Comparison of anaerobic speed reserve and maximal aerobic speed methods to prescribe short format high-intensity interval training

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, Delta 15% ASR, or Delta 25% 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% vVO(2max), 47.2%, 31%, 7.5%, 6.7%, 3.9%, 4.6%, 24.2%, and 14.6% during Delta 15% ASR, and 48.1%, 31.5%, 7.6%, 8.4%, 3.6%, 4.1%, 20.2%, and 3.4% during Delta 25% ASR session, respectively. Only the residuals in RPE were significantly (p < 0.001) higher in 110% vVO(2max) and Delta 15% ASR in comparison to Delta 25% ASR. Time spent >= 90% HRmax/VO2max was maximized during Delta 15% 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 vVO(2max) for prescription of 10-min HIIT session comprised of 15-s work and passive recovery intervals.