When straining under trouble, the intracerebral narcotic resource "shipdorfin" is secreted, which in turn, lifts the brain's limiter.
Furthermore, through various means the physical power is increased by a very real, and appropriate, hundred or so times over.
One could rightly call the state that they have fallen into as a 'berserker'.KAGAAAA!!Just like that, Zuikaku...Ohhhh! Good job!REST IN PEAAAAACEEEE!!!Wild Liberation