Physiological Responses During High-Intensity Interval Training in Young Swimmers

This study analyzed whether 100- and 200-m interval training (IT) in swimming differed regarding temporal, perceptual, and physiological responses. The IT was performed at maximal aerobic velocity (MAV) until exhaustion and time spent near to maximalVO(2) peak oxygen uptake (⩒O(2)peak), total time limit (t(Lim)), peak blood lactate [La(−)] peak, ⩒O(2) kinetics (⩒O(2)K), and rate of perceived exertion (RPE) were compared between protocols. Twelve swimmers (seven males 16.1 ± 1.1 and five females 14.2 ± 1 years) completed a discontinuous incremental step test for the second ventilatory threshold (VT(2)), ⩒O(2)peak, and MAV assessment. The swimmers subsequently completed two IT protocols at MAV with 100- and 200-m bouts to determine the maximal ⩒O(2) (peak-⩒O(2)) and time spent ≥VT(2), 90, and 95% of ⩒O(2)peak for the entire protocols (IT(100) and IT(200)) and during the first 800-m of each protocol (IT(8x100) and IT(4x200)). A portable apparatus (K4b(2)) sampled gas exchange through a snorkel and an underwater led signal controlled the velocity. RPE was also recorded. The Peak-⩒O(2) attained during IT(8x100) and IT(4x200) (57.3 ± 4.9 vs. 57.2 ± 4.6 ml·kg(−1)·min(−1)) were not different between protocols (p = 0.98) nor to ⩒O(2)peak (59.2 ± 4.2 ml·kg(−1)·min(−1), p = 0.37). The time constant of ⩒O(2)K (24.9 ± 8.4 vs. 25.1 ± 6.3-s, p = 0.67) and [La(−)] peak (7.9 ± 3.4 and 8.7 ± 1.5 mmol·L(−1), p = 0.15) also did not differ between IT(100) and IT(200). The time spent ≥VT(2), 90, and 95%⩒O(2)peak were also not different between IT(8x100) and IT(4x200) (p = 0.93, 0.63, and 1.00, respectively). The RPE for IT(8x100) was lower than that for IT(4x200) (7.62 ± 2 vs. 9.5 ± 0.7, p = 0.01). Both protocols are considered suitable for aerobic power enhancement, since ⩒O(2)peak was attained with similar ⩒O(2)K and sustained with no differences in t(Lim). However, the fact that only the RPE differed between the IT protocols suggested that coaches should consider that nx100-m/15-s is perceived as less difficult to perform compared with nx200-m/30-s for the first 800-m when managing the best strategy to be implemented for aerobic power training.