Zuniga, J., Berg, K., Noble, J., Harder, J., Chaffin, M., & Hanumanthu, S. H. (2008). Physiological responses and role of VO2 slow component to interval training with different intensities and durations of work. ACSM 55th Annual Meeting Indianapolis, Presentation Number 1277.

This study compared four interval training sessions with different intensities and durations of work in order to determine the effect on mean VO2, total VO2 (liters per minute) for the exercise session, and duration of exertion at 90% maximum work rate, and the effects on biomarkers of fatigue such as blood lactate concentration and rating of perceived exertion. A secondary objective was to determine the extent that the VO2 slow component plays in the total oxygen demand of IT. Male and female triathletes (N = 12) performed four different interval training protocols on a cycle ergometer with different intensities and durations of work. VO2 was measured every 30 seconds. Heart rate (HR) and rating of perceived exertion were measured at the end of every resting and work period, and blood lactate concentration was measured every 10 min during the interval training session.

The 90% maximum work rate sessions produced higher values for total VO2 and total time completed for each session when compared to 100% of maximum work rate sessions. The 30-seconds interval durations (30 seconds work and 30 seconds rest) produced higher values for total VO2, total time completed for each session, mean VO2 (ml/kg/min) and heart rate and lower blood lactate concentration when compared to the 3-minute (3 minutes work and 3 minutes rest) interval durations. All interval training protocols showed a significant rise of VO2 (VO2 slow component) across the duration of each interval training session.

Implication. Short duration not quite maximal intensity interval training sessions facilitate performing the greatest volume of work and stimulation of oxygen transport system factors. Intervals of 30-30 seconds allowed athletes to perform a longer session, with a higher total and mean VO2 and heart rate and lower blood lactate concentration than 3-3 minutes duration. Exertion at 90% maximum work rate facilitated longer sessions with a higher total VO2 than did 100% intensity. All protocols showed a slow component effect in the total oxygen demands of IT.

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