Especially keeping the head in balance is an important function of the neck muscles. An average head weighs roughly 4.2 kilos; this doesn’t seem that much, but try to tilt 4.2 kilos in front of your body with stretched arms. That’s going to be pretty difficult!
Neck muscles have to be well adjusted to each other. If you bend your head forward, the muscles on the front will have to tighten and the muscles on the back will have to relax.
To hold your head up, you have to tighten your muscles with the same strength, otherwise your head will fall back or forwards.For all of this you’ll need good muscle coordination. They work together as a team and when one doesn’t function as it should, the whole team doesn’t function.