The effect of caffeine ingestion on cycling performance

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Dalsky, Gail P.
Costill, David L.
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Thesis (M.A.)
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The intent of this thesis was to study the effects of caffeine ingestion on substrate utilization and muscle metabolism during exercise, as reflected by endurance time to exhaustion. For this purpose, seven trained cyclists performed work bouts at 80% of maximal oxygen consumption to exhaustion after ingestion of caffeine (CAF trial) end under control (CON trial) conditions.Although the work time to exhaustion was not significantly different between the CAF trial, 91.8 (S.E. ± 7.7) min and the CON trial, 85.2 (S.E. ± 10.5) min, five of he subjected did show an average 18% increase in performance following ingestion of 330 mg caffeine. Since there was no elevation of FFA prior to exercise, it was expected that no muscle glycogen sparing would occur during the first 30', 41.7 (S.E. ± 6.1) mM/kg in the CAF trial and 42.1 (S .E. + 6.6) mM/kg in the CON trial. Serum glycerol concentration was significantly (P< .05) during the CAF trial at 10' and 30'. R values were significantly lower during the CAF trial, .87 (S.E. ± .01) than the CON trial, .91 (S.E. ± .01) at exhaustion. Significantly lower (p<.05) perceived exertion ratings were also observed during the CAF trial. These data suggest a positive effect on endurance exercise performance following caffeine ingestion.