The aim of this study is to evaluate the effects of a partially supervised exercise program on different aspects of physical fitness, despite VO2peak, lung function, quality of life and sleep quality in children, adolescents and adults with Cystic Fibrosis.

There is growing consensus that exercise in subjects with cystic fibrosis (CF) may yield improvements in measures of physical fitness, lung function and quality of life. In most of the training studies exercise capacity was expressed as peak oxygen uptake (VO2peak), which has been found to be one of the best predictors of survival in subjects with CF. Those subjects with a higher VO2peak related to age and gender specific predicted VO2peak (%pred) have a better prognosis than those with a lower VO2peak (%pred). VO2peak represents the cardiorespiratory endurance is one aspect of physical fitness.

Physical fitness may be subdivided into health-related fitness and skill/performance-related fitness. Cardiorespiratory endurance, muscular strength and endurance, body composition and flexibility are often referred to as health-related fitness. Balance, coordination, speed, agility and power are often described as skill/performance related fitness, reflecting the performance aspect of physical fitness. It has been shown, that children and adolescents with a lower skill / performance related fitness are less physical active than those with a higher skill/performance related fitness. This may lead to physically inactive in daily life, less motivation to take part in organized sport and as a consequence to a lower VO2peak.

The primary outcome parameters of this study is to evaluate the effects 12-month partially supervised exercise program on 1) health-related fitness (endurance expressed as maximal workload, muscular strength) and skill / performance related fitness (balance, power, agility)and 2) habitual physical activity (steps / day; intensity expressed in METs) in a large group of subjects with CF. Secondary outcome parameters include forced exspiratory volume in 1 second (FEV1), sleep-wake cycle, quality of sleep, quality of life, and exercise related barriers and barrier management in physical exercise.

In total 100 subjects with CF 6 year and older will be included. Habitual physical activity and sleep will be recorded by accelerometer before subjects enter the exercise program, and after 6 month and after 12 month. Check-ups, lung function measurement and testing of physical fitness will be performed at baseline, after 6 and 12 month.

During the first six month the participants will be contacted by telephone every two weeks. After six month individual counseling by telephone will be stopped.

The exercise program is planned as a "low-threshold exercise program "with low barriers to participate. Participants will be asked about their interests and preferences of sports activities to conceive the exercise program together with the participants. Along with counseling participants will be motivated to increase physical activity by at least 10-20 minutes per day.

The investigators expect to gain another insight into different aspects of physical fitness, habitual physical activity and sleep from the results of this study. Up to know, there are only a few trails investigated different aspects of physical fitness that means balance, flexibility, power as parameters of health-related fitness and skill/performance-related fitness. The investigators assume that participants with higher values are more physical active than those with lower values and these participants will have a higher cardiorespiratory endurance.

Inclusion Criteria:

• Confirmed diagnosis of CF
• Informed consent

Exclusion Criteria:

• Cardiac arrhythmias with exercise
• Patients with cor pulmonale
• Colonization with Burkholderia cenocepacia, Methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Gram-negative (MRGN) pathogens (3 and 4 MRGN)
• Patients with untreated diabetes