The Science and Application of High-Intensity Interval Training (HIIT)
The 30-15 Intermittent Fitness Test
The 30-15 IFT is an incremental, intermittent running test designed to improve run-based high-intensity interval training (HIIT) prescription. In comparison with continuous and/or linear tests, using the final speed reached at the end of the 30-15 test (VIFT) enables lower inter-individual differences in acute cardiorespiratory responses to HIIT – in other words, responses to HIIT are more similar between athletes using VIFT. This is because VIFT is a compound measure of maximal aerobic power, anaerobic speed reserve, inter-effort recovery, and change of direction abilities – all components of performance for team and racquet sports (Buchheit 2005, 2008).