Research says ...
Study title: Influence of pre-exercise glucose ingestion of two concentrations on paraplegic athletes
Authors: O. Spendiff and I. Campbell (2004)
Source: Journal of Sports Sciences 23,21-30
Most athletes ingest commercially available sports drinks during the hour before exercise in an attempt to improve their performance. A sports drink with around 8% carbohydrate concentration is most commonly recommended for able-bodied athletes. Lower concentrations are thought to have negligible effect on performance, whilst higher concentrations can slow fluid and glucose delivery. The concentration of carbohydrate that is most beneficial for paraplegic athletes during the hour before exercise has not previously been reported.
To compare the physiological response and performance of paraplegic athletes when taking a pre-exercise 4% carbohydrate drink and an 11% carbohydrate drink.
Eight physically active men with paraplegia participated in the study. Each athlete performed two test sessions, one week apart, where the only difference between sessions was the carbohydrate concentration of a pre-exercise drink. Each trial consisted of one hour of exercise at 65% maximum oxygen uptake on a wheelchair ergometer, followed by a 20-minute performance test. Athletes consumed an orange flavoured glucose drink 20 minutes before the one-hour test, of either 4% or 11% carbohydrate concentration. Following the one-hour test, athletes were given a five-minute rest before undertaking a 20-minute performance test, where a freely chosen push rate was used to cover as much distance as possible. The effect of the different drinks was assessed by measuring selected physiological variables, including rate of oxygen uptake, ventilation, heart rate, respiratory exchange ratio, blood glucose, blood lactate and free fatty acid concentration, together with distance covered in the 20-minute performance test.
The main finding of the study was that 4% and 11% concentration carbohydrate drinks taken pre-exercise were absorbed by paraplegic athletes in a similar way to able-bodied athletes. Few statistically significant differences were detected in physiological variables, with only the free fatty acid concentration being significantly lower for the high carbohydrate trial. There was also a tendency for a higher blood glucose concentration and respiratory exchange ratio and a greater power output for the high carbohydrate trial.
The authors conclude that, despite possible autonomic dysfunction and loss of muscle mass for low legion paraplegic athletes, pre-exercise ingestion of high and low concentrations of carbohydrate did not cause a hypoglycaemic response and was not detrimental to performance. The higher blood glucose concentration, respiratory exchange ratio and power output and lower free fatty acid concentration for the high carbohydrate drink, led the authors to suggest that a higher concentration carbohydrate drink may be appropriate for paraplegic athletes.
Dixon
Dr. Sharon Dixon is a lecturer in sports biomechanics at the University of Exeter, specializing in causes and interventions for lower extremity injury. She has a Ph.D. in running biomechanics, has represented Great Britain at road running and has a marathon personal best of 2:45
______________________________________________________________________________
| Title |
Research says... |
| Author |
Dixon, Sharon; Denison, Jim |
| Source |
The Coach (Peterborough, England) |
| Publisher |
Descartes Publishing Ltd. |
| /Issue |
26 |
Date |
Jan/Feb 2005 |
| SIRC Article # |
S-994509 |
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