Inertial Measurement Units’ Reliability for Measuring Knee Joint Angle during Road Cycling

We explore the reliability of joint angles in road cycling obtained using inertial measurement units. The considered method relies on 3D accelerometer and gyroscope measurements from two such units, appropriately attached to adjacent body parts, measuring angle connecting joint. investigate effects applying a simple drift compensation technique an error-state Kalman filter. consider knee particular, conduct trials, 5 20 minute one, for seven subjects, closed, supervised laboratory environment use optical motion tracking system as reference. As expected adaptive solution, filter gives more stable results. root mean square errors per pedalling cycle are below 3.2°, both trials all implying that units not only reliable short measurements, is usually assumed, but can be reliably used longer well. Considering accuracy results, presented reasonably extended open, unsupervised environments other angles. Implementing supports development cheaper efficient monitoring equipment, opposed expensive systems. Consequently, cyclists have affordable way position tracking, leading better bicycle fitting, avoidance prevention certain injuries