Runners knee, also known Patellofemoral pain syndrome, or PFPS for short, this injury is so widespread among runners that it was named after them. In fact, survey shows that runners knee injuries make up to 40 percent of all running injuries. Runner’s knee happens when the patella (the kneecap) fails to move smoothly in the femoral groove at the lower end of the thigh bone, resulting in irritation of the cartilage on the underside of the kneecap, leading to crippling pain.
Symptoms: Runners knee is typically described as intense pain behind or around the kneecap that comes on during a run, or afterward. The pain gets worse when using the stairs, running downhill, after extended periods of sitting or during activities that require knee bending motions.
Causes: The leading causes of PFPS are weak hip rotator muscles and/or glutes, too much uphill running, and improper running mechanics. Also, runners who overpronate are at a higher risk of getting injured.
Fix it: For starters, stop running and take a break from any activity that puts too much stress on the knees. You can also reduce your weekly mileage by half and avoid running on successive days as long as you can run pain-free. Next, ice the injured knee for 15 to 20 minutes, two to three times per day, or just right after running if you feel any pain post-run.
Prevent it: To bulletproof your knees against PTFS, you will have to strengthen your lower body muscles—especially the hips, glutes, quads and calves. You can strengthen these muscles with clamshell, side lifts, lateral side steps, squats, and lunges—exercises you can do in the comfort of your home. Plus, make sure also to stretch your hip flexors, and hamstrings on a regular basis. And stick to flat or uphill terrain, running on softer running surfaces whenever you can. In addition, develop proper running form and run in the proper footwear, and, if you have to, wear motion-control shoes.