The delta concept does not effectively normalise exercise responses to exhaustive interval training.
J Sci Med Sport
; 2024 Jul 31.
Article
in En
| MEDLINE
| ID: mdl-39138044
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 (VÌO2max) 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⯱â¯12â¯years, height 178⯱â¯10â¯cm, body mass 75.2⯱â¯13.7â¯kg, VÌO2max 51.6⯱â¯5.3â¯ml·kg-1·min-1) undertook an incremental test to exhaustion to determine the gas exchange threshold and VÌO2max as prescription benchmarks. On separate occasions, participants then completed four high-intensity interval training sessions of identical intensity (70â¯%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 50â¯% to 89â¯% and from 11â¯% to 50â¯% of the total variability, respectively. For the group mean time to exhaustion of 20.3â¯min, inter- and intra-individual standard deviations reached 9.3â¯min (coefficient of variationâ¯=â¯46â¯%) and 4.5â¯min (coefficient of variationâ¯=â¯22â¯%), 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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
J Sci Med Sport
Journal subject:
MEDICINA ESPORTIVA
Year:
2024
Document type:
Article
Country of publication:
Australia