Midtarsal break

How it works

The human foot is built as a stiff lever. When you walk, the heel lifts, the ligaments across the middle of the foot lock, and the whole foot pivots on the ball and toes². The stiffness pushes you forward with little wasted effort.

Chimpanzees and other apes have a different foot. Their midfoot bends when they push off, at the joint between the heel bones and the bones of the arch¹. This bend is called a midtarsal break. It lets the foot wrap around a branch and grip it. It is part of what makes an ape foot good for climbing and poor for long walks³.

Some humans have it too. In 2013 Jeremy DeSilva and Simone Gill at Boston University filmed 398 adults walking barefoot across a pressure-sensing mat. About 1 in 13 of them, 7.7%, showed a clear bend in the midfoot as they pushed off¹. These people had flatter arches and looser ligaments at the joint¹. None of them knew their feet did this.

People with a midtarsal break can often spread their toes wide and grip objects with their feet. There is no evidence that it causes harm. It is a leftover from ancestors who lived partly in trees.

Try it

1. Take off your shoes and socks. Stand on a hard floor.
2. Ask someone to film your foot from the side, at floor level, while you walk slowly.
3. Watch the middle of the foot as the heel lifts. In most people the foot stays straight from heel to ball until the heel is well off the ground.
4. If the foot folds in the middle before the heel is up, you have a midtarsal break.
5. Try picking up a pen or a sock with your toes. People with a flexible midfoot usually find it easy.