Do IndyCar drivers qualify as athletes? Kiwi superstar Scott Dixon gives an eye-opening account of what's really involved with preparing for raceday.
It was the late 1990s when Scott Dixon made the move that would change his life and propel him towards becoming one of America's premier modern day motor racing stars.
The super professional Kiwi trained hard for his move to open-wheeler racing.
Dixon, the Australian Formula Holden champion, had decided to bypass Supercars to chase his IndyCar dream. But despite his rigorous preparation, the young Kiwi was in for a rude physical awakening.
"I started training pretty heavily while I was still racing in Australia, before I got to America to race in Indy Lights," he tells NZME from Indiana, where he is preparing for Monday's famous Indianapolis 500.
"It was a shock, the physicality of it, definitely for the first portion of that season. Depending on the circuit that weekend, it was very, very tough."
Fellow Kiwi Scott McLaughlin's first full IndyCar season has further boosted New Zealand's interest in the famous series.
And it has thrown the spotlight on what these drivers actually go through, and what McLaughlin is dealing with in his already-promising transition to a new craft.
Or to repeat a common question: Do IndyCar drivers qualify as athletes?
Sift through the driver testimonies and talk to someone like the 40-year-old Dixon, and you are left absolutely amazed at what they cope with physically.
While incredible speeds on congested tracks provide the outward thrills, the remarkable strength and endurance needed to handle notoriously difficult cars is astonishing.
There are huge downward forces involved - which aids cornering but makes steering overall much harder - along with the famous and potentially debilitating g-forces on drivers caused by acceleration.
There are various types of IndyCar tracks and a few like the famous one in Indiana are so dangerous that newcomers Romain Grosjean, from the F1 ranks, and Nascar legend Jimmie Johnson have opted to sit them out for now.
But whatever the various danger levels, the physical demands are always extreme.
Dixon, the current and six-time champion, has prepared his mind and body so well that he is confident of continuing to succeed despite having reached his 40s. But don't let the veteran's continuing success fool you in terms of just how tough the sport is.
Dixon says that the mentally draining Indy500 is physically easier to cope with.
Shorter tracks, like in Iowa, are tougher as they demand constant correction to the right while turning left. Studies show the Iowa Speedway smashes drivers with up to six times the force of gravity for about half of each 18 second lap.
The typical IndyCar driver exhaustion levels were found to equal those of elite 1500-metre swimmers and marathon runners in one American academic study. The g-forces can be so great that drivers are unable to breathe when cornering at some tracks.
Dixon found his body shape was even being skewed when he raced on predominantly oval tracks early in his career, the body being pressed in one direction.
The recent introduction of aero screens – a windscreen – for safety reasons has also added to the heat problems the drivers deal with.
"I try to explain driving an IndyCar like this," Dixon says.
"When people do go-karting for seven minutes their hands are sore and they are out of breath. Well, times that by 100.
"The g-loads are high, your heart rate is 160 to 180. A lot of us do extensive training based on triathlons and long endurance events to have the cardiac capacity you need.
"A lot of our practice days are gone now, so conditioning is much more important, because you used to get fit by testing.
"When I first came to the series we did 50 to 60 tests a year. Now we're limited to five or six. And it's hard to get fit by not driving the car.
"How you feel after the race often depends on how good the car is – some of the hardest days are when you are further down the pack.
"It's kind of tough on the whole body - IndyCar is probably the toughest car and the steering weight is very high.
"When Grosjean first tested from F1, he was shocked about how physical the car was."
Scottish IndyCar great Dario Franchitti, an advisor at Dixon's Chip Ganassi team, went on a special mission aimed at letting the public understand what the likes of Dixon endure.
"You hear that talk about whether drivers are really athletes, and I get asked that from time to time, so I wanted to have some concrete numbers to go off," Franchitti told roadandtrack.com.
"I'd always been curious myself, so now I can tell people exactly what we're dealing with inside the car."
With help from team engineers, who used on-board data and sensors throughout the car, he found that braking could involve applying a force just over 60kg. A driver might have to do this 250 times in an 85-lap race.
Steering involved constant push down/pull up forces of 15kg – with well over 1000 reps of these during such a race.
Breathing is the subject which might cause the most surprise.
Of the Mid-Ohio course, Franchitti said: "Remember, you can't breathe above a certain number of G forces, so you get into the corner and brace yourself like a fighter pilot does when he's making a hard turn.
"You're at turn one, hold your breath, get through the corner, breathe, breathe, breathe on the straight, brace yourself for turn two, hold your breath (and so on). It's kind of mental really."
Franchitti described the scene after a particular qualifying session, with drivers "just staring into space or whatever – no one had anything left to give".
Tremendous neck strength is also needed so drivers can keep their head vertical, which is why they develop wrestler-quality muscles.
"If you can't hold your head up, and it's happened to all of us at one time or another, it's game over. You start going backwards right away," Franchitti said.
There is one key factor which makes driving in IndyCar particularly tough - the lack of power steering. This subject looms large when talking to Dixon.
"IndyCar is the last formula without power steering, so there are high loads and the kick back in the (steering) wheel from bumps and corrections is extremely high so it is extremely physical," Dixon told NZME.
"I think for a lot of us, power steering is about the safety side.
"You have to be very quick in getting your hands off the wheel if you are about to touch a wall, or crash because of the amount of energy which goes into your hands. I've found out the hard way plenty of times.
"From a safety standpoint, power steering is something that needs to be added. The car itself is fairly strong on the suspension side so it takes a pretty big hit, but that hit goes straight through the steering wheel.
"I've broken fingers and bones and wrists, torn ligaments off my hand, I've had two or three surgeries on my hands from crashes.
"You will see the veterans get their hands off the wheel very quickly if they are spinning or about to hit the wall."
It's not getting any easier either.
When asked about his toughest ever race, Dixon suggests a couple last year, after aero shields were mandated. The St Petersburg street course was particularly tough.
New cool suits are being tried by some, complementing the inlet cooling and helmet pumpers. But drivers still get "baked". Dixon might lose two or three kilos during a race.
It's a game of swings and roundabouts.
"Indy is the least physical because of the very long straights, the corners are very quick, it's kind of in and out, short corners," Dixon says.
"But those super speedways are mentally really draining with up to 32 others on the track, speeds up to 240mph (386kph), within inches, continually monitoring and gauging and understanding where the car needs to be.
"Don't get me wrong…the average heart rate is pretty high and the long races are exhausting depending on the temperature.
"But as far as flat out work, those street courses are generally toughest because you are continually fighting the car and the cooling temperatures are not very good.
"It's funny – you get into that zone of not realising how far you are pushing the body until you stop, lose the adrenaline and come down a bit."
Athletes or not? The answer is pretty clear.