Physiological and performance responses to a training camp in the heat in professional Australian football players

Int J Sports Physiol Perform. 2014 Jul;9(4):598-603. doi: 10.1123/ijspp.2013-0284. Epub 2013 Oct 1.

Abstract

Purpose: To examine the physiological and performance responses to a heat-acclimatization camp in highly trained professional team-sport athletes.

Methods: Eighteen male Australian Rules Football players trained for 2 wk in hot ambient conditions (31-33°C, humidity 34-50%). Players performed a laboratory-based heat-response test (24-min walk + 24 min seated; 44°C), a YoYo Intermittent Recovery Level 2 Test (YoYoIR2; indoor, temperate environment, 23°C) and standardized training drills (STD; outdoor, hot environment, 32°C) at the beginning and end of the camp.

Results: The heat-response test showed partial heat acclimatization (eg, a decrease in skin temperature, heart rate, and sweat sodium concentration, P < .05). In addition, plasma volume (PV, CO rebreathing, +2.68 [0.83; 4.53] mL/kg) and distance covered during both the YoYoIR2 (+311 [260; 361] m) and the STD (+45.6 [13.9; 77.4] m) increased postcamp (P < .01). None of the performance changes showed clear correlations with PV changes (r < .24), but the improvements in running STD distance in hot environment were correlated with changes in hematocrit during the heat-response test (r = -.52, 90%CI [-.77; -.12]). There was no clear correlation between the performance improvements in temperate and hot ambient conditions (r < .26).

Conclusion: Running performance in both hot and temperate environments was improved after a football training camp in hot ambient conditions that stimulated heat acclimatization. However, physiological and performance responses were highly individual, and the absence of correlations between physical-performance improvements in hot and temperate environments suggests that their physiological basis might differ.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acclimatization*
  • Australia
  • Exercise Test
  • Heart Rate
  • Hot Temperature*
  • Humans
  • Humidity
  • Male
  • Motor Skills
  • Physical Conditioning, Human / methods*
  • Physical Endurance
  • Plasma Volume
  • Respiration
  • Running
  • Skin Temperature
  • Sodium / metabolism
  • Sports*
  • Sweat / metabolism
  • Sweating
  • Task Performance and Analysis
  • Time Factors
  • Young Adult

Substances

  • Sodium