According to the website Eye Opener, there are several reasons why stepping on a LEGO toy hurts so much, despite the minuscule size of the building bricks.

For starters, each small LEGO can take up to 4,240 Newtons of force without breaking. That means unless you weigh 953 pounds, they won’t be crushed or even give a little.

Also, when a person is walking, each step carries approximately twice their normal body weight. If running, the impact of a person’s foot on the ground is nine times their weight.

The fact that the bottom of the foot is one of the most sensitive areas on a body plays a part as well. The foot has 100 to 200 thousand exteroceptors, or nerves, which connect directly to the brain.

All of this combines so that when a person steps on a LEGO, the pressure and pain concentrated around an item as small as a pebble creates a very strong response throughout the body.

Fortunately, despite the tremendous amount of pain, not much actual damage is generally done by stepping on the building bricks.

Source: Eye Opener