The following log is my humble attempt at understanding the bio-mechanics of the foot. The image above is a 3D print of an anatomically correct foot skeleton, consisting of 26 bones. It is also over 25% of your body's total musculo-skeletal anatomy, hitting the ground every time you walk or run! This really demonstrates the complexity and beauty of the system which we use for transport. I find the geometry fascinating, it seems the volume distribution relates directly to function, becoming thinner in the middle and thicker at the extremities.

I stumbled upon this article which I thought was very informative, it describes the foot as a vault, which has three main weight bearing focal points. If we consider a bio-mechanical ideal gait then the pressure distribution is as illustrated below. By averaging these points we can then obtain the gaitline, it is by calculating this line from the 16 sensors that we can diagnose the patient.

Once diagnosed the methodology to create the insole is not so clear and subject to much contraction within the field. I am starting to build my own process but I'll refrain to elaborate until I've done more research and testing.

To end this log I just wanted to share a quick update on the hardware, it most definitely took much longer than it should but it's now working properly. You can see below the insoles inserted in an old pair nike. The target sample rate of 40ms was achieved, I've even managed to get it down to 20ms which could come in useful in certain sports.

Finally, a brief real time replay in the software, even though there is much work to be done on the analytical side I think it's interesting to see the prominence of the three main weight bearing points.