|Title of the paper:||Effect of high intensity interval training (HIIT) on performance and vascular function in elite triathletes|
|Authors:||Hayate, N.1, Hirokatsu, T.2,3,4, Seiji, M.5, Takeshi, O.2|
|Institution:||(1) (2) Ryutsu Keizai University, (3) NTT EAST, (4) NTT WEST, (5) University of Tsukuba|
|Department:||(1) Graduate School, (2) Faculty of Sport and Health Sciences, (5) Faculty of Health and Sport Sciences|
High intensity interval training (HIIT) has become popular as a training protocol to improve endurance performance. Regarding to triathlon, previous studies conducted performance tests simulating the sprint distance (swim 750m, bike 20km, run 5km) and demonstrated that HIIT improves athletic performance in non-elite triathletes. However, effects of HIIT has not yet been explored in elite triathletes and in distance of the Olympic game (1.5km, 40km and 10km, respectively) and official time trial of Japan Triathlon Union (JTU; swim 400m, run 5km) except for 5-km run. This study investigated the effects of HIIT on performance (run 5km, 10km; swim 400m) and vascular function in university elite triathletes.
Subjects were elite-level triathletes belonging to a university triathlon team (4 men and 1 woman). The HIIT-based running program (100m [120-130% maximal oxygen uptake] × 20-35, 400m [105-110%] × 3-10, 120sec [100-105%] × 0-7, 30sec [all out] × 0-6) included 3-4 sessions per week for 5 weeks according to the previous study (García-Pinillos et al., 2017). They were asked to maintain their swimming and cycling routines. Time trials (5 and 10-km run and 400-m swim), Wingate test, and assessment of vascular function were performed before and after the training period.
Running and swimming time improved after the 5-week HIIT program (5-km run, effect size [ES] = 0.50; 10-km run, ES = 0.85; swim, ES = 0.75). Particularly, personal best time was achieved in 5-km run (n = 1) and swim (n = 3). Peak and mean power of Wingate test were greater after the training period compared to before the intervention (ES = 6.50 and 5.74, respectively), suggesting that the HIIT program increased anaerobic capacity. The HIIT program increased leg blood flow and vascular conductance at rest and decreased resting vascular resistance relative to before the training period. In addition, pulse wave velocity, an index of arterial stiffness, was lower after the intervention period compared to before the period. It is possible that the HIIT program increased aerobic capacity via an improvement in peripheral blood circulation and a decrease in left ventricular afterload.
These results suggest that HIIT improves performance of elite triathletes in the Olympic distance and JTU official time trial.
García-Pinillos F, Cámara-Pérez JC, Soto-Hermoso VM, Latorre-Román PÁ. A high intensity interval training (HIIT)-based running plan improves athletic performance by improving muscle power. J Strength Cond Res 31: 146-153, 2017