Digital Health for Patellofemoral Pain

Inclusion Criteria: * Age 18-45 years * Clinical diagnosis of patellofemoral pain * Symptoms for at least 3 months * Anterior or retropatellar knee pain provoked by at least two aggravating activities such as stair ambulation, squatting, running, jumping, or prolonged sitting * Baseline pain intensity of at least 3/10 on the Numeric Rating Pain Scale * Ability to provide written informed consent and comply with study procedures Exclusion Criteria: * Previous knee surgery * Patellar dislocation or obvious instability * Ligament injury, clinically important meniscal injury, moderate to severe knee osteoarthritis, or other major structural knee pathology * Major hip, ankle, or lumbar disorders substantially affecting lower-limb function * Neurological disorders affecting movement or balance * Pregnancy * Structured PFP rehabilitation within the previous 3 months * Any other condition deemed unsuitable by the investigators