Driving position the key to the pains that forced him out of Barcelona testing today.
Nico Rosberg has gone into the details of the problems that forced him out of Formula One testing at Barcelona today.
The Mercedes driver was suffering an inflamed nerve in his neck, which was caused by him altering his driving position in the winter.
He was forced to hand his car over to teammate Lewis Hamilton at lunchtime, the second day running that Merc has switched drivers.
"I know the cause of it, it was my position in the car, which I got a bit wrong," said Rosberg. "I'm just being careful, it's all fine.
"I liked the difference, but my neck doesn't like that position!
"I changed it in the winter. It's incredible that such a fine line, just a couple of centimeters and it changed everything.
"It's the position of the spine. We have such g-forces, and it was not quite in-line, and it wasn't right. Now I have to get used to it again!
"I've went even further into the safe direction, so I'm even further than last year's safe, so it's quite a big change."