Molecules and Neck Protection.

Polymer molecules in human tissue can resist bending forces similar to the bending elasticity of flexible beams.

This means the molecules linked together in your muscle tissue bend similarly to 2x4s!

A polymer is just a large molecule made by the covalent linking of multiple identical or similar monomers together.

Monomers are the small molecules, the building blocks, the subunits, of polymers

Covalent bonds are the stable chemical links between atoms. Atoms linked by two or more covalent bonds cannot rotate around the bond axis. This becomes the major influence of the molecule's three dimensional shape and stability.

This is why we have a particular form or shape, or look like we do.

Once bent, pulled, or squeezed, molecules try to drift back to their
equilibrium distribution. The configurations of molecules in cells are
not randomized moment to moment. Once in one configuration, a molecule
tends to stay in that same configuration. Cells are not disordered.

The behavior of the polymer is this:

In the absence of an externally applied force, a 'bump', pull, squeeze, or bend, entropy
drives a long polymer into a compact form. Like a ball of loose string
the polymer may in fact look springy.

Once pulled, bent, squeezed, sheared or with some hydrodynamic force the polymer becomes extended.

When the force is removed the polymer chain returns to the more favorable compact form. Hence there is a dissipation of force and polymers are called entropy springs.

Take one hand, push quickly and forcefully on the side of your other bicep. The force dissipates down into the forearm up into the shoulder and some out into the universe as heat. When you
release the hand the bicep springs back. Your molecules turn your bicep
back into its original form.

The deformation of a beam is usually expressed in terms of its deflection from its original unloaded position. The deflection is
measured from the original neutral surface of the beam to the neutral
surface of the deformed beam. The configuration assumed by the deformed
neutral surface is known as the elastic curve of the beam.

Adding more material to the beam, or trussing the beam, you are reducing the deformation caused by a given force.
Adding more muscle tissue to the neck means you are adding more polymers and therefore more
entropy springs. This way, when there is a collision, with the added
muscular material it means your neck is now capable of dissipating more
force,and reducing deformation.