Initial estimation of the in vivo material properties of the seated human buttocks and thighs

摘要

On average, people are sedentary for 70% of the day, either seated or lying down. Of particular interest for this work is the seated posture; while seated the buttocks and thigh tissues experience loading for prolonged periods of time. When modeling human body interactions with seating devices and in the design of these devices, it is necessary to appropriately model the material characteristics of the soft tissue in the thigh and buttock areas. Thus, there is a pressing need forin vivo, experimentally measured data that describe the mechanical behavior of the soft tissue within the buttocks and thigh regions of humans in the seated posture. We developed an innovative experimental set-up to gatherin vivoforce–deflection data for both men and women in six regions located along the buttocks and thighs. Then, using anatomical measures, cadaver measures, and reported literature on regional tissue thickness, the data were converted to normal stress and strain curves. Next, these curves were described using the Mooney–Rivlin material model. Finally, best-fit mechanical parameters were reported, along with the original force–deflection data. Results indicated that, in general, the male tissue differed from female tissue, and that the mechanical properties differed between regions. Thus, when developing computer models that represent the human body, different material properties should be considered for men and women. Furthermore, appropriate properties should be used for the body region being evaluated. These data are unique in that they are quantifiedin vivo, represent the seated body position, and include multiple regions for both men and women. The material properties presented in this work will lead to improved numerical models, and consequently improved device design.