Is it important to position foot in subtalar joint neutral position during non-weight-bearing molding for foot orthoses?
Lee WC, Lee CK, Leung AK, Hutchins SW. J Rehabil Res Dev. 2012 May;49(3):459-66.
I used to make birky cork orthotics for skiing under the Superfeet brand during the 80's and 90's which was an unweighted vacuum casting technique using hot cork, a plastic bag over the foot and a vacuum to pull the air out of the bag against the foot, resulting in atmospheric pressure molding the cork against the sole of the foot. The cork blank sat on a plastic former during the process. The idea was to get the foot into sub-talar neutral during the forming time because if you did not do this the resulting shape could be twisted in the transverse and frontal planes making the result less tolerable and less stable inside a boot. This was before I was trained as a pod so we did not always understand the full implications of what we were doing but we certainly had to deal with recurring problems if they happenned. We did sometimes alter the result(medial or lateral wedging) to give what we thought was better skiing function.....not gait function
regards Phill Carter
For those that may be interested in the history of these techniques, the individual that invented that casting method and the Superfeet brand of insoles and alpine ski insole system was one of my (and Eric Fuller's) biomechanics professors at CCPM, Dr. Christopher Smith.
We learned the plastic-bag-over-the-foot-casting-technique in 1981 from Dr. Smith.