The purpose of this study was to examine the effects of chainring type (circular vs. the non- circular Rotor Q-Ring) on performance during a 1km time trial and physiological responses over a six week period. Eight competitive male cyclists and triathletes were pre-tested using the original circular chainring. Graded submaximal exercise tests were followed by the 1km time trial with subjects using their own racing bicycle. The circular chainrings were then removed and replaced with Rotor Q-Rings during the intervention period. Subjects trained and raced with this alteration to their bicycles and repeated the submaximal and 1km performance tests for the next four weeks. Post-testing occurred with the original circular chainrings for the final week of testing. Oxygen consumption, carbon dioxide output, heart rate, ventilation, respiratory exchange ratio, and perceived exertion were continuously measured during the submaximal tests. Blood lactate concentration was measured during the last 30 s of each three minute stage. The main findings were: 1) Significant increases in performance in the 1km time trial with Rotor Q-Rings compared to circular chainrings. Subjects completed the time trial on average 1.6 seconds faster (p < 0.05), increased average speed approximately 0.7 kph (p < 0.05), and increased average power approximately 26 watts (p < 0.05). 2) During submaximal testing, oxygen consumption during weeks 2-4 and heart rate during weeks 1-3 were significantly lower (p < 0.05) with Rotor Q-Rings compared to circular chainrings. Furthermore, 1km time trial improvements occurred after just one week employing the Rotor Q-Rings and results were consistent over subsequent 1km time trials with the Rotor Q-Rings. Performance levels returned to initial values during final testing with the circular chainrings. The maximal oxygen consumption results from the Pre-test and week 5 Post-test further demonstrated that positive performance effects were only evident with the Rotor Q- Rings. While it appears from this study that there may also be positive long term effects as noted by the significant reduction in submaximal oxygen consumption and heart rate during the intervention period (i.e., cycling with Rotor Q-Rings), the majority of the physiological measures we examined do not equivocally support the notion that an adaptation period is necessary for this increased 1km time trial performance.



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URL: http://digitalcommons.calpoly.edu/kine_fac/102