Function and Fashion
A modern shoe last is not a replica of the human foot. It is a generalization of the human foot, accounting for natural articulation and volumetric changes as the foot moves and flexes.
A high-quality running or walking shoe will have a thoughtfully designed last. A major shoe brand will enlist the help of shoe manufacturers, podiatrists, and kinesiologists to develop biomechanically ideal shapes.
How does a last differ from a human foot?
The surface of a last is smooth and firm with graceful transitions. The human foot has an irregular shape with a variety of soft and wrinkled surfaces.
Most shoe lasts do not have individual toes. Sandals will eventually have a slot for the toe position. The new toe shoe trend calls for lasts with toes, but these are rare. The vast majority of shoe lasts do not have toes.
The heel ditch, which lifts your heel off the ground, is absent in the human foot. The toe spring of a last is also absent in the human anatomy, but it aids walking and helps the shoe flex with the foot without creasing. The circumference measurements around the foot are larger than the foot itself to account for volumetric changes as the foot flexes under load while walking.
The shoe last's length is also slightly longer than the foot. This extra length allows the foot to move within the shoe while walking or running. The last's general outline and increased length allow it to appeal to a wide variety of feet. The length of the last at the front of the toe allows the designer to tailor the shoe to fashion trends.
Shoe lasts vary in size and measurement, or "graded," in a systematic arithmetic manner. Shoe lasts are also symmetrical, with the right side being a mirror image of the left. Human anatomy does not follow such rules regarding size and symmetry.
