Effectiveness of Tai Chi for people with chronic obstructive pulmonary disease (COPD)

INTERVENTION: Sun‐style Tai Chi exercise training Short form Sun‐style Tai Chi is a low‐impact exercise which involves both upper and lower limb. This form consists of 21 moves in total and it was designed by Dr Lam, who is a general physician and Tai Chi master in Australia. The duration of the course is 12 weeks (2 times per week for 12 weeks, about 1 hour each time) Assessments, for exercise capacity, muscle strength, balance and health related quality of life, will be performed at baseline and also after 12 weeks Tai Chi training CONDITION: chronic obstructive pulmonary disease (COPD) PRIMARY OUTCOME: exercise capacity ‐ measured by the edurance shuttle walking test SECONDARY OUTCOME: balance ‐ measured by a series of balanace tests including semi‐tandem and tandem standing, walking, sit to stand, single leg stance and functional reach test health related quality of life ‐ measured by chronic respiratory disease questionnaire Lung function, lung volume and diffusion capacity ‐ measured by full lung function test subjective physical performance ‐ measured by functional performance inventroy questionnaire the acceptance of Tai Chi ‐ measured by a subjective feedback questionnaire INCLUSION CRITERIA: mild to severe COPD