My 12 year old son was at basketball camp from 8:30 am till 4:30 pm which is a whole lot more activity than he's been doing. On the 3rd day his knee started hurting. It hurts to put much weight on it and hurts to bend it. He said he was doing a lay-up when he heard a popping sound. It is slightly swollen in the front, right below the knee cap, the pain is in the same area. We have kept ice on it for the past day, but it still bothers him. The pain is not unbearable, he hasn't taken any pain relievers, but he has a fairly high tolerance for pain and is not a whiner.