In vivo viscoelastic properties of human thigh under compression estimated by experimental results obtained with pendulum test

Abstract

Viscoelastic properties of human skin or muscle are very important to investigate the biomechanical behavior of human body. However, since it is difficult to measure them in vivo, only a few limited methods have been introduced so far. The purpose of this study is to propose a method to estimate the viscoelastic properties of in vivo human thigh under compression. Pendulum tests were carried out and a two-degrees-of-freedom model was used to analyze the pendulum motion of lower extremity. Kelvin-Voigt model was used to represent the viscoelastic behavior. The viscoelastic properties were obtained with an optimization formulation that minimized the difference between analysis and experimental results. The stiffness property obtained with the proposed method was in reasonably good agreement with those obtained with other existing methods, especially in vivo indentation method. Moreover, the damping property which had rarely been obtained in the previous studies could be also obtained with the proposed method.