Changes in fitness are associated with changes in body composition and bone health in children after cancer

Aim: This study examined the effects of physical activity on the fitness, body composition and mental health of children after cancer or bone marrow transplantation. Methods: We focused on 22 children aged from seven to 14 years who had received chemotherapy and/or bone marrow transplantation in our medical centre. Ten children took part in a six-month exercise programme, and 12 children who did not exercise formed the control group. At baseline and at the end of the trial, we measured aerobic fitness, body composition, bone density and assessed the child's mood and quality of life. We pooled all participants together post hoc to compare changes in fitness with the various study outcomes. Results: We found no differences between groups in changes in fitness, body composition or mental health indices. Significant correlations were found between changes in aerobic fitness and changes in lean body mass (r = 0.74, p = 0.002), bone mineral content (r = 0.57, p = 0.026) and femoral neck bone mineral density (r = 0.59, p = 0.027) in all participants. Conclusion: Group-based exercise training did not improve aerobic fitness in children after cancer or bone marrow transplantation. However, changes in fitness throughout the study period were associated with changes in body composition and bone health in all participants.