Re: Foot othoses and cycling
I would pay close attention to what Kevin has written here and read his papers STJ Axis Location Rotational Equilibrium Theory Foot Function and Effect of Lower-Limb Anatomy on Knee Loads During Seated Cycling.
When I make an orthosis for a cyclist, much of what goes into determining what that individual needs I have learned here on PA. Pay very close attention to Kevin's comment that "any motion of the foot and lower extremity that is not occurring with the sagittal plane, is wasted or inefficient motion".
I tend to make a sulcus length low volume orthosis with a full length poron/neoprene top cover. Cycling, skating etc. are unique in that the foot is in a perpetual stance phase of gait, hence my suggestion to make the device sulcus length. As Kevin pointed out, forefoot valgus, plantarflexed first rays etc can be addressed as well and if you evaluate the cyclist on the bike you can determine what is most efficacious. At times addressing the cleat/pedal interface is even more beneficial and cost-effective and that is where your training and clinical experience come in.
"If we all worked on the assumption that what is accepted as true is really true, there would be little hope of advance." - Orville Wright
David G. Wedemeyer, D.C., C.Ped.