Low-volume, high-intensity interval training (HIIT) consisting of 60s work and 60s recovery (60s/60s) repeated for 10 repetitions has previously been found to produce beneficial cardiopulmonary, cellular, and metabolic adaptations in healthy and at-risk populations. There is currently relatively little information pertaining to the acute changes that take place during individual training sessions. The purpose of this study was to examine the acute physiological responses to 60s/60s x 10 HIIT protocols using several combinations of work and recovery intensities.
Eleven healthy adults (mean age + s.d. = 26.0 ± 5.3 yrs) performed four HIIT trials on separate days at varying percentages of peak power output (PPO) that consisted of the following work/recovery intensities: a) 80% PPO/0% PPO (80/0); b) 80% PPO/50% PPO (80/50); c) 100% PPO/0% PPO (100/0) and; d) 100% PPO/50% PPO (100/50). 100/50 produced higher (p < 0.05) peak, average, and nadir %V[Combining Dot Above]O2peak compared to the other protocols.
Other than the nadir values resulting from the 80/0 trial, all trials produced average, peak, and nadir %V[Combining Dot Above]O2peak and %HRpeak values that were within exercise intensity ranges (≈45-90% V[Combining Dot Above]O2max; ≈65-90% HRmax) recommended by the American College of Sports Medicine (ACSM) for improvement of cardiopulmonary function. 80/50 and 100/0 produced similar average HR and peak HR, RPE, blood lactate and %V[Combining Dot Above]O2peak values.
However, the average %V[Combining Dot Above]O2peak was significantly higher (∼9.3% absolute) in 80/50. It appeared that use of the 80/0, 80/50, and 100/0 protocols would be appropriate for individuals who are at the low to moderate end of the cardiopulmonary fitness spectrum.
J Strength Cond Res. 2016 Mar 18. [Epub ahead of print] Acute Cardiopulmonary And Metabolic Responses To High-Intensity Interval Training (Hiit) Protocols Using 60s Of Work And 60s Recovery. Rozenek R1, Salassi JW 3rd, Mier NM, Fleming J. 11Department of Kinesiology, California State University Long Beach, 1250 Bellflower Blvd., Long Beach, California, USA, 90840.