Comparison of four specific dynamic office chairs with a conventional office chair: Impact upon muscle activation, physical activity and posture
article
Prolonged and static sitting postures provoke physical inactivity at VDU workplaces and are therefore discussed as risk factors for the musculoskeletal system. Manufacturers have designed specific dynamic office chairs featuring structural elements which promote dynamic sitting and therefore physical activity. The aim of the present study was to evaluate the effects of four specific dynamic chairs on erector spinae and trapezius EMG, postures/joint angles and physical activity intensity (PAI) compared to those of a conventional standard office chair. All chairs were fitted with sensors for measurement of the chair parameters (backrest inclination, forward and sideward seat pan inclination), and tested in the laboratory by 10 subjects performing 7 standardized office tasks and by another 12 subjects in the field during their normal office work. Muscle activation revealed no significant differences between the specific dynamic chairs and the reference chair. Analysis of postures/joint angles and PAI revealed only a few differences between the chairs, whereas the tasks performed strongly affected the measured muscle activation, postures and kinematics. The characteristic dynamic elements of each specific chair yielded significant differences in the measured chair parameters, but these characteristics did not appear to affect the sitting dynamics of the subjects performing their office tasks. © 2011 Elsevier Ltd and The Ergonomics Society.
Topics
Dynamic office chairsEMGPhysical activityPostureVDU/computer workplaceDynamic elementsEMGErector spinaeMuscle activationOffice chairPhysical activityPostureRisk factorsSitting postureStructural elementsActivation analysisMuscleDynamicsadultarticlebiomechanicsbody posturechaircontrolled studyelectromyogramequipment designerector spinae muscleergonomicsfemalehumanhuman experimentjob performancejoint anglemalemuscle contractionmusculoskeletal system parametersnormal humanoffice chairphysical activitysittingskeletal muscletrapezius muscle
TNO Identifier
442915
ISSN
0003-6870
Source
Applied Ergonomics, 43(2), pp. 296-307.
Pages
296-307
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