The scientists here investigated the prevalence and association between MetS and LS among Japanese middle-aged and older adults. MetS was diagnosed using the modified National Cholesterol Education Program Adult Treatment Panel III criteria, and LS was assessed using the LS risk test, which includes the stand-up test, two-step test, and the 25-question Geriatric Locomotive Function Scale. The prevalence of LS was significantly higher in individuals with MetS. The association between MetS and LS remained significant after adjusting for age and sex.