Beyond BMI: The Role of Anthropometric Measurements in Predicting Plantar Pressure Distribution and Gait Biomechanics.

Plantar pressure (PP) is a key biomechanical parameter for assessing foot function, gait abnormalities, and injury risk. Although body mass index (BMI) correlates with PP magnitude/distribution during gait, it is a coarse metric that collapses body composition into a ratio of mass to height, implicitly assuming uniform body proportions and mass distribution. The effects of individualized anthropometric parameters on PP signatures remain under-characterized, with a gap in incorporating body-shape measures beyond BMI. This exploratory study examined associations among anthropometric measurements, plantar peak pressure (PPP) outcomes, and model-predicted lower-limb joint kinetics. Data from 21 participants (normal-weight, overweight, obese) were collected using Xsens inertial measurement units and a Tekscan walkway. Joint kinetics were predicted with the AnyBody musculoskeletal model using two upper-body mass scaling approaches: constant-percentage-based (CPB) and body-shape-based (BSB). Pearson correlation analysis showed BMI had limited association with plantar peak pressure (PPP), yielding only two significant correlations across groups. In contrast, anthropometric measures, particularly limb lengths and circumferences, showed more frequent associations. Lower arm and shoulder lengths each exhibited up to five significant correlations, while chest, thigh, ankle, and wrist circumferences were meaningful. Compared with CPB, BSB yielded more frequent and generally larger-magnitude PPP-kinetic correlations, indicating that anthropometry-informed scaling altered the observed association patterns. In the normal-weight group, BSB identified seven significant correlations versus two with CPB; in the obese group, correlations exceeding 0.9 occurred nine times with BSB versus three with CPB. These results highlight the limited and inconsistent associations of BMI with PPP and support further investigation of detailed anthropometry in individualized PP and gait assessment.