Q Factor in cycling: kinematic and physiological effects

Disley, Benedict Xavier Edward St. John (2014). Q Factor in cycling: kinematic and physiological effects. University of Birmingham. Ph.D.

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Abstract

Q Factor represents the horizontal distance between pedals on a bicycle, measured from the outside edge of each crankarm. The action of pedalling is based upon human gait, which utilises a step width lower than standard Q Factors (150mm for road bicycles). The aims of this thesis were to understand the kinematic and physiological effects of manipulating Q Factor. Lower Q Factors than standard afforded increased gross mechanical efficiency and individually determined optimal Q Factor (OQ) provided increased power output during laboratory time trials. Self selected Q Factor (SSQ) was lower than standard in trained cyclists and could be predicted using a simple suspension task. The use of SSQ compared with Q Factors higher and lower than SSQ provided a combination of kinematic stability and increased efficiency, lowering the risk of injury and the oxygen cost of cycling. Lower Q Factors than the standard 150mm for road bicycles provide performance and kinematic benefits that have not been examined previously. As part of the overall package of bicycle fit, individual cyclists will be able to make measurable improvements by finding and utilising their self selected Q Factor.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):