Gait Event Detection During Running Using a Bending Angle Sensor Attached to Loose-Fitting Clothing

The purpose of this study was to verify the accuracy of cycle time (t_g) and contact time (t_c) during running using a bending angle sensor attached to loose-fitting clothing in comparison with 3D motion capture data. For the measurements, 20 healthy adult males wore loose-fitting pants with a bending angle sensor attached to the right knee. They ran on a treadmill at 8, 10, and 12 km/h for 90 s. A 3D motion capture device and the bending angle sensor simultaneously measured the right knee joint motion. Knee extension peaks for acquiring foot-strike and toe-off were detected from knee joint angular acceleration to acquire t_g and t_c from the sensor data. The absolute mean error (MAE), mean bias error (MBE), and root mean square error (RMSE) for t_c and t_g were obtained. The RMSE for t_c was 21.4 ms at 8 km/h and less than 20 ms at 10 and 12 km/h, while the MAE, MBE, and RMSE were all within 10 ms for t_g. These results indicate that the bending angle sensor attached to loose-fitting clothing enables t_g and t_c detection.