Runners who suffer from the common knee pain referred to as patellofemoral pain (PFP) may benefit from hip strengthening exercises, according to a new study.

Researchers at Indiana University-Purdue University Indianapolis based their study on the theory that stronger hips would correct running form errors that contribute to PFP.

For the study, five female runners suffering from PFP and a control group of four additional runners had hip strength measurements taken before and after a six-week period of their normal running routine. Hip strength measurements were also taken for all of the runners before and after the next six-week period in which they all performed 30 to 45 minutes of hip-strengthening exercises twice a week.

They found that the injured runners were able to greatly reduce and, in some cases, even eliminate their pain after strengthening their hips.

PFP is one of the most common running injuries. It is caused when the thigh bone rubs against the back of the knee cap. Runners with PFP typically do not feel pain when they begin running, but once the pain begins, it gets increasingly worse. Once they stop running, the pain goes away almost immediately.