Combined Hip Abductor and External Rotator Strengthening and Hip Internal Rotator Stretching Improves Pain and Function in Patients With Patellofemoral Pain Syndrome: A Randomized Controlled Trial With Crossover Design. - Jellad A; Kalai A; Guedria M; Jguirim M; Elmhamdi S; Salah S; Frih ZBS (Orthopaedic journal of sports medicine, 2021)