Is Heel Strike Running Faster? No!
The two main reasons heel strike running is slower than forefoot running is that for one, too much muscle energy is needed to drive the elogated stride thats tied to disrupting the natural spring properties of the leg and foot. For another, heel strike running and foot overpronation go hand-in-hand because its a natural component of the heel-to-toe movement path of the foot after touchdown. This not only projects excessive bending and twisting strain up the leg, it also impairs the stretch-shortening cycle of the Achilles tendon, thereby limiting elasticity effectiveness as well as increasing energy costs.
