Running shoe sole stiffness evaluation method based on eigen vibration analysis

Abstract

Running shoes have a wide range of functional requirements, such as shock attenuation, flexibility, stability and fit. These requirements vary with the conditions of the running activity, such as the runner's skill and running velocity. In the design of shoes for high speed running, sole bending and torsional moduli are important factors because excessive sole deformation can cause considerable energy loss in the contact phase. In this article, the propulsion impulse (PI) calculated by the horizontal ground reaction force in constant running velocity is proposed as a measure of running ease. In constant running speed, a reduction in PI is equivalent to a reduction in kicking power. This can help reduce runner fatigue. PI depends on sole stiffness distribution. To predict PI, a sole stiffness prediction method based on eigen vibration analysis is proposed in this article. After confirming the validity of the proposed method it is discussed further using an ASICS high speed running shoe design as an example.