1 Faculty of Kinesiology and Rehabilitation Sciences, Department of Rehabilitation Sciences, Research Group for Rehabilitation in Internal Disorders, Leuven, Belgium; Clinical Department of Respiratory Diseases, UZ Leuven, BREATHE Department CHROMETA, Leuven, Belgium. Electronic address: daniel.langer@kuleuven.be.
2 Faculty of Kinesiology and Rehabilitation Sciences, Department of Rehabilitation Sciences, Research Group for Rehabilitation in Internal Disorders, Leuven, Belgium; Clinical Department of Respiratory Diseases, UZ Leuven, BREATHE Department CHROMETA, Leuven, Belgium.