Physical activity is considered to be an effective strategy to improve children’s health and reduce the risk of developing chronic diseases;​ osteoporosis and obesity being two examples with particularly high morbidity and increased mortality. An exercise program to improve both bone and reduce fat would be ideal. Problematically, bone is known to respond primarily to brief bouts of high-impact activity, while the traditional exercise recommendation to reduce fat is longer duration, low to moderate intensity aerobic activity. The overall aim of the current work was to develop a novel exercise program for pre and peripubertal children to improve bone and minimise the accumulation of fat.

The thesis describes four studies, presented as two published manuscripts, one in press and another under review. In the first study, we conducted a comprehensive systematic review, to determine the effects of previous bone-targeted exercise interventions on bone, muscle and fat in school-age children. Meta-analyses were conducted to quantify the findings of the sixteen studies included in the review. We concluded that improvements in fat have previously been observed as secondary benefits of bone-targeted in-school exercise programs.

The subsequent study, described in papers two and three, examined the CAPO Kids exercise program, which was specifically designed to improve indices of musculoskeletal, cardiovascular and metabolic health, and physical performance of pre and peripubertal boys and girls. The program was a nine-month, cluster randomised controlled exercise intervention, incorporated into the school schedule of Year 5 and 6 students three times per week, for ten minutes per session. Activities comprised high-intensity jumping and capoeira, a Brazilian sport that combines martial arts with dance. A range of health outcomes were examined before and after the 9-month program. We found that the CAPO Kids program improved parameters of bone and metabolic health including heel bone quality, waist circumference, estimated maximal oxygen consumption and resting heart rate.

The final study was an observational examination of the metabolic and mechanical loads associated with the CAPO Kids activities. We determined energy expenditure during the 10- minute CAPO Kids session, and ground reaction forces of eleven CAPO Kids manoeuvres, in a sub-group of participants. We confirmed that the CAPO Kids program generates metabolic and mechanical loads of a magnitude that are typically recommended to promote healthy adaptations in fat and bone.

Overall, the current thesis demonstrates the potential for simultaneous benefits of the CAPO Kids program to both musculoskeletal and metabolic systems of pre and peripubertal children. Furthermore, CAPO Kids was a simple, appealing and feasible program, able to be implemented during school time, without disrupting the normal academic schedule. Based on those findings, we conclude that future translation of brief high intensity impact exercise programs into the broader school system holds promise for paediatric health and chronic disease prevention.