I'm 15 and was recently diagnosed with "teenage girl knee pain" - a very un-scientific name I know, but it basically means that my knees aren't fully grown and that the gristle beneath my knee cap is still very soft and my knees are being damaged by exercise. I'm supposed to keep my legs straight as much as possible so that my knees are relaxed, bending my knees puts too much pressure on my knees and makes them ache and crack and grind. Any kind of exercise is difficult as I can't bend down, run, jump, suddenly change direction or go up hills or stairs. I am able to walk on flat ground for a while but even that becomes unbearable after a while. The physiotherapist I went to see told me I would grow out of it in a year or two, but I have been out of P.E and any other kind of exercise for almost 6 months now and I'm really starting to pile on the pounds which my boyfriend doesn't really mind but is taking a real wedge out of my self confidence. It's not like I eat unhealthily or too much, it's just the lack of exercise. I really want to lose a bit of weight and I'm really struggling with it because of my knees.. If anyone has and tips or suggestions I would be very grateful, thanks.