Based on the study of Breyer et al. (2010) exploring the effects of a Nordic walk programme on physical activity in patients with COPD in which they show that the Nordic-walk was able to increase physical activity levels after a 3 month programme (movement intensity, 0.4+/-0.14) in comparison to controls (movement intensity, -0.05+/-0.28), for the comparison between S and C considering changes in physical activity levels as the main outcome, for an alpha of 0.05 and beta 0.1, 24 subjects are required per branch to show statistical significant differences with a 90% power. Assuming a 30% dropouts we plan to include 64 subjects (32 patients per branch, S and C).