Validation of smart insoles for the measurement of vibration exposure of workers and athletes

Wearable sensors are becoming increasingly common in daily life for medical care, athletic training, or even daily activity monitoring [1]-[3]. As these systems advance, so do their potential application, but their use for monitoring vibration exposure is limited or absent, despite the adverse effects of vibration on health being well known among the scientific community. To address this deficit, we propose a system of sensorized smart insoles capable of measuring triaxial vibration exposure according to ISO 2631-1. Each insole allows measurement of the vibration exposure and contact pressure at the forefoot and rearfoot, as well as the temperature inside the shoe. We used the insoles to measure the vibration exposure of five male subjects in three different testing conditions: 1) indoor condition (Politecnico di Milano laboratory, atop a triaxial shaker; 2) outdoor condition riding a mountain bike; and 3) skiing. The vibration exposure along the three mutually perpendicular axes was compared with that measured using instrumentation compliant with the current standards (ISO 8041). Results show that the proposed system allows direct monitoring of vibration exposure at the feet, also accounting for the vibration reduction provided by the shoe sole.