Most of the research on tai chi has been done in older individuals in the area of balance and fall prevention. This area of research is important because fall-related injuries are the leading cause of death from injury and disabilities among older adults. One of the most serious fall injuries is hip fracture; one-half of all older adults hospitalised for hip fracture never regain their former level of function. Because tai chi movements are slow and deliberate with shifts of body weight from one leg to the other in co-ordination with upper body movements (sometimes with one leg in the air), it challenges balance and many have long assumed it helps improve balance and reduce fall frequency. This assumption has been credited and strongly supported by some research.
One study compared men age 65 and older who had more than 10 years of experience practising tai chi and no involvement in any other regular sports and physical activity, with similar-aged men who had not practised tai chi or any other physical activities (they were sedentary). It was found that men who studied tai chi performed better on tests of balance, flexibility, and cardiovascular function. In another study involving 22 men and women aged 22 to 76 years with mildbalance disorders, it was found that eight weeks of tai chi training significantly improved function on a standard balance test (called the Romberg test).