By Matthew Lawyue

Sometimes it's just hard to walk away from the game. Athletes retire for a variety of reasons: an aging body that can no longer handle the physical strains, career-ending surgery, or simply the loss of passion to compete. Whatever the reason, it's unsettling for some retired athletes to find their days unencumbered when they have become accustomed to early morning practices, workouts, and competition all their lives. For these newly-minted retirees, the decision to "unretire" and get back into the competition is often an easy one. For most, however, the hard part comes in trying to relive their past glories. A few athletes manage to make more than just a comeback. They become a symbol that is bigger than sports; an icon that reaches the hearts of people around the globe. Here are 22 athletes who retired, only to jump back in.