There are several commercially available devices especially designed to reduce the transmission of forces into the foot and leg from a detonating mine. This device was inspired by the spider boot. This article presents some of the benefits this device offers to users who are exposed to a mine blast: http://maic.jmu.edu/journal/4.2/focus/sb/spiderboot.htm.
Mines are an unfortunate legacy of wars in many countries. For people who must work clearing mines or work in close proximity to known minefields, this device may be of use. In the event that the person sets off a mine, the device provides some separation from the explosion, as well as shielding the user from ejecta and absorbing some energy from the blast.
The "arms" of the shoe are designed to blow off and distort in the event of a blast. The voids underneath the footplate act to distribute forces over the foot and absorb energy. There is room for improving this energy absorbing zone, potentially using a honeycomb or some other porous structure, perhaps making a "birds nest" with the polymer.
Ensuring that the shoe is strong enough for walking and potentially running is also a priority. This may be especially important in hot climates, where high ambient temperatures could weaken the plastic, or at least make it more likely to creep.
This is a super easy one to print, other than the massive amount of plastic. The shoe should max out the work envelope on your machine, whatever that is. You want the footprint as large as possible.
After it is printed, thread some webbing through the slots on the side, and strap on your sturdiest boot. You may have to get creative to get a nice binding. A snowboard binding would be great to clip in, if you have one lying around. Otherwise, just use string. If you don't know knots, tie lots.