Longevity

With the rigors and strain of professional sports, especially those involved in combat sports, most athletes have probably 8 to 10 years of productivity.

- Bobby Motus

But some are gifted with biological components that allow them to be back year after year. Pro athletes are aging but they seem to stay in the game longer.

Retiring then unretiring, Manny Pacquiao, three years shy of hitting 50, is a prime example of endurance and durability. He should permanently retire from politics.

Other pro boxers hitting the squared ring past 40 were the brothers Klitschko, Wladimir and Vitaly, who fought until they were 41. A disciplined Bernard Hopkins retired from the sport at the age of 51. At the age of 45, George Foreman unretired after 10 years and defeated Michael Moorer for the world heavyweight title in 1994.