I am in the process of dumping 50 pounds (again!). Long story - short, I am 39 and after about a year of chronic knee pain I finally had an MRI. I was told I had degenerative osteo-arthritis. I can't run anymore (wasn't very good at it anyway). I can still ride my bike, but I like to mix things up. I am considering buying one of those 12'x3' "easy set" pools but I'm not really sure what (aerobic or other) exercises I can do in that shallow a pool. Any suggestions??