Safety and Feasibility of High-intensity Interval Training Program in CF Patients

"* Rehabilitation stay in hospitalization with 18 days of training sessions~* Training on an ergometer~* Sessions supervised by an Adapted Physical Activities (APA) teacher or a physiotherapist~ * Control group: 5 times / week; continuous work 20 to 30 min; around the 1st aerobic ventilation threshold~ * Intervention group: 2 times / week: maintenance sessions + 3 times / week: IHTI sessions - alternating 30s work / 30s rest repeated 6 times; at 60% of the maximum heart rate at the 1st session then increase as fast and large as possible"