my 12 year old daughter is playing softball regularly and for the last few months...every time she squats down her knees pop and crack...loudly and painfully....they also make a noise when she stands up again....she does not experience pain when running or standing in the field...only squating. she weighs about 135 pounds, is 5 feet 2 or three inches and otherwise in very good health. how concerned should we be...should she see her pediatrician for this matter? what about fruits/veggies...???