What is Runner’s Knee? Runner’s Knee can refer to a number of injuries resulting from overuse,causing pain around the knee cap (patella). Patellofemoral pain syndrome (PFPS) is the most common type of Runner’s Knee. It’s name comes from it’s high prevalence in runners, where the repeated stress on the knee causes irritation where the patella rests on the thigh bone. The pain can be sudden and piercing or chronic and dull. Runner’s Knee is most likely to occur when the hamstrings and quadriceps are too tight and inflexible. This leaves the patella unsupported creating pressure and causing it to...