Comparison of thoracic kyphosis and postural stiffness in younger and older women.

BACKGROUND CONTEXT An increase in thoracic kyphosis and postural stiffness is commonly associated with aging and many pathological conditions. Simple clinical measurements are needed to estimate the relative degree of postural stiffness to determine whether clinical interventions, such as exercise, are beneficial. PURPOSE To compare the amount of kyphosis and postural stiffness in the thoracic spine of younger and older women. STUDY DESIGN/SETTING Experimental design conducted at a large health science center in southeastern Texas. PATIENT SAMPLE Fifty-one healthy adult women, 25 between the ages of 21 and 51 years and 26 aged 66 to 88 years. OUTCOME MEASURES Index of kyphosis (IK) measured with a surveyor's flexicurve. Differences, percent change and ratios between IK measures taken in the relaxed and maximally erect positions were used to estimate postural stiffness. METHODS Subjects were measured while standing in their usual relaxed posture and again in their maximally erect posture by three different raters. IK measures were calculated by each rater and averaged for further data analysis. Independent t tests were used to compare the two age groups at the .05 alpha level. RESULTS Significant differences were found in both the relaxed (p= .018) and erect (p< .001) IK measures of younger and older women. The differences, percent change and ratio between the two IK measures were also significantly different in that the younger women demonstrated a greater degree of active reduction of their kyphosis (in the erect posture) than older women. CONCLUSIONS Age-related differences in thoracic kyphosis and postural stiffness were documented between younger and older women by means of repeated flexicurve measurements performed in both a relaxed and a maximally erect position.