International Journal of Pediatrics optimal training mode for CF patients has yet to be deﬁned. Our recommendations (see Table 1) are based on training studies available, as well as, our own clinical and practical experience in the work with children and adolescents with CF. We support the approach of combining endurance and strengthening activities as well as exercises to improve ﬂexibility, balance, and motor skills [7]. In addition to exercise training, an active lifestyle is generally recommended to improve exercise capacity, for example, using stairs instead of an elevator. We therefore recommend including a detailed description of training methods and parameters (duration, intensity, frequency, and rest periods) in future studies. In particular, this may help comparing results of diﬀerent training studies. Despite the beneﬁcial eﬀects of regular (structured) exercise, habitual physical activity levels (activities that can easily incorporated in daily life) have been shown to contribute to the overall health in children with CF. 3. Conclusion Physical activity is well recognized as part of health care and rehabilitation programmes in CF; however the relation- ships between activity, ﬁtness, and health are still poorly understood. Higher levels of habitual activity have been associated with higher aerobic and anaerobic capacity, a better quality of life, and improved survival. However, longitudinal studies are needed to support and justify programmes of regular exercise on the overall health status of children and adolescents with CF. To date, there is no evidence that children and adolescents with CF should not be physically active in daily life. Moreover, as part of their CF management, it would be desirable to inform patients, and their parents about the beneﬁcial eﬀects of exercise, but also its potential risks, and additionally provide patients with training recommendations. Ideally, these would be based on previously performed standard clinical exercise testing. It is necessary to instruct clinicians, health care support staﬀ, patients and parents regarding adequate exercises and sports activities during rehabilitation programmes that can be implemented in normal daily life. Abbreviations CF: Cystic ﬁbrosis CPF: Cardiopulmonary ﬁtness Peak V˙O2: Peak oxygen consumption FEV1: Forced expiratory volume in 1 s FFM: Fat free mass ATP: Adenosine Triphosphate V˙O2: Oxygen consumption peak V˙E: Peak ventilation HR: Heart rate peak HR: Peak heart rate VC: Vital capacity WAnT: Wingate Anaerobic Test BMI: Body mass index CFTR: Cystic ﬁbrosis transmembrane conductance regulator SaO2: Oxygen saturation 5 V˙ E: Expired ventilation V˙ CO2: Volume of carbon dioxide ECG: Electrocardiogram CO2: Carbon dioxide FVC: Forced vital capacity GET: Gas exchange threshold MVV: Maximum voluntary ventilation fR: Respiratory rate PETCO2: End-tidal pressure of carbon dioxide. Competing Interests The authors do not have any competing interests to declare. References [1] R. M. Malina, C. Bouchard, and O. Bar-Or, Growth, Matura- tion, and Physical Activity, Human Kinetics, Champaign, Ill, USA, 2nd edition, 2004. [2] R. J. Shepard, Aerobic Fitness and Health, Human Kinetics, Leeds, UK, 1994. [3] S. R. Boas, “Exercise recommendations for individuals with cystic ﬁbrosis,” Sports Medicine, vol. 24, no. 1, pp. 17–37, 1997. [4] T. Radtke, D. Stevens, C. Benden, and C. A. Williams, “Clinical exercise testing in children and adolescents with cystic ﬁbrosis,” Pediatric Physical Therapy, vol. 21, no. 3, pp. 275–281, 2009. [5] M. Barker, A. Hebestreit, W. Gruber, and H. Hebestreit, “Exercise testing and training in German CF centers,” Pediatric Pulmonology, vol. 37, no. 4, pp. 351–355, 2004. [6] D. Stevens, P. J. Oades, N. Armstrong, and C. A. Williams, “A survey of exercise testing and training in UK cystic ﬁbrosis clinics,” Journal of Cystic Fibrosis. In press. [7] W. Gruber, D. M. Orenstein, K. M. Braumann, and G. Hu¨ls, “Health-related ﬁtness and trainability in children with cystic ﬁbrosis,” Pediatric Pulmonology, vol. 43, no. 10, pp. 953–964, 2008. [8] H. Hebestreit, S. Kieser, S. Junge et al., “Long-term eﬀects of a partially supervised conditioning programme in cystic ﬁbrosis,” European Respiratory Journal, vol. 35, no. 3, pp. 578– 583, 2010. [9] P. H. Klijn, S. W. Terheggen-Lagro, C. K. Van der Ent, J. Van der Net, J. L. Kimpen, and P. J. Helders, “Anaerobic exercise in pediatric cystic ﬁbrosis,” Pediatric Pulmonology, vol. 36, no. 3, pp. 223–229, 2003. [10] A. J. Moorcroft, M. E. Dodd, J. Morris, and A. K. Webb, “Individualised unsupervised exercise training in adults with cystic ﬁbrosis: a 1 year randomised controlled trial,” Thorax, vol. 59, no. 12, pp. 1074–1080, 2004. [11] A. Turchetta, T. Salerno, V. Lucidi, F. Libera, R. Cutrera, and A. Bush, “Usefulness of a program of hospital-supervised physical training in patients with cystic ﬁbrosis,” Pediatric Pulmonology, vol. 38, no. 2, pp. 115–118, 2004. [12] K. Wassermann, J. E. Hansen, D. Y. Sue, R. Casaburi, and B. J. Whipp, Principles of Exercise Testing and Interpretation, Lippincott Williams & Wilkins, Philadelphia, Pa, USA, 3rd edition, 1999. [13] J. Bradley and F. Moran, “Physical training for cystic ﬁbrosis,” Cochrane Database of Systematic Reviews, no. 1, Article ID CD002768, 2008.