|dc.description.abstract||Aim: The present investigation aimed to explore the placebo effect of pre-exercise carbohydrate
feeding via the ingestion a carbohydrate sports drink on short duration high intensity exercise. A
secondary aim was to examine the effectiveness of the carbohydrate drink on short duration
high intensity exercise.
Methods: 8 subjects (3 males and 5 females, mean age ± SD = 21.1 ± 2.0 years, range = 18-25
years) completed the study. A randomised within-subjects repeated measures design was
utilised to assess differences in: total performance duration, average heart rate, peak heart rate,
RPE measured at minute two, five and immediately at the end of the exercise test. 30 minutes
prior to exercise subjects were required to drink 250ml of either a carbohydrate drink, a non
carbohydrate drink or a perceived 50/50 chance of receiving either drink (each subject
unknowingly received the non carbohydrate drink for this condition). The experimental trials
required subjects to continuously cycle until exhaustion on a cycle ergometer at a set cadence
of 75RPM and at an intensity of 90% maximal power output.
Results: A repeated measures ANOVA test revealed a significant difference in the total
performance duration between the “told carbohydrate” condition compared to the “told non
carbohydrate condition” (P=0.01), and very close to the accepted significance of <0.05 between
the “told carbohydrate” and the “told 50/50” condition (P=0.06). No significant difference was
observed between the “told 50/50” condition and the “told non carbohydrate” condition (P=0.97).
No difference was observed been trials in the average heart rates (bpm), peak heart rates (bpm)
and RPE measured at minute two, 5 and at the end of the test (all P=>0.05).
Conclusion: The present study did not demonstrate a placebo effect of ingesting a 32g
carbohydrate drink 30 minutes before high intensity short duration exercise. The present study
did provide some indication of a possible performance enhancement from the actual ingestion of
a 32g carbohydrate drink ingested 30 minutes before high intensity short duration exercise. The
findings should however be treated with caution and further research should be undertaken
addressing the limitations of the study before pre-exercise carbohydrate feeding or the placebo
effects can be confirmed or rejected as a performance-enhancing aid in relation to high intensity
short duration exercise.||en_US