title: Metabolic and kinematic effects of self-selected Q Factor during bike fit.
abstract: Correct bicycle fit is important, and kinematic instability must be addressed to reduce the risk of knee injury. A change in Q Factor (horizontal distance between crank arms) has been shown to decrease metabolic cost. The combined effect upon gross mechanical efficiency (GME) and knee variability is unclear, however; there is no known simple method to predict self-selected Q Factor (SSQ). The SSQ was hypothesized to provide the greatest GME and least variability at the knee. Ten trained cyclists completed bouts of submaximal cycling at a range of Q Factors. The effectiveness of hanging and stepping tasks as predictors of SSQ was also tested. Measured SSQ (142 mm) provided the best combination of GME and knee stability compared with other Q Factors, and could be accurately predicted using a simple hanging task. The SSQ has the potential to lower the risk of knee injury and provide increased efficiency whilst cycling.
authors.affiliation: a School of Sport, Exercise, and Rehabilitation Sciences, University of Birmingham , Birmingham , United Kingdom.
authors.forename: Benedict Xavier
authors.initials: BX
authors.lastname: Disley
authors.forename: Francois-Xavier
authors.initials: FX
authors.lastname: Li
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D001696:Biomechanical Phenomena; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D010809:Physical Fitness / Q000502:physiology*; D011237:Predictive Value of Tests; D012016:Reference Values; D015203:Reproducibility of Results