Both groups received rehabilitation consisting of 2 sessions per week for 6 weeks with totally identical content except that Tai Chi exercises were incorporated to the TC group.
Each session would last for 1 h and 20 min with 6–10 subjects per session. Upon entering the intervention protocol, all subjects in both groups were required to participate in the 30 min educational session conducted by physiotherapist to improve their knowledge and skills in COPD management. A COPD booklet and home diary would be provided as supplementary materials. The formal pulmonary rehabilitation program in the PRP group would consist of warm up and cool down exercise and aerobic exercises. Patients performed 5 min warm-up exercises. Then, two aerobic activities including treadmill exercise and lower limb ergometry exercise lasting for 20 min each were prescribed. 15 min rest was given between each exercise. After the aerobic exercises, 5 min cool down followed by 15 min of relaxation exercise was conducted before subjects completed that session. In the TC group, the formal pulmonary rehabilitation program was totally identical to the PRP group, except 15 min of Tai Chi exercises was substituted to the 15 min of relaxation exercise. 5 forms of Sun Style Tai chi were taught by Tai Chi accredited physiotherapist for ease of mastery. PRP group was instructed to perform 1 h daily of unsupervised home exercises consisting of 5 min warm up, 5 min of Thera-Band exercises, 30 min of aerobic exercises, 5 min cool down and 15 min of relaxation exercises for 5–7 days a week. Thera-Band exercises, which utilized a rubber-based resistance band known to optimize muscle strengthening exercises, was also taught as home exercises for both groups. The TC group was also instructed to perform 1 h daily of totally identical unsupervised home exercises as the PRP group except for 15 min of Tai chi replacing the relaxation exercises for 5–7 days a week. Both groups were instructed to document home exercises in their compliance diary