Discussing with a class mate brought up a few videos and documentaries about shoe design and how they explore using a wide range of materials and test rigs when trying to find the new natural feel of running.
Nike Lab: Innovation x innovators
Tinker Hatfield: footwear designs ep. 2
A class mate referred me to a member of Massey University staff who specialises is Bio-materials amongst other things. I have arranged a meeting with her on Thursday morning to discuss my project and hopefully gain some insight into using sustainable materials. She sent through a link to a Portuguese brand called Zouri who use ocean plastics when making sustainable sandals.