The human center of gravity is the point where the human body rests under normal conditions without rotating, remaining balanced without active effort to remain upright. An unstable center of gravity requires only a small push to ruin someone's equilibrium, whereas a stable equilibrium is much stronger and can remain stable even under significant force.
The natural center of gravity shifts according to posture, with a lower center of gravity, or CG, creating a stronger balance. Crouching, sitting and kneeling all create a stable CG, making it easy to remain balanced even when pushed by outside factors. Standing upright is less stable, as the CG is higher and easier to unbalance.
Center of gravity is only one part in maintaining balance, with several other factors determining if someone can remain upright. An individual will maintain balance with an increase of friction in their footing or being assisted by special footwear. Someone balancing on a rope or a wooden beam will crouch down to lower their center of gravity, actively equalizing their balance in the process. Individuals with greater mass have a stronger balance due to a more stable center of gravity, requiring less effort to remain upright than shorter or smaller people.