KINETIC AND KINEMATIC ANALYSIS OF STANCE WITH AND WITHOUT ARM SUPPORT IN INCOMPLETE SPINAL CORD INJURED SUBJECTS

There is a lack of studies concerning standing stability in subjects with incomplete spinal cord injury (SCI). The aims of this study were to analyze the changes of center of pressure (COP), joint moment, joint angle, and muscle activities in patients with incomplete SCI during quiet stance with and without arm support. Ten cervical-thoracic cord incompletely injured patients (mean age: 47.8 +/- 13.4 years old) participated in this study. They performed quiet standing with each leg on separate force plate (AMTI, USA) for 5 s with and without holding the walker to obtain the kinetic data. The kinematic data of joint angles were recorded by Motion Analysis System (Vicon 250, Oxford, UK). The electromyographic activities of trunk muscles and quadriceps were recorded by surface electrodes. The results indicated that the COP sway area and the normalized COP sway area significantly (P < 0.01) increased from 94.9 +/- 61.3 mm(2) to 254.6 +/- 91.8 mm(2) and from 0.0013 +/- 0.0007 to 0.0037 +/- 0.0012, respectively, in patients with incomplete SCI, while standing with arms released from walker. The ankle and knee moments also increased significantly (P < 0.05) during stance without support. However, the joint angles and recorded muscle activities were not significantly different between those with and without support. The conclusion was that the proprioceptive feedback of postural sway, and the motor control strategies of knee-ankle muscles would be important for patients with incomplete SCI during stance without arm support.