Objective: Physical performance reference values play an important role in the evaluation process and in developing treatment plans for older adults, yet data is extremely limited in individuals 90 years and older, the “oldest old.” The 5 Times Sit to Stand Test (5XSST) is one of the most frequently used methods of quantifying functional lower extremity strength. To improve the classification and interpretation of 5XSST scores, we aim to develop 5XSST reference values in individuals 90 years and older.

Methods: Participants were members of The 90+ Study, a longitudinal cohort study of individuals 90 years and older. Participants performed the 5XSST with arms folded (traditional test) or using their arms to push from the chair (modified test). We calculated means, standard deviations, and percentiles (5^th,10^th,25^th,50^th,75^th,90^th,95^th) by test type, and by age category. We used linear regression to compare mean scores by sex (men and women), age category (90-91, 92-94, and 95+), test type (traditional and modified), living situation (home alone, home with another person, nursing homes/assisted living), and falls in the past year (0, 1+).

Results: The 974 participants had a mean age of 93 (range=90.0-103.1,SD=2.5) years. Mean 5XSST time was 16.2(SD=6.3) seconds for the traditional test and 23.1(SD=11.8) seconds for the modified test. 5XSST times were slower with increasing age. We present 5XSST reference values by test type and age category.

Conclusions: The reference values we present will allow providers to correctly classify and interpret 5XSST scores in individuals 90 years and older.