ABSTRACT
The purpose of the study was to compare the degree of intersubject variability in the cardiorespiratory, metabolic, and perceptual responses to high-intensity interval training (HIIT) prescribed based on the relative anaerobic speed reserve (ASR) or maximal aerobic speed (MAS) and to identify the optimal % ASR for execution of such HIIT. Seventeen male physical education students (age: 23.6 ± 1.1 years, height: 180.2 ± 5.9, body mass: 78.3 ± 8.1 kg; % body fat: 14.3 ± 2.7%) volunteered to execute three randomly scheduled 10-min HIIT exercises at 110% vVO2max , Δ15% ASR, or Δ25% ASR. Analysis of variance for repeated measures and the least significant difference post-hoc test were used to compare the physiological responses and the mean of individual residuals between the training sessions. The coefficients of variation (CV) of time spent ≥90% of maximal oxygen uptake (VO2max ) and maximal heart rate (HRmax ), peak VO2 , mean VO2 , peak HR, mean HR, blood lactate [La], and rating of perceived exertion (RPE) were 48.7%, 35.9%, 9.3%, 7%, 3.5%, 4.8%, 32%, and 16.9% during 110% vVO2max , 47.2%, 31%, 7.5%, 6.7%, 3.9%, 4.6%, 24.2%, and 14.6% during Δ15% ASR, and 48.1%, 31.5%, 7.6%, 8.4%, 3.6%, 4.1%, 20.2%, and 3.4% during Δ25% ASR session, respectively. Only the residuals in RPE were significantly (p < 0.001) higher in 110% vVO2max and Δ15% ASR in comparison to Δ25% ASR. Time spent ≥90% HRmax /VO2max was maximized during Δ15% ASR session, albeit this was not significantly different from other sessions. The ASR-based method leads to reduced CVs of physiological and perceptual responses during 10-min HIIT; however, only reductions in [La] and RPE may be considered practically meaningful. Practitioners can use vVO2max for prescription of 10-min HIIT session comprised of 15-s work and passive recovery intervals.
