I started training my neck when training martial arts. I emulated Mike Tyson' routines.
Injuries took me out of the game but I continued training my neck, and powerlifting got it to nearly 17 inches.
In 2015 a newly-minted 19-year-old girl hit me from behind at a claimed 45 mph. I was actually in the damn bike lane.
I tore my sternocleidomastoids, but the left had no morphological changes. The right one is shredded, so my head is permanently left-shifted because of the muscle imbalance.
Same collision to a women or a pencil neck geek would have them in the morgue or on a machine for life.
Train your neck.
TRAIN YOUR NECK.