In Chris Leben's final UFC bout against Uriah Hall at UFC 168, he refused to answer the bell for the second round. No one argued with his decision. It was obvious that Leben had nothing for Hall and that another round would simply result in more pointless brain trauma for the shot fighter.

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Shortly afterward Leben announced his retirement from mixed martial arts on the MMA Hour.

Luke Thomas says it's a good thing and that Leben's sudden and uncharacteristic concern for his own health and welfare showed a kind of sanity that no professional fighter can afford to bring into the cage.

Here's what Leben told Ariel Helwani:

"I'm 33 years old now, which isn't the oldest for a fighter. But like I tell people, it's not how old you are, but it's how long you've been doing it. And I've been doing this game for quite a while," Leben said.

"I've got a lot of years ahead of me. I would like to still have my head on my shoulders and have a brain when I'm raising kids and doing all the other stuff that I want to be part of. I think it might just be time for me to gracefully bow out."

Here's Leben's farewell interview from the MMA Hour: