INDIANAPOLIS — The 330 players arriving at the league’s annual combine have been preparing for this week’s “Underwear Olympics” like a prize fighter gets ready for his big night, pumping iron and cutting carbs.

They’ve been following strict programs designed to help them get stronger, run faster and jump higher in anticipation of getting poked and prodded, measured and treasured.

“The hardest thing for these kids to really understand when they get to the combine and the pro day is they get one shot at all these drills,” said Loren Landow , who trained Stanford star Christian McCaffrey among more than two dozen NFL hopefuls at Landow Performance in suburban Denver over the last two months.

“Whereas your strength coach in college used to let you do it over and over until you got your best time, now that’s not the case when you’re being evaluated in a time crunch,” Landow said. “They’re going to give you one opportunity and it’s all about how well you perform at that moment with high levels of stress and some fatigue on you.”

That’s why they’ve been training with such single-minded focus since their bowl games.

“It’s a lot of just trying to improve all the funky drills that they have you doing at the combine that you know aren’t necessarily things that we practice as a football player on a daily basis,” said Wyoming offensive lineman Chase Roullier, who trained with Landow.

That’s been the formula ever since Mike Mamula absolutely killed it at the 1995 combine and rocketed into the first round, where the Philadelphia Eagles traded the 12th overall pick and two second-round selections to Tampa Bay so they could move up five spots and get the Boston College defensive end at No. 7.

Mamula was among the first players to train specifically for the tests he’d face at the combine: the 40-yard dash, the three-cone drill that measures agility and the 225-pound bench press.

Now everybody targets this week in Indy like Mamula did all those years ago.

Today’s prospects train six days a week for eight weeks or more all so they can impress NFL executives who will test their speed, strength, skills and brain power while also checking out their medical background and any off-field history for any red flags.

“I feel like it’s definitely getting us ready for the combine as far as all the guys we’re competing against each other,” said Air Force receiver Jalen Robinette , who led the nation in yards per catch in 2016. “Because it’s a real big interview/competition there at the combine. And being able to break down the drills and mentally be practicing everything, it’s awesome. Literally every day I hear new stuff about the combine that they teach me here.

“Preparation is everything.”

They pretty much follow the same basic program because they’ll be doing the same tests at the combine. But the training is also personalized by position.

“I’ll talk to the agents and from the agents’ perspective, I’ll say, ‘What are the scouts telling you that they want to see from your player? Do they want to see them heavier, lighter?” Landow said. “At the end of the day, I don’t think you ever go wrong in providing a little bit more mobility, flexibility to an athlete and getting them stronger. More explosive is always the key in this short window so they can really show their best in all their ‘measureables.’”

These players have all undergone mock combines, too, where they put all their training together for dry runs to give them a taste of what this week will bring.

“I think it makes the hugest difference,” Roullier said. “If I were to go in there and do this stuff cold, I mean, I’d have an idea of what I’d be doing because it’s all stuff that I’ve done in the past. But my technique would be just awful, you know, it’s just all these little things that you need to change and I’m able to get coached up on all of them. It’s just continuing to improve those little things and it makes a huge difference in the numbers.”

This training isn’t cheap. It can cost tens of thousands of dollars, although the pricing structure changes for draft wannabes and sure bets.

“If an athlete is an NFL combine invite, the agent will pay for everything,” Landow said. “If you have a kid who may be a bubble guy who didn’t get the combine invite but you know can play, the agents will typically foot the bill. Some guys if they’re a priority free agent maybe at best, sometimes it’s coming out of their own pocket.”

For a combine invitee, the cost can run into the tens of thousands of dollars.

“I know with housing and food and all that it ends up being like 10, 20 grand that my agent’s dropping just in these few months up to the combine. So, it’s a lot,” said Roullier, who’s out to ensure this week that the training pays big dividends.