{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T18:06:53Z","timestamp":1780682813517,"version":"3.54.1"},"reference-count":35,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T00:00:00Z","timestamp":1780617600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background\/Objectives: Lower-limb muscle quantity and quality may be associated with mobility performance, but the relationship between bioelectrical impedance analysis (BIA)-derived lower-limb indices and slow Timed Up and Go (TUG) performance remains insufficiently established. This cross-sectional study examined the associations of lower-limb muscle mass and phase angle (PhA) with TUG performance and explored ROC-derived values for slow TUG performance in 280 community-dwelling Japanese adults. Methods: Lower-limb muscle mass and segmental lower-limb PhA were measured using multifrequency segmental BIA and averaged across both legs. Multiple linear regression analyses were used to examine associations between TUG time and BIA-derived indices after adjusting for age and body size. Receiver operating characteristic analyses were performed for slow TUG performance, defined as TUG \u2265 9 s and \u226510.2 s, and Youden index-derived values were calculated as exploratory estimates. Results: Lower-limb PhA was independently associated with TUG performance across both body-size adjustment models, whereas lower-limb muscle mass was retained only in the model adjusted for BMI. For slow TUG performance, the lower-limb muscle mass-to-body weight ratio showed moderate discriminatory ability, with AUCs of 0.75 for TUG \u2265 9 s and 0.78 for TUG \u2265 10.2 s. Standardized lower-limb PhA showed AUCs of 0.65 and 0.64, respectively. The Youden index-derived standardized PhA value was Z = \u22121.04 for both TUG thresholds; however, these ROC-derived values were not internally or externally validated. Conclusions: Lower-limb BIA-derived indices, particularly segmental lower-limb PhA, were associated with TUG performance in community-dwelling Japanese adults. The ROC-derived values should be interpreted strictly as exploratory, hypothesis-generating estimates and should not be used for clinical screening or individual-level clinical decision-making without validation in larger independent cohorts.<\/jats:p>","DOI":"10.3390\/jcm15114388","type":"journal-article","created":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T17:18:16Z","timestamp":1780679896000},"page":"4388","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Lower-Limb Phase Angle and Muscle Mass Ratio Are Associated with Slow Timed Up and Go Performance in Community-Dwelling Japanese Adults"],"prefix":"10.3390","volume":"15","author":[{"given":"Daisuke","family":"Homma","sequence":"first","affiliation":[{"name":"Division of Orthopaedic Surgery, Graduate School of Medical and Dental Sciences, Niigata University, 757 Asahimachi-dori, Ichiban-cho, Chuo-ku, Niigata 951-8510, Japan"},{"name":"Department of Rehabilitation, Niigata Bandai Hospital, 2-2-8 Yachiyo, Chuo-ku, Niigata 950-0909, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2289-7499","authenticated-orcid":false,"given":"Norio","family":"Imai","sequence":"additional","affiliation":[{"name":"Division of Comprehensive Musculoskeletal Medicine, Graduate School of Medical and Dental Sciences, Niigata University, 757 Asahimachi-dori, Ichiban-cho, Chuo-ku, Niigata 951-8510, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dai","family":"Miyasaka","sequence":"additional","affiliation":[{"name":"Division of Orthopaedic Surgery, Niigata Bandai Hospital, 2-2-8 Yachiyo, Chuo-ku, Niigata 950-0909, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Moeko","family":"Yamato","sequence":"additional","affiliation":[{"name":"Department of Rehabilitation, Niigata Bandai Hospital, 2-2-8 Yachiyo, Chuo-ku, Niigata 950-0909, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Masafumi","family":"Ishisaki","sequence":"additional","affiliation":[{"name":"Department of Rehabilitation, Niigata Bandai Hospital, 2-2-8 Yachiyo, Chuo-ku, Niigata 950-0909, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tsubasa","family":"Sugahara","sequence":"additional","affiliation":[{"name":"Department of Rehabilitation, Niigata Bandai Hospital, 2-2-8 Yachiyo, Chuo-ku, Niigata 950-0909, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mie","family":"Yamada","sequence":"additional","affiliation":[{"name":"Department of Rehabilitation, Niigata Bandai Hospital, 2-2-8 Yachiyo, Chuo-ku, Niigata 950-0909, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hayato","family":"Suzuki","sequence":"additional","affiliation":[{"name":"Division of Orthopaedic Surgery, Tachikawa General Hospital, 24-1 Asahioka, Nagaoka 940-8621, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6912-2386","authenticated-orcid":false,"given":"Yoji","family":"Horigome","sequence":"additional","affiliation":[{"name":"Division of Comprehensive Musculoskeletal Medicine, Graduate School of Medical and Dental Sciences, Niigata University, 757 Asahimachi-dori, Ichiban-cho, Chuo-ku, Niigata 951-8510, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Atsushi","family":"Sakagami","sequence":"additional","affiliation":[{"name":"Division of Orthopaedic Surgery, Niigata Bandai Hospital, 2-2-8 Yachiyo, Chuo-ku, Niigata 950-0909, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yoichiro","family":"Dohmae","sequence":"additional","affiliation":[{"name":"Division of Orthopaedic Surgery, Niigata Bandai Hospital, 2-2-8 Yachiyo, Chuo-ku, Niigata 950-0909, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Naoto","family":"Endo","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery, Saiseikai Niigata Kenoh Hospital, 5001-1 Kamisugoro, Sanjo 955-0091, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Izumi","family":"Minato","sequence":"additional","affiliation":[{"name":"Division of Orthopaedic Surgery, Niigata Rinko Hospital, 1-114-3 Momoyamacho, Higashi-ku, Niigata 950-0051, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9511-9773","authenticated-orcid":false,"given":"Hiroyuki","family":"Kawashima","sequence":"additional","affiliation":[{"name":"Division of Orthopaedic Surgery, Graduate School of Medical and Dental Sciences, Niigata University, 757 Asahimachi-dori, Ichiban-cho, Chuo-ku, Niigata 951-8510, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,5]]},"reference":[{"key":"ref_1","unstructured":"World Health Organization (2026, March 19). 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