[Jonty30]

You can make the best helmets possible, but that isn’t going ti stop the brain from bouncing around inside the skull, while bits of it are torn off from the natural bone fragments that sit along the edges of the skull plates.

[Straight Vermonter]

You can make the best helmets possible, but that isn’t going ti stop the brain from bouncing around inside the skull,

The helmets slow the impact precisely so that doesn't happen.