The supination resistance test is something I put a lot of weight on when making foot orthotic decisions. When I first started teaching on the Clinical Biomechanics Boot Camps we did spend a lot of time on the supination resistance test and on the concept of supination resistance, as it was so new to so many of the participants, but as time went by less time was spent on it as the test has the clinical application of the test was so widely used by so many clinicians.
Kevin Kirby, DPM first described the supination resistance test and we have done a lot of work on it with a number of studies both published and unpublished that explore the concept. Along with that research I have been using it clinically for a very long time and we did do a lot of practical workshops on it in the boot camps, it soon became obvious just how useful it was to use clinically when it came to foot orthotic decision making in clinical practice. Podiatry Arena does have a lot of threads on it and they do get updated regularly.
The supination resistance test is a test used to work out about just how much force is needed to supinate or invert the foot and then applying that knowledge to how much force is needed to come from the design features in the foot orthotic. If the force to supinate the foot is higher or above average, then the force needed from a foot orthotic needs to be high as well. There is no point using a soft flexible foot orthotic in those with a high supination resistance as the orthotic is probably going to be flattened by the high forces and do nothing. If the supination force in the foot is low, then a soft flexible foot orthotic is going to be more than adequate. If using a rigid inverted type of foot orthotic in those feet with a low supination resistance is probably going to sprain the ankle as the forces are too high.
In our research we used a specifically made device that we built ourselves to quantify it but that device of ours really has no practical use in clinical practice as its too cumbersome, so the use of the hands and manually estimating the supination resistance is adequate. There are some commercially devices on the market, such as the Keystone that can be used to put a number on it.
We did a deep dive into the supination resistance test in an episode of PodChatLive: