He couldn't believe how this had gotten flipped around so ridiculously. He hadn't been the one to get out of shape in order to need a stricter regiment. And yet here they were, and now he couldn't back out because Gamora was smiling and that was exactly the sort of thing he wanted, even if it was at his own expense.
"Yeah, sure," he said, puffing up a little, shoulder pushed backward because that's how one looked more intimidating, apparently. "I can do it. You won't even need to fix anything. I'll keep up. Of course I will. Don't be silly."
He would not be able to keep up. But that wasn't the point.