Chronic Obstructive Pulmonary Disease (COPD)-patients (caused by smoking-level) and Alpha-1-Antitrypsin-deficiency patients showed different developments during rehabilitation in regard to improvement of 6-minute-walking distance. The aim of this study is to investigate differences between training adaptations in COPD-patients and Alpha-1-deficiency patients. Both groups take part in a standardized multimodal 3-week-rehabilitation with strength and endurance training. In addition to conventional diagnostic procedures, muscle biopsies from the M. vastus lateralis will be conducted before and after rehabilitation program followed by biochemical, histochemical and immunohistochemical analysis of the probes.