RELATIONSHIP BETWEEN STANDING POSTURE AND STABILITY

Background and Purpose. This study determined whether persons with sta bility impairments have postural aberrations. We investigated whole-bo dy posture and its relationship to center-of-gravity (COG) stability. Subjects. Data from 27 subjects with vestibular hypofunction and 26 su bjects without vestibular impairment were analyzed. Method. An optoele ctronic full-body system measured kinematics. Force plates measured gr ound reaction forces while subjects stood Ic idl their feet 30 cm apar t and eyes open and with their feet together and eyes closed. Results. The subjects with vestibular hypofunction demonstrated less stability than the subjects without impairment, but there were no postural diff erences. Subjects with vestibular hypofunction had more weight on the left lower extremity during standing with feet apart. In all subjects in both groups, during standing with feet apart, the COG was anterior to the ankle, knee, back, and shoulder and posterior to the hip and ne ck. Subjects had an anterior pelvic tilt, extended trunk and head, rig ht: laterally flexed trunk and pel iis, and flexed knees. With their f eet together, subjects increased their anterior pelvic tilt; trunk, he ad, and knee flexion; and anterior COG position. Conclusion and Discus sion. Posture and stability had a low correlation. Subjects with bilat eral vestibular hypofunction did not demonstrate a forward head or bac kward trunk lean, as has been reported anecdotally. Changing from stan ding with feet apart to feet together increased whole-body movement pa tterns to control standing stability.