Foot ligament stiffness variations with changes in loading rate and anatomical location

Foot ligaments are non-linear viscoelastic structures that become stiffer as loading rate increases. This study aims to characterize the rate dependent stiffness of foot ligaments at various loading rates. After excising and potting bone-ligament-bone specimens, ligaments were displaced to 10% strain during 34 cycles of triangle waves and at randomized physiological frequencies (1, 2, 3, 5, 10 Hz). The association between ligament stiffness and loading rate was determined. Results indicate that stiffness significantly increased as displacement rate increased for all ligaments (p = 0.0007).