title: Concurrent repeatability and reproducibility analyses of four marker placement protocols for the foot-ankle complex.
abstract: 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.
authors.affiliation: Department of Mechanical and Aerospace Engineering, 'Sapienza' University of Rome, via Eudossiana, 18, Roma 00184, Italy; Department of Mechanical Engineering, The University of Sheffield, Pam Liversidge Building, Mappin Street, Sheffield S1 3JD, UK. Electronic address: roberto.dimarco@uniroma1.it.
authors.forename: Roberto
authors.initials: R
authors.lastname: Di Marco
authors.affiliation: Department of Economics and Management, Industrial Engineering (DEIM), University of Tuscia, Via del Paradiso, 47, 01100 Viterbo, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Rossi
authors.affiliation: Department of Civil and Structural Engineering, The University of Sheffield, Sir Frederick Mappin Building, Mappin Street, Sheffield S1 3JD, UK; INSIGNEO Institute for in silico medicine, The University of Sheffield, Sir Frederick Mappin Building, Mappin Street, Sheffield S1 3JD, UK; Department of Civil and Environmental Engineering, Politecnico di Milano, Milano 20133, Italy.
authors.forename: Vitomir
authors.initials: V
authors.lastname: Racic
authors.affiliation: Department of Mechanical and Aerospace Engineering, 'Sapienza' University of Rome, via Eudossiana, 18, Roma 00184, Italy; Department of Mechanical and Aerospace Engineering, New York University Tandon School of Engineering, Brooklyn, NY 11201, USA.
authors.forename: Paolo
authors.initials: P
authors.lastname: Cappa
authors.affiliation: Department of Mechanical Engineering, The University of Sheffield, Pam Liversidge Building, Mappin Street, Sheffield S1 3JD, UK; INSIGNEO Institute for in silico medicine, The University of Sheffield, Sir Frederick Mappin Building, Mappin Street, Sheffield S1 3JD, UK.
authors.forename: Claudia
authors.initials: C
authors.lastname: Mazzà
mesh_terms: D000328:Adult; D000842:Ankle / Q000502:physiology; D001696:Biomechanical Phenomena; D005080:Exercise Test; D005260:Female; D005528:Foot / Q000502:physiology; D005684:Gait; D006801:Humans; D007596:Joints / Q000502:physiology; D008297:Male; D055595:Mechanical Phenomena; D008954:Models, Biological; D015203:Reproducibility of Results
keywords: Foot kinematics; Repeatability; Reproducibility; Statistical parametric mapping; Treadmill and overground walking