Measurement of bicycle and rider kinematics during real-world cycling using a wireless array of inertial sensors

Measurements of bicycle kinematics (roll and steer) and rider movements (joint angles and rider lean) typically require a purpose-built instrumented bicycle and/or a motion capture laboratory, which make it difficult or impossible to take measurements during real-world cycling (unconstrained riding outside of a laboratory). In this paper, I present an approach for using an array of 11 wireless inertial sensors to measure the kinematics of a bicycle and rider that can be quickly and easily configured to any rider-bicycle system. A series of simple alignment movements is used to align the sensors to the rider and bicycle, which enables calculations of bicycle speed, roll rate and angle, steer rate and angle, and yaw rate as well as the rider’s ankle, knee, and torso lean angles. Other than the wheel radius of the bicycle, no additional measurements of the subject or bicycle are required for the calculations. To demonstrate the utility of my approach, I used the system to measure the rider-bicycle kinematics of a subject riding his bicycle during a one hour ride through a variety of terrain, including paved roads, dirt roads, and off-road mountain biking trails. The dataset highlights the effect of terrain on steer and rider lean, provides insights into rider strategy and technique, and confirms that an array of wireless inertial sensors can provide measurements of bicycle and rider kinematics. My approach enables meaningful data to be collected in real-world environments to explore how bicycle design, rider preferences, rider ability, terrain, and environment affect bicycle and rider behaviour, performance, and control strategies.