Fig. 3From: Foot progression angle estimation using a single foot-worn inertial sensorMeasurement setup. An IMU is secured under the shoelaces and its’ coordinate system (\(\psi ^X\)) is displayed in red. The retroflective markers are places on the second metatarsal and the calcaneus, which is assumed to be a FPA of 0°. The foot reference coordinate system is shown in green (\(\psi ^F\))Back to article page