Auckland 1020 New Zealand. High-Intensity Kayak Performance After Adaptation to Intermittent Hypoxia

Context: Live-high train-low altitude training produces worthwhile gains in per-formance for endurance athletes, but the benefi ts of adaptation to various forms of artifi cial altitude are less clear. Purpose: To quantify the effects of intermittent hypoxic exposure on kayak performance. Methods: In a crossover design with a 6-week washout, we randomized 10 subelite male sprint kayak paddlers to hypoxia or control groups for 3 weeks (5 days/week) of intermittent hypoxic exposure using a nitrogen-fi ltration device. Each dayʼs exposure consisted of alternately breathing hypoxic and ambient air for 5 minutes each over 1 hour. Performance tests were an incremental step test to estimate peak power, maximal oxygen uptake, exercise economy, and lactate threshold; a 500-m time trial; and 5 × 100-m sprints. All tests were performed on a wind-braked kayak ergometer 7 and 3 days pretreatment and 3 and 10 days posttreatment. Hemoglobin concentration was measured at 1 day pretreatment, 5 and 10 days during treatment, and 3 days after treatment. Results: Relative to control, at 3 days posttreatment the hypoxia group showed the following increases: peak power 6.8 % (90 % confi dence limits