A Randomized Study of the Effects of T\'ai Chi on Muscle Strength, Bone Mineral Density, and Fear of Falling in Women with Osteoarthritis.

Abstract Purpose: Individuals with osteoarthritis can experience difficulty walking and poor strength, possibly leading to falls and fractures. Exercise has been found to increase strength and bone mineral density. The purpose of this study was to determine the effects of 6 months of t\'ai chi on knee muscle strength, bone mineral density, and fear of falling in older women with osteoarthritis. Methods: Eighty-two (82) women with osteoarthritis, recruited from outpatient clinics and community health centers, were randomly assigned to either a t\'ai chi group and took part in a t\'ai chi program, or a control group. Of these, 30 subjects (mean age = 63 years) in the t\'ai chi group and 35 (mean age = 61 years) in the control group completed post-test measures at 6 months. Results: After the 6-month study period, subjects in the t\'ai chi program had significantly greater knee extensor endurance (pre- to post-test mean increase = 36.4 W/kg, versus 1.1 W/kg for the controls), and significantly greater bone mineral density in the neck of the proximal femur (mean change = 0.09, versus -0.10 for the controls), Ward\'s triangle (mean change = 0.04, versus -0.04 for the controls), and trochanter (mean change = 0.07, versus -0.05 for the controls) than the controls. However, knee extensor and flexor strength did not differ significantly between the groups. The fear of falling during daily activities reduced significantly more in the t\'ai chi group (mean change = -2.40, versus 0.66 for the controls). Conclusions: T\'ai chi increased knee extensor muscle endurance and bone mineral density in older women with osteoarthritis, and decreased their fear of falling during daily activities. Further study with long-term follow-up is needed to substantiate the role of t\'ai chi exercise in the prevention of fall and its related fracture.