Effects of a Dynamic Chair on Chair Seat Motion and Trunk Muscle Activity during Office Tasks and Task Transitions.

Corina Nüesch,Lars Donath,Jan-Niklas Kreppke,Annegret Mündermann

doi:10.3390/ijerph15122723

Abstract

Employing dynamic office chairs might increase the physical (micro-) activity during prolonged office sitting. We investigated whether a dynamic BioSwing® chair increases chair sway and alters trunk muscle activation. Twenty-six healthy young adults performed four office tasks (reading, calling, typing, hand writing) and transitions between these tasks while sitting on a dynamic and on a static office chair. For all task-transitions, chair sway was higher in the dynamic condition (p < 0.05). Muscle activation changes were small with lower mean activity of the left obliquus internus during hand writing (p = 0.07), lower mean activity of the right erector spinae during the task-transition calling to hand writing (p = 0.036), and higher mean activity of the left erector spinae during the task-transition reading to calling (p = 0.07) on the dynamic chair. These results indicate that an increased BioSwing® chair sway only selectively alters trunk muscle activation. Adjustments of chair properties (i.e., swinging elements, foot positioning) are recommended.

Highlights

Physical inactivity is considered an independent risk factor for many non-communicable diseases and has been entitled as biggest public health problem of the 21st century [1]
Our results indicate that (a) the path length of the chair center was significantly longer for the dynamic chair during calling and all task transitions and (b) muscle activation during all tasks did not differ between the chairs but showed small to notable changes during the task transitions reading to calling, calling to writing and typing to writing
The observed altered chair motion was associated with only small differences in trunk muscle activation levels for sitting on the dynamic chair compared to the static chair

Summary

Introduction

Physical inactivity is considered an independent risk factor for many non-communicable diseases and has been entitled as biggest public health problem of the 21st century [1]. Projections have indicated that the metabolic equivalent (MET) of daily physical work will drop to 190 MET hours per week in 2030 because of technological development and automation [2]. Most persons in developed countries spend more than half of their waking hours in seated postures which negatively affects mortality and increases the risk of, for instance, cardiovascular disease, diabetes, back pain, stroke, and obesity [3]. It is important to increase leisure time physical activity (PA). Besides leisure time PA opportunities, work places involving mainly sitting activities (e.g., office, libraries, lecture halls) represent a challenging and promising setting for encouraging PA

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