The purpose of this study was to investigate the effects of two, three times a week, 8-week training programmes on the aerobic power and anaerobic performance of 30 prepubescent girls, with a mean age of 9.6 y. Peak oxygen uptake assessed by an incremental discontinuous treadmill test, and peak power in 5 s and mean power over 30 s estimated from a Wingate anaerobic test were used as the criterion measures. Twelve girls trained using a continuous cycle ergometer programme, 11 girls followed a sprint running programme and the control group consisted of 7 girls. Both training groups significantly (p < 0.05) increased their peak oxygen uptake and peak power in 5 s. However, the increase reported here are lower than those generally observed in adolescents following training. The control group demonstrated no significant (p > 0.05) change in either variable. No significant (p > 0.05) changes in mean power over 30 s were observed in any group.