It is just like when Zoro overdid it in Thriller bark, or to a degree what happened to Lucci after Enies lobby. King got beaten by Zoro, he was already in bad shape and took a beating from GB, now he will need time to recuperate just like when Zoro performed poorly vs the PX in Sabody because of what he had to do during Thriller bark, King is the same with the difference he lost 2 times so take a beating 2 times in a short amount of time.