Every NFL fan, whether fanatic or casual, should know about the dreaded 30 year old wall when it comes to the running back position.
To describe it in one sentence, it is that age when a running back has already peaked and begins a drastic downfall to end his career.
With that being said, the running back has one of the shortest NFL lifespans of nearly any other position in the sport, especially when you see players like Brett Favre, who are well over 40, still throwing the ball around like he was still 25 years old.
The following list contains the top 15 running backs who hit the age 30 wall and had a dramatic decline in his individual production across the board.
Besides the drop in stats, the only other criteria for this list was that the player cannot still be playing in the NFL as of the date stamp of this article.
(Click here to see the top 10 running backs who broke through the 30-year-old wall.)