The aim of the present study was to show if the use of continuous-running training vs. intermittent-running training has comparable or distinct impact on aerobic fitness in children. At first, children were matched according to their chronological age, their biological age (secondary sexual stages), and their physical activity or training status. Then, after randomization 3 groups were composed. Sixty-three children (X 9.6 +/- 1.0 years) were divided into an intermittent-running training group (ITG, 11 girls and 11 boys), a continuous-running training group (CTG, 10 girls and 12 boys), and a control group (CG, 10 girls and 9 boys). Over 7 weeks, ITG and CTG participated in 3 running sessions per week. Before and after the training period, they underwent a maximal graded test to determine peak oxygen uptake (peak VO2) and maximal aerobic velocity (MAV). Intermittent training consisted of short intermittent runs with repeated exercise and recovery sequences lasting from 5/15 to 30/30 seconds. With respect to continuous training sessions, repeated exercise sequences lasted from 6' to 20'. Training-effect threshold for statistical significance was set at p < 0.05. After training, peak VO2 was significantly improved in CTG (+7%, p < 0.001) and ITG (+4.8%, p < 0.001), whereas no difference occurred for the CG (-1.5%). Similarly, MAV increased significantly (p < 0.001) in both CTG (+8.7%) and ITG (+6.4%) with no significant change for CG. Our results demonstrated that both continuous and intermittent-running sessions induced significant increase in peak VO2 and MAV. Therefore, when adequate combinations of intensity/duration exercises are offered to prepubertal children, many modalities of exercises can successfully be used to increase their aerobic fitness. Aerobic running training is often made up of regular and long-distance running exercises at moderate velocity, which causes sometimes boredom in young children. During the developmental years, it seems therefore worthwhile to use various training modalities, to make this activity more attractive and thus create conditions for progress and enhanced motivation.