Jamaal Charles has insisted that he will be able to play in the NFL for another six seasons.

The Kansas City Chiefs running back is 28 years old, so would be 34 if he plays in the 2020 season, but no player aged 34 or older has rushed for 1,000 yards in a season since John Riggins reached the mark in 1984.

Charles told NBC Sports: "I want to play another six years. 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. Football is changing, sports are just changing. You can see basketball, like Kobe Bryant, he is still playing at 36. You see [39-year-old San Antonio Spurs forward] 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 had 1,033 rushing yards, 291 receiving yards and 14 total touchdowns during the 2014 NFL season.