Development of running motion evaluation system based on 9-axis inertial sensor

Abstract

We have developed a system for easily and comprehensively measuring and evaluating running form characteristics, which uses a single, compact, and lightweight 9-axis inertial sensor attached to the waist. First, in order to establish a group of variables for the purpose, each variable obtained from the sensor was compared with the equivalent one from a high-precision 3D motion capture system (MoCap) and force plate measurement system (FP) for the verification of its validity and reliability. 15 items of spatiotemporal, kinematic and kinetic variables during running were collected synchronously. All the variables except one variable were correlated with the MoCap or FP at a moderate level or higher and also confirmed to be highly reliable. Second, we also conducted a field test with 107 runners of different running levels. It was found that the developed system was able to evaluate running form characteristics appropriately to show difference between athletes’ and recreational runners’ groups in their motion as shown in laboratory tests of previous research. In addition, useful information like time-series changes in the motion of runner in a competitive race was obtained with high sensitivity that had not been achieved before, demonstrating that the system takes advantage of wearable sensor to be available widely without the constraint of measurement condition.