title: On the Skill of Balancing While Riding a Bicycle.
abstract: Humans have ridden bicycles for over 200 years, yet there are no continuous measures of how skill differs between novice and expert. To address this knowledge gap, we measured the dynamics of human bicycle riding in 14 subjects, half of whom were skilled and half were novice. Each subject rode an instrumented bicycle on training rollers at speeds ranging from 1 to 7 m/s. Steer angle and rate, steer torque, bicycle speed, and bicycle roll angle and rate were measured and steering power calculated. A force platform beneath the roller assembly measured the net force and moment that the bicycle, rider and rollers exerted on the floor, enabling calculations of the lateral positions of the system centers of mass and pressure. Balance performance was quantified by cross-correlating the lateral positions of the centers of mass and pressure. The results show that all riders exhibited similar balance performance at the slowest speed. However at higher speeds, the skilled riders achieved superior balance performance by employing more rider lean control (quantified by cross-correlating rider lean angle and bicycle roll angle) and less steer control (quantified by cross-correlating steer rate and bicycle roll rate) than did novice riders. Skilled riders also used smaller steering control input with less variation (measured by average positive steering power and standard deviations of steer angle and rate) and less rider lean angle variation (measured by the standard deviation of the rider lean angle) independent of speed. We conclude that the reduction in balance control input by skilled riders is not due to reduced balance demands but rather to more effective use of lean control to guide the center of mass via center of pressure movements.
authors.affiliation: Department of Mechanical Engineering, The University of Michigan, Ann Arbor, Michigan, United States of America.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Cain
authors.affiliation: Department of Mechanical Engineering, The University of Michigan, Ann Arbor, Michigan, United States of America.|Department of Biomedical Engineering, The University of Michigan, Ann Arbor, Michigan, United States of America.|School of Kinesiology, The University of Michigan, Ann Arbor, Michigan, United States of America.
authors.forename: James A
authors.initials: JA
authors.lastname: Ashton-Miller
authors.affiliation: Department of Mechanical Engineering, The University of Michigan, Ann Arbor, Michigan, United States of America.
authors.forename: Noel C
authors.initials: NC
authors.lastname: Perkins
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008954:Models, Biological; D009048:Motor Skills / Q000502:physiology*; D011434:Proprioception / Q000502:physiology*