Growing Pains – Often the angle of the knee increases, not allowing the kneecap to track properly, which causes pain. The problem is often worse with fatigue because the muscles have less control and don’t stabilize the movement. The problem can also be worse at times of growth as often there is more stress on the bones, joints and muscles at this time.
For treatment to be effective the cause must be identified, allowing it to be addressed.
This may be a reason why your child avoids running. Professional advise should be sought if the problem persist.