Diurnal variation in cycling performance: Influence of warm-up |
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| Authors: | Greg Atkinson Clare Todd Thomas Reilly James Waterhouse |
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| Institution: | 1. School of Sport, Exercise and Health Sciences , Loughborough University , Loughborough , UK m.gleeson@lboro.ac.uk;3. School of Sport, Health and Exercise Sciences , Bangor University , Bangor , UK |
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| Abstract: | We examined the effects of time of day on a cycling time trial with and without a prolonged warm-up, among cyclists who tended towards being high in “morningness”. Eight male cyclists (mean?±?s: age = 24.9?±?3.5 years, peak power output = 319?±?34?W, chronotype = 39?±?6 units) completed a 16.1-km time trial without a substantial warm-up at both 07:30 and 17:30?h. The time trial was also completed at both times of day after a 25-min warm-up at 60% of peak power. Power output, heart rate, intra-aural temperature and category ratings of perceived exertion (CR-10) were measured throughout the time trial. Post-test blood lactate concentration was also recorded. Warm-up generally improved time trial performance at both times of day (95% CI for improvement = 0 to 30?s), but mean cycling time was still significantly slower at 07:30?h than at 17:30?h after the warm-up (95% CI for difference = 33 to 66?s). Intra-aural temperature increased as the time trial progressed (P <?0.0005) and was significantly higher throughout the time trials at 17:30?h (P = 0.001), irrespective of whether the cyclists performed a warm-up or not. Blood lactate concentration after the time trial was lowest at 07:30?h without a warm-up (P = 0.02). No effects of time of day or warm-up were found for CR-10 or heart rate responses during the time trial. These results suggest that 16.1-km cycling performance is worse in the morning than in the afternoon, even with athletes who tend towards ‘morningness’, and who perform a vigorous 25-min warm-up. Diurnal variation in cycling performance is, therefore, relatively robust to some external and behavioural factors. |
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| Keywords: | Circadian rhythms intra-aural temperature morningness time trial |
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