title: Stand up: comparison of two electrical screed levelling machines to reduce the work demands for the knees and low back among floor layers.
abstract: Electrical screed levelling machines are developed to reduce kneeling and trunk flexion of sand-cement-bound screed floor layers. An observational intervention study among 10 floor layers was performed to assess the differences between a self-propelled and a manually moved machine. The outcome measures were work demands, production time, perceived load, discomfort and applicability. Compared to the self-propelled machine, the duration of kneeling (∆13 min; p = 0.003) and trunk flexion (∆12 min; p < 0.001) was shorter using the manually moved machine, and the duration of pushing and pulling increased (∆39 min; p < 0.001). No significant or relevant differences were found for production time, perceived load and discomfort. Nine out of ten floor layers found the manually moved machine applicable and three out of ten found the self-propelled machine applicable. When compared with the traditional manner of floor laying, both electrical machines reduced the exposure towards kneeling and trunk flexion. Practitioner Summary: Electrical machines may help to reduce high physical work demands on floor layers. A manually moved machine is better applicable for the installation of screed floors in residences with smaller floor areas. A self-propelled machine is better applicable on large floor areas with a minimum width of 4 m.
authors.affiliation: a Coronel Institute of Occupational Health, Academic Medical Center, University of Amsterdam , Amsterdam , The Netherlands.
authors.forename: Steven
authors.initials: S
authors.lastname: Visser
authors.affiliation: a Coronel Institute of Occupational Health, Academic Medical Center, University of Amsterdam , Amsterdam , The Netherlands.|b Arbouw , Harderwijk , The Netherlands.
authors.forename: Henk F
authors.initials: HF
authors.lastname: van der Molen
authors.affiliation: a Coronel Institute of Occupational Health, Academic Medical Center, University of Amsterdam , Amsterdam , The Netherlands.
authors.forename: P Paul F M
authors.initials: PP
authors.lastname: Kuijer
authors.affiliation: a Coronel Institute of Occupational Health, Academic Medical Center, University of Amsterdam , Amsterdam , The Netherlands.
authors.forename: Judith K
authors.initials: JK
authors.lastname: Sluiter
authors.affiliation: a Coronel Institute of Occupational Health, Academic Medical Center, University of Amsterdam , Amsterdam , The Netherlands.
authors.forename: Monique H W
authors.initials: MH
authors.lastname: Frings-Dresen
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D060389:Construction Industry / Q000379:methods; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008161:Lumbosacral Region / Q000502:physiology*; D008297:Male; D008328:Man-Machine Systems; D009784:Occupational Diseases / Q000517:prevention & control*; D011187:Posture / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology; D014938:Work Capacity Evaluation
keywords: Ergonomic measures; floor layers; knees; low back; work demands