Association Between Ankle Dorsiflexion and Frontal Projection Angle in PFPS

Inclusion Criteria: 1. Anterior or retropatellar knee pain from at least 2 of the following Activities : (1) prolonged sitting; (2) stair climbing; (3) squatting; (4) running; (5) kneeling; and (6) hopping/jumping. 2. Insidious onset of symptoms unrelated to a traumatic incident and persistent for at least 6weeks. 3. VAS equal to or greater than 3. 4. Age of the subject 18-35 years to limit the possibility that PFPS over age 35 may have been complicated by arthritic changes, and also the subjects should have closed epiphyseal growth plates. 5. BMI under 30 kg/m2, both gender For the control group, subjects were recruited to this study if they had: 1. No previous history or diagnosis of knee pathology. 2. No pain with any of the above-mentioned provocative activities. 3. No history of lower limb or spinal pathology. Exclusion Criteria: 1. A history of any of the following condition: meniscal or other intraarticular pathologic conditions; cruciate or collateral ligament involvement. 2. A history of traumatic patellar subluxation or dislocation. 3. Previous surgery in the lower extremities within the 12 months prior to participation in the study. 4. Any balance impairments are secondary to a vestibular or neurological disorder or secondary to the use of medication. 5. Any lower limb bony/congenital deformity