Assessing the Validity and Reliability of using One Inertial Measurement Unit to Measure Wheelchair Kinematics on Elite Wheelchair Court Sport Athlete

The measure of wheelchair speed and rotation (kinematics), using Inertial Measurement Units (IMU) can help athletes, coaches and practitioners identify important training paradigms in wheelchair court sports. However, there are several different IMU algorithms currently used. One of these algorithms uses three IMU (3IMU), and is considered the “gold standard” for measurements in the field. It has shown high levels of validity in field testing and incorporates methods to handle common errors, but the cost of outfitting an athlete with three sensor may limit sports from using this technology. An algorithm that uses only one IMU (1IMU) placed on the wheel hub of a wheelchair, and uses the Madgwick filter to measure the orientation the sensor, has been developed to measure the speed and rotation of the chair. While some preliminary validation work on 1IMU outputs has been promising, this algorithm not been rigorously tested. However, if this algorithm proves to be reliable and valid, the cost of measuring wheelchair kinematics for a whole team becomes substantially less. The purpose of this investigation was to further assess the ability of 1IMU to accurately and reliability measure continuous and discrete kinematic data, during basic movement patterns in wheelchair court sports. Elite wheelchair basketball and wheelchair rugby players were recruited, and they performed maximal sprint and agility tests. The validity and the reliability of the 1IMU outputs were measured and compared to 3IMU as well as timing gates and video. Further, the impact on these kinematic outputs because of poor measurements in wheel sizes as a reduction in sampling rates from 200Hz to 25Hz was evaluated. It was determined that 1IMU provides good to excellent levels of agreement with 3IMU and video for most kinematic data. Further, it was determined that sampling rates of 100Hz should be used to ensure that kinematic metrics defining peak linear and rotational speeds are preserved. However, it was also determined that further investigations are required to generate more accurate data for linear speed during turns. Overall, it is recommended that 1IMU can be used in testing protocols to measure wheelchair kinematics.Ph.D