Pain under the kneecap, or patellofemoral pain, has been called “Runner’s Knee” because it’s often cited as the most common injury in runners. The injury may also cause pain and swelling around the kneecap. It’s been called the most common injury in sports, with one in four active people suffering from its effects, according to the University of North Carolina at Chapel Hill, including basketball players, hikers, and swimmers.
“Athletes can fatigue the quad muscles, moving the kneecap out of alignment and causing irritation under the kneecap,” says Dr. Alvin Loosli, a former physician for the U.S. Olympic swim team. Exercising with Rrunner’s knee over long periods of time can break down cartilage, leading to problems with arthritis as athletes age.
How to prevent it:
People with weak quads are 5.5 times more likely to have patellofemoral pain than those with stronger quads, according to a 2008 study published in the American Journal of Sports Medicine. Researchers studied about 1,600 U.S. Naval Academy recruits, analyzing their biomechanics and strength before training started, and after to 2.5 years. Forty of those recruits developed runner’s knee, suggesting that weak quads made recruits more likely to develop the injury, as well as weak hamstrings, which made participants 2.9 times more likely to get injured. Flat feet and stiff knees upped injury risk as well.
“Make sure the quads are strong,” Loosli says. Swimmers can add fins to their workouts to help strengthen quads, while other athletes can do squats or wall sits. Riding a bike is a great way to tone quads, too. Loosli recommends cycling 35 to 45 minutes twice a week with some intense intervals thrown in to help build quad muscles.