I started treating cyclists and teaching cycling biomechanics during my Biomechanics Fellowship back in ’84 – ’85. Varus wedges either placed inside the bike shoe or placed between the bike shoe sole and the cleat are modifications that have been used for at least the last 27 years to take a cyclist with an inverted forefoot to rearfoot alignment and getting them to function on the bike more normally.
A little podiatric-cycling treatment history is in order here. At the time of my Biomechanics Fellowship, Harry Hlavac, DPM, who practiced about 20 miles away from CCPM in Mill Valley, was developing and patenting a new device he called the « BioPedal » which was a bike pedal that allowed the cyclist to either invert or evert the dorsal surface of the pedal in order to improve the cyclist’s biomechanics. Unfortunately, for Harry and his Biopedal, this was also the time that clipless pedal systems were becoming popular which allowed us to simply wedge the bike cleat with a shim material, such as coins, washers or korex, to produce the same varus or valgus wedge effect for the cyclist without the expense and extra mass of the « BioPedal ».
Since that time, I have done demonstrations at one of the larger bike shops in Sacramento showing how using varus cleat wedges can improve the tracking of the knee during cycling in cyclists with inverted forefoot deformities. The effects can be quite dramatic in some individuals with highly inverted forefoot positions. Currently these wedges are available commercially which greatly simplify the alignemt process for the cyclist. The wedges can also be stacked together in neutral alignment for treating limb length issues in cyclists.
In addition, two decades ago, I was a researcher in a bike study back with the Department of Mechanical Engineering at UC Davis that was eventually published in the Journal of Biomechanics (Ruby P, Hull ML, Kirby KA, Jenkins DW: The effect of lower-limb anatomy on knee loads during seated cycling. J Biomech, 25 (10): 1195-1207, 1992). In this study we used an instrumented bicycle pedal which measured forces at the shoe-pedal interface just like a force plate to determine which lower extremity measurements correlated to knee joint loads: STJ axis location and forefoot to ground alignment with the STJ in neutral position.
Hope this helps.