Senior Honors Projects, 2010-current

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Date of Award

Summer 2013

Document Type


Degree Name

Bachelor of Science (BS)


Department of Kinesiology


Michael J. Saunders

Nicholas D. Luden

M. Kent Todd


The purpose of this study was to examine the effects of carbohydrate ingestion on cycling time trial performance and gastrointestinal tolerance during endurance exercise. Eight trained male cyclists (age: 25  6 years old, height: 180  4 cm, weight: 77  9 kg, and VO2max: 62  6 ml/kg/min) completed the study. Subjects consumed either a placebo beverage (PL), a high glucose beverage (HG: 1.5 g/min), a moderate glucose beverage (MG: 1.0 g/min), or a glucose and fructose beverage (1.5 g/min; 2:1 ratio) during approximately 3 hours of exercise, which consisted of 2 hours of constant load cycling (55% Wmax) followed by a computer-simulated 30- km time-trial. Gastrointestinal distress was assessed every 30 minutes during the first 2 hours of cycling and throughout the time-trial, and performance was measured by time to complete the time-trial. Treatment differences were analyzed using one-way ANOVA with simple contrasts performed between individual treatments. Frequencies of gastrointestinal distress symptoms were calculated. Time-trial performance was improved with GF consumption compared to PL and HG (p<0.05), but not versus MG. GI distress scores were generally low throughout all trials, and were not significantly affected by the treatments. In conclusion, cycling performance was improved with GF ingestion in comparison to HG, but differences in performance could not be attributed to decreased GI complaints with GF. Performance in the GF trial was not significantly faster than MG, so it is not clear whether GF beverages improve performance in comparison to recommended doses of glucose alone.



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