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Mixed-Method Precooling Enhances Self-Paced 20-km Cycling Time-Trial Performance When Apparent Temperature Is >46 °C
Julian Andro P Ramos1, Kagan J Ducker1, Hugh Riddell1
1Curtin School of Allied Health, Curtin University, Perth, Australia.
International Journal of Sports Physiology and Performance
|February 20, 2024
Summary
Mixed-method precooling (PreC) significantly improved 20-km cycling performance in hot-humid conditions (46°C AT). PreC did not benefit performance in hot-dry (35°C AT) or moderately hot-humid (40°C AT) environments.
Area of Science:
- Exercise Physiology
- Environmental Extremes
- Sports Performance
Background:
- Precooling (PreC) strategies aim to reduce thermal strain and enhance endurance performance.
- The effectiveness of PreC is often dependent on the level of thermal strain experienced.
- Mixed-method PreC combines different cooling techniques to optimize physiological responses.
Purpose of the Study:
- To investigate the impact of mixed-method PreC on 20-km cycling time-trial (CTT) performance.
- To evaluate the influence of varying apparent temperatures (AT) on the efficacy of PreC.
- To determine optimal environmental conditions for applying mixed-method PreC.
Main Methods:
- 12 trained male cyclists/triathletes completed six 20-km CTTs under three ATs: 35°C (hot-dry), 40°C (moderately hot-humid), and 46°C (hot-humid).
- Each AT condition involved trials with 30 minutes of mixed-method PreC and control (CON) trials without PreC.
- Physiological markers including core and skin temperature, heart rate, and perceived exertion were monitored.
Main Results:
- Performance (2.5-km split time) improved with PreC only in the 46°C AT condition (P=.02).
- PreC lowered skin temperature in 46°C AT (P=.01) and increased heart rate variability compared to CON.
- Perceived exertion and thermal comfort were significantly lower with PreC in 46°C AT.
Conclusions:
- Mixed-method PreC is recommended before 20-km CTTs in hot-humid (≥46°C AT) conditions.
- Application of PreC may be beneficial in moderately hot-humid (∼40°C AT) conditions but not recommended for hot-dry (∼35°C AT) conditions.
- Environmental temperature and humidity are critical factors determining the effectiveness of precooling strategies for cycling performance.
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