Elsevier

Gait & Posture

Volume 58, October 2017, Pages 98-102
Gait & Posture

Short communication
In-situ force plate calibration: 12 years’ experience with an approach for correcting the point of force application

https://doi.org/10.1016/j.gaitpost.2017.07.111Get rights and content
Under a Creative Commons license
open access

Highlights

  • In-situ calibration can reduce errors in the point of force application by 60%.

  • Correction of the PFA should occur across the entire face of the plate.

  • Different calibration coefficients develop in a varied manner over the years.

  • Recalibration of force plates is recommended regularly, at least every 5 years.

  • Force plates should always be recalibrated after remounting.

Abstract

Force plates are common assessment tools used in biomechanics to measure ground reaction forces during motion capture or strength exercises. While the accuracy of the resulting kinetic data is critical for accurate gait analysis, factors such as plate mounting are thought to influence the measured point of force application (PFA) of the ground reaction forces. The aim of this study was therefore to present an accurate in-situ PFA calibration method. In addition, the approach was evaluated by examining the required PFA corrections over a period of ten years, which included plate remounting and a change of foundation.

The in-situ PFA calibration was performed on six plates by assessing the locations of up to 98 points of force application per plate using an instrumented pole. Application of the in-situ PFA calibration approach reduced the root mean square errors by up to approximately 60% compared to the manufacturers calculation. Correction coefficients were strongly dependent on the individual platform as well as the location of the applied force on the plate. Remounting of the plates altered the plate coefficient corrections considerably, while changes over time were notable but not as extensive. We therefore recommend that plates should be recalibrated after remounting, but also at least every 5 years, in order to ensure the preservation of an accurate PFA.

Keywords

Ground reaction force plates
In-situ calibration
Point of force application

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