title: Wheelchair pushrim kinetics measurement: A method to cancel inaccuracies due to pushrim weight and wheel camber.
abstract: The commercially available SmartWheelTMis largely used in research and increasingly used in clinical practice to measure the forces and moments applied on the wheelchair pushrims by the user. However, in some situations (i.e. cambered wheels or increased pushrim weight), the recorded kinetics may include dynamic offsets that affect the accuracy of the measurements. In this work, an automatic method to identify and cancel these offsets is proposed and tested. First, the method was tested on an experimental bench with different cambers and pushrim weights. Then, the method was generalized to wheelchair propulsion. Nine experienced wheelchair users propelled their own wheelchairs instrumented with two SmartWheels with anti-slip pushrim covers. The dynamic offsets were correctly identified using the propulsion acquisition, without needing a separate baseline acquisition. A kinetic analysis was performed with and without dynamic offset cancellation using the proposed method. The most altered kinetic variables during propulsion were the vertical and total forces, with errors of up to 9N (p<0.001, large effect size of 5). This method is simple to implement, fully automatic and requires no further acquisitions. Therefore, we advise to use it systematically to enhance the accuracy of existing and future kinetic measurements.
authors.affiliation: Department of Physical Activity Science, Université du Québec à Montréal, Canada; Pathokinesiology Laboratory, Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR)- site Gingras-Lindsay Rehabilitation Institute of Montreal, Canada. Electronic address: felix@felixchenier.com.
authors.forename: Félix
authors.initials: F
authors.lastname: Chénier
authors.affiliation: Pathokinesiology Laboratory, Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR)- site Gingras-Lindsay Rehabilitation Institute of Montreal, Canada; Department of Automated Manufacturing Engineering, École de technologie supérieure, Montréal, Canada.
authors.forename: Rachid
authors.initials: R
authors.lastname: Aissaoui
authors.affiliation: Pathokinesiology Laboratory, Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR)- site Gingras-Lindsay Rehabilitation Institute of Montreal, Canada; School of Rehabilitation, Faculty of Medicine, University of Montreal, Canada.
authors.forename: Cindy
authors.initials: C
authors.lastname: Gauthier
authors.affiliation: Pathokinesiology Laboratory, Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR)- site Gingras-Lindsay Rehabilitation Institute of Montreal, Canada; School of Rehabilitation, Faculty of Medicine, University of Montreal, Canada.
authors.forename: Dany H
authors.initials: DH
authors.lastname: Gagnon
mesh_terms: D000328:Adult; D016477:Artifacts; D006801:Humans; D007700:Kinetics; D055595:Mechanical Phenomena; D008875:Middle Aged; D014910:Wheelchairs; D055815:Young Adult
keywords: Biomechanics; Instrumented wheels; Kinetics; Signal processing; SmartWheel; Wheelchairs