A strong neck is important in protecting the brain. Let's break it down.
1. The brain sits in cerebral fluid.
2. When there is an impact to the head the brain will move towards the area of impact. If the blow is hard enough it will even impact the cranium.
3. Now the brain is pinned against that side of the cranium from the force of the blow and as the head moves away from the impact it remains pinned against the skull.
Now comes the very critical reaction from the neck muscles. Will the brain be protected or bounce around in the cranium?
4. If the neck muscles cannot prevent the head from reaching the end of it’s range of motion and avoid a sudden jarring, the brain will be thrown from the side it is pinned against to the far side at extreme speeds smashing it into the skull and causing the brain to “bounce” back and forth damaging tissue.
5. BUT if the neck muscles are strong and can slow down the head movement before the head reaches the end of it’s range of motion and prevents the sudden stopping of the head, the brain will slowly move back to its proper position in the cranium instead of being smashed against the far side of the skull protecting the brain.