Studies have shown that increasing the stiffness of the big toe joint in soles improves sprint performance. I 3D printed (SLS for strength) stiffer soles, with grooves to reduce mass. I used FEA to make sure the soles would be stiff and strong enough to avoid cracking.

Using the scanned dimensions I designed the spike soles.

It's fascinating to see how feet do not conform to the idealised foot shape of shoes

The challenge was to make the sole light, durable and stiff, so I chose Nylon 6,6

I needed a simple way for people to measure their feet at home so that they could have custom shoes

I got sprinters to draw around their feet with a pen on graph paper and also to paint their foot and step on graph paper

I uploaded the foot scan and used it as the basis to design the CAD

I found a shoemaker to help. We picked the closest matching last (foot mould) to make the upper.

Making a new last for each shoe is wasteful and costly. I added plasticine to get a standard last to match the sole.

Here's the upper and the sole - before glueing. I added a foam layer for cushioning. 

Radical! Kenyan Kitenge fabric. Two different sole designs and ready for testing.

Sprinters run on the balls of their feet and spike needles provide the grip. I realised I had missed a secondary need - grip when slowing down.

When you stop sprinting and slow down, you need grip on your heels, so I added that in the next iteration.