WATCH: DeAngelo Williams Celebrates Becoming The NFL's Oldest Running Back With a 300+ Pound Hang Clean

The oldest running back in the NFL is still a beast in the weight room.

For most people, a birthday means kicking their feet up and relaxing with a big slice of cake.

For Steelers running back DeAngelo Williams, it means getting in the gym and hang cleaning roughly 300 pounds.

At 33 years of age, Williams is now the oldest running back currently on an NFL roster. Fred Jackson, at 35, was the only active running back older than Williams in 2015, but he's currently a free agent.

Like a fine wine, Williams seems to be getting better with age. In 2015, he recorded 907 rushing yards and 11 rushing touchdowns, his highest totals since 2009 and 2008, respectively. Judging by the fact he's still dominating the weight room, we don't see Williams slowing down any time soon.

 RELATED: DeAngelo Williams' Workout For Pro Bowl Speed and Agility

Photo Credit: Getty Images // Thinkstock