Toro Rosso's Carlos Sainz Jr had 46G impact in F1 Russian GP shunt

The Spaniard was airlifted to hospital after ploughing nose first into a Tecpro barrier at Turn 13 on Saturday.

Sainz passed a series of tests and was released in the early evening before being to race on Sunday morning.

Team principal Franz Tost explained that Sainz changed the brake mapping just before Turn 13 and when he braked, the rears locked sending the car out of control.

"He touched the wall with the front-left at around 204 kilometres per hour and then he crashed into the Techpro barrier at around 150 km," said Tost.

"The impact was around 46G. It took a long time to get him out of the car, but Carlos was not injured.

"He was brought to the hospital and the doctors checked him and he could leave the hospital fortunately yesterday evening.

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"Today he was checked here at the medical centre. The doctors said that he is 100 per cent healthy and he is able to do the race.

"We had before the discussion, Carlos and my side, and he wants to race, he's in a good shape and therefore he will do the race.

"It was not his mistake, the car just went out of control."

Sainz's Toro Rosso has required a major rebuild, with the Spaniard set to start the race from the back of the grid.

"We did not change the monocoque, but everything else has changed - a new suspension, new nose, new floor, new rear wing, new engine, new gearbox," said Tost.

Sainz said he remained conscious throughout and can remember the whole incident.

"I was lucky that nothing happened to me," he said. "It took a while to get me out but I was always conscious and I always knew what was going on.

"My main concern at that point was to let everyone know that I was fine because I was completely fine.

"I was downshifting and putting it into neutral to let my engineers know all was moving and I was doing everything.

"It was just the radio that was not working, that's why everything was so tense, hectic at that moment.

"My main concern was to let my parents and all of you guys know that I was OK.

"The first thing I did when I got to hospital was look at the crash to see what happened even though I could remember perfectly."

When asked if he was nervous about the race, he said: "No, it's just one race more.

"The accident yesterday was a tough one but it is already on the back of my mind.

"Turn 13 on the first lap will be a bit emotional but from there on it will go back to normal.

"I'm more than ready to race, my mind is telling me to race and I think it's the best thing I can do at the moment."