Comparison of hierarchical and six degrees-of-freedom marker sets in analyzing gait kinematics

Abstract

The objective of this study was to determine how marker spacing, noise, and joint translations affect joint angle calculations using both a hierarchical and a six degrees-of-freedom (6DoF) marker set. A simple two-segment model demonstrates that a hierarchical marker set produces biased joint rotation estimates when sagittal joint translations occur whereas a 6DoF marker set mitigates these bias errors with precision improving with increased marker spacing. These effects were evident in gait simulations where the 6DoF marker set was shown to be more accurate at tracking axial rotation angles at the hip, knee, and ankle.

Keywords::

• inverse kinematics
• hierarchical marker set
• marker clusters
• forward dynamics

Acknowledgements

We gratefully acknowledge the Shriners Hospitals for Children® for the initial concept for this study, their financial support, and their motion data.

Conflict of disclosure statement

No potential conflict of interest was reported by the authors.

Notes

^1. Email: [email protected]

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^4. Email: [email protected]

^5. Email: [email protected]

Additional information

Funding

This work was supported by Shriners Hospitals for Children® [grant number RAB #8510].