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Updated: Jun 13, 2026
Lower-Limb Biomechanical Characteristics Associated with Unplanned Gait Termination Under Different Walking Speeds
Published on: August 25, 2020
Lower-Limb Phase Angle and Muscle Mass Ratio Are Associated with Slow Timed Up and Go Performance in
Daisuke Homma1,2, Norio Imai3, Dai Miyasaka4
1Division of Orthopaedic Surgery, Graduate School of Medical and Dental Sciences, Niigata University, 757 Asahimachi-dori, Ichiban-cho, Chuo-ku, Niigata 951-8510, Japan.
Abstract:
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 ≥ 9 s and ≥10.2 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 ≥ 9 s and 0.78 for TUG ≥ 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 = -1.04 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.
