When examining RCTs and NRCTs there were very small to small improvements in all body composition outcomes relative to controls (SMD range 0.05 0.36). all of which were statistically significant except for fat mass and lean/fat-free mass (Fig. 2). In comparison, UCTs yielded generally more favourable effect sizes: small to moderate reductions in mass (SMD t 95% CI 0.18 t 0.14). BMI (SMD 0.32 t 0.14). percentage body fat (SMD 0.53 t 0.13) and fat mass (SMD 0.42 t 0.23) Further examination of both study designs shows sig- nificant heterogeneity for BMI (UCTs), percentage body fat (RCTs/NRCTs and UCTs) and fat mass (UCTs) (Fig. 2). There was no significant heterogeneity when the following subgroup analyses were performed: intervention types (BMI, percentage body fat and fat mass), age groups BMI and fat mass (less than 12 years) and training vol- ume IBMI (less than 25 and 25-50 h). percentage body fat less than 25 h) and fat mass (all subgroups)