This trial aims to analyze whether the resistive inspiratory manoeuvre (RIM) performed previously to autogenic drainage (AD) technique improves the effectiveness in terms of mucus clearance during a typical bronchial drainage session in adults, stable CF patients.

It is a multicenter study. 4 different Spain Cystic Fibrosis Foundations are included in the study (Madrid, Valencia, Murcia and Aragón). All patients will perform three different arms of treatment in a crossover randomization. Each arm of treatment will be apply only in one session. The wash-out period will be one week. Before starting the trial, all patients will perform a control session without any intervention, only the outcome measures will be assess.

During the study period the patients' pharmacological treatment remained unchanged

Inclusion Criteria:

• Cystic Fibrosis (CF) diagnosed ( established by genotype or sweat sodium>70 mmol/l or sweat chloride of>60 mmol/l)
• Clinically stable at time of study entry (defined as no requirement for antibiotics or change in respiratory medication in the preceding 4 wk);
• Chronic sputum production, at least ≥ 15 ml /24h
• Familiar and trained in the use of autogenic drainage technique (at least 6 months) and resistive inspiratory manoeuvre (at least three previous sessions)
• To be able to provide written, informed consent

Exclusion Criteria:

• Lung function: Forced expiratory volume in 1 second < 30 % pred . ; Forced vital capacity < 40 % pred.
• Active haemoptysis during the previous month
• Supplemental oxygen or non-invasive ventilation (NIV)