Date of Award
Master of Science (MS)
Kinesiology and Health Science
Many devices are available for measuring the height of a CMJ. An inertial measurement unit (IMU) measures linear acceleration, orientation, and angular velocity. As an alternative to using IMU estimates of flight time, CMJ height could be estimated by integrating the IMU time-series signal for vertical acceleration to derive CMJ take-off velocity in order to track whole-body center of mass (WBCoM) movement, yet this approach would require valid IMU acceleration data. Thus, the purpose of this study was to quantify the effects of IMU sensor location and number on the validity of vertical acceleration estimation in CMJ. Thirty young adults from a university setting completed this study. Seven IMUs were placed at the approximate center of mass of the trunk, thighs, shanks, and feet. A total of 15 WBCoM models were created from the 7 IMUs. Using the four segments of the lower body, 1-,2-,3-, and 4-segment IMU models were constructed. Root mean square error (RMSE) was estimated between the acceleration derived from each IMU model against acceleration derived from a force platform. RMSE values from the best performing 1-,2-,3-, and 4-segment IMU models were analyzed for main effects using a 1-way analysis of variance. Notably, all of the best performing models contained IMU acceleration data from the trunk. The best performing 2- and 3-segment IMU models returned significantly lower RMSE values, on average, than the 4- segment model (p = 0.041, p = 0.021, p = 0.061). The average RMSE of the best performing 2- and 3-segment models produced an error of 20% relative to gravitational acceleration, with this error likely to be lower when viewed within the context of specific CMJ events and peak forces. Further investigation into improving IMU technology, procedures, and data processing are needed to reduce RMSE errors to a more acceptable level of validity relative to force platform dynamometry.
Althouse, Dianne, "Effects of IMU Sensor Location and Number on the Validity of Vertical Acceleration Time-Series Data in Countermovement Jumping" (2022). All Graduate Plan B and other Reports. 1657.
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