I was 47 when I started Tae Kwon Do.  It kicked my butt so bad that my instructor use to whisper in my ear, "No die, No die."  

What I retained from the experience other than a new skill set, was the stretching excercises.  Like these guys said, my muscle tone shifts with the time of the year with more activity in the summer and less in the winter.  The stretcing keeps my joints limber.

One man in his sixties, saw the benifit of the stretching and now has a school for seniors that teaches Tae Kwon Do stretching techniques. It's caught on around here like wildfire.

You can actually buy VHS tapes with the techniques and do at home.  Theres techiniques for every part of your body so even in a wheel chair, there is benefit.

It's also a great confidence builder to know you can kick 6" above your head.

Cute story:

I'm traveling with a kid half my age and in way better shape.  He works out twice a week in a health club. We get stranded by actualy terrorist security alert in Pittsburgs airport for hours.  He gets into this I can do much more than you shit so I say, can you put your back on the wall and then without moving your back touch the front of your knee to the wall.  "That's easy."

I laughed my ass off as he tried time after time.

What the hell do you guys know about being old? [;)]

Of course,this does not apply to Thomas Jefferson..............he IS old! [:D]

A bit younger than you Mr. Kettle. [:D]