Some older cycling books and articles recommend the practice of "ankling." This refers to changing the angle of the foot fairly drastically during the course of the pedal stroke, so that the toe is pointed upward at the top of the stroke, and downward at the bottom. The idea is to make more use of the muscles of the lower leg, and to permit "pedaling in circles", i.e., applying more force to the cranks at top and bottom dead center.

This practice is pretty much discredited these days. If carried to an extreme, it can cause injury. This happened to me when I was a teen-ager; I had read about ankling, and had just acquired my first pair of toe clips, just before setting out on my first overnight tour. I ankled for about the first 30-40 miles, when there was a sudden sharp pain in one of my Achilles tendons. I had to lower the saddle, remove the toe clips, and finish out the 4 day tour pedaling on my arches, because I couldn't bear the slightest load on the front of my foot, pulling on the Achilles tendons. For about a month thereafter, I would need to massage my Achilles tendons for about 5 minutes each morning before I would be able to walk. 40 years later, I've still not completely recovered from this injury.