I've been seriously thinking of joining Ponce De Leon baseball. For a guy over 50, I'm still in pretty good shape. I can sprint (not as fast as once, but still flat out), run mile after mile, and my shoulders still work. I'd have to learn how to slide again.
I'll be playing Ponce this spring - took 2011 off to recover from shoulder and heart surgeries (unrelated incidents). I'll be looking to play in the weeknight league.
Slding in Ponce? Not necessary. You can just give yourself up at the base (no Buster Posey catcher crushing collisions allowed). You wouldn't be the first geezer to not slide for a season....
