Effect of 3D printed foot orthoses stiffness on muscle activity and plantar pressures in individuals with flexible flatfeet : a statistical non-parametric mapping study
Article [Accepted Manuscript]
Is part of
Clinical biomechanics ; vol. 92, no. February 2022.Publisher(s)
ElsevierAuthor(s)
Affiliation
- Université de Montréal. Faculté de médecine. École de kinésiologie et des sciences de l'activité physique
- Hôpital Sainte-Justine. Centre de réadaptation Marie Enfant. Centre de recherche
- École polytechnique (Montréal, Québec). Institut de génie biomédical
- Centre interdisciplinaire de recherche en réadaptation et intégration sociale
- Université Laval. Faculté de médecine. Département de réadaptation
Abstract(s)
Background
The 3D printing technology allows to produce custom shapes and add functionalities to foot orthoses which offers better options for the treatment of flatfeet. This study aimed to assess the effect of 3D printed foot orthoses stiffness and/or a newly design posting on muscle activity, plantar pressures, and center of pressure displacement in individuals with flatfeet.
Methods
Nineteen individuals with flatfeet took part in this study. Two pairs of foot orthoses with different stiffness were designed for each participant and 3D printed. In addition, the flexible foot orthoses could feature an innovative rearfoot posting. Muscle activity, plantar pressures, and center of pressure displacement were recorded during walking.
Findings
Walking with foot orthoses did not alter muscle activity time histories. Regarding plantar pressures, the most notable changes were observed in the midfoot area, where peak pressures, mean pressures and contact area increased significantly during walking with foot orthoses. The latter was reinforced by increasing the stiffness. Concerning the center of pressure displacement, foot orthoses shifted the center of pressure forward and medially at early stance. At the end of the stance phase, a transition of the center of pressure in posterior direction was observed during the posting condition. No effect of stiffness was observed on center of pressure displacement.
Interpretation
The foot orthoses stiffness and the addition of posting influenced plantar pressures during walking. The foot orthoses stiffness mainly altered the plantar pressures under the midfoot area. However, posting mainly acted on peak and mean pressures under the rearfoot area.