The connective tissue of the human body is like the lattice that goes on the top of a garden fence, the type that opens up to reveal diamond spaces between the wood and closes up to a straight line. When connective tissue is unhealthy or has been subject to the type of forces that make it close up into a straight line the connective tissue can get stuck in this closed position.
In a healthy state connective tissue is able to open up to reveal the diamond spaces of the lattice, which further show a 3 dimensional honeycomb structure within each diamond that fills with fluid like hyaluronic acid. The basic fluids of the body act as natural lubricants to the body tissues and need motion to spread the fluids around. Thus motion is lotion.
When motion is not lotion then motion becomes degeneration, in my opinion.