I have read up on this on the HSF site today because I am a bit concerned. I have a lot of bone pain but last night I could not move my legs at all - it was as if my hips had just locked. The pain was pretty bad. It only lasted a minute or two but I felt very shaky after - scared I think I have read that bone damage due to APS is quite rare. I would be interested to hear your experiences. The same thing happened a few weeks ago - but this time my arms and again not for long.