A New Multi-Adjustable Experimental Seat for Investigating Biomechanical Factors of Sitting Discomfort

A new experimental seat was designed to investigate sitting biomechanics. Previous literature suggested links between sitting discomfort and shear force, however, research on this topic is limited. The evaluation of sitting discomfort derived from past research has been primarily associated with seat pressure distribution. The key innovative feature of the experimental seat is not only pressure distribution evaluation but shear forces as well. The seat pan of the experimental seat compromises of a matrix of 52 cylinders, each equipped with a tri-axial force sensor, enabling us to measure both normal and tangential forces. The position of each cylinder is also adjustable permitting a uniform pressure distribution underneath the soft tissue of the buttocks and thighs. Backrest, armrests, seat pan and flooring are highly adjustable and equipped with forces sensors to measure contact forces. The backrest consists of three adjustable panels: lumbar, thoracic and neck; each can rotate freely as well as provide movement in both fore-aft and vertical directions. Seat pan length and height as well its inclination are also adjustable. All adjustments with the exception of the armrests can be controlled by a computer through one of two interfaces (desktop computer or a tablet).. The purpose of this paper will be to present the technical specifications of the new experimental seat and its evaluation. This experimental seat could be pivotal for the current gap missing in research related to sitting as well as a useful tool for seat manufacturers.