title: A wearable system for multi-segment foot kinetics measurement.
abstract: This study aims to design a wearable system for kinetics measurement of multi-segment foot joints in long-distance walking and to investigate its suitability for clinical evaluations. The wearable system consisted of inertial sensors (3D gyroscopes and 3D accelerometers) on toes, forefoot, hindfoot, and shank, and a plantar pressure insole. After calibration in a laboratory, 10 healthy elderly subjects and 12 patients with ankle osteoarthritis walked 50m twice wearing this system. Using inverse dynamics, 3D forces, moments, and power were calculated in the joint sections among toes, forefoot, hindfoot, and shank. Compared to those we previously estimated for a one-segment foot model, the sagittal and transverse moments and power in the ankle joint, as measured via multi-segment foot model, showed a normalized RMS difference of less than 11%, 14%, and 13%, respectively, for healthy subjects, and 13%, 15%, and 14%, for patients. Similar to our previous study, the coronal moments were not analyzed. Maxima-minima values of anterior-posterior and vertical force, sagittal moment, and power in shank-hindfoot and hindfoot-forefoot joints were significantly different between patients and healthy subjects. Except for power, the inter-subject repeatability of these parameters was CMC>0.90 for healthy subjects and CMC>0.70 for patients. Repeatability of these parameters was lower for the forefoot-toes joint. The proposed measurement system estimated multi-segment foot joints kinetics with acceptable repeatability but showed difference, compared to those previously estimated for the one-segment foot model. These parameters also could distinguish patients from healthy subjects. Thus, this system is suggested for outcome evaluations of foot treatments.
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratory of Movement Analysis and Measurement, ELH 137/ Station 11, CH-1015 Lausanne, Switzerland. Electronic address: hossein.rouhani@epfl.ch.
authors.forename: H
authors.initials: H
authors.lastname: Rouhani
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratory of Movement Analysis and Measurement, ELH 137/ Station 11, CH-1015 Lausanne, Switzerland. Electronic address: julien.favre@epfl.ch.
authors.forename: J
authors.initials: J
authors.lastname: Favre
authors.affiliation: Centre Hospitalier Universitaire Vaudois and University of Lausanne (CHUV), Department of Orthopaedic Surgery and Traumatology, Lausanne, Switzerland. Electronic address: xavier.crevoisier@chuv.ch.
authors.forename: X
authors.initials: X
authors.lastname: Crevoisier
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratory of Movement Analysis and Measurement, ELH 137/ Station 11, CH-1015 Lausanne, Switzerland. Electronic address: kamiar.aminian@epfl.ch.
authors.forename: K
authors.initials: K
authors.lastname: Aminian
mesh_terms: D000368:Aged; D000843:Ankle Joint / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D005260:Female; D005528:Foot / Q000502:physiology*; D005684:Gait / Q000502:physiology; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000379:methods*; D010003:Osteoarthritis / Q000503:physiopathology*; D016138:Walking / Q000502:physiology*
keywords: Gait; Inertial sensors; Inverse dynamics; Multi-segment foot kinetics; Pressure insole