Author Identifier

Wouter Timmerman

https://orcid.org/0000-0002-6085-9330

Document Type

Journal Article

Publication Title

Journal of Science and Medicine in Sport

Volume

27

Issue

12

First Page

875

Last Page

882

Publisher

Elsevier

School

School of Medical and Health Sciences

Funders

Conselho Nacional de Desenvolvimento Científico e Tecnológico (200700/2015-4)

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, 27(12), 875-882. https://doi.org/10.1016/j.jsams.2024.07.019

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

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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Link to publisher version (DOI)

10.1016/j.jsams.2024.07.019