Effects of warm-up and precooling on endurance performance in the heat.

Institute of Sports Science, University of Dortmund, Otto-Hahn-Str 3, 44227 Dortmund, Germany.
British journal of sports medicine (Impact Factor: 4.17). 07/2007; 41(6):380-4. DOI: 10.1136/bjsm.2006.032292
Source: PubMed

ABSTRACT To examine the effects of different thermoregulatory preparation procedures (warm-up (WU), precooling (PC), control (C)) on endurance performance in the heat.
20 male subjects completed three treadmill runs to exhaustion (5 days apart). In each session, all subjects performed an incremental running test after WU (20 min at 70% maximum heart rate (HR)), after PC (wearing a cooling vest (0 degrees C-5 degrees C) for 20 min at rest) or without particular preparation (C). After a 5-min break, the exercise protocol commenced at a workload of 9 km/h and was increased by 1 km/h every 5 min until the point of volitional fatigue. Running performance, HR, blood lactate concentration, tympanic temperature and skin temperature were measured in each trial.
In the PC condition, the running performance (32.5 (5.1) min; mean (SD)) was significantly (p<0.05) higher than in WU (26.9 (4.6) min) and in C conditions (30.3 (4.3) min). During the first 30 min of testing, HR, tympanic temperature and skin temperature were significantly (p<0.05) lower after PC than after WU. There were no significant differences in lactate concentration; however, there was a trend to lower values after WU.
The use of an ice-cooling vest for 20 min before exercising improved running performance, whereas the 20 min WU procedure had a distinctly detrimental effect. Cooling procedures including additional parts of the body such as the head and the neck might further enhance the effectiveness of PC measures.

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    ABSTRACT: Exercise in hot conditions alters the physiological response to the ensuing exercise bout and may hasten the onset of fatigue. Regardless of the environment, often preexercise procedures are employed in order to ensure the commencement of exercise in an optimally prepared state to perform. Two such pre-exercise procedures often proposed as being of benefit involve warming up and pre-cooling, respectively. While both have been shown to have ergogenic benefits, they are somewhat contradictory in nature. It is well documented that optimal muscular function of the contractile fibres occurs with an increased muscle temperature. Accordingly, the practice of a warm up prior to exercise commencement is endemic to most sports and athletes and is often based on the premise of increasing muscle temperature. In contrast, it is equally well documented that reducing body temperature by cooling the periphery of the body, including the musculature, is also ergogenic for exercise performance. Accordingly, the practice of pre-cooling is regularly used by athletes from a range of sports and environments. This contradiction between increasing and decreasing respective body temperatures to improve exercise performance raises interesting questions regarding the mechanisms behind the regulation of exercise in the heat. Consequently, the underlying physiological mechanisms to both warm up and pre-cooling procedures are seemingly related to thermoregulatory control. As such, this chapter will review the respective literature on both warm up and pre-cooling in relation to exercise in the heat. Included in this synthesis of relevant literature will be the physiological and performance responses to these respective pre-exercise interventions in the heat. Additionally, a comparison of the respective roles and interaction of both procedures will be discussed and finally, recommendations for the integration of both practices will be provided.
    Body Temperature Regulation, Edited by A.B. Cisneros and B.L. Goins, 01/2009: pages 209-226; Nova Science Publishers Inc.., ISBN: 978-1-60741-282-3


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