Kinesiologia

Gait & Posture 22 (2005) 338–345 www.elsevier.com/locate/gaitpost

Sagittal spine and lower limb movement during sit-to-stand in healthy young subjects
Elizabeth A. Tully*, Mohammad Reza Fotoohabadi, Mary P. Galea
School of Physiotherapy, The University of Melbourne, Parkville, Vic. 3010, Australia Received 14 April 2004; received in revised form 22 July 2004; accepted 19 November 2004Abstract This study aimed to determine the sagittal movement relationships between thoracic, lumbar spine and hip joints during sit-to-stand (STS). Forty-seven healthy young adults were videotaped performing STS at their preferred speed from a chair set at 100% knee height. Forward trunk lean prior to buttock lift-off (LO) was accomplished by concurrent lumbar and hip flexion (1:3). As the lumbarspine flexed the thoracic spine extended, resulting in a LO trunk angle of 45.78 (Æ5.88) with respect to a horizontal reference. Following LO, the hip(s) and lumbar spine extended and the thoracic spine flexed, with the standing thoracic angle approximating the initial thoracic posture in sitting. # 2004 Elsevier B.V. All rights reserved.
Keywords: Sit-to-stand; Movement analysis; Thoracic spine;Lumbar spine

1. Introduction The ability to stand up from sitting on a chair is an essential prerequisite for walking and therefore independent function [1]. Inability to effectively perform sit-to-stand (STS) can lead to severe mobility impairment, for example, in young children with cerebral palsy [2], and in older people experiencing musculo-skeletal problems [3–5]. Inability to perform thisessential activity may lead to dependence, institutionalization and even death in elderly subjects [6]. Although a seemingly simple task, STS requires the coordinated interaction of linked body segments to transport effectively the body’s centre of mass in a horizontal then vertical direction while maintaining balance over a small base of support, the feet. The basic kinematics include flexion of thetrunk and hips to bring the centre of mass forward, followed by bilateral extension of the lower limb joints and trunk extension to raise the body mass in a vertical direction over the feet [7]. Previous STS studies have investigated various aspects of this task, such as the total time taken, velocity and
* Corresponding author. Tel.: +61 3 8344 4171; fax: +61 3 8344 4188. E-mail address:e.tully@unimelb.edu.au (E.A. Tully). 0966-6362/$ – see front matter # 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.gaitpost.2004.11.007

acceleration of body segments [7,8], and the kinematics (joint angles) and kinetics (joint moments) of the lower limb joints before and after buttocks ‘lift-off’ (LO) [8–10]. Although sagittal trunk movement during STS has been measured with respect to ahorizontal reference [11,12], the contribution of the thoracolumbar spine has not been subjected to any detailed analysis since few models have included markers on the spine. In most studies the spine has been viewed as a rigid body, the ‘trunk segment’, defined by a straight line joining markers on the first thoracic and first sacral spine [13], or shoulder and greater trochanter [12,14– 16], a methodwhich fails to clarify the respective contribution of hip and thoracolumbar spine to the measure of sagittal trunk angle. In some studies the mobile lower cervical joints have been included as part of the trunk segment [7,17]. Nikfekr et al. [18] placed markers along the midline spine at the level of C7, T3, T6, T9, T12 and the sacrum. However, these authors chose to measure whole trunk kinematics(C7–sacrum), and although linear displacement of the spinal markers was measured in vertical and lateral directions no thoracic or lumbar spinal angles were calculated. It appears that the results of previous studies have influenced assessment and training of patients with

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dysfunctional STS. For example, it is suggested that there...