Product development of a shoe outsole

Abstract

Knee Osteoarthritis (KOA) is a prevalent degenerative joint condition characterized by the gradual deterioration of the articular cartilage, leading to pain, stiffness and functional impairment. KOA affects a significant portion of adults and the elderly population in Singapore and cases are expected to climb in the coming years. Hence, it is crucial to optimize existing methods and rehabilitation solutions to delay onset of the development of KOA. Past rehabilitation solutions and mechanical interventions such as lateral wedge insole shoes, variable stiffness intervention shoes, lateral offset shoe sole and AposHealth therapy device have been sufficiently studied in prior researches. In the recent years, newer interventions have surfaced and have shown in findings that ultimately, the most effective approach to slow the progression of KOA is to lower the knee adduction moment (KAM) by shifting the center of pressure of the foot (COP) laterally. However, many of the said rehabilitation solutions and mechanical interventions have limited effects in the reduction of KAM. Therefore, this study hypothesized that a variation of flexibility and stiffness along different parts of the outsole based on different design factors would potentially achieve this objective. Different geometrical shapes, arrangement and pattern density were first studied before being tested – both physical and simulated. The main motivation for this was to determine the best design for a flexible shoe outsole. From the experimental results and key findings obtained, certain design variables showed a strong correlation to flexibility and the top design was selected to be implemented onto the shoe outsole.