A Comparison of Postural Control Characteristics between Subjects with Kyphosis and Controls

Introduction & It is known that postural control performance in upright standing position could be affected by abnormal posture alignment. Despite the fact that kyphosis is one of the most common spine abnormality, the effect of thoracic curve abnormality at sagittal plane on postural stability has received little attention to date. Therefore, the purpose of our study was to investigate the dynamic and static postural control among individuals with kyphosis in comparison with a control matched group. Nineteen males with increased normal thoracic kyphosis (> 40 degrees) were randomly selected as kyphotic group. Eighteen controls matched for age, weight and height were selected to participate in the study. We measured the amount of kyphosis using flexible ruler as a noninvasive and reliable method. Dynamic and static postural stability were assessed using the biodex stability system and the balance error scoring system respectively. ANOVA with repeated measures followed by Tukey HSD test and independent t-test were employed for statistical analyses (p<0.05). For dynamic postural assessment, the means of all stability indices were significantly higher in the kyphotic individuals than controls in the eyes-closed condition. With the platform in the most unstable position, kyphotic group were detected to have significantly poorer balance performance than controls in both eyes-open and eyes-closed conditions. For static balance evaluation, no difference was noted between both groups in stability performance during double and tandem stances. During the single-limb stance trials, the kyphotic group had poorer performance than controls while standing on the firm surface and foam surface (firm surface: p=0.044; foam surface: p=0.000). The findings suggest that postural control especially dynamic postural stability may be altered in individuals with increased thoracic kyphosis.