Comparison of feetme insoles with a motion capture system coupled to force plates for assessing gait and posture

Abstract

Traditional gait measurement systems are often limited by factors such as cost, complexity, prolonged setup times, and requirements for specialized training and expertise. Wearable pressure- and motion-sensing insoles have opened new possibilities for accessible gait analysis in real-life conditions. This study evaluated the equivalence of FeetMe insole measurements of gait parameters to those of a laboratory gold standard, optoelectronic motion capture system coupled to force platforms (MoCap/FP). Gait and posture parameters were assessed in 37 healthy adults by FeetMe insoles and by MoCap/FP system simultaneously. Means and variances were compared, and inter-device agreement was assessed for each parameter. Between-device equivalence was demonstrated for all parameters assessed (two one-sided t tests: P < .001). For static parameters, six of 13 variables presented excellent interclass correlation coefficients (ICCs ≥ 0.90) and three had good ICCs (≥ 0.75 to < 0.90). Moreover, 10 of 11 spatiotemporal parameters showed excellent accuracy (ICCs ≥ 0.90), and three of four kinetic parameters showed moderate-to-good accuracy (ICCs between 0.78 and 0.89). In summary, FeetMe can be considered as a valid gait measurement tool compared to the high precision MoCap/FP system and could be used in clinical practice to assess a wide range of gait and posture parameters, overcoming some limitations of traditional systems.

Keywords: FeetMe; Force platform; Gait analysis; Optoelectronic motion capture system; Pressure sensor insole system; Vertical ground contact force..

Fig. 1

(a) Participant during non-assisted walking on force platforms with FeetMe insoles inside the shoes and reflective markers for the Vicon optoelectronic motion capture (MoCap) system attached to the outside of the shoes. (b) FeetMe insoles. (c) Schematic representation of the walk trajectory on the force plates and the position of MoCap cameras. (d) Aquashoes from Decathlon with reflective markers and FeetMe insoles inside the shoes.

Fig. 2

Bland-Altman analyses of FeetMe and MoCap/FP measurements of static stabilometry parameters: (a) bCoP AP dim, (b) bCoP ML dim, (c) total weight, and (d) weight ratio. The solid line represents the mean difference between the systems, with the upper and lower lines (dotted lines) representing the limits of agreement. bCoP AP = anterior-posterior bipodal center of pressure, bCoP ML = medial-lateral bipodal center of pressure, dim = dimensions.

Fig. 3

Bland-Altman analyses of kinetic parameters recorded by the FeetMe and MoCap/FP systems during walking. (a) Dynamic uCoP AP dim during a stance, (b) Dynamic uCoP ML dim during a stance, (c) Heelmax load and (d) Toemax load (n = 11,515 for all measurements). The solid line represents the mean differences between the systems, with the upper and lower lines (dotted lines) representing the limits of agreement. Each point represents the value for a given stride. uCoP AP = anterior-posterior of unipodal center of pressure, uCoP ML = medial-lateral of unipodal center of pressure, dim = dimensions, N = number.

Fig. 4

Bland-Altman per stride analyses of the FeetMe and MoCap/FP measurements of spatiotemporal parameters (a) stride length (StrideLen; stride n = 5250), (b) stride duration (StanceDur; stride n = 5250), (c) velocity (stride n = 5250) and (d) double-support duration (DoubleSupDur; stride n = 4782). The solid line represents the mean difference between the systems, with the upper and lower lines (dotted lines) representing the limits of agreement. Each point represents the value for a given stride.