There isn't really any such thing as regular yoga. I do know that in the US, many people associate yoga with hatha yoga, which usually means that the focus is on the building blocks of poses and on stretching-type poses.
Inertia is resistance to change. You hate looking at people's feet and yet you stay in your job as a shoe salesman year after year.
The definition of inertia is when an object remains still or moves in a constant direction at a constant speed. Inertia will continue unless the object meets some external force. The more inertia an object has, the less the object will change its motion when it meets another force. The ground is the force, the motion, that causes the object to no longer have inertia and to instead stray from its speed and direction.