Forty eight-year-old retired NFL player Herschel Walker has started his training for his second MMA fight to be held in December.
Once an athlete, always an athlete, and Walker is living proof that professional athletes don't have an expiration date when it comes to sports.
Walker isn't the only sports figure to keep on playing well after others would retire.
Here we have the top 15 athletes over 40 of all time.
Satchel Paige became the oldest "rookie" in MLB history when he was brought up from the Negro League to the Cleveland Indians.
He became the first Negro League player in history to be inducted into the Baseball Hall of Fame in 1971.
Richard Petty has won the Daytona 500 seven times, and he is regarded as one of the greatest drivers in NASCAR history.
Petty's final victory came at the age of 47.
Herschel Walker made a name for himself in the NFL as a two-time Pro Bowler, and he also won the Heisman Trophy while playing for the University of Georgia in 1982.
He has since retired from football, but he is now competing in MMA competitions at the age of 48.
Martina Navratilova is one of the greatest tennis players (male or female) to ever step on the court. She holds the record for the most career titles of any professional tennis player (again, male or female), and she won two mixed doubles titles at Wimbledon and the Australian Open at the age of 46.
Looking past Favre's current personal problems, there is no denying his accomplishments.
Along with numerous other accomplishments, Brett Favre holds the record for the most consecutive starts by a quarterback in the NFL.
Chris Chelios is a three-time Stanley Cup champion, and he just recently retired in August.
Chelios now works as an executive adviser to the general manager of the Detroit Red Wings.
Jack Nicklaus has been the most dominant force in golf the sport has ever seen.
His name is synonymous with greatness, and he still holds the record for the most victories in major championships.
Andersen holds the record for all-time leading scorer in NFL history, and he holds the all-time scoring record for two different NFL teams: The New Orleans Saints and the Atlanta Falcons.
He retired from the NFL in 2008 at the age of 48.
Today, we might associate George Foreman for his "Lean, Mean Grilling Machine," but he is also one of the greatest professional boxers of all time.
After the age of 40, Foreman won 17 of his 20 fights.
Torres became the first swimmer to compete in five different Olympic games, and in 2008, she won three silver medals in the 50 meter freestyle, the 4x100 medley relay and the 4x100 freestyle relay.
At 41 years old!
The late George Blanda became the first player to ever score over 2,000 points in his career, and he is one of only two professional football players to play in four different decades.
Sadly, Blanda passed away last month at the age of 83.
Nolan Ryan had over 1,000 strikeouts after his 40th birthday, and he retired at the age of 46 holding the record for the most career strikeouts.
He played for 27 seasons in the major leagues.
Who doesn't love Gordie Howe?
Gordie Howe played hockey in six different decades (40s-60s), and he holds the record for the most games played with 1,767.
Kareem played in the NBA until the age of 42, and he holds many NBA records including most points scored (38,387), most minutes played (57,446), and most All-Star selections (19).
It's hard to argue with this one.
Jerry Rice is one of the greatest (if not the greatest) receivers in NFL history.
Rice holds the record for just about every statistic regarding receivers including most receptions, most receiving yards, and I'm missing one...
Oh yeah: Most touchdowns.