One study took adults who practiced tai chi three times a week for 12 weeks (60-minute classes). These adults were given a battery of physical-fitness tests to measure balance, muscular strength and endurance, and flexibility before and after the 12 weeks. After just six weeks, statistically significant improvements were observed in balance, muscular strength, endurance, and flexibility measures. Improvements in each of these areas increased further after 12 weeks. The authors of the study concluded that tai chi is a potent intervention that improved balance, upper- and lower-body muscular strength and endurance, and upper- and lower-body flexibility in adults.
Individuals who practiced tai chi for one year had higher aerobic capacity than sedentary individuals around the same age. The authors state that tai chi may be an additional form of aerobic exercise.