Author and graduation date: David Wade DOUGLASS, May, 1998

Committee members: Jeanne F. Nichols (Chair), Michael J. Buono, Patricia N. L. Dintrone

Thesis title: Endurance Performance Effects of Hyperoxic vs. Normoxic Breathing During Interval Training In Female Cyclists

The purpose of this study was to determine the differential effects on performance of hyperoxic vs. normoxic breathing during high-intensity interval training in female cyclists. At the peak of their competitive season, 16 cyclists ( 34.9 + 1.7 yr, VO2max 56.7 + 2.0 ml/kg/min, mean + SE) were randomly assigned (single blind) to either hyperoxic (40-45% O2) or normoxic training, which consisted of eigiht, 2-min. maximum effort intervals with 4 minute recovery performed in the laboratory on each subject's own bike once per week for six weeks. O2 was delivered from tanks via tygon tubing to Hans Rudolph facemasks worn by all subjects. Control subjects received room air, but also wore masks to ensure blinding of condition. SaO2 was measured by finger oximetry periodically throughout the training. Outcome variables measured pre/post training on a Lode cycle ergometer with a Vmax 29 metabolic cart were VO2max, lactate threshold (LT), leg fatigue (sec) at 110% peak power output (PPO110), and a 1.5 mile hill-climb time trial on an outdoor course familiar to all subjects. The level of significance was set at p <0.20 to adjust for low power. Group (Con/O2) by time (pre/post) repeated measures ANOVA indicated significant training (time) effects for PPO110 (Con: 80.2 + 6.6-100.6 + 8.7 sec, pre-post; O2: 60.0 + 4.4 -75.2 + 7.6 sec, p = .001), power output at LT (Con: 150 + 14-164 + 17 W, pre-post; O2: 161 + 11 -164 + W, p = .07), PPO (Con: 283 + 9-305 + 12 W; O2: 296-296 W, pre-post, p = .022), and a significant interaction in PPO (p = .099). These data do not indicate a training benefit from hyperoxic breathing, even though desaturation of hemoglobin was reversed. An increase in the volume of training while in a hyperoxic condition should be examined.

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