Assessing Functional Capacity in Directly and Remotely Monitored Home-based Settings: A Protocol for a Multinational Validation Study in Individuals With Chronic Respiratory Diseases

The goal of this validation study is to provide further evidence of the metrological properties of the 6-minute stepper test in individuals with chronic obstructive pulmonary disease (COPD) or interstitial lung disease (ILD). The main questions it aims to answer are: 1. Is the 6-minute stepper test valid when compared to the 6-minute walk test and a maximal cardiopulmonary cycling test? 2. Does the 6-minute stepper test give the same results when conducted through direct (i.e., therapist in person) and remote (i.e., videoconferencing) monitoring? 3. Is the 6-minute stepper test safe when conducted at the home of the individual with direct (i.e., therapist in person) or remote (i.e., videoconferencing) monitoring? Participants will: * Conduct the 6-minute stepper test (several trials on separate days) * Conduct the 6-minute walk test (1 trial on 1 day) * Conduct a maximal cardiopulmonary test on a cycle ergometer (1 trial on 1 day) * Participate in a semi-structured interview to provide their feedback with regards to the 6-minute stepper test