By any reasonable measurement, Adrian Peterson is one of the best running backs of his era, and probably in NFL history. He's led the league in rushing yards three times and rushing touchdowns twice. He's made the Pro Bowl in every season that didn't get cut short due to injury or suspension and he's a four-time first-team All-Pro. In nine seasons, he has rushed for 11,675 yards and 97 touchdowns. Those figures rank 17th and 10th all-time, respectively.

According to AP himself, the back end of his career is going to be even more special. “Not to be cocky or anything, but I know, at 31, my end is going to be better than my beginning," the Vikings star told Peter King of The MMQB.  "One thing I know, and will remain true: These young guys will never outwork me. I put my body through the grind. Just knowing how my body remains healthy, age is not really affecting me. It’s my mindset. I don’t get into the 30-year-old running-back thing, that you’re done at 30. I am getting stronger with age. Honest, last year [when he won his third rushing title at age 30] was a disappointment to me, because I know I can do more. Honest, it was.”

Peterson considers last year -- when he led the NFL in carries, rushing yards, and rushing touchdowns -- a disappointment? Well, I guess that's one way to make sure you're always motivated.

Not only is he still striving to be better than last season but AP also plans on playing a pretty long time. While he told King he may not make it to age 40, he said he'll get pretty close. “I can, but will I? Honestly, I don’t think I will," Peterson said. "Mentally, I don’t know. Once I get to 38, I don’t think I’ll have the same love of the game. Sometimes I get tired of training camp. I think I can endure five more [camps], but after that, I don’t know.”

Adrian Peterson is motivated to stay great. (USATSI)

Peterson has previously stated a desire to play until he is 38 years old. He told the Pioneer Press last summer that he planned on staying in the game that long, to aid his quest to break both Emmitt Smith's career rushing yardage record (18,355 yards) and Eric Dickerson's single-season record (2,105 yards).

He told King that while he is still focused on those goals, he doesn't so much care about single-year rushing titles anymore.  “I don’t spend too much time thinking about [winning another rushing title]," Peterson said. "But it’s a seed planted in my brain, and it’s sticking there. Everything in me is championship, championship and then breaking records. It’s a part of me. I am pushing myself to the max to win a Super Bowl, and then to break Emmitt’s record and Eric Dickerson’s [single-season rushing] record. It is my everyday life, what I think of every day. Mostly it’s that Super Bowl. Then the whole world will remember you.”

Speaking of that final goal, AP is convinced that the Vikes are a legit Super Bowl contender this season. “We are going to have a good chance to win it this year -- win everything,” he said. “Sit back and watch. Sit back and watch. You can be like, ‘I thought you guys were at least a couple of years away.’ Nope. You sit back and watch, this year.”

Minnesota finished last season 11-5, good enough to win the NFC North. They lost to the Seahawks in the first round of the playoffs, though. Apparently, adding Alex Boone in free agency, getting back Phil Loadholt and John Sullivan back from injury, and drafting Laquon Treadwell and Mackensie Alexander (among others) in the draft is enough to make Peterson think his team can get over the hump.