Leg stiffness is an important parameter when performing various motions. Ground reaction force, duration of support, displacement of the body mass center as well as step frequency during running or jumping depend on stiffness of the leg (McMahon, 1990; Farley, 1996; Granata, 2001). It is not clear yet how foot stiffness changes with deformation, how it is related to the deformation speed, the number of repetitions, what influence does soft tissues have on stiffness of a foot. The aim of this research is to determine whether foot compression-displacement dependency changes when compressing foot repeatedly; does foot stiffness depend on compression speed. The specimen was a right foot with normal longitudinal arch from a Caucasian female. 25 kN force Tinius Olsen H25K-T testing machine was used in the study. The compression rate was 25 mm/min, 50 mm/min, 100 mm/min and 500 mm/min until 1000 N force was reached. The deformation and stiffness of the foot at different compression speeds were analyzed when 400 and 700 N force was reached. Despite the compression speed differences the values of Intraclass correlation coefficient show data repeatability when compressing the foot repeatedly. The foot stiffness remained stable at 25-100 mm/min foot compression speed. At compression speed higher than 100 mm/min foot stiffness decreased significantly. The regression equation was derived to describe dependence between stiffness and relative deformation of foot with soft tissue.