Fig. 2
The effect of hypoxic dose (km h) on change in high-intensity, intermittent running performance (YYIR). Three studies have been excluded from this graph due to absence of a normoxic control group [36], risk of publication bias [40] and a particularly small sample size [39]. YYIR Yo-Yo intermittent recovery test, filled circle: hypoxic training, open circle: intermittent hypoxic exposure, filled triangle: live high, train low and high, open triangle: live high, train low, d intervention duration (days), km h kilometre hours (height above sea level in meters/1000 total number of hours of exposure)