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Updated: Apr 3, 2026
A Real-World High-Intensity Interval Training Protocol for Cardiorespiratory Fitness Improvement
Published on: February 22, 2022
Interval training in the boundaries of severe domain: effects on aerobic parameters
Tiago Turnes1, Rafael Alves de Aguiar2, Rogério Santos de Oliveira Cruz2
1Human Performance Research Group, Center for Health and Sport Science, Santa Catarina State University, Pascoal Simone, 358, Coqueiros, Florianópolis, SC, CEP 88080-350, Brazil. tiagoturnes89@gmail.com.
Purpose:
Although time spent at VO2max (t@VO2max) has been suggested as an optimal stimulus for the promotion of greater VO2max improvements, scientific findings supporting this notion are surprisingly still lacking. To investigate this, the present study described t@VO2max in two different severe-intensity interval training regimens and compared its effects on aerobic indexes after a 4-week intervention.
Methods:
Twenty-one recreational cyclists performed an incremental exercise test and six time-to-exhaustion tests on four different days to determine VO2max, lactate threshold (LT), critical power (CP) and the highest intensity (IHIGH) and lowest exercise duration (TLOW) at which VO2max was attained. Subjects were assigned to the lower (LO, n = 11, 4 × 5 min at 105% CP, 1 min recovery) or the upper severe-intensity training groups (UP, n = 10, 8 × 60% TLOW at 100% IHIGH, 1:2 work:recovery ratio). t@VO2max was measured during the first and last training sessions.
Results:
A significantly higher t@VO2max was elicited in the UP during training sessions in comparison with the LO group (P < 0.05), and superior improvements were observed in VO2max (change in measure ± 95% confidence interval) (6.3 ± 1.9 vs. 3.3 ± 1.8%, P = 0.034 for interaction terms) and LT (54.8 ± 11.8 vs. 27.9 ± 11.3%, P = 0.023 for interaction terms). The other aerobic indexes were similarly improved between the groups.
Conclusion:
The present results demonstrated that UP training produced superior gains in VO2max and LT in comparison with LO training, which may be associated with the higher t@VO2max.
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