So as pertaining to deadlift....

Obviously you won't lift if you don't have the grip strength to hold onto the bar as you come up, but does the opposite hold true? If you have a weak link in say your low back is there some mechanism by which you lose your grip on the bar?

I've busted through my stall, but noticed something in retrospect. I would start the top set with regular grip and switch to the alternate grip on my 3rd rep or so as grip was failing on 2nd rep, but fail on the 4rth regardless.

Well since busting my stall I noticed I've already upped PR by 10lbs AND hit all five reps with a regular grip. Is it possible my grip strength has improved that much, or is it that there is some inhibition of grip strength when there is a weak link elsewhere in the lift?