Precooling and warm-up effects on time trial cycling performance during heat stress

Loading...
Thumbnail Image
Date
2014
Journal Title
Journal ISSN
Volume Title
Publisher
University of Alabama Libraries
Abstract

The aim of this study was to investigate the separate and combined effects of precooling and warm-up on a subsequent cycling time trial in a hot environment. METHODS: Nine healthy men (mean±SD age=24±5 years; body mass=74.7±4.5 kg; height=171.4±7.7 cm; body fat=12.9±5.2%) completed 3 simulated 16.1-km time trials on a cycle ergometer in a hot environment (~33 °C, 45% relative humidity) after: 1) 20 min of fluid ingestion (10 °C ) followed by 30 min of ice-slurry ingestion (-1 °C ) coupled with ice-vest (PREC), 2) 30 min of ice-slurry ingestion coupled with ice-vest followed by 20 min of warm-up including ice-slurry and ice-vest (COMBO), 3) 30 min of fluid ingestion (10 °C) followed by 20 min of warm-up (WU). RESULTS: At baseline, rectal temperature (T_re ), mean skin temperature ( ₸_sk ), and mean body temperature (₸_b ) were similar among treatments (all P>0.05). After treatment administration and before the start of the time trial, T_re was lower in PREC (36.1±0.3) and COMBO (36.9±0.4) compared to WU (37.6±0.2) (all P<0.05). ₸_sk and ₸_b were all lower in PREC than COMBO and WU, and were lower in COMBO than WU (all P<0.05). Tre remained lower in PREC than WU throughout exercise and was lower in PREC than COMBO for the first 12 km (all P<0.01), while T_re in COMBO remained lower than WU for the first 4 km. ₸_sk during PREC was lower than COMBO at 4 and 8 km and lower than WU at 0 and 4 km, while during COMBO it was lower than WU at 0 and 4 km (all P<0.05). Heart rate (HR) at baseline was lower in PREC than COMBO and WU (68±10, 106±12, 101±13 beats/min, respectively; P<0.001). During exercise, HR increased similarly among all treatments throughout exercise (all P>0.05). Local sweat rate (SR) was lower in PREC than COMBO and WU for the first 4 km (P < 0.05), but whole-body SR was not different among treatments (all P>0.05). Performance times were not different among treatments (PREC: 31.96±2.05 min; COMBO: 32.64±2.90 min; WU: 33.09±3.09 min; P>0.05). CONCLUSION: Despite mitigating thermal strain during exercise, precooling alone, or combined with warm-up, did not result in improved performance of a 16.1-km simulated cycling time trial.

Description
Electronic Thesis or Dissertation
Keywords
Kinesiology
Citation