How so ?
Last weak chapter luffy said that he had the hardest busoshoku he came across .
But in this chapter we now know it was not a person but a piece of armor with haki on it .So lets see how hard\tough his really body is with haki .
I misspoke I should have probably said his haki is as strong as Luffy's. I assume that his real body is tough, but like he said he doesn't like pain so he uses clones and imbues them with haki so he doesn't have to get directly involved. With the giant scar on his face I assume he has taken damage directly before, but without knowing who he fought it makes it hard to estimate his strength.