Shaquille O'Neal claims to be "the greatest athlete" and challenged numerous top athletes in their own sports, such as Pittsburgh Steelers quarterback Ben Roethlisberger in football, Olympic swimmer Michael Phelps, retired boxer Oscar De La Hoya, St. Louis Cardinals first baseman Albert Pujols, and beach volleyball Olympians Misty May-Treanor and Kerri Walsh. O'Neal reportedly stole the idea from Steve Nash, who hired an entertainment lawyer to address the issue and is now listed as an executive producer of the show.

Source: Wikipedia.org