I ankle carry a Kahr PM9 80% of the time. If your steel toe boots go above your ankles then the holster will likely have to accommodate the boot & leg. So I am thinking that holster fit around the combination could be an issue or the fit inside the pant leg could too, because of larger overall diameter.
Just about any activity short of running works OK for me when ankle carrying. Get the pant diameter and inseam length right and you should be good to go. Not the best place to carry as it slow and awkward to get to as well as telegraphs your action. Better than under the seat in the car.
Mike