The physical body is constantly subject to the forces of gravity, which is a good thing since gravity keeps us connected to the Earth. However, gravity exerts a huge amount of pressure on the body, causing it to droop, sag and compress, which can lead to joint pain, reduced breath capacity and decreased digestion.
The main thing that holds you up against the forces of gravity are your bones. The Skeletal System forms the scaffolding of your physical body. (They also protect your internal organs and make red blood cells). The Skeletal System is designed so your bones can stack up on one another, so you can stand up vertically, against the forces of gravity, with minimal energy or effort.
If your bones are properly aligned, you are able to stand your ground with little effort, transmuting the forces of gravity down your body and into the grounding quality of Earth. If your bones are not properly aligned, mainly due to tightened musculature, you will need to use extra energy & muscles to support yourself.
If the BodyMind complex has the experience of needing to exert a lot of energy simply to stand up, the subconscious mind forms the belief that life is hard and that it takes a lot of effort & energy simply to exist. This belief diminishes the vitality of the Root Chakra and minimizes the spirits ability to expand into higher realms of consciousness.