Effect of a hot environment on performance of prolonged, intermittent, high-intensity shuttle running

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Deutscher übersetzter Titel:Auswirkung von Hitzebelastung auf die Leistung bei langdauerndem, intermittierendem, hochintensivem Pendellauf
Autor:Morris, J.G.; Nevill, M.E.; Lakomy, H.K.A.; Nicholas, C.; Williams, C.
Erschienen in:Journal of sports sciences
Veröffentlicht:16 (1998), 7, S. 677-686, Lit.
Format: Literatur (SPOLIT)
Publikationstyp: Zeitschriftenartikel
Medienart: Gedruckte Ressource
Sprache:Englisch
ISSN:0264-0414, 1466-447X
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Erfassungsnummer:PU199810305003
Quelle:BISp

Abstract des Autors

In this study we examined the performance during, and the physiological and metabolic responses to, prolonged, intermittent, high-intensity shuttle running in hot (ca. 30øC, dry bulb temperature) and moderate (ca. 20øC) environmental conditions. Twelve male students, whose mean (+/-s x) age, body mass and maximal oxygen uptake (VO2max) were 22+/-1 years, 69.8+/-1.8 kg and 56.9+/-1.1 ml/kg/min respectively, performed intermittent high- and low-speed running involving five sets of ca. 15 min of repeated cycles of walking and variable speed running followed by 60 s run/rest exercise until fatigue. The total distance completed in the hot and moderate trials was 8842+/-790 m and 11,280+/-214 m respectively (P<0.01). This decrement in performance occurred even though no differences existed in the level of dehydration, rating of perceived exertion, blood glucose and lactate, plasma free fatty acid and ammonia concentrations between the two trials. However, water consumption was almost twice as great in the hot trial (hot vs moderate: 1.18+/-0.12 vs 0.63+/-0.07 l/h, P<0.01). Rectal temperature (hot vs moderate: 39.4+/-0.1 vs 38.0+/-0.1øC, P<0.01) and heart rate (hot vs moderate: 186+/-2 vs 179+/-2 beats/min, P<0.05) were higher at the end of the hot condition that at the same point in time in the moderate condition. The correlation between the rate of rise in rectal temperature and the distance completed during the hot condition was -0.94 (P<0.01); for the moderate condition it was -0.65 (P<0.05). The reduced performance in the hot condition was associated with high body temperature; the precise mechanisms by which the performance decrement was brought about are, however, unclear. Verf.-Referat