Presenting : Gabriel Moisan, PhD

INTRODUCTION/INTRODUCTION
Postural control impairments are common following a stroke and have impact on mobility, reduce independence and increase the risk of falls. Most previous studies assessed these impairments in stroke survivors (SS) during a quiet standing (QS) task and focused on centre of pressure (COP) measurements. Assessing the postural control impairments during tasks more representative of real-life situations, such as voluntary stepping response (VSR) and use centre of mass (COM) and spatiotemporal measurements will enhance our understanding of how the postural control system is impaired in SS.

OBJECTIVE/OBJECTIF
To identify the postural control impairments encountered by SS during QS and VSR tasks.

METHODS/MÉTHODOLOGIE
Twenty SS and sixteen healthy controls (CON) were recruited to perform QS and VSR tasks while ground reaction forces and whole-body motion were respectively measured with two force plates and a passive three-dimensional motion analysis system. Displacement and speed variation of the COM, displacement of the COP and spatiotemporal data were calculated and compared between the SS and CON groups.

RESULTS/RÉSULTATS
During the QS task, the SS group exhibited greater maximal COP displacement in the mediolateral direction and COM displacement in the vertical direction compared to the CON group. During the VSR task, the SS group exhibited smaller step length, brake force, posterior foot placement in relation to the pelvis and COM excursion in anteroposterior direction compared to the CON group.

CONCLUSIONS/CONCLUSIONS
SS presented decreased static and dynamic postural stability compared to healthy counterparts. The increased postural sway during QS, the smaller anteroposterior maximal COM displacement before losing balance and the altered voluntary compensatory steps during the VSR task place SS at greater risk of falling when they face a postural challenge in the community.