Differentiating Common Workplace Postures through Plantar Pressure: Laying the Groundwork for a Low-Cost Instrumented Insole

Prolonged weight bearing (WBR) at work is a suspected risk factor for the development of musculoskeletal disorders that commonly occur in the feet. No objective measure to quantify time spent in different WBR postures currently exists, creating a barrier in investigating the connection between WBR and foot pain. This study aimed to develop a prototype design for a low-cost instrumented insole system capable of differentiating workplace postures (sitting, standing and walking). Three objectives were defined: 1) quantify and differentiate the pedobarographic characteristics associated with each posture, 2) classify the postures from plantar pressure characteristics and 3) develop an insole system with off-the-shelf sensors capable of classifying workplace postures. Pressure measures near the hindfoot and central/lateral forefoot were found to simultaneously differentiate the postures, and machine learning algorithms accurately classified the postures using plantar pressure metrics. This foundational work facilitates the deployment of a low-cost instrumented insole for workplace studies where it will provide the objective evidence needed to resolve the link between WBR and foot pain.