PHYSIOLOGICAL RESPONSES DURING INTERVAL TRAINING WITH DIFFERENT INTENSITIES AND DURATION OF EXERCISE

Zuniga, JM, Berg, K, Noble, J, Harder, J, Chaffin, ME, and Hanumanthu, VS. Physiological responses during interval training with different intensities and duration of exercise. J Strength Cond Res 25(5): 1279-1284, 2011-The purpose of this study was to compare 4 interval training (IT) sessions with different intensities and durations of exercise to determine the effect on mean <(V)over dot>o(2), total <(V)over dot>o(2), and duration of exertion >= 95% maximum power output (MPO), and the effects on biomarkers of fatigue such as blood-lactate concentration (BLC) and rating of perceived exertion. The subjects were 12 recreationally competitive male (n = 7, mean 6 SD age = 26.2 +/- 3.9 years) and female (n=5, mean +/- SD age = 27.6 +/- 4.3 years) triathletes. These subjects performed 4 IT sessions on a cycle ergometer varying in intensity (90 and 100% MPO) and duration of exercise (30 seconds and 3 minutes). This study revealed that IT using 30-second duration intervals (30-30 seconds) allows the athlete to perform a longer session, with a higher total and mean <(V)over dot>o(2) HR and lower BLC than 3-minute durations. Similarly, submaximal exertion at 90% of MPO also allows performing longer sessions with a higher total <(V)over dot>o(2) than 100% intensity. Thus, the results of the present study suggested that to increase the total time at high intensity of exercise and total <(V)over dot>o(2) of a single exercise session performed by the athlete, IT protocols of short durations (i.e., 30 seconds) and submaximal intensities (i.e., 90% MPO) should be selected. Furthermore, performing short-duration intervals may allow the athlete to complete a longer IT session with greater metabolic demands (<(V)over dot>o(2)) and lower BLC than longer (i.e., 3 minutes) intervals.