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The effect of the rotor crank system on time-trial cycling performance

Hopker, James G., Jobson, Simon A., Galbraith, Andy, Coleman, Damian A, Nevill, Alan M. (2009) The effect of the rotor crank system on time-trial cycling performance. Journal of Sports Sciences, 26 (S2). S111-S111. ISSN 0264-0414. E-ISSN 1466-447X. (doi:10.1080/02640410802306202) (Access to this publication is currently restricted. You may be able to access a copy if URLs are provided) (KAR id:23818)

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The Rotor (ROT) is a cycle crank configuration that allows the pedals to move independently in an attempt to eliminate the “dead spots”, where torque output is minimal. Delta efficiency has been found to be significantly improved during an incremental test when using ROT in a group of untrained cyclists (Santalla et al., 2002: Medicine and Science in Sports and Exercise, 34, 1854-1858). However, no study has investigated whether ROT affects cycling performance directly. Therefore, the purpose of this study was to investigate the effect of ROT on time-trial cycling performance.

Following institutional ethics approval, 12 competitive male cyclists (Age mean 34.6, s = 7.1 years, Mass mean 75.9, s = 7.8 kg, max mean 4.5, s = 0.3 L•min-1, Wmax mean 363, s = 37.7 W) provided written informed consent to participate. All subjects completed two 40.23-km time-trials on a Kingcycle ergometer in each of two conditions, i) using conventional bicycle cranks (CON) and ii) using the Rotor system (ROT). Cyclists trained for 6-weeks prior to the experimental trials as either habitual ROT users or habitual CON users. Power output, speed, heart rate, , RER and gross efficiency were measured for the duration of each time-trial.

A two-way repeated measures ANOVA (pedalling system used during the test [CON, ROT] x habitual pedalling system [CON, ROT]) was performed to determine if there was a significant condition effect on the following variables: power output, speed, heart rate, , RER and gross efficiency. Statistical significance was set at P < 0.05 for all tests. Power output was not different between conditions (CON mean 255, s = 44 W vs. ROT mean 253, s = 40 W; P > 0.05). Indeed, no effect due to the pedalling system used during tests was found for any of the measured variables (P > 0.05). Furthermore, there was no interaction effect between the two factors for any of the measured variables (P > 0.05). However, there were marked differences between conditions for some individuals. For example, power output was ~11% higher during the CON trial vs. the ROT trial for one subject but ~12% lower in another.

These results suggest that the Rotor crank system does not impact on time-trial cycling performance. However, marked differences were observed between CON and ROT in some individuals, suggesting that ROT may be beneficial in some instances.

Item Type: Article
DOI/Identification number: 10.1080/02640410802306202
Subjects: R Medicine > RC Internal medicine > RC1200 Sports medicine
Divisions: Divisions > Division of Natural Sciences > Sport and Exercise Sciences
Depositing User: James Hopker
Date Deposited: 21 Jan 2011 16:59 UTC
Last Modified: 16 Nov 2021 10:02 UTC
Resource URI: (The current URI for this page, for reference purposes)
Hopker, James G.:
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