Adding short sprints to exercise at Fatmax: implications for acute energy balance and enjoyment in overfat boys

[Truncated abstract] It is well established that exercise plays an important role in the prevention and management of obesity in children, but the optimal type of exercise to achieve this is not known. Recent research suggests that training at a specific low-moderate exercise intensity that maximises fat oxidation (Fatmax) may be favourable for fat loss and easily adhered to. However, higher intensity exercise results in increased energy expenditure per unit of time which is more likely to invoke a negative energy balance with a lower time investment. One of the major concerns with prescribing continuous high intensity exercise to individuals carrying excess body fat is that they may not adhere to a long-term training program, due to feelings of discomfort and displeasure. Interestingly, when children are observed during spontaneous physical activity or free-play, they most commonly engage in unstructured games or sports that require multiple short sprint efforts of 3-4 sec in duration, interspersed with longer duration low-moderate intensity exercise. This nature of exercise may be simulated by sprint interval exercise to provide a means of increasing the intensity of exercise whilst keeping the exercise enjoyable, in order to maximise the energy expenditure of paediatric-specific exercise training protocols. The research presented in this thesis explores the acute influence of adding short, maximal sprint efforts to continuous exercise at Fatmax on energy expenditure and fat oxidation (during and post-exercise), post-exercise energy intake and enjoyment in boys. A preliminary aim was to determine whether there is potential for a single graded exercise protocol with 3-min stages to be utilised for the estimation of Fatmax in boys carrying excess body fat (overfat). A single graded exercise test is the most commonly utilised technique for estimating Fatmax in adults and children, but no research has validated its use in an overfat paediatric population.