Relative sit-to-stand power cut-off points and their association with negatives outcomes in older adults

Background: The purposes of this study were: i) to evaluate the association of sit-to-stand (STS) power and body composition parameters [body mass index (BMI) and legs skeletal muscle index (SMI)] with age; ii) to provide cut-off points for low relative STS power (STSrel), ii) to provide normative data for well-functioning older adults and iv) to assess the impact of low STSrel on negative outcomes.Methods: Cross-sectional design (1369 older adults). STS power parameters assessed by validated equations, BMI and Legs SMI assessed by dual-energy X-ray absorptiometry were recorded. Sex- and age-adjusted segmented and logistic regression analyses and receiver operator characteristic curves were used.Results: Among men, STSrel showed a negative association with age up to the age of 85 years (‒1.2 to ‒1.4%year-1; pyear-1; prel were 2.5 W∙kg-1 in men and 1.9 W∙kg-1 in women. Low STSrel was associated with frailty (OR[95%CI]= 5.6 [3.1, 10.1]) and low habitual gait speed (HGS) (OR[95%CI]= 2.7 [1.8, 3.9]) in men while low STSrel was associated with frailty (OR[95%CI]= 6.9 [4.5, 10.5]) low HGS (OR[95%CI]= 2.9 [2.0, 4.1]), disability in activities of daily living (OR[95%CI]= 2.1 [1.4, 3.2]), and low quality of life (OR[95%CI]= 1.7 [1.2, 2.4]) in women. Conclusions: STSrel declined with increasing age in both men and women. Due to the adverse outcomes related to STSrel, the reported cut-off points can be used as a clinical tool to identify this condition among older adults.