ObjectiveIt is recommended that cancer survivors incorporate physical activity into their daily lives after in-hospital rehabilitation. However, there is a lack of training programmes focusing on the specific needs of cancer survivors. TriaGO! - an 8-month intervention study of aerobic endurance training for cancer survivors - was therefore examined. The training programme aims to meet the participants’ physical needs and provide socio-emotional support, in the form of an exercise programme that challenges participants to aim to compete in an Olympic- distance triathlon (1,000 m swimming, 45 km cycling, 10 km running) after 8 months’ of training.MethodsThe TriaGO! training programme was provided to in-hospital rehabilitated cancer survivors (n = 12). Each patient invited a healthy friend or family member to train with them (a so called buddy (n = 12)). The 8-month programme involves supervised training sessions, combining cycling, swimming and running, which progress in frequency, duration and intensity. Physical health was measured at the start, 4 and 8 months, using objective parameters of aerobic fitness, muscular fitness and body composition.ResultsA total of 22 out of 24 participants successfully completed the training programme and the triathlon. Both the cancer survivors and their buddies showed significant improvements in physical health. Cancer survivors showed improvements in aerobic fitness, as increases in VO2max and VO2peak of 5.5 ml.kg−1.min−1 and 0.26 ml.min−1 respectively (p <0.0001). Buddies underwent similar significant increases; 5.39 ml.kg−1.min−1 and 0.18 ml.min−1, respectively.ConclusionThe TriaGO! training programme introduces the concept of supervised endurance training for cancer survivors. Through measurement of ob-jective parameters, this study demonstrated that significant physical reconditioning is possible in cancer survivors. A supervised programme would be recommended for all cancer patients after in-hospital treatment, in order to facilitate the transition to incorporation of physical activity into daily life.LAY ABSTRACTFollowing the rehabilitation of cancer survivors in hospital, there is need for training programmes that can be carried out at home, to help patients to incorporate physical activity into their daily lives The aim of this study was to measure the impact of a training programme of supervised physical activity for use after in-hospital rehabilitation. The training programme, designed to meet the physical needs of cancer survivors and provide socio-emotional support. It was offered to a group of 24 cancer survivors and their healthy buddies, with the aim of completing an Olympic-distance triathlon (1 km swimming, 45 km cycling, 10 km running) after 8 months. Supervised training sessions, combining cycling, swimming and running, were provided, increasing in frequency, duration and intensity. During the 8-month training programme the subjects’ physical health was measured 3 times using objective parameters of aerobic fitness, muscular fitness and body composition. Out of 24 participants, 22 successfully completed the training programme and finished the triathlon. The excellent improvements in physical health achieved in this study demonstrate the feasibility of physical reconditioning in cancer survivors.