Lewis Hamilton revealed his back was left in "a real mess" as the heavy bouncing of his car took its toll on his body.
Both Mercedes drivers qualified in the top 10 for today's Azerbaijan Grand Prix, but it was still far from a comfortable ride for them. Hamilton and George Russell are suffering more than most, with the team unable to solve the issue which is costing performance and causing pain.
It is particularly bad this weekend, with the Baku street circuit notoriously bumpy along its long and fast main straight. Hamilton said he was "sore" after practice on Friday, and was holding his back in agony after Sunday's race after telling his race engineer that the pain was "killing" him. The Briton has now revealed that he needed treatment to be able to take part.
"Nothing we seem to do, like we have changed so many things but we just can't seem to... it is crazy because in Barcelona we didn't have any [porpoising] and then everywhere else we've had it," said the seven-time world champion to the Press Association.
"It is a phenomenon we just cannot get our heads around. It is the same thing underneath the car that keeps on coming back. Honestly, on Friday we had so much bottoming I could not finish my long runs because my back was in a real mess.
"Thank god for [physio] Angela [Cullen], who gave me physio and acupuncture and I was still in quite a bit of pain on Saturday morning. Now we don't have it as bad at the end of the straight but it is the corners where you are trying to keep it out of the wall but I am hoping on heavy fuel it will be better."
Meanwhile, team-mate Russell may have qualified in fifth for the race in Baku, but his mind was on larger issues when it came to his post-session interviews on Saturday. "I think it's just a matter of time before we see a major incident," declared the young Brit as he spelled out his worries over ground-effect aerodynamics.
"A lot of us can barely keep the car in a straight line over these bumps. We are going around the last two corners at 300 kilometres an hour, bottoming out – you can visibly see on the tarmac how close the cars are running to the ground. Even Formula 2 are in the same position as well, they have a similar sort of philosophy.
"And it's sort of just unnecessary with the technology we have in today's environment. It just seemed unnecessary that we are running a Formula 1 car over 200 miles an hour millimetres from the ground. It's a recipe for disaster. So I don't really know what the future holds. But I don't think we can sustain this for three years or however long these regulations are enforced for."
