Any guy that competes in mixed martial arts is a tough tough guy. No doubt about it.
All the men on this list can take a lot more punishment than you or I. That does not stop people from questioning their "chin".
By a fighters "chin" being in question, their ability to take a punch and fight through adversity comes into question.
In mixed martial arts anyone can get dropped from a strike at any time, but some fighters have dropped to the canvass more frequently than others.
These are the top 10 most questioned chins in MMA history.