Theoretical and correlation data indicate that abnormal patterns of frontal plane knee tracking and knee flexion angle are important factors in the development of overuse injuries in cycling. Currently, bicycle “fitters” typically rely on visual assessments to apply current theories. However, practitioners are limited by a lack of prospective data, an unknown applicability to the field setting and unvalidated methods that are subjective and experience dependent. The current gold standard for motion analysis, 3D video motion, is largely limited to use in resource rich laboratory settings, and the complex multivariate data can still be difficult to interpret. Here we propose a novel to cycling method of relative accelerometry, employing triaxial accelerometers and functional principal component analysis (fPCA), as a valid cost effective means capable of discriminating between common bicycle fit conditions. Procedure: Ten to 20 experienced competitive subjects age 13 and older, with a good bike fit, and free of biomechanic dysfunction, as determined by the survey and physical assessment, will undergo motion analysis while cycling on a stationary trainer in each one of six randomized fit conditions including current fit, standardized fit, high seat, low seat, varus cleat wedge and valgus cleat wedge. Trials will be recorded simultaneously by manual rating, 2D and 3D video, foot-bed pressure sensors, and triaxial accelerometers.