3. Maximum inspiratory and expiratory pressures (PInmax and PExmax). Completion of these Specific Objectives will position our research group to conduct future studies of 1) mechanisms of exercise limitation and 2) antioxidant therapies, both in this defined population and those who are at risk of developing pulmonary fibrosis. The long term impact of this application is thus to develop effective pulmonary rehabilitation strategies for IPF patients, based on knowledge of underlying changes in oxygen metabolism and oxidant stress.