Finding your pace

I haven't been to the gym for almost a year now due to a back issue that can be aggravated by comfy chairs, fast movements, and alas,  tumbling on mats.  (Still kind of angry about that, but that's not the point of this post.)  After about five months or so of not being in the gym, besides putting on a few pounds, I realized I was feeling "old" when I got up from my chair, walked across a parking lot, or took a walk with the dogs–almost as if my body was forgetting how to function on a basic...