Even when receiving optimal medical treatment, individuals with chronic obstructive pulmonary disease (COPD) commonly experience daily symptoms of dyspnoea and fatigue [1,2]. Consequently exercise intolerance may render activities of daily life problematic, leading to a downward spiral in which there is a progressive reduction in physical activity [3][4][5][6][7][8]. Thus, individuals with COPD can end up in a vicious circle of physical deconditioning, including loss of lower limb muscle mass and strength, loss of balance and osteoporosis [8][9][10][11].In the past 20 years, pulmonary rehabilitation has become an integrated part of the management of individuals with moderate to very severe COPD [12,13]. Pulmonary rehabilitation, defined as an evidence-based, multidisciplinary and comprehensive intervention for patients with chronic respiratory diseases who are symptomatic and often have decreased daily life activities, is designed to reduce symptoms, optimise functional status and increase participation in activities of daily living [14]. Pulmonary rehabilitation, which usually involves an initial assessment, exercise training, education and behaviour change, is safe and effective in individuals with COPD [14][15][16]. Indeed, improvements in health-related quality of life, functional mobility and lower limb muscle function have been reported [17]. Exercise training is the cornerstone of pulmonary rehabilitation and mostly consists of aerobic exercises (stationary cycling, treadmill walking and/or ground walking) in combination with muscle strengthening exercises (resistance training and/or transcutaneous neuromuscular electrical stimulation) [14,15,18,19].T'ai chi is a traditional Chinese form of conditioning exercise derived from martial arts. When practised correctly, t'ai chi is thought to strengthen the body's vital energy and enhance the passage of this energy throughout the body to confer its healthpromoting effects. T'ai chi has spread worldwide as improvements in physical and emotional functioning have frequently been reported in older adults [20] [25] present new insights into the effects of Sun-style t'ai chi in individuals with COPD. 42 individuals with COPD were randomly assigned to a usual care control group or a twice weekly supervised Sun-style t'ai chi training in combination with an unsupervised, home-based t'ai chi training programme (including a t'ai chi training booklet and DVD) on the remaining 5 days a week (30 min per day) for a total duration of 12 weeks. Improvements in lower limb muscle function, balance, functional exercise performance, health-related quality of life and mood status following Sun-style t'ai chi were significantly better compared to the usual care control group. Indeed, the mean differences between groups in changes in incremental shuttle walk distance, endurance shuttle walk time, and health-related quality of life questionnaire scores exceeded the minimal important difference of 47.5 m, 186 s or 0.5 points per question, respectively [26][27][28]. Interestingly, indiv...