plus targeted ankle training) or an Exercise-Only group for 8 weeks under physiotherapist guidance. Outcomes include improvements in knee pain scores (Kujala Scale), ankle flexibility changes, and muscle coordination measured with non-invasive sensors. If effective, ankle flexibility training could provide a low-cost addition to current treatments, helping patients resume activities with less pain. The study follows international ethical guidelines and has received preliminary ethics approval (No. TJUS-2025-054).

Inclusion Criteria:

• Aged 18-30 years
• Diagnosed with patellofemoral pain (PFP) per clinical guidelines (anterior knee pain aggravated by ≥2 activities: running, squatting, stair climbing)
• Ankle dorsiflexion range of motion (ROM) <10° (measured via goniometer in weight-bearing)
• BMI 18.5-28 kg/m²
• Engage in regular physical activity (≥3 sessions/week)

Exclusion Criteria:

• Ankle fractures
• Achilles tendon rupture
• Rheumatoid arthritis
• Gout, or systemic diseases
• Prior knee/ankle surgeries
• Concurrent lower limb injuries (e.g., ligament tears, meniscal pathology)
• Neurological disorders affecting mobility
• Participation in other lower limb rehabilitation programs within 3 months