San Francisco 49ers

49ers RB Jerick McKinnon has been taking rigorous AP course this spring

Minnesota Vikings running back Jerick McKinnon is stopped by Detroit Lions cornerback Nevin Lawson on Thursday, Nov. 24, 2016 in Detroit.
Minnesota Vikings running back Jerick McKinnon is stopped by Detroit Lions cornerback Nevin Lawson on Thursday, Nov. 24, 2016 in Detroit. The Associated Press

Jerick McKinnon has a leg up on the other new 49ers: He's already painfully familiar with the kind of inclined running hill the team installed last offseason and which was the bane of every rehabbing and not-quite-in-tiptop-shape player last year.

McKinnon's been working on a similar, 40-degree incline hill at a gym in Houston that belongs to one-time teammate and mentor Adrian Peterson. The 35,000-square-foot facility features an artificial hill, a sand running course and a boxing facility, all of which are put to use in Peterson's famously grueling 3 1/2-hour, offseason workouts.

"The hill work gets you right – that incline!" McKinnon said in a recent phone interview.

The recently signed 49ers running back said that Peterson, a seven-time Pro Bowler widely considered one of the top runners in the last quarter-century, took him under his wing when the Minnesota Vikings drafted McKinnon in the third round in 2014. He traveled to Houston to train alongside Peterson the following spring.

"He kind of just mentored me and brought me along," McKinnon said. "The first time I came down here I liked the results that I got. So I keep coming back every offseason."

The gym, named O Athletik, also is the offseason home of Bills defensive end Jerry Hughes, Redskins offensive tackle Trent Williams and a handful of other NFL players, most of them from the Houston area.

McKinnon is from Georgia, and he's never been a slouch when it comes to gym work. During the 2014 combine, he bench pressed 225 pounds 32 times; only two defensive lineman that year squeezed out more. In college his coaches had to tell him to tone down his lifting after he started squatting nearly 600 pounds.

Still, he said he couldn't imagine a more thorough training regimen than Peterson's.

"Running hella hills," he said. "We do a lot of hill work, track stuff, box in the offseason, work on our hands for pass (protection) and stuff like that. Basically honing in on little details."

The routine ought to have McKinnon ready for the 49ers' offseason program, which begins April 16. Kyle Shanahan, leery of the praise that's already been heaped on his team, said his first goal is to "humble" his players.

He told the San Francisco Chronicle recently that one week of the offseason program will be dedicated to working with Navy SEAL veterans, something his Atlanta Falcons teams did in the past.

The work is designed to foster camaraderie and mental toughness and will involve classroom work as well as some famously SEAL-like activities outside the classroom. The Falcons, for example, did drills that involved hauling 240-pound logs until their arms and shoulders burned.

After surviving Camp Peterson, McKinnon said he's ready for what awaits him in Santa Clara.

"I don't know what they have in store for us, but I'm pretty sure it will be some hard work and some good team bonding," he said. "Yeah, I'll be looking forward to it."

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