Foot contact surface effect to the metatarsals loading character during inversion landing

Abstract

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.

Stress distribution of metatarsals during forefoot strike versus rearfoot strike: A finite element study

“…Poisson's ratio=0.3) [23]. As in previous works [11] and other literatures [24], the stiffness of the Cartilage, Plantar Fascia and Ligament is set at 1, 350 and 250 MPa, respectively; the Poisson's ratio is set as 0.4. The phalanges are assumed to have the same material properties as the bones [16].…”

“…The coefficients of the hyperelastic material used for the encapsulated soft tissue is C10=0.08556, C01=-0.0841, C11=-0.02319, C02=0.00851, D1 = 3.65273, D2=0. [11,25]. The data was obtained through an in vivo compression measurement with several cohorts and inverse parameter fitting, the model had been used in serval published biomechanical works [11,12,13].…”

“…[11,25]. The data was obtained through an in vivo compression measurement with several cohorts and inverse parameter fitting, the model had been used in serval published biomechanical works [11,12,13]. When D2=0, it represents full incompressibility.…”

“…The collision force of touching down is 1.5-3 times of the body weight [3]. Full contact was defined between the foot surface and the ground, with a surface to surface contact condition and the friction coefficient between foot plantar and the rigid plate was 0.6 [11,16,29].…”

“…FEM is commonly used in many biomechanical investigations with great success due to its ability to model complex material properties and irregular geometry as well as the capacity of simulating the internal stress in bones and tissue. Many published studies have focused on the foot stress under static standing load [11][12][13]. Stress in the bony foot structure was simulated during balance standing by Cheung noting a clear effect of the soft tissue stiffening and of the use of different types of foot support design [12,13], including the modelling of foot with medical conditions such as diabetic foot [14].…”