Improving aerobic power in primary school boys: a comparison of continuous and interval training

The purpose of this study was to assess whether the magnitude of change in aerobic power was different in boys (mean age 10.25 +/- 0.50 y) who followed a high-intensity interval training protocol, compared to those who followed a moderate-intensity continuous training protocol. Boys were assigned to either a control group (n = 15), a continuous training group (n = 10), or an interval training group (n = 10). They completed peak oxygen uptake tests at baseline and following an 8-week training period. The control group continued with normal activity habits, whilst the continuous training group followed a 20-minute steady-state cycle protocol at 80-85 % of the maximal heart rate, and the interval training group completed 30-s sprints on a cycle ergometer, interspersed with active rest periods. The two training protocols were designed to incur similar cardiovascular work over the 20 minutes of each training session. Significant increases (p < 0.05) in peak oxygen uptake were noted for both the interval and continuous training groups. The interval training group showed marked pre- to post-increases in both peak oxygen pulse, oxygen pulse at the ventilatory threshold, and ventilatory threshold that were not apparent in the continuous group boys. It would appear that a high-intensity interval protocol confers a different training effect in comparison to continuous steady-state training in boys. Possible mechanisms that underpin these adaptations may include increased blood volume and a concomitant adjustment in stroke volume.