The effects of heavy continuous versus long and short intermittent aerobic exercise protocols on oxygen consumption, heart rate, and lactate responses in adolescents.

This study compared the physiological responses to heavy continuous (HC), short-intermittent (SI), and long-intermittent (LI) treadmill exercise protocols in non-endurance adolescent males. Nine adolescents (14 +/- 0.6 years) performed a maximal incremental treadmill test followed, on separate days, by a SI [30 s at 110% of maximal aerobic velocity (MAV) with 30 s recovery at 50%], a LI (3 min at 95% of MAV with 3 min recovery at 35%), and a HC (at 83% of MAV) aerobic exercise protocol. VO(2) and HR were measured continuously, and blood samples were obtained prior to and after the protocols. The duration of exercise and the distance covered were longer (p < 0.05) in HC and LI versus SI. All participants reached 80 and 85% of VO(2)peak irrespective of the protocol, while more participants reached 90 and 95% of VO(2)peak in the intermittent protocols (9 and 6, respectively) versus HC (5 and 3, respectively). The time spent above 80 and 85% of VO(2)peak was higher in HC and LI versus SI; the time above 90% was higher only in LI versus SI, and the time above 95% was higher in LI versus HC and SI. The total VO(2) consumed was greater in HC and LI versus SI. Lactate was higher after LI versus HC. In conclusion, when matched for exhaustion level, LI is more effective in stimulating the aerobic system compared to both HC and SI, while HC aerobic exercise appears equally effective to SI. Nevertheless, adolescents have to exercise for a longer time in HC and LI to achieve these effects.