An Official Journal of ISB www.JAB-Journal.com TECHNICAL NOTE 574 Journal of Applied Biomechanics, 2014, 30, 574-580 http://dx.doi.org/10.1123/jab.2013-0333 © 2014 Human Kinetics, Inc. Mathieu Lalumiere, Dany H. Gagnon, and Guillaume Desroches are with the Pathokinesiology Laboratory in the Center for Interdisciplinary Research in Rehabilitation of Greater Montréal at the Institut de réadapta- tion Gingras-Lindsay-de-Montréal in Montréal, QC, Canada as well as the School of Rehabilitation at the Université de Montréal in Montréal, QC, Canada. François Routhier and Laurent Bouyer are with the Center for Interdisciplinary Research in Rehabilitation and Social Integration (CIRRIS) at the Institut de réadaptation en déicience physique de Québec in Québec City, QC, Canada as well as the Department of Rehabilitation at the Université Laval in Québec City, QC, Canada. Address author cor- respondence to Dany H. Gagnon at dany.gagnon.2@umontreal.ca. Upper Extremity Kinematics and Kinetics During the Performance of a Stationary Wheelie in Manual Wheelchair Users With a Spinal Cord Injury Mathieu Lalumiere, 1,2 Dany H. Gagnon, 1,2 François Routhier, 3,4 Laurent Bouyer, 3,4 and Guillaume Desroches 1,2 1 Institut de réadaptation Gingras-Lindsay-de-Montréal; 2 Université de Montréal; 3 Institut de réadaptation en déficience physique de Québec; 4 Université Laval No comprehensive biomechanical study has documented upper extremity (U/E) kinematics and kinetics during the performance of wheelchair wheelies among manual wheelchair users (MWUs). The aim of this study was to describe movement strategies (kinematics), mechanical loads (kinetics), and power at the nondominant U/E joints during a wheelie among MWUs with spinal cord injury (SCI). During a laboratory assessment, 16 MWUs with SCI completed four wheelie trials on a rigid surface. Each participant’s wheelchair was equipped with instrumented wheels to record handrim kinetics, while U/E and wheelchair kinemat- ics were recorded with a 3D motion analysis system. The greatest mean and peak total net joint moments were generated by the shoulder lexors (mean = 7.2 ± 3.5 N·m; peak = 20.7 ± 12.9 N·m) and internal rotators (mean = 3.8 ± 2.2 N·m; peak = 11.4 ± 10.9 N·m) as well as by the elbow lexors (mean = 5.5 ± 2.5 N·m; peak = 14.1 ± 7.6 N·m) during the performance of wheelies. Shoulder lexor and internal rotator efforts predominantly generate the effort needed to lift the front wheels of the wheelchair, whereas the elbow lexor muscles control these shoulder efforts to reach a state of balance. In combination with a task-speciic training program that remains essential to properly learn how to control wheelies among MWUs with SCI, rehabilitation profes- sionals should also propose a shoulder lexor, internal rotator, and elbow lexor strengthening program. Keywords: biomechanics, elbow, paraplegia, rehabilitation, shoulder For manual wheelchair users (MWUs), it is important to acquire the ability to independently and safely perform wheelies (ie, to remain stable on the rear wheels). In the everyday life of a MWU, this ability frequently facilitates the performance of other wheelchair skills (eg, crossing a door step, turning in a restricted space, negotiating rough ground, ascending and descending a curb, or going down a steep ramp) 1 and allows temporary seated position changes linked to health-related beneits (eg, preservation of skin integrity at the buttocks, reduced neck discomfort or pain). 2,3 For these reasons, rehabilitation professionals assess and teach this wheelchair skill in clinical practice. Only a few biomechanical studies have investigated the perfor- mance of wheelies among MWUs. 4–10 Some of these studies have examined the balance strategies used to maintain static balance on the rear wheels, 4–7 whereas some others have focused on the most appropriate task-speciic training approach to implement in clinical practice. 8–10 Surprisingly, no comprehensive biomechanical study has documented upper extremity (U/E) kinematics and kinetics during the performance of wheelchair wheelies among MWUs. Hence, the current study aims to quantify the kinematics and kinet- ics at the nondominant shoulder, elbow, and wrist joints during the performance of a stationary wheelie among experienced MWUs with a spinal cord injury (SCI). Methods Participants Sixteen individuals who sustained a SCI at least one year before the study, use a manual wheelchair as their primary mean of mobility (> 4 hours per day), are able to perform wheelies independently, and experience very little to no shoulder pain in daily life (mean Wheelchair User Shoulder Pain Index 11 [WUSPI] score = 0.11 ± 0.15/10) volunteered to participate in this study (Table 1). Individu- als were excluded if they had associated condition(s) that could hinder their ability to independently perform wheelchair wheelies. Ethical approval was obtained from the Research Ethics Commit- tee of the Center for Interdisciplinary Research in Rehabilitation of Greater Montréal. Experimental Tasks During the laboratory assessment, participants performed four wheelies with their personal wheelchair on a solid low-resistance surface. The choice of using their personal wheelchair was motivated by the fact that each participant had personalized their wheelchair itting and adjustments over time, including the most forward rear