Adam Clarke on Judges 5:22

Then were the horsehoofs broken - In very ancient times horses were not shod; nor are they to the present day in several parts of the East. Sisera had iron chariots when his hosts were routed; the horses that drew these, being strongly urged on by those who drove them, had their hoofs broken by the roughness of the roads; in consequence of which they became lame, and could not carry off their riders. This is marked as one cause of their disaster.