A study from Springfield College in Massachusetts showed that T’ai Chi is an ideal exercise for a person with arthritis (Journal of the American Geriatrics Society, 2000, Vol 48, Iss 12, pp 1553-1559).
The ends of bones where they come together at joints are soft so they have to be protected by a thick white gristle called cartilage. Arthritis occurs when cartilage is damaged, and once damaged, cartilage cannot heal.
People with arthritis should exercise to strengthen their muscles. This helps to stabilize their joints so they are not so loose that every movement chips off more cartilage. Exercises that put hard force on joints break cartilage, so the best exercise for people with arthritis is one that strengthens muscles without applying great force on joints. In T’ai Chi, a person moves very slowly for extended periods of time. Slow movements put great force on muscles to cause significant gain in strength without putting much force on joints.