SUMMARYThe present study reports the development of a detailed three-dimensional (3D) finite element (FE) foot model for investigating the effect of the material properties and thicknesses of the landing mat on stress distribution and concentration point within the metatarsals during landing at an inversion position. Foam material mat insert between the foot and ground with different thicknesses had been systematic studied. The predicted plantar pressure distribution showed a good agreement with the experimental data of controlled biomechanical tests. Results showed that mat insert with optimal properties and thickness could reduce the peak plantar pressure by about 36% comparing to the barefoot-solid ground condition. The fifth metatarsal was the most vulnerable part during the inversion landing, and the peak stress point was located near the proximal part. Material sensitivity study showed that the metatarsals' stress level was affected by the material property of the mat and its thickness. Meanwhile, the influence of thickness for soft material was more effective than that for the hard material.

The deep transverse metatarsal ligaments (DTML) play an important role in stabilizing the metatarsal bones and manipulating foot transverse arch deformation. However, the biomechanical research about DTML in the foot maneuver is quite few. Due to the difficulties and lack of better measurement technology for these ligaments experimental monitor, the load transfer mechanism and internal stress state also hadn’t been well addressed. The purpose of this study was to develop a detailing foot finite element model including DTML tissues, to investigate the mechanical response of DTML during the landing condition. The DTML was considered as hyperelastic material model was used to represent the nonlinear and nearly incompressible nature of the ligament tissue. From the simulation results, it is clearly to find that the peak maiximal principal stress of DTML was between the third and fourth metatarsals. Meanwhile, it seems the DTML in the middle position experienced higher tension than the sides DTML.

This study analyzed the plantar pressure distribution character as the foot position between normal to inversion. Eight healthy male volunteers have participated in the test with the foot position from normal to 20 inversion angles which controlled by wedges. The results of this test showed that the centre of the pressure was clearly transferred from centre to lateral side when the foot position was changed from normal to inversion. In addition, the contact area varied largely between the normal and inversion condition, but changed a little between two inversion loading situations. The finding of this study suggests that the foot injuries could attributed to more of inappropriate foot positioning than the magnitude of loading force.

This study aims to evaluate the effectiveness of diabetic therapeutic footwear design in preventing the foot ulcer. A total of 36 type 2 diabetic patients were investigated. The foot plantar pressure was measured with Novel-Pedar insole pressure measure system. The subjects were measured under common leather shoes and common running shoes. Different regions of plantar surface were analyzed. Comparing with two different conditions, Generally, except other toes region, the peak pressure values in running shoes were lower than the leather shoes. Both midfoot and medial forefoot region were significantly different between two intervene. Running shoes might be useful for preventing the diabetic foot ulcer. Because they could reduce the peak pressure effectively than the leather shoes, and make the distribution of the pressure on the foot sole more reasonably.

Injuries of the base of the fifth metatarsal are among the most common of all skeletal injuries of the foot. The fracture is considered by previous research to be an avulsion due to the slip fascia, however, the mechanism of the plantar slip fascia’s function still not very clear. In this study, a detailed three-dimensional (3D) finite element (FE) model was developed by reconstruction of CT images. A sensitivity study was conducted to evaluate the effect of varying stiffness of the slip fascia on the fifth metatarsal’s deformation. The results showed that the largest vertical displacement was appeared in the metatarsal’s head part, and the difference was up to 10.5%, while the Young’s modulus of the slip fascia increasing from 50MPa to 500MPa.