Cystic fibrosis (CF) is an autosomal recessive genetic disease characterized by recurrent airway infections, affecting many systems including lung, pancreas and sweat glands. Cough is an important defense mechanism for clearing the secretions that increase in respiratory diseases. There have been studies investigating the effect of expiratory muscle training on disease groups such as chronic obstructive pulmonary disease, multiple sclerosis, parkinson's disease, and the elderly and healthy individuals. Studies that evaluating effects of expiratory muscle training in cystic fibrosis are limited in the literature. The aim of this study was to evaluate the effect of cough strength in children and adolescents with CF and the effect of expiratory muscle training program on cough strength, exercise capacity, respiratory muscle strength and quality of life.

Inclusion Criteria:

• Diagnosed with cystic fibrosis
• 8-18 years
• Clinically stable during last six weeks

Exclusion Criteria:

• hemoptysis
• low saturation (SpO2<90%)
• acute lower respiratory tract infection
• cardiac problems (heart failure, arrhythmia, cardiomyopathy, etc.)
• cognitive problems
• pneumothorax