Merck Manual

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When the Front of the Knee Hurts
When the Front of the Knee Hurts
When the Front of the Knee Hurts

Normally, the kneecap (patella) moves up and down the thighbone during running. People may feel pain in the kneecap because thigh muscles are weak or the feet roll in too much (pronation). As a result, the kneecap rubs abnormally against the thighbone, causing increased wear and tear.