When most athletes are ready to pack it in and call it a career, a select few become like a fine wine and just get better with age. Don’t get us wrong, there are plenty of dong-pic-sending old fogies that don’t know when to call it quits, but that isn’t this list. To celebrate the birthday of Herschel Walker, a man that has conquered the NFL (and USFL!) for more than a decade and is now wrecking shop in MMA, here's a rundown of those that are Still Doing It: The Top 10 Athletes Over 40