Percy definitely started working out a lot after the war. He never wanted to be caught unprepared again, and so he spent a lot of his time not only training his sword fighting, but also weightlifting. Part of this had to do with the fact that he wanted to be able to carry Annabeth no matter how weak he got. After Tartarus, everything he did was to prepare for a situation as bad as that one. He also started eating a lot more, which in turn led him to gaining more muscle mass. He was terrified of looking like the walking corpse he turned into when he was hidden by the death mist, so he bulked a shit ton of protein and fats. At first, Annabeth didn’t quite notice a difference, but by the end of their senior year, Percy was ripped. He looked godly, and it came to the point where Annabeth had to become territorial around other girls because he just looked that good. It definitely flipped a switch in her. Percy had always been good looking, and he’d always been charming. But ever since the summer he’s been overly protective and down right sexy. Even if he had started to tower over her, she could definitely get used to it.