title: Evaluation of a "walk-through" ladder top design during ladder-roof transitioning tasks.
abstract: This study evaluated the effect of an extension ladder "walk-through" top design on kinetic and kinematic behaviors and the outward destabilizing forces induced on the ladder during transitioning at elevation. Thirty-two male participants performed stepping tasks between a ladder top and a roof at simulated elevation in a surround-screen virtual-reality system. The experimental conditions included a "walk-through" and a standard ladder top section supported on flat and sloped roof surfaces. Three force platforms were placed under the ladder section and in the roof to measure propulsion forces during transitions. A motion measurement system was used to record trunk kinematics. The frictional demand at the virtual ladder base was also calculated. The results indicate that under optimal ladder setup (angle 75.5 °), the frictional demand at the ladder base remains relatively small for all experimental conditions. Also, the "walk through" ladder top eased the ladder-to-roof transitions but not the roof-to-ladder transitions.
authors.affiliation: Division of Safety Research, National Institute for Occupational Safety and Health, 1095 Willowdale Rd., Morgantown, WV 26505, USA. Electronic address: psimeonov@cdc.gov.
authors.forename: P
authors.initials: P
authors.lastname: Simeonov
authors.affiliation: Division of Safety Research, National Institute for Occupational Safety and Health, 1095 Willowdale Rd., Morgantown, WV 26505, USA.
authors.forename: H
authors.initials: H
authors.lastname: Hsiao
authors.affiliation: Division of Safety Research, National Institute for Occupational Safety and Health, 1095 Willowdale Rd., Morgantown, WV 26505, USA.
authors.forename: J
authors.initials: J
authors.lastname: Powers
authors.affiliation: Division of Safety Research, National Institute for Occupational Safety and Health, 1095 Willowdale Rd., Morgantown, WV 26505, USA.
authors.forename: D
authors.initials: D
authors.lastname: Ammons
authors.affiliation: Division of Safety Research, National Institute for Occupational Safety and Health, 1095 Willowdale Rd., Morgantown, WV 26505, USA.
authors.forename: T
authors.initials: T
authors.lastname: Kau
authors.affiliation: Division of Safety Research, National Institute for Occupational Safety and Health, 1095 Willowdale Rd., Morgantown, WV 26505, USA.
authors.forename: D
authors.initials: D
authors.lastname: Cantis
authors.affiliation: Division of Safety Research, National Institute for Occupational Safety and Health, 1095 Willowdale Rd., Morgantown, WV 26505, USA.
authors.forename: J
authors.initials: J
authors.lastname: Zwiener
authors.affiliation: Division of Safety Research, National Institute for Occupational Safety and Health, 1095 Willowdale Rd., Morgantown, WV 26505, USA.
authors.forename: D
authors.initials: D
authors.lastname: Weaver
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control*; D000328:Adult; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D004867:Equipment Design; D017276:Friction; D006801:Humans; D008297:Male; D008875:Middle Aged; D012449:Safety; D013647:Task Performance and Analysis; D014584:User-Computer Interface; D016138:Walking; D055815:Young Adult
keywords: Fall; Ladder; Stability