Effects of active warm up on thermoregulation and intermittent-sprint performance in hot conditions.
This study examined the effects of active warm up on thermoregulatory responses and intermittent-sprint cycle performance in hot conditions (35.5+/-0.6 degrees C, RH 48.7+/-3.4%). Eight trained males performed a 36-min, intermittent-sprint test (IST) after no (WUP 0), 10-min (WUP 10) or 20-min warm up (WUP 20). The IST contained 2-min blocks consisting of a 4-s sprint, 100s active recovery and 20s passive rest. Twice during the IST, there was a repeated-sprint bout (RSB) comprising five, 2-s sprints separated by approximately 20s. There were no significant differences between trials for mean work (3870+/-757 versus 4028+/-562 versus 3804+/-494Jsprint(-1)), peak power (W) or work decrement (%). However, mean work was significantly less in RSB2 than RSB1 for WUP 20 only (P<0.05). Plasma lactate was significantly higher after active warm up (WUP 20=WUP 10>WUP 0; P<0.05), but not significantly different between conditions following either RSB. Rectal temperature (T(re)) was significantly higher after active warm up (37.0+/-0.3 versus 37.3+/-0.3 versus 37.7+/-0.1 degrees C for WUP0, WUP10 and WUP20, respectively) and throughout the IST. The longer active warm up resulted in a greater increase in T(re) and was associated with a decrease in short-term repeated-sprint ability (with incomplete recovery), but not prolonged, intermittent-sprint performance in the heat. As active warm up did not improve performance (<40min), team-sport athletes may minimise changes in T(re) (and the likelihood of heat illness) by avoiding excessive warm up when competing in the heat.
Bishop
David
D
Facoltà di Scienze Motorie, Università degli Studi di Verona, Italy. bishop@motorie.univr.it
Maxwell
Neil S
NS
D000328:Adult; D001833:Body Temperature Regulation / Q000502:physiology*; D016552:Ergometry; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods; D006358:Hot Temperature; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D015233:Models, Statistical; D010807:Physical Endurance / Q000502:physiology*; D012420:Running / Q000502:physiology*; D013312:Stress, Physiological; D055815:Young Adult
D019344:Lactic Acid