Fred Jackson doesn't pay any attention to the supposed memo that running backs over 30 can't play at a high level.

"They keep sending it to me," said Jackson with a laugh, "but I keep throwing it in the trash whenever I get it."

Jackson turned 33 on February 20 and ended the 2013 season with 1,277 yards from scrimmage in becoming the second back in Bills history with more than 4,000 yards rushing and 2,000 yards receiving. He scored nine rushing TDs and accounted for 890 yards in Buffalo's ground game that ranked second in the NFL in total yards.

To put Jackson's campaign in perspective, only nine other backs in NFL history have recorded seasons of over 800 yards rushing and 300 receiving after age 31. You may have heard some of their names before - Walter Payton and LaDanian Tomlinson, among others.

"To me, age is just another number," added Jackson in an interview with Bob Papa and Ross Tucker on Sirius XM. "I still feel like I've got a lot left in the legs, a lot of tread left on the tires."

So how is it that a 33-year old running back is outpacing athletes 10 years younger?

"When you do lose a step so to speak, you have to be able to take advantage of other parts of the game," said Jackson.

So while some backs try desperately to maintain their speed by shedding pounds, Jackson has actually gotten heavier in recent years, adding lean muscle to his frame to help punish would-be tacklers who might have a speed advantage. Maybe that's why he flexes after touchdowns.

"I've always prided myself on being a physical running back, and I have to be now more than ever," he said. "That was just one of the ways I figured out I'd be able to last a little bit longer on the field. It worked out for me last year and hopefully it'll keep me going in the league as long as possible."

In addition to the added size, Jackson has also benefited from sharing the workload with C.J. Spiller, who last year finished just short of a 1,000-yard campaign despite being hobbled with an ankle injury.

"That definitely gives me the opportunity to be out here three or four more years and competing with these guys and getting this thing turned around. That's the number one goal, getting this thing turned around and giving this city something to be excited about and that's what I want to do before I'm out of here."