Author(s): HAICHUN, W., XIAOLAN, Z., Institution: BEIJING SPORT UNIVERSITY, Country: CHINA, Abstract-ID: 378

INTRODUCTION:
The metatarsal bones, integral components of the metapodial complex, play a critical role in the transmission of stress and serve as a pivotal element in the attenuation of axial loads in speed skating. Conventional biomechanical approaches have demonstrated proficiency in characterizing the impact of technical manoeuvers on foot kinetics; however, they fall short in shedding light on the internal mechanical repercussions instigated by variations in biomechanical parameters. This significantly constrains the advancement of principled analysis aimed at enhancing the technical manoeuvers in speed skating. The objective of this investigation was to develop a sophisticated three-dimensional (3D) finite element model (FEM) of the foot in conjunction with a speed skate to examine the mechanical behaviour of the metatarsal and metatarsophalangeal joints under various loading conditions.
METHODS:
A 3D FEM was reconstructed utilizing data from computed tomography and 3D scanning. The models validity was ascertained through the comparison of FEM-predicted outcomes with in vivo measurement data. The FEM was subjected to push-off angles derived from video analysis of an elite skater, with angles set at 42°, 49°, 56°, 63°, and 70°, respectively. Boundary conditions and loading parameters for the FEM stipulated that the distal ends of the tibia and fibula, along with the associated soft tissues, were fixed. The displacement of the ice surface was constrained in all four cardinal directions. The applied forces included a ground reaction force and an Achilles tendon force, quantified at 640N and 480N respectively, while the frictional force between the ice surface and the skate blade was set at a coefficient of 0.003.
RESULTS:
The error rates of validation of plantar soft and blade bottom were less than 10%. During the skating propulsion phase, maximal stress is localized at the fifth metatarsal, with the third metatarsal experiencing the least. A decrease in the push-off angle correlates with reduced stress in the first and second metatarsals and increased stress from the third to fifth metatarsals. The most significant stress fluctuations are observed in the first and fifth metatarsals, with changes of 5.229 MPa and 6.379 MPa, respectively. Additionally, the stress at the first and second metatarsophalangeal joints decreases correspondingly, with variations of 0.011 MPa and 0.004 MPa.
CONCLUSION:
The alteration in the angle of push-off exerts a discernible influence on the mechanical behaviour of the Metatarsal and Metatarsophalangeal Articulations. These findings offer fresh insights into the biomechanics of skating, potentially guiding the design of sports equipment and the refinement of training programs.