I'm a Junior Player that plays around 4-5 hours of tennis every single day pretty much 7 days a week and my knees are aching a little after each day. They have always been sore but lately it has been a deeper soreness. It isn't an intense pain or anything sharp, just a dull aching that is very slowly becoming more noticeable. Is there anything I can do? I have good footwork and all that and my coach has said I am doing nothing wrong as far as my feet are concerned. Any advice?