False grip on back exercises

I read something a while back saying to use a false grip (no thumbs) when doing pull ups, pull downs, rows, etc. Its suppose to take the biceps out of the movement. ive been doing it for a while now and it seems to work to focus more on the back. I just wanted to know other peoples opinion on this. do you do it or not and why?

How much harder does it make the exercise?

it makes it a lil harder in the beginning, until you get used to it...
I do it too, and also for benchpressing I use no thumbs

Yeah, I usually alternate between grips for pullups every month or so just to change it up a bit. It definetly hits the back alot more going palms out.

Yo, why...?

I don't really know to be honest...
I've seen a lot of pro's train with their thumbs under the bar instead of around it and I've grown to like it...

Word...

Nah, cus I'm thinking, apart from the fact that it plays havoc wit your wrists, in that you can't keep them straight, the risk of dropping that motherfu*ker increases tremendously when there's only support on one side...

And of course, you should always squeeze the bar and attempt to bend it when benching, to generate more power... No thumbs makes that impossible...

Never saw a pro lift thumbless either to be honest...

I dunno, just seems pointless to me...