Document Type
Journal Article
Publication Title
Journal of Science and Medicine in Sport
Publisher
Elsevier
School
School of Medical and Health Sciences
Funders
Conselho Nacional de Desenvolvimento Científico e Tecnológico (200700/2015-4)
Abstract
Objectives: This study was designed to quantify inter- and intra-individual variability in performance, physiological, and perceptual responses to high-intensity interval training prescribed using the percentage of delta (%Δ) method, in which the gas exchange threshold and maximal oxygen uptake (V̇O2max) are taken into account to normalise relative exercise intensity. Design: Repeated-measures, within-subjects design with mixed-effects modelling. Methods: Eighteen male and four female cyclists (age: 36 ± 12 years, height: 178 ± 10 cm, body mass: 75.2 ± 13.7 kg, V̇O2max: 51.6 ± 5.3 ml·kg−1·min−1) undertook an incremental test to exhaustion to determine the gas exchange threshold and V̇O2max as prescription benchmarks. On separate occasions, participants then completed four high-intensity interval training sessions of identical intensity (70 %Δ) and format (4-min on, 2-min off); all performed to exhaustion. Acute high-intensity interval training responses were modelled with participant as a random effect to provide estimates of inter- and intra-individual variability. Results: Greater variability was generally observed at the between- compared with the within-individual level, ranging from 50 % to 89 % and from 11 % to 50 % of the total variability, respectively. For the group mean time to exhaustion of 20.3 min, inter- and intra-individual standard deviations reached 9.3 min (coefficient of variation = 46 %) and 4.5 min (coefficient of variation = 22 %), respectively. Conclusions: Due to the high variability observed, the %Δ method does not effectively normalise the relative intensity of exhaustive high-intensity interval training across individuals. The generally larger inter- versus intra-individual variability suggests that day-to-day biological fluctuations and/or measurement errors cannot explain the identified shortcoming of the method.
DOI
10.1016/j.jsams.2024.07.019
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Comments
Bossi, A. H., Timmerman, W., Cole, D., Passfield, L., & Hopker, J. (2024). The delta concept does not effectively normalise exercise responses to exhaustive interval training. Journal of Science and Medicine in Sport. Advance online publication. https://doi.org/10.1016/j.jsams.2024.07.019