correct E.?

[bianca]

how is it correct?

one is prone to do smth or
one is prone to doing smth??

thanks

[Francois]

The first one is good to me.

[Noego]

A few sentences from Google:

"But some players, even tough ones prone to fighting, like Brendan Shanahan, believe a good debate is in order."

"Every dog, especially one who's prone to fighting, should be obedience trained."

Second set of examples:

"The merely brave man is prone to fight recklessly; and he who fights recklessly, without any perception of what is expedient, must be condemned."

(from the Art of War this one!)

"Parents, we're told, push their children around, and it makes perfect sense that adolescents in particular are prone to fight back."

So unless someone could provide a grammatical rule, they both forms seem to be correct.