Correlates between kinematics and baropodometric measurements for an integrated in-vivo assessment of the segmental foot function in gait.

Baropodometry and multi-segmental foot kinematics are frequently employed to obtain insight into the mechanics of the foot-ground interaction in both basic research and clinical settings. However, nothing hitherto has been reported on the full integration of kinematics with baropodometric parameters, and only a few studies have addressed the association between intersegmental kinematics and plantar loading within specific foot regions. The aim of this study was to understanding the relationships between foot joint mobility and plantar loading by focusing on the correlation between these two measures. An integrated pressure-force-kinematics system was used to measure plantar pressure and rotations between foot segments during the stance phase of walking in 10 healthy subjects. An anatomically-based mask was applied to each footprint to obtain six regions according to the position of the markers; hence each kinematic segment was paired with a corresponding area of the plantar surface. Relationships between segmental motion and relevant baropodometric data were explored by means of correlation analysis. Negative, weak-to-moderate correlations (R(2)<0.5) were found between pressure (mean and peak) and inter-segmental range of motion across all foot joints except the Calcaneus-Midfoot. Temporal profiles of sagittal-plane kinematics and baropodometric parameters were well correlated, particularly at the ankle joint. Larger motion in the foot joints during walking was associated with lower plantar pressure in almost all regions. The study helps improve our understanding of the relationship between joint mobility and plantar loading in the healthy foot and represents a critical preliminary analysis before addressing possible clinical applications.