Aim: Our study aimed to evaluate the acute responses and exercise--induced muscle damage of five different high--intensity interval training (HIT) protocols adjusted by the maximum velocity obtained in the 30--15 Intermittent Fitness Test (V IFT ).
Methods: Sixteen well--trained intermittent sport players (mean ± SD;; age, 24.6 ± 2.7 years; V̇O 2max , 58.3 ± 5.9 ml∙min∙kg --1 ) participated in five different HIT protocols separated by six days in between (P 240 : 4×4 min at 80% V IFT ; P 120 : 7×2 min at 85%; P 30 : 2×10×30 s at 90%; P 15 : 3×9×15 s at 95%; P 5 : 4×6×5 s sprints). Blood lactate (La), blood pH, serum creatinkinase (CK), heart rate (HR), session rating of perceived exertion (session--RPE), delayed onset muscle soreness (DOMS) and countermovement jump (CMJ) height were measured.
Results: A significant main effect for protocol ( p < 0.05) was found for the acute responses of HR, session-RPE and La with values increasing in longer intervals from P 15 to P 120 and P 240 while blood pH responded inversely. In contrast, P 5 produced the highest La concentration and blood pH decreases. 24 h post exercise CK, DOMS and the decrease in CMJ height were significantly higher after P 5 compared to all other protocols ( p < 0.05).
Conclusion: HIT protocols of different interval duration and intensity result in varying acute physiological and perceptual demands and exercise--induced muscle damage. Longer intervals with submaximal intensity lead to higher acute cardio circulatory responses, whereas sprint protocols induce the highest muscle damage and muscle soreness.