Pelvic and Shoulder Movements in the Frontal Plane During Treadmill Walking in Adults With Stroke Eva De Bujanda, MSc,*,† Sylvie Nadeau, PhD,*,† and Daniel Bourbonnais, PhD*,† Analysis of lateral displacement (LD) in the frontal plane during gait could provide information about asymmetric impairments and balance disorders for patients with stroke. The purpose of this study was to quantify the LD and lateral acceleration (LA) of the shoulders and pelvis of patients who were hemiparetic and walking at slow, natural, and fast speeds on a treadmill, and to compare the results with those for control subjects walking at similar speeds. A convenience sample of 10 patients with chronic stroke and 10 control subjects participated in this study. A videographic system was used to record the positions in the frontal plane of markers placed on the seventh cervical vertebra (shoulder level) and on the posterior iliac spines (pelvis level). Then, the LDs and LAs were calculated. The temporal parameters of the gait cycle were also determined using foot switches. The symmetry in the LAs and in the time spent in single stance was computed. Results showed that patients with stroke had larger LDs and LAs than the control group when walking at similar speeds. Results for patients with stroke also indicated that LAs were greater on the paretic side, whereas single stance percentages were greater on the nonparetic side. The data were almost sym- metric for the control subjects. These findings indicate that the pelvis and shoulder of a patient with stroke have different rhythmic activity in the frontal plane compared with those of control subjects performing at similar speeds. Key Words: Balance— frontal kinematics— stroke— treadmill walking. © 2004 by National Stroke Association Persons who have sustained a stroke usually present an abnormal and asymmetric gait pattern that can be noted in clinical observations. They load more on their unaffected limb and spend a greater proportion of the gait cycle in stance on this limb. 1-5 Furthermore, the transfer of weight bearing during the transition from the double-stance to the single-stance (SS) phase toward the affected side is impaired. 6 Many impairments, such as muscular weakness, spasticity, decreased sensitivity, and lack of coordination, might be responsible for these char- acteristics. 3,7-9 Another important factor that affects the gait independence of patients after stroke is the distur- bance of their body balance. 7,9,10 According to MacKinnon and Winter, 11 frontal-plane balance is particularly difficult during gait because of the narrow width of the base of support during the SS phase and the medio-lateral displacement (LD) of the body that produces a continuous imbalance. Frontal balance con- sists in controlling the center of mass (CM) trajectory laterally to maintain it within the base of support. 11,12 It regulates the horizontal dynamic movements of body segments during gait to avoid falls. The lateral balance of the upper body depends on the mediolateral placement of the foot, 11,13 and is maintained mostly by the hip abductors during quiet stance 14 and in the SS phase of walking. 15 Lateral balance during walking can be studied by con- sidering the linear LD and lateral acceleration (LA) of the From the *Centre de recherche interdisciplinaire en re ´adaptation du Montre ´al me ´tropolitain, Site Institut de re ´adaptation de Montre ´al, and †E ´ cole de re ´adaptation, Faculte ´ de me ´decine, Universite ´ de Montre ´al, Montre ´al, Que ´bec, Canada. Received December 13, 2003; accepted February 25, 2004. Supported by a MSc scholarship (E.D.B.) from the Fonds de la recherche en sante ´ du Que ´bec (FRSQ) and the Canadian Institute of Health Research (CIHR) (S.N.). This research received financial sup- port from FRSQ and CIHR. Address reprint requests to Sylvie Nadeau, PhD, Centre de recherche interdisciplinaire en re ´adaptation du Montre ´al me ´tropolitain, Site Insti- tut de re ´adaptation de Montre ´al, 6300 ave Darlington, (Montre ´al Que ´bec) H3S 2J4, Canada. E-mail: sylvie.nadeau@umontreal.ca. 1052-3057/$—see front matter © 2004 by National Stroke Association doi:10.1016/j.jstrokecerebrovasdis.2004.02.006 Journal of Stroke and Cerebrovascular Diseases, Vol. 13, No. 2 (March-April), 2004: pp 58-69 58