FT, I know I'm not as old and beat up as you are, based on our conversations, but sometimes I may feel like it.... That said, I do have some injuries that came up the last couple years and feel your pain. I'm totally behind Stone's assertion. Find someone/someplace that can give GOOD advice on strength building (and flexibility is always good). Maybe that's a few appointments with a PT guy who can give you a program to go work on your own.

Keep the faith, and don't worry about speed, but working some relative strength is key to off-setting injuries and being healthy.