Max Verstappen revealed concerns over the state of his spine as he unleashed a scathing criticism of the "out of control" bumpy track surface at Circuit of The Americas.

The four-time world champion arrives in Austin for Sunday's United States Grand Prix after claiming his first two victories of the season in back-to-back races.

Speaking to the media on Thursday, Verstappen was unexpectedly passionate over the state of the circuit, which is generally considered as one of the most popular among the drivers on the F1 calendar.

"You see also the track state from what I saw in WEC (World Endurance Championship), it was extremely badly bumpy," Verstappen said.

"I'm not really looking forward to that to be honest, for your spine. I was joking about that in the last race but it's not really a joke to be honest because we mentioned this already for years that it's actually getting a bit out of control.

"I'm sure it's going to be quite tough to find the right compromises around this track in places where it's just extremely bumpy. I don't know how our car is going to respond to that."

The Red Bull driver appeared to be urging the event organisers to place greater emphasis on improving the surface for the event in future.

"Of course, you can use the excuse that the soil is the problem, but then you should have known that you need to make sure that you reinforce it more," Verstappen continued.

"I love this track. I love this place. It's one of the best layouts ever and it's one of the venues, best cities to be at. But for me, the bumps that we have are unacceptable.

"Over time, they've been grinding a little bit here and there, but it's just putting a plaster on the big problem - that's just what's coming underneath.

"That's what you need to actually tackle in the first place. Of course, it means you need to really fully open up the track. That costs a lot of money and time, but honestly, that's the only way to get rid of it because these bumps are not natural and they are out of control."

Verstappen then explained that medical checks had shown that "the bottom end" of his spine "doesn't look that great".

The 29-year-old said: "That I think sometimes people don't really understand that because I can tell you from the checks that I've done from my spine, the bottom end doesn't look that great, the spine.

"I know that's part of racing. I know that can be part of sport, but it's of course also further damage from the cars that we had the last few years.

"Now, if we continue with finding this acceptable to drive on, then, you are going to suffer with that much more."

Norris: I need to take headache tablets

Reigning world champion Lando Norris revealed that he takes headache tablets before driving at certain tracks due to their bumpiness.

Norris also explained that if COTA was a brand-new circuit, it wouldn't meet the requirements to be added to the calendar.

"If you build a new track now, the rules, the regulation of building a new track, the tolerances you have to be within are pretty small," Norris said.

"It certainly doesn't fit anywhere close to what those regulations are now, but it's an old track, not a new track.

"It's pretty bad. There's a lot of places… I need to take headache tablets before I go out simply because it's so bumpy and you're hitting your head pretty hard against the headrests and things because of the bumps. It's certainly not a nice thing.

"There's not much we can do. We complain about it. It's something we've brought up many, many times, but there's only so much we can complain about things."

Mercedes driver George Russell said the bumpy nature of the circuit is "just part of racing," but expressed concern over the general standard of surfaces throughout the year.

"It's bumpy, but I think it's just part of racing," Russell said.

"I'd say my general view is F1 tracks probably need to be repaved every couple of years just to make it a bit more consistent because we're going to tracks now where tarmac's coming up, it's falling apart, it's causing more issues than not.

"We're not an IndyCar or an F2 car that run their ride heights, reasonably high. Our ride heights are 10mm at the end of the straight, a centimetre from the ground, so any time you bump you really feel it.

"The side profile of the tyres now since we've been at the 18-inch is substantially smaller.

"The circumference of the tyre is the same. The circumference of the rim is far greater, so you've lost all of that effective suspension in the tyre, which was a damper, which we kind of don't have anymore. Not ideal, but not much we can do."

Friday October 23
6pm: United States Grand Prix Practice One (session starts at 6.30pm)*
8pm: The F1 Show
9.45pm: United States Grand Prix Practice Two (session starts at 10pm)*
11.50pm: F1 Academy Race 1*

Saturday October 24
6.15pm: United States Grand Prix Practice Three (session starts at 6.30pm)
8.30pm: United States Grand Prix Qualifying build-up*
10pm: UNITED STATES GRAND PRIX QUALIFYING*
12am: F1 Academy Race 2*
12.45am: Ted's Qualifying Notebook*