Date of Award


Degree Name

MS in Kinesiology




Robert D. Clark, Ph. D.


The development of noncircular chainrings to improve cycling performance has been in progress since the 1980’s and continues apace. The aim of this study was to compare performance time and physiological responses in cycling using a standard circular chainring versus a noncircular chainring developed in 2005: the Rotor Q-Ring. Eight competitive male cyclists were pre-tested using the original circular chainrings and also on the initial week of testing. The intervention consisted of cycling with Rotor Q-Rings for four weeks. Post-testing occurred with the original chainrings for the final week of testing. Testing consisted of a maximal or submaximal graded exercise test followed by a 1 k time trial. Oxygen consumption, carbon dioxide output, heart rate, ventilation, respiratory exchange ratio, and perceived exertion were continuously measured during the tests. Blood lactate concentration was measured during the last 30 s of each three minute stage. Five minutes after the submaximal test, participants performed an “all out” 1 k trial for time as well as maximum and average power. The main findings were: 1) Participants were on average 1.6 seconds faster in the 1 k time trial with Rotor Q-Rings compared to a circular chainrings. 2) There was a significant increase in average power (26.7 watts) and average speed (0.7 kph) during the 1 k time trial with Rotor Q-Rings. 3) Oxygen consumption (during weeks 2-4) and heart rate (weeks 1-3) were significantly lower with Rotor Q-Rings during submaximal testing when compared to circular chainrings. However, in contrast to our hypotheses no benefits were observed for other submaximal dependent measures (i.e., CO2, VE, RER, RPE, GE, DE, and lactate).

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