Functionality and performance of customized sole inlays for various sports applications

To increase product value and consumer satisfaction customization has become a major aspect in product development. From the consumers' perspective this trend towards individual fitting is certainly positive as long as it does not negatively influence other sports specific functionality parameters. The current study is dealing with this interaction heading towards customizing effects in footwear. A long term field test was conducted to determine which design parameters of a customized insole embodies the highest benefit for the athlete perceived performance. A test assembly of 20 athletes evaluated a traditional and a customized insole under three different sport conditions 1) indoor sports, 2) outdoor sports, and 3) running). A questionnaire was designed that asked for nine functions at six decisive foot segments (heel, metatarsal, forefoot; lateral, medial); 1) optimal roll off, 2) cushioning, 3) force transmission, 4) feet support, 5) bedding, 6) secure step, 7) avoid slipping 8) avoid pressure and 9) avoid pain. These items were subjectively evaluated by our test persons and finally correlated with initially collected objective measures. Static and dynamic plantar pressure measurements provided data for individual foot sole profiles. Results showed four important outcomes. Firstly, different sports applications require different functional insoles to ensure optimal athlete perception and performance. Secondly the grade of customization increases their perceived performance. Thirdly objective and subjective data are both required to ensure optimal insole supply. And fourthly subjects are rather limited in their ability to distinguish effects of insole design modifications. Especially the last finding raises the question how far customization should be expanded and where it unnecessarily goes beyond practical relevance.