Objectives: Three–dimensional gait analysis is the gold standard for measurement and description of gait. Gait variability can arise from intrinsic and extrinsic factors and may vary between walking conditions. This study aimed to define the inter-trial and inter-session repeatability in gait analysis data of children with cerebral palsy (CP) who were walking in four conditions, namely barefoot or with ankle–foot orthosis (AFO), and overground or treadmill. Design: Test-retest repeatability study. Setting: Rehabilitation facility with a human motion analysis laboratory. Participants: Ten ambulatory children with spastic CP (age=5–15years). In addition, two control datasets (N=56; N=18) of typically developing children were used as a reference. Main Outcome Measures: Inter–trial and inter–session variability was measured using intra-class correlations (ICCs) with accompanying confidence intervals, standard error of measurement (SEM), as well as the SEM expressed as percentage (%SEM) of the total joint-range-of-motion of typically developed children. Results: Overall we found good to excellent ICC-values and favourable SEM-values for the inter-session Gait Profile Score (ICC=0.85–0.98, SEM=0.45–0.91°) and Gait Variable Scores (ICC=0.85–0.99, SEM=0.22–1.11°) for the lower-limb joints. The %SEM was the highest for the ankle joint (%SEM=0.8%–3.0%). For the continuous waveform data, only in the ankle joint, differences were observed. Namely, smaller SEM-values for the AFO-condition (mean inter–trial=0.14° ; mean inter-session=1.121°) in comparison to the barefoot-condition (mean inter–trial= 0.55° ; mean inter–session=2.22 °). For all the kinetic parameters, the treadmill conditions showed smaller SEM values in comparison to the overground condition. Conclusions: All conditions proved to be repeatable, showing good to excellent ICC values. The ankle kinematics were more repeatable when the participants were walking with their AFOs in comparison to barefoot walking. Taking the total joint range–of–motion into account, the knee joint showed the most repeatable motion, while ankle motions showed the lowest repeatability. For kinetics, treadmill conditions showed better repeatability than the overground conditions.

The authors have declared no competing interest.

NCT06355869

This study was funded by Interreg-2-Seas-program 2014-2020 co-funded by the European Regional Development Fund under subsidy contract No 2S05-038 (M.O.T.I.O.N. project)

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Ethics Committee Reasearch UZ/KU Leuven studynumber: S65337

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