The original Tread Heavy concept is to continue the reinforcement from the back of the heel through the bottom of the heel and the ball of the foot (and of course, you could continue through the toe too!)

The Tread Heavy Sock is a remedy to the question I had when I first started knitting socks. “Why is it only reinforced on the back of the heel?” These are designed for those of us who tread heavy in or out of our shoes.