Conventional methods to prescribe exercise intensity are ineffective for exhaustive interval training

Bossi, Arthur Henrique; Cole, Diana; Passfield, Louis; Hopker, James

Abstract

Purpose: To compare methods of relative intensity prescription for their ability to normalise performance (i.e., time to exhaustion), physiological, and perceptual responses to high-intensity interval training (HIIT) between individuals.

Methods: Sixteen male and two female cyclists (age: 38 ± 11 years, height: 177 ± 7 cm, body mass: 71.6 ± 7.9 kg, maximal oxygen uptake (V˙O2max): 54.3 ± 8.9 ml·kg−1 min−1) initially undertook an incremental test to exhaustion, a 3 min all-out test, and a 20 min time-trial to determine prescription benchmarks. Then, four HIIT sessions (4 min on, 2 min off) were each performed to exhaustion at: the work rate associated with the gas exchange threshold (W˙GET) plus 70% of the difference between W˙GET and the work rate associated with V˙O2max; 85% of the maximal work rate of the incremental test (85%W˙max); 120% of the mean work rate of the 20 min time-trial (120%TT); and the work rate predicted to expend, in 4 min, 80% of the work capacity above critical power. Acute HIIT responses were modelled with participant as a random effect to provide estimates of inter-individual variability.

Results: For all dependent variables, the magnitude of inter-individual variability was high, and confidence intervals overlapped substantially, indicating that the relative intensity normalisation methods were similarly poor. Inter-individual coefficients of variation for time to exhaustion varied from 44.2% (85%W˙max) to 59.1% (120%TT), making it difficult to predict acute HIIT responses for an individual.

Conclusion: The present study suggests that the methods of intensity prescription investigated do not normalise acute responses to HIIT between individuals.

Citation

Bossi, A. H., Cole, D., Passfield, L., & Hopker, J. (2023). Conventional methods to prescribe exercise intensity are ineffective for exhaustive interval training. European Journal of Applied Physiology, 123(8), 1655-1670. https://doi.org/10.1007/s00421-023-05176-6

• Journal Article Type: Article
• Acceptance Date: Mar 7, 2023
• Online Publication Date: Mar 29, 2023
• Publication Date: 2023-08
• Deposit Date: Mar 28, 2023
• Publicly Available Date: Mar 28, 2023
• Print ISSN: 1439-6319
• Electronic ISSN: 1439-6327
• Publisher: Springer
• Peer Reviewed: Peer Reviewed
• Volume: 123
• Issue: 8
• Pages: 1655-1670
• DOI: https://doi.org/10.1007/s00421-023-05176-6
• Keywords: Intermittent exercise, Individual response, Delta concept, Adaptive variability, Trainability