Figure 2. Overview of the experimental protocol. IET, incremental exercise test; MSS, maximal sprint speed; IFT, 30-15 incremental fitness test. HIIT_ASR, high-intensity interval training using anaerobic speed reserve (ASR); HIITv_IFT, HIIT using finial velocity during 30-15_IFT test (V_IFT); HIIT_MAS, HIIT using maximal aerobic speed (MAS).