One of my friends most likes to run and bike, which may be the causes of his Patellofemoral Pain Syndrome. She often feels pain under and around the knee and the pain often gets worse with walking, kneeling, going up or down stairs. In order to relieve pain, now she limits the activities like running and biking, puts ice or a cold pack on the knee and even often needs to take medicines like ibuprofen or naproxen. She often tells me to take protective measures before doing sports.