Why isn't there more faking being hurt in fights?

[Fraz]

No one feigns injury in mma, these are the toughest heros on planet earth

 

[Fantastic_Man]

Is it really ? Don't feel like searching for it but how would it be possible to implement the rule when any good "actor" could fake being hurt and then claim an Adrenalin surge .

It actually is illegal. Seems like a ridiculous rule to try and enforce, but I guess it just falls into the category of "we don't enforce this rule" like cage grabbing.