This study was designed to determine the impact of glycerol hyperhydration, compared with a placebo hyperhydration, on the run performance during an Olympic distance triathlon. Ten competitive triathletes (mean peak oxygen consumption, VO2 peak = 65.5 ± 5.5 ml.kg.-1min-1) undertook two simulated Olympic Distance Triathlons in 31° C and 61% relative humidity. The trials were split into two work phases: a fixed workload phase comprising a 18-20 min swim and a 60 min cycle and, a self regulated time trial run over 10 kilometres conducted on a treadmill. One hundred and fifty min prior each trial, either a glycerol solution (1 g.kg.-1 body mass (BM) in a 4% carbohydrate – electrolyte drink) or a placebo of equal volume of the 4% carbohydrate-electrolyte solution was ingested over one hour. The total fluid intake in each trial was 23 ml.kg.-1 BM. A randomised, double blind, cross over design was used. Due to either 1) the arduous nature of the trials 2) the side effects associated with the ingestion of glycerol 3) or the combination of the two aforementioned reasons, only five of the 10 subjects completed the final 10 km self regulated time trial for both treatments. Only the data obtained from these five subjects were reported in this study. Glycerol ingestion expanded body water over the placebo by 154 ml (26%). At 60 and 90 min after the start of drinking, urine output was significantly higher with glycerol than placebo treatment (216.4, 366.4 ml vs 81.0, 242.0 ml, respectively) but significantly higher at 120 min in the placebo (421.6 ml vs 131.2 ml). There were no significant differences in heart rate and rectal temperature during the swim and cycle phases. However, there were significant increases in heart rate (at 5, 10, 15, 25 and 30 min) and rectal temperature (at 5, 20 and 30 min) during the 10 km run in the glycerol trial. The mean 10 km run time for the placebo trial was 40 min 21 sec (± 2.9 min) while the glycerol trial was 39 min 22 sec (± 2.0 min). The mean difference of 2.1% in finishing time between trials was not significant. Three of the five subjects in the glycerol trial improved their 10 km time by 7.0, 2.4 and 2.7%, respectively. The finishing time for one subject did not change for both trials while another subject had deteriorated by 2.3% in the glycerol trial. In the glycerol treatment, five subjects complained of bloating and nausea while only one subject complained of feeling unwell in the placebo treatment. Data from this study have shown that glycerol hyperhydration did not significantly improve performance while plasma volume expansion and subsequent lower rectal temperature and lower heart rates were not evident. The exact mechanisms of how glycerol hyperhydration can improve performance warrant further investigation. / Masters in Applied Science
| Identifer | oai:union.ndltd.org:ADTP/266041 |
| Date | January 2004 |
| Creators | Van Ewyk, Gerald |
| Publisher | University of Ballarat |
| Source Sets | Australiasian Digital Theses Program |
| Detected Language | English |
| Rights | Copyright Gerald T Van Eywk |
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