ASICS use 3D computational models to better understand the role of stability in running shoes. Optimizing with simulation reduces the risk of lower extremity injuries for runners, as well as enhancing performance. Sole structure and heel eversion angle are particularly important for understanding stability. Alongside experimental methods, models created in Simpleware software for export to Abaqus simulation tools help ASICS reduce prototyping time and costs, as well as manufacturing waste.
Tsuyoshi Nishiwaki and Mai Nonogawa
ASICS Corporation, Institute of Sport Science
To predict shoe stability, a scan of the foot of a healthy female volunteer was obtained using X-ray computed tomography. The image data was imported to Simpleware ScanIP software to build a 3D model prior to the generation of a Finite Element model representing different parts of the foot (soft tissue, bones, cartilage, ligaments and plantar fascia). The detail of the model enabled ASICS to be confident in the accuracy of their anatomical simulation.
Heterogeneous numerical model considering soft tissue, bones, cartilage, ligaments and plantar fascia
Abaqus v.6.14-2 was used with the model to calculate deformation modes on polymer foam sheets with three types of hardness. Results showed good agreement with experimental testing, validating simulation as a way of enhancing existing ASICS methods. The numerical model was confirmed to accurately predict sole stability, leading ASICS to successfully update the design of their soles to improve performance for customers.
Heel eversion calculated by the proposed model corresponding to foot flat phase
Motion capture system with force plate to measure heel eversion angle, shoe stability parameter
ASICS have successfully created accurate, highly optimized models tailored to specific running conditions. The model is therefore valuable for shoe stability designing, reducing prototyping costs and time, and skipping practical prototyping to improve sustainability. Products have been introduced as practical designing examples, with research contributing to an improved understanding of running shoe stability and reducing excessive foot joint motion, or pronation, during the contact phase in running.
The new ASICS GEL-Kayano 25 (released June 1, 2018) developed with Simpleware Software