Quote Originally Posted by exwrestler
I have one of those neck harnesses, and I do 2 sets of 25 reps with a 25 lb plate attached. I incorporate this with my floor work at the end of my boxing work out everytime. Nothing like a strong neck, and while I havent had my first boxing match yet, I know it F#$ing helps to have a strong neck. It did wrestling anyways, one useful thing I've brought from wrestling too, when warming up to loosen up my neck, I balance myself on my neck and walk a 360 on my toes. Strengthens/loosens the neck great. Try it!
Bridging is good for a flexible and strong back, and if done onto your head you can also strengthen your neck. Former champ Kostya Tszyu used to do this exercise and so did a lot of other fighters.

The harness is good too because it allows you to progressively strengthen your neck.

You can also strengthen your neck using a towel. In the end having a big neck helps but by itself isn't going to prevent you from getting knocked out. Look at Tyson for instance, he had a neck like a tree trunk later in career but as he got bigger so did his stance. The record speaks for itself.