INTERMITTENT HYPOXIA OF LITTLE VALUE TO RUGBY PLAYERS PERFORMING AT ALTITUDE
Hamlin, M. J., Hinckson, E. A., Wood, M. R., & Hopkins, W. G. (2004). Effect of intermittent normobaric hypoxic exposure at rest on rugby players' performance at 1650 m. Medicine and Science in Sports and Exercise, 38(5), Supplement abstract 2731.
This study investigated the effect of intermittent normobaric hypoxic exposure on performance in generic and game-specific rugby tests at altitude. Club and junior representative rugby players who were sea-level residents performed baseline tests before being assigned to one of three groups: hypoxia-altitude (N = 9), normoxia-altitude (N = 6), and normoxia sea-level (N = 7). The hypoxia-altitude group experienced 9-13 sessions of intermittent hypoxic over 15 days, and then repeated the performance tests within 12 hours of traveling to an altitude of 1650 m. The normoxia-altitude group experienced placebo exposures by breathing room air before performing the tests at altitude, whereas the normoxia sea-level group experienced placebo exposures before performing the tests at sea level. Hypoxic exposure sessions consisted of alternately breathing through a hand-held face mask six minutes of hypoxic gas and four minutes ambient air for one hour at rest. Oxygen in the gas was reduced progressively from 13% on day 1 to 9% on day 15. Ambient air replaced hypoxic gas for the placebo exposures. Performance measures were: maximum speed, submaximum heart-rate speed and submaximum lactate speed during a 20-m incremental running test, mean time in six 70-m sprints, various mean measures from seven 5.5-min circuits of a rugby simulation, and mean time in a second set of sprints.
At altitude, there were clear impairments in maximum and heart rate-speed, defensive sprint time, and scrum power, and a clear improvement in 30-m sprint time. Relative to the normoxia-altitude group, the hypoxia-altitude group experienced a clear improvement in heart-rate speed and slight improvement in lactate speed while effects on all other performance variables were trivial or unclear.
Implication. Altitude of 1650 m had a positive effect on some sprints but a detrimental effect on 20-m running performance and scrum power. Intermittent hypoxic exposure improved some physiological measures of performance but otherwise had little effect in preparing rugby players for performance at altitude.
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