Detection of excessive pronation and supination for walking and running gait with smart socks

Excessive pronation and supination are gait conditions that could lead to such injuries as ankle sprains, shin splints, Achilles tendinitis and others. Early detection of excessive pronation and supination in running and walking gait are important for injury prevention not only for professional athletes but also for the general population. Unfortunately, the typical equipment necessary for detection of these conditions is relatively expensive and therefore is not widely used by non-professionals. Moreover, most of the typical equipment is either designed for operation under laboratory conditions only or is too bulky and consequently affects the performance of the wearer during the performed activity. This study proposes a method for pronation and supination detection by using smart textile socks with integrated pressure sensors and a specific sensor measurement processing algorithm. Each sock has five sensors, one on the heel, two in the middle and two in the front sole area. These sensors are knit from a conductive thread and have a resistivity inversely proportional to the pressure, which allows monitoring of the feet pressure at different parts during a physical activity. A special pressure vector is calculated from the sensor values to characterize the step. The value of this pressure vector give information about the step and allows detection of excessive supination and pronation in the gait. The preliminary tests demonstrated a significant difference between the pressure vector of a normal gait and gait performed with pronation and supination, thus allowing detection of these gait conditions.