In-Season Repeated-Sprint Training in Hypoxia in International Field Hockey Players

Repeated-sprint training in hypoxia (RSH) studies conducted "in-season" are scarce. This study investigated the effect of discontinuous, running-based RSH, on repeated-sprint treadmill performance in hypoxia in a team sport cohort, prior to international competition. Over a 6-week "in-season" period, 11 elite male players (Malaysia national team) completed eight multi-set RSH sessions on a non-motorized treadmill in a normobaric hypoxic chamber (FiO(2) = 13.8%). Three testing sessions (Sessions 1, 5, and 8), involved three sets of 5 x 8-s sprints, with 52-s recovery between sprints and 4-5 min between sets. Training sessions (Sessions 2, 3, 4, 6, and 7) consisted of four to five sets of 4-5 x 8-s sprints. During testing sessions, maximum sprinting speed was recorded for each sprint with values averaged for each set. For each set, a peak speed and fatigue index were calculated. Data were compared using two-way repeated measures ANOVA (sessions x sets). Average speed per set increased between testing sessions (p = 0.001, ?(2)(p) = 0.49), with higher values in Session 8 (25.1 +/-& nbsp;0.9 km.h(-1), +4 +/- 3%, p = 0.005), but not Session 5 (24.8 +/- 1.0 km.h(-1), +3 +/- 3%, p = 0.405), vs. Session 1 (24.2 +/- 1.5 km.h(-1)). Peak sprinting speed in each set also increased across testing sessions (p = 0.008, ?(2)(p) = 0.382), with Session 8 (26.5 +/-& nbsp;1.1 km.h(-1)) higher than Session 5 (25.8 +/-& nbsp;1.0 km.h(-1), + 1 +/- 4%, p = 0.06) and Session 1 (25.7 +/- 1.5 km.h(-1), +4 +/- 4%, p = 0.034). Fatigue index differed between sessions (p = 0.04, ?(2)(p) = 0.331, Session 1; -6.8 +/- 4.8%, Session 5; -3.8 +/-; 2%, Session 8; -5.3 +/- 2.6%). In international field hockey players, a 6-week in-season RSH program improved average and peak, repeated treadmill sprint speeds following eight, but not five sessions.</p>