E. Murphy1, Y. An1, S-R. Lee1, R. Wood2

1New Mexico State University, Las Cruces, NM, 2Boise State University, Boise, ID

Rising from supine to an upright position has the potential to evoke dizziness, and thereby presents a risk of falling. Surprisingly, little evidence is available to characterize the functional consequences of rising from a supine position. The Timed Up-and-Go (TUG) test is commonly used to describe the risk of falling in older adults. Recently, we have established that the percentage of time spent in the active propulsion (APT) phase of the gait cycle is inversely associated with history of falls. PURPOSE: To determine the reliability of TUG time and APT following supine and seated rest, and to assess the main effect of position on TUG time and APT. METHODS: 40 older adults (age=73.5±1.0 yrs, height = 165.8±7.9 cm, weight = 74.0±16.2 kg) completed the TUG after at least 10mins of seated and supine rest on two separate days, one week apart. The order of the conditions was randomized. TUG time to completion was recorded and gait data were collected using a force-plate embedded walkway. APT was derived as the proportion of the gait cycle when center of gravity exceeded the base of support in single limb stance to contralateral heel contact. Intraclass correlations (comparing day 1 to day 2 values) were used to determine the determine the reliability of our measures. The main effect of resting condition (seated v. supine) was tested by applying repeated measures ANOVA to day 1 observations. RESULTS: ICC of TUG time after seated rest was 0.91, p<0.001, and after supine rest was 0.95, p<0.001. ICC of APT after seated rest was 0.74, p<0.001 and 0.74, p<0.001 after supine rest. There were significant main effects of condition on time to complete the TUG (10.3±0.4 seconds versus 11.9±.7 seconds after seated and supine rest respectively, p<0.001), and APT (69.3±4.1% and 56.3±4.9% after seated and supine rest, respectively, p<0.05). CONCLUSION: TUG time and APT during the TUG are reliable following either supine or seated resting conditions. These data support the hypothesis that physical function is poorer and risk of falls is heightened immediately after rising from supine rest compared to seated rest. The risk of falls following supine rest is further evident by an average TUG time approaching 12 seconds. These results may assist clinicians in more appropriate screening, and in developing treatment strategies to reduce falls risks and falls.

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