The Impact of Foot Insole on the Energy Consumption of Flat-Footed Individuals During Walking
Mohammad Karimi, Niloofar Fereshtehnejad, Fatemeh Pool
Foot Ankle Spec September 5, 2012
Nothing new under the sun, I first came across this paper in about 1991, http://intl-poi.sagepub.com/content/12/2/73.full.pdf html
We later (about 1993) attempted to repeat as an undergraduate project at Northampton (Denver Jane Greenhalgh, nee Wilson) with compressed felt "cobra pads" versus "reverse cobra pads"- I honestly can't remember the results.