Physical Activity and Fibrosing Interstitial Lung Disease

60 patients with fibrosing interstitial lung disease will be included in this study. Initial assessments at the beginning will be conducted for an overview of initials abilities and divided in 3 sessions. The first session (day 1) patients will be tested on maximal cardiopulmonary exercise testing with different devices to evaluate oxygen transport, and on different functional tests like 6minute walk test, sit to stand test, .. The second session (day 6) is composed by respiratory tests like spirometry, plethysmography and diffusing capacity of nitric oxyde and carbon monoxyde at rest and exercise. The last session, one week after the first (day 9), patients will performed a maximal cardiopulmonary treadmill testing, strength testing and physical activity questionnaire. Between day 1 and day 9, patients will be asked to wear an accelerometer to quantify daily physical activity and completed quality of life questionnaire. Then, patients will be randomised in control group (concentric cycling) and experimental group (eccentric cycling). They will be trained 3 times/week during 12 weeks at the same intensity, verified by gas exchange analysis (50 à 70% VO2reserve). The training is composed of aerobic training (eccentric or concentric cycling according to randomisation), muscle training and adapted sports. All assessments of the beginning will be also conducted after 12 weeks of training (3 months after inclusion) to study impact of training and between groups to compare the two cycling modalities in this population. To allow a follow-up after training, all assessments will be conducted 6 and 12 months after the inclusion.