title: Discovery of the pendulum and spring dynamics in the early stages of walking.
abstract: The authors investigated the self-selected, overground walking patterns of 7 children (aged 11 months to 1 year, 5 months) at the initiation of walking (brand-new walkers [BNWs]) and for the next 6 months at 1-month intervals. Walking speed, stride length, and stride frequency increased significantly between the first 2 visits without significant changes in height and weight. The authors calculated sagittal plane angular accelerations of the center of mass over the foot for each step as an indicator of the escapement pulse. Results for the acceleration profiles changed after the 1st visit to positive, single-peaked accelerations that occurred < 0.20 s after initial foot contact. Increases in sagittal plane hip angular displacement and decreases in frontal plane pelvic angular displacement were observed. The pattern changes suggest that children quickly discover appropriately timed and directed escapements that initiate and support the conservative sagittal plane pendulum and spring dynamics observed in older children.
authors.affiliation: Department of Physical Therapy and Athletic Training, Sargent College of Health and Rehabilitation Sciences, Boston University, 635 Commonwealth Avenue, Boston, MA 02215, USA. kgholt@bu.edu
authors.forename: Kenneth G
authors.initials: KG
authors.lastname: Holt
authors.forename: Elliot
authors.initials: E
authors.lastname: Saltzman
authors.forename: Chia-Ling
authors.initials: CL
authors.lastname: Ho
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Kubo
authors.forename: Beverly D
authors.initials: BD
authors.lastname: Ulrich
mesh_terms: D000054:Acceleration; D001827:Body Height; D001835:Body Weight; D002657:Child Development; D005260:Female; D005500:Follow-Up Studies; D005684:Gait; D006801:Humans; D007223:Infant; D008297:Male; D004856:Postural Balance; D011601:Psychophysics; D016138:Walking; D016474:Weight-Bearing