Body Weight–Adjusted Grip Strength Better Discriminates Locomotive Syndrome Defined by the Stand-Up Test: A Cross-Sectional Study

Locomotive syndrome (LS) is commonly assessed using lower-limb performance tests such as the stand-up test; however, these tests may be impractical in community screening settings.Grip strength is easy to measure as a marker of physical function, but its interpretation is strongly influenced by body size.This cross-sectional study compared the discriminatory performance of unadjusted grip strength and weightadjusted grip strength (grip strength-to-body weight ratio; GWR) for LS defined by the stand-up test and examined the interpretability of body size-adjusted grip strength indices.We analyzed 678 community-dwelling adults aged 50 years.Grip strength was measured twice for each hand in the standing position, and the mean of the maximal values from both hands was used.GWR was calculated as grip strength divided by body weight.The LS stage 1, defined by the stand-up test, was the primary outcome.Discriminatory performance was assessed using receiver operating characteristic analysis, and areas under the curve (AUCs) were compared using the DeLong method; sexstratified analyses and LS stage 2 were examined secondarily.In the overall analysis, GWR showed higher discrimination for LS stage 1 than unadjusted grip strength, and similar patterns were observed in men and women.In supplementary analyses using LS stage 2, GWR consistently demonstrated higher discrimination than unadjusted grip strength.GWR was more closely aligned with stand-up test-defined LS than unadjusted grip strength, suggesting that adjusting grip strength for body size may improve the interpretation of routinely collected grip strength data in community screening.