Effect of Core Exercises on Patellofemoral Pain Syndrome

Inclusion Criteria: 1. Patients of both genders with an age range of 18- 35 years old. 2. Gradual development of pain in the front of the knee lasting more than 12 weeks. 3. Patients with body mass index 18- 25 kg m2. 4. Pain is aggravated by at least 2 of the following activities: jumping, running, prolonged sitting, stair climbing, kneeling, and squatting. 1. Positive patellar grinding test. 2. Insidious onset of symptoms, unrelated to a traumatic damage. Exclusion Criteria: 1. Traumatic patellar subluxation or dislocation. 2. A history of any of the following conditions: meniscal or other intra articular pathologic conditions; cruciate or collateral ligament involvement. 3. Any lower limb bony or congenital deformities. 4. Previous knee and hip joint surgeries. 5. Osteoarthritis in the ankle, knee, or hip joints. 6. Conditions that affect muscle strength such as diabetes mellitus or rheumatoid arthritis.