Narrator: This IndyCar driver

is withstanding an intense acceleration.

It feels like 50 pounds of weight on his head.

When you have 3 to 5 g's pushing on you,

so three to five times your body weight,

you can't actually breathe.

Narrator: That's why some drivers train

with this contraption before a race.

It's called the iron neck,

and it helps IndyCar drivers

work out a part of the body most athletes overlook.

Rossi: So, we all have the same car,

we all have the same tire.

So you're only really competing against the people

that have the same equipment as you.

So, really, it's the driver

that makes the biggest difference.

[engines revving]

Narrator: Since 1909, a small number

of highly skilled drivers

have raced these single-seat, open-cockpit vehicles,

costing around $1 million today.

And the premier race is the Indianapolis 500,

where 33 drivers push their limit for 500 miles

in under three hours.

So, in 2016, I won the Indianapolis 500.

Narrator: Rossi won a prize of $2.5 million.

Rossi: And I was a rookie,

which was a surprise to everyone, including myself.

Narrator: But it took a lot of training, strategy,

and racing to get there.

It's just a whole lot that goes into racing

than just driving.

Narrator: Days before the race,

drivers hit the gym for their final workouts.

This isn't just any gym, either.

This is PitFit, which specializes

in training for motorsports.

Rossi: We're one of the few sports

that has to deal with g-force.

Narrator: Drivers have to withstand

an intense acceleration on their body

that can feel like a 50-pound weight on their head.

This means working out a very specific body part.

Rossi: You have to train your neck.

And that's probably the weirdest thing

about being an IndyCar driver,

is you have to kind of have a weird-shaped neck.

The biggest machine is called the iron neck.

It is made for wrestlers, but IndyCar has adopted it.

So, it has kind of a bungee cord that comes up,

and it connects to a disk around your head,

and you can kind of,

somebody can be pulling the bungee cord,

you could be pulling the bungee cord.

Narrator: Drivers also have to operate

under extreme temperatures.

The cockpit, on a summer day,

when we have a summer race,

can get to 135, 140 degrees.

We lose up to 6 to 8 pounds in the race,

just from dehydration and lack of water.

Rossi: And so we spend a lot of time in the sauna.

You'll do a two-minute sprint on a treadmill,

you'll get off, you'll go straight into a sauna,

and you'll do a five-minute reaction drill on an iPad.

Narrator: And drivers train to endure

all the intense heat, g-force,

and other factors for 2 1/2 hours straight.

When a lot of that lactic acid builds up,

weight that you can usually move with your eyes closed,

you struggle to move even once.

Narrator: To prepare his body for this sustained work,

Rossi focuses on exercises that contract muscles

but don't have a lot of movement.

For example, if you take a bench press,

you'd put an amount of weight on

that you can do 15 to 20 times,

but what you actually do is you'll move the weight up,

and then halfway down, you'll hold it for eight seconds.

That is really one of the big things that we do,

as IndyCar drivers, to make sure

that you have the muscular endurance

to compete for 2 1/2 hours.

So, I was introduced to racing by my father.

For my 10th birthday,

he took me to a go-kart school in Las Vegas,

and it was supposed to be

a once-in-a-lifetime opportunity.

Really, from that point forward, I had the passion

and desire to become a professional race-car driver.

The mental game is a huge part of racing.

It's a sport where you lose way more than you win.

You have to get in the car with a very good understanding

of what you're going to do, how you're going to do it,

and what your objectives are.

Narrator: Endurance isn't just a physical test.

It's a mental one, too.

This is where strategy comes into play.

Rossi: For us, the strategy, really,

is to move forward pretty aggressively

in the first stint, the first opening laps,

just to give yourself that buffer.

You don't ever want to fall outside the top 10.

That's really hard to recover from.

So you want to kind of be in the top five

at 100 laps in,

and then, really, in the final stint,

you want to be in the top three.

And just at that point, it becomes a chess match.

And when I won the Indianapolis 500,

my strategists came up with a strategy

that was pretty crazy and pretty aggressive,

that was basically having us skip the final pit stop.

And so we had to conserve a crazy amount of fuel.

We ran out of fuel in turn four, coming to the finish,

and we were able to win.

A lot of times, Indianapolis becomes a fuel race.

If you're out front leading, pushing,

pushing through clean air, you get worse fuel mileage

than if you're following behind a car.

Obviously, the less fuel you burn,

the less horsepower you have, the slower you go.

So there are trade-offs.

So you're always trying to manage the best balance

between saving fuel and going as quick as possible.

Narrator: Once a driver decides on a strategy,

the next step is making it second nature.

When you're operating at 230 miles an hour,

you can't be thinking of things on a conscious level.

You can't say, "OK, I'm gonna turn in here.

I'm going to break here. I'm gonna do this and this."

Everything has to come kind of from a subconscious level.

Narrator: On Carb Day,

we found the drivers down on the track

working with their teams.

With 36 hours left before the race,

this is their last chance to work out any final kinks.

We have a two-hour practice session

just to double-check if we need

any slight adjustments to the car,

and, I guess, how to save fuel the most efficient way.

So we can do some practice with that on the track

before we get out there for the race.

What's pretty cool about IndyCar

is you can also make quite a few adjustments

in the cockpits.

You can change wing settings,

you can change tire pressures.

All of that has an effect on the balance of the car.

Narrator: We weren't allowed to film

under the bodywork of an IndyCar,

but Andretti Autosport gave us a tour

of one of their vehicles.

So, the steering wheel of an IndyCar

sets you back the price of a nice family sedan,

about $35,000.

So, the neutral button is the button that the driver pushes

to get the car into neutral out of first gear

when he comes into the pit lane.

PLC is pit lane speed control.

There's a speed limit in pit lane.

H2O is what you might think, it's water,

and that's, basically, the driver drink bottle.

So, these two top paddles are shift up and shift down.

That's how we go up and down

through the gears in the gearbox.

There's no gear lever or anything inside the car.

Narrator: Drivers only get a couple hours of practice

before any race.

But every drive, even a practice one,

comes at a cost.

To go practice in a race car is

$30,000 to $50,000 every single time you do it.

Narrator: Carb Day, while expensive, is crucial

to get the right conditions for race day.

How it was started was, the teams,

after qualifying, back in the '70s and '80s,

needed to tune in the carburetors

for the conditions that were going to be on the weekend.

Obviously, motor technology and engine technology

has advanced since then

and everything's fuel-injected now,

so it doesn't really matter.

Narrator: This is also the last chance the driver gets

to practice with their pit crew.

[engine revving]

You know, races can be won or lost on pit lane.

If you have a problem in a pit stop

and you lose three to four seconds,

that can be five or six positions on track.

[engine revving]

Narrator: It can cost an average of $1 million

to race a car at the Indy 500

and up to $10 million for an entire season

to pay for fuel, tires,

parts, and the team itself.

And all of this team's training, strategizing,

and practicing leads up to one day,

the 105th running of the Indianapolis 500.

Rossi: It all disappears as soon as the green flag waves.

You don't really feel anything at that point.

It's just going out there

and trying to beat everyone around you.

Race day morning is, like, five hours,

because you wake up, and immediately

you feel the energy of this place come alive.

Obviously, I'm starting second in the race.

My plan, I think initially, will probably be to sit

and see what other guys are doing.

Narrator: In the 105th running of the Indianapolis 500,

Colton Herta placed 16th,

and Alexander Rossi placed 29th.

They are ranked seventh and 12th overall

in the NTT IndyCar Series.

It's amazing to be an IndyCar driver.

It's everything that I would've hoped for.

You get to drive really fast race cars all across the US,

and there's not a day that goes by

that I don't take it for granted

and really enjoy my job.

[engine revving]

You actually feel everything through your butt.

All of us have little butts,

so we can feel a little bit more. [laughs]

If the car slaps the ground,

what we call bottoming,

or if the rear slides or the front slides,

you all feel it through your butt first.