Kinematic data for the Concurrent repeatability and reproducibility analysis of four gait models for foot-ankle complex

Multi-segment
models of the foot have been proposed in the past years to overcome limitations
imposed by oversimplified traditional approaches used to describe foot
kinematics, but they have been only partially validated and never compared. This
paper presents a unique comparative assessment of the four most widely adopted
foot kinematic models and aims to provide a guidance for the clinical
interpretation of their results.

Sensitivity of the models to
differences between treadmill and overground walking was tested in nine young
healthy adults using a 1D paired t-test.
Repeatability was assessed by investigating the joint kinematics obtained when
the same operator placed the markers on thirteen young healthy adults in two
occasions.  Reproducibility was then assessed
using data from three randomly selected participants, asking three operators to
repeat the marker placement three times. The analyses were performed on
sagittal kinematics using curve similarity and correlation indices (Linear Fit
Method) and absolute differences between selected points.

Differences between treadmill and overground gait were highlighted
by all the investigated models. The two most repeatable and reproducible
investigated models had average correlations higher than 0.70, with the lowest
values (0.56) obtained for the midfoot. Averaged correlations were always
higher than 0.74 for the former and 0.70 for the latter, with the lowest
obtained for the midfoot (0.64 and 0.51). For all investigated models, foot kinematics
generally showed low repeatability: normative bands must be adopted with
caution when used for comparison with patient data.