Age-associated Decline In 20-sec Stepping Test Performance In Independent, Community-dwelling Older Women

Abstract

PURPOSE: To determine if there is an age-related decline in ST performance in independent, community-dwelling women (age 66-89 yrs; n = 1163). METHODS: Subjects completed an eyes open, 20-sec ST and fitness testing. ST measures included head total movement distance (TMD), head greatest placement (MMD), knee total movement distance (KMD) and stepping rate (STEP) determined with a KINECTTM infrared depth sensor. Ratio of KMD/TMD is an index of upper-body sway relative to lower-body. Fitness was defined by self-selected walking speed (NW), fast-walking speed (FW), timed up and go (UPGO), chair stand five-times (CS), and maximum voluntary knee extension force (MVC). Subjects were divided into age groups 65-69 (n = 178), 70-74 (n = 293), 75-79 (n = 417), 80-84 (n = 251), and > 85 (n = 24) yrs and differences examined by ANOVA; significance p < 0.05. Associations between age and ST measures were evaluated using Pearson product moment correlation. RESULTS: Individuals between 75-79 and 85+ groups were shorter, while body mass declined across each group, leveling off at 80 yrs. % body fat was greater, but equal in 80-84 and 85+ groups. TMD was greatest in 80-84 group; all others were similar. TMD and KMD increased in 75-79 through 85+ group. MMD was not different among groups. KMD/TMD was similar and greater in 75-79 and 80-84 yrs, while, 85+ was greater than all groups. Sway per STEP (TMD/KMD/STEP) increased progressively across groups. There was a progressive reduction in fitness variables beginning with 75-79 group. ST variables, except MMD, were significantly correlated with age, but coefficients were low (r = -0.23-0.12, p < 0.05). CONCLUSIONS: Age-related decline in ST performance observed primarily as a progressive increase in sway (KMD/TMD, and KMD/TMD/STEP) indicates reduced balance in accordance with our previous findings. Progressive reduction in static/dynamic balance negatively affects physical function (e.g. decrements in walking speed, TUG etc.) as observed here. This supports our recent findings that ST differentiates physical disability, indicates risk of falling, and “need for assistance”. Supported by JSPS (Grant number: 20 K11656)