Using Anaerobic Speed Reserve To Prescribe High-intensity Interval Training

High-intensity interval training (HIIT) is the optimal training stimulus for maximal oxygen uptake (VO2max) enhancement. The intensity of short format HIIT exercise can be defined by using different physiological anchors and their accuracy for individualization of HIIT exercise should be investigated. PURPOSE: The purpose of the study was to compare the degree of inter-subject variability in the cardiorespiratory, metabolic and perceptual responses to HIIT prescribed based on the relative anaerobic speed reserve (ASR) or maximal aerobic speed (MAS/vVO2max) and to identify the optimal % ASR for execution of such HIIT. METHODS: Seventeen male physical education students (age: 23.6 ± 1.1 years, height: 180.2 ± 5.9, weight: 78.3 ± 8.1 kg; % body fat: 14.3 ± 2.7 %) volunteered to execute three randomly scheduled 10-minute HIIT exercises at 110% vVO2max, Δ15% ASR or Δ25% ASR. Analysis of variance (ANOVA) 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. RESULTS: The exercise intensity was significantly different between all HIIT sessions (p < 0.001). Peak heart rate (HR) (190,5 ± 6,9 vs 186,9 ± 6,5, p < 0.05), mean HR (179,8 ± 7,4 vs 176,9 ± 8,4, p < 0.05), mean oxygen uptake (VO2mean) (44,5 ± 3,7 vs 42,2 ± 3, p < 0.01), Rating of Perceived Exertion (RPE) (9,9 ± 0,3 vs 8,2 ± 1,4, p < 0.001) and blood lactate [La] (12 ± 2,4 vs 7,3 ± 2,3, p < 0.001) were all significantly higher in Δ25% ASR compared to 110% vVO2max, while VO2mean (44,5 ± 3,7 vs 42,7 ± 2,9, p < 0.05), RPE (9,9 ± 0,3 vs 8,4 ± 1,2, p < 0.001) and [La] (12 ± 2,4 vs 8,2 ± 2, p < 0.001) were significantly higher in Δ25% ASR compared to Δ15% ASR exercise session. There were no significant differences between 110% vVO2max and Δ15% ASR exercise sessions in any of the investigated physiological variables. The residuals in RPE were significantly higher in 110% vVO2max (p < 0.001) and Δ15% ASR (p < 0.001) in comparison to Δ25% ASR. CONCLUSION: The ASR-based method is not significantly superior to MAS-based method in eliciting lower inter-subject variability of cardiorespiratory, metabolic and perceptual responses during 10-minute short format HIIT. Therefore, practitioners can use vVO2max as anchor to prescribe HIIT exercise.