The tai chi intervention took place twice a week for 12 weeks, and each session lasted for 60 min- utes. Classes were taught by a tai chi master with more than 20 years of teaching experience. In the first session, he explained the theory behind tai

chi and its procedures and provided participants with printed materials on its principles and tech- niques. In subsequent sessions, participants prac- ticed 10 forms from the classic Yang style of tai chi18 under his instruction. Each session included a warm-up and self-massage, followed by a review of principles, movements, breathing techniques, and relaxation in tai chi. Throughout the inter- vention period, participants were instructed to practice tai chi at home for at least 20 minutes each day. At the end of the 12-week intervention, participants were encouraged to maintain their tai chi practice, using an instructional DVD, up until the follow-up visit at 24 weeks.