The primary aim of the research is to evaluate whether an alternative model of cystic fibrosis (CF) physiotherapy care can produce statistically significant improvements in clinical and patient reported outcomes, and whether this alternative model is economically advantageous and/or sustainable.

Children randomised to the control group will receive 24-months of current model of CF care at Great Ormond Street Hospital (GOSH).

Children randomised to the intervention group will receive 24-months of current model of CF care at GOSH PLUS a weekly structured, individually prescribed and personally supervised exercise intervention at a local fitness facility or at school. The exercise prescription will include aerobic, anaerobic, strength, core conditioning and stretching components.

The main objectives of the study are:

1. Determine differences, if any, in lung function between the two groups;
2. Determine differences, if any, in exercise capacity between the two groups;
3. Evaluate cost of care of alternate model of care versus current model of care.

Inclusion Criteria:

• Patients with a documented diagnosis of Cystic Fibrosis;
• Male or female aged 6 years or older at baseline and <17years old at the end of the 2-year study;
• Currently under the primary care of the GOSH CF Unit;
• Able to perform Spirometry with a baseline FEV1 percentage predicted of 40% or higher, as measured on at least 3 occasions in the previous year, during times of clinical stability (i.e. not during an exacerbation, and not during or within 2 weeks of intravenous antibiotics);
• The participant's parent or legal guardian must be able to give informed consent; assent will be sought from all children.

Exclusion Criteria:

• Patients who have had lung transplantation;
• Patients listed for lung transplantation;
• Clinically significant disease or medical condition other than CF or CF-related conditions that in the opinion of the multi-disciplinary clinical team, would compromise the safety of the patient;
• Orthopaedic impairment that compromises exercise performance;
• Mental impairment leading to inability to cooperate;
• Unable to understand both verbal and/or written instructions English. Children will need to be able to understand exactly what the physiotherapists are instructing them do, for safe and effective exercise training sessions. Information sheets and questionnaires are only available in English;
• Participants, parents or legal guardians who are unwilling to sign consent to participate in the study.

The following criteria will not exclude a child from participating in the study, but based on the hospital's exercise laboratory's infection control protocol, may preclude the participant from Cardiopulmonary Exercise Testing.

• Patients with Methicillin-Resistant Staphylococcus Aureus;
• Patients with Burkholderia Cepacia.