Chiefs' Jamaal Charles: 'I want to play another 6 years'

Kansas City Chiefs running back Jamaal Charles is quickly approaching 30, long thought to be the cut off point for running back productivity, but he feels he won't slow down until long after that point.

"I want to play another six years," Charles told the Chiefs official website. "I'm seeing guys at 37 or 38 still playing football in the trenches and that's somewhere where you don't want to play. So I just want to change the game with the running backs. I want this to last longer and then when I retire, I'll be happy with where I end my career at."

Very few running backs have been able to remain productive well into their thirties, with Curtis Martin perhaps the best recent example of a player able to sustain excellence past 30. In 2004, Martin rushed for 1,697 yards and 12 touchdowns at the age of 31.

But examples like Martin are few and far between. Charles thinks that's changing.

"Football is changing, sports are just changing," Charles said. "You can see basketball, like Kobe Bryant, he is still playing at 36. You see Tim Duncan. I think back in the days you couldn't play for long because there were a lot of people that didn't know the fundamentals of hitting, running people over. That's not my form."

Charles is coming off a down year and suffered a torn ACL in 2011 but with his yards per carry (5.5) being the highest average of all time, there is a chance he could have an impact well into his thirties.