Benefits of Tai Chi
Muscle strength. Tai chi can improve both lower-body strength and upper-body strength.
“Tai chi strengthens both the lower and upper extremities and also the core muscles of the back and abdomen.”
Flexibility. Tai chi can boost upper- and lower-body flexibility as well as strength.
Balance. Tai chi improves balance and, according to some studies, reduces falls. Proprioception — the ability to sense the position of one’s body in space — declines with age. Tai chi helps train this sense, which is a function of sensory neurons in the inner ear and stretch receptors in the muscles and ligaments. Fear of falling can make you more likely to fall; some studies have found that tai chi training helps reduce that fear.
https://www.health.harvard.edu/staying-healthy/the-health-benefits-of-tai-chi
Gathering energy in navel allows it to be stored and then shared with the vital organs.
From The Taoist Soul Body, by Mantak Chia