No abstract

High-intensity interval training applied at submaximal, maximal, and supramaximal intensities for exercising at V[Combining Dot Above]O2max (t95V[Combining Dot Above]O2max) has shown similar adaptation to low-volume sprint interval training among active subjects. Thus, the aim of the present study was to investigate t95V[Combining Dot Above]O2max during 2 different intermittent exercises in the severe-intensity domain (e.g., range of power outputs over which V[Combining Dot Above]O2max can be elicited during constant-load exercise) and to identify an exercise protocol that reduces the time required to promote higher aerobic demand. Eight active men (22 ± 2 years, 72 ± 5 kg, 174 ± 4 cm, 47 ± 8 ml·kg·min) completed the following protocols on a cycle ergometer: (a) incremental test, (b) determination of critical power (CP), (c) determination of the highest constant intensity (IHIGH) and the lowest exercise duration (TLOW) in which V[Combining Dot Above]O2max is attained, and (d) 2 exercise sessions in a randomized order that consisted of a constant power output (CPO) session at IHIGH and a decreasing power output (DPO) session that applied a decreasing work rate profile from IHIGH to 110% of CP. Time to exhaustion was significantly longer in DPO (371 ± 57 seconds vs. 225 ± 33 seconds). Moreover, t95V[Combining Dot Above]O2max (186 ± 72 seconds vs. 76 ± 49 seconds) and O2 consumed (29 ± 4 L vs. 17 ± 3 L) were higher in DPO when compared with the CPO protocol. In conclusion, data suggest that the application of a DPO protocol during intermittent exercise increases the time spent at high percentages of V[Combining Dot Above]O2max.

The purpose of this study was to compare cardiopulmonary, neuromuscular, and metabolic responses to severe-intensity intermittent exercises with variable or constant work rate. Eleven cyclists (28 ± 5 years; 74 ± 7 kg; 175 ± 5 cm; 63 ± 4 mL·kg·min) performed the following tests until exhaustion on separate days: 1) an incremental test; 2) in random order, two constant work rate tests at 95% and 110% of the peak power for the determination of Critical Power (CP); 3) 2-4 tests for the determination of the highest power that still permits the achievement of maximal oxygen uptake (PHIGH); and 4) two random severe-intensity intermittent exercises. The last two sessions consisted of a constant work rate (CWR) exercise performed at PHIGH or a decreasing work rate (DWR) exercise from PHIGH until 105% of CP. Compared to CWR, DWR presented higher time to exhaustion (635 ± 223 vs. 274 ± 65 s), time spent above 95% of VO2max (t95%VO2max) (323 ± 227 vs. 98 ± 65 s), and O2 consumed (0.97 ± 0.41 vs. 0.41 ± 0.11 L). Electromyography amplitude (RMS) decreased for DWR but increased for CWR during each repetition. However, RMS and VO2 divided by power output (RMS/PO and VO2/PO ratio) increased in every repetition for both protocols, but to a higher extent and slope for DWR. These findings suggest that the higher RMS/PO and VO2/PO ratio in association with the longer exercise duration seemed to have been responsible for the higher t95%VO2max observed during severe DWR exercise.

In conclusion, IPC does not improve the 2000-m rowing ergometer performance of trained athletes regardless of the length of ischaemia-reperfusion cycles.

Supplemental Digital Content is Available in the Text.