What is axial loading?

An axial load is a force administered along the lines of an axis.

This is typically used to describe an injury in which there is compression of the spine from the head, such as when a person dives head first into shallow water and hits the top of his head on the bottom. This frequently causes fractures of the spine and possibly spinal cord injury.

It is also commonly used to describe a specific strength of materials known as their uniaxial compressive or tensile strength and also to find the variation of their strength with increasing confining pressure (as used in triaxial testing).