title: Description and analysis of hand forces in medicine cart pushing tasks.
abstract: The primary objectives of this study were to describe and analyze the hand force exertion patterns of experienced nursing home nurses and nursing students during dynamic medicine cart pushing tasks in Initial, Sustained, Turning, and Stopping motion phases. A 2 × 2 × 2 factorial experiment was conducted with 22 participants to estimate the effects of lane congestion, precision cart control, and floor surface on horizontal hand forces. Root mean squared (RMS) lane deviation patterns were also described to provide an indicator of cart handling difficulty across the different study conditions. Descriptive statistics revealed that nurses exerted greater mean hand force (10%) and made more (12%) lane deviation than students and that the highest two-hand forces of 147N were measured in the Turning phase on carpet. Strong correlations between work experience group, body mass, and BMI required that force data for nurses and students be collapsed in analytical models where no group differences existed. Predicted pushing forces on carpeted floor surface were significantly greater than on tile in Initial (14N), Sustained (14N) and Turning (18N), except in stopping where pulling forces were 37N lower. High lane congestion predicted significant peak force increases of 4N and 7N in Sustained and Turning, respectively, but decreased by 20N in Initial. High precision control led to significant decreases in two-hand forces that ranged from 4 to 20N across motion phases. Complex interactions among the experimental factors suggest that work environment (lane congestion and floor surface) and work demands (precision control) should be included in the evaluation of pushing tasks and considered prior to making renovations to nursing home environments.
authors.affiliation: Liberty Mutual Research Institute for Safety, Center for Physical Ergonomics, USA. jon.boyer@childrens.harvard.edu
authors.forename: Jon
authors.initials: J
authors.lastname: Boyer
authors.forename: Jia-Hua
authors.initials: JH
authors.lastname: Lin
authors.forename: Chien-Chi
authors.initials: CC
authors.lastname: Chang
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D005430:Floors and Floorcoverings; D017276:Friction; D006225:Hand / Q000502:physiology*; D006801:Humans; D008404:Massachusetts; D008875:Middle Aged; D009735:Nursing Homes; D009740:Nursing Staff; D010865:Pilot Projects; D013312:Stress, Physiological / Q000502:physiology*; D013338:Students, Nursing; D013647:Task Performance and Analysis; D055815:Young Adult