As athletes transition off the basketball court and onto the golf course for retirement, it's important to remember just how tough these guys really are. One of our favorite examples is Charles Oakley. He is one of the top 20 all-time players when it comes to activity with over 1,000 games played. That's a tough ass career for the former all-star to be battling on the boards with the likes of Horace Grant and Charles Barkley. Oakley famously played for the Knicks, but he also balled for the Bulls, Raptors, Rockets and Wizards. He was the player happy in the trenches, an enforcer on the basketball court and a hardcore power forward.