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Updated: Jan 14, 2026
Postural Organization of Gait Initiation for Biomechanical Analysis Using Force Platform Recordings
Published on: July 26, 2022
The effect of inaccurate initial contact events on kinematics in healthy and pathological gait
Bernhard Dumphart1, Djordje Slijepcevic2, Fabian Unglaube3
1Center for Digital Health & Social Innovation, St. Pölten University of Applied Sciences, Austria; Institute of Health Sciences, St. Pölten University of Applied Sciences, Austria; Vienna Doctoral School of Pharmaceutical, Nutritional and Sport Sciences, University of Vienna, Austria.
Background:
Clinical gait analysis (CGA) is the established gold standard for clinical decision-making. While previous research has identified error sources that affect the quality of CGA (e.g., marker placement and soft tissue artifacts), the impact of inaccurately identified initial contact (IC) events has not been systematically investigated. As IC events define the beginning and end of the stance phase, they directly impact spatiotemporal, kinematic, and kinetic parameters.
Research Question:
To what extent do inaccurately detected IC events affect sagittal hip, knee, and ankle kinematics at IC across different cohorts?
Methods:
The impact of inaccurately detected IC events on sagittal hip, knee, and ankle kinematics at IC was investigated in healthy individuals (n=28) and two patient populations, patients with cerebral palsy (CP, n=208) and patients with malrotation deformities and/or frontal malalignments of the lower extremities (MD, n=1122). IC events were incrementally shifted by ±1 to ±6 frames to systematically simulate inaccuracies. The mean absolute error (MAE) was calculated for the hip, knee, and ankle kinematics between the waveforms based on the original IC and each shifted IC.
Results:
Kinematics of the sagittal knee and ankle are highly sensitive to inaccurate ICs, with a median MAE exceeding 2° within two frames for MD and healthy participants and three frames for patients with CP. The hip kinematics showed a lower sensitivity to IC inaccuracies.
Significance:
These results highlight the importance of accurately identified IC events in CGA to ensure reliable data. Based on our results, we recommend adopting stricter error tolerance thresholds of 13.3 ms to 20.0 ms (i.e., two to three frames at 150 Hz) for gait event detection algorithms to reduce potential errors in clinical assessments.
