Sprinting

Sprinting is a method of transportation that allows the player to move faster, at the expense of depleting more hunger.

Activating
To sprint, the player can press while moving, or double tap. The player cannot sprint if their hunger bar is at or below.

Ocelots, iron golems, wither skeletons, baby zombies, zombie pigmen, endermen and villagers can also sprint like the player.

Usage
Sprinting allows the player to move at around 5.612 meters/second, 30 percent faster than the normal walking speed of around 4.317 m/s. The player can turn while sprinting, which will slightly reduce their speed. Sprinting will also increase the speed of flying in Creative mode, and slightly increase the speed of swimming. Although “sprinting” while mounted on a minecart, boat, horse or pig increases the field of vision like actual sprinting, their speed does not increase.

While sprinting, it is possible to jump across up to four blocks horizontally, instead of the usual two blocks, though the player will not jump higher.

Sprinting will reduce the player's saturation, and once their saturation is 0 it will deplete the hunger bar at a rate of $1/2$ every 40 meters, or 7 seconds.

Sprinting produces particles at the player's feet corresponding to the block type they are running on. When a player attacks any mob (excluding squid) while sprinting, the mob suffers a larger knockback than usual.

Sprinting ends when the player collides with a solid block, sneaks, blocks, attacks a mob, or after 30 seconds. Sprinting will also end if the hunger bar lowers to or below.

Trivia

 * Sprinting and holding down jump at the same time is usually faster, but actually becomes slower when under the effect of a high level speed potion.
 * Sprinting and jumping while under a 2 block high ceiling causes a player to move at a speed almost twice as fast as regular sprinting speed, but it will consume a hunger point every second.
 * This can be sped up even more by decreasing the ceiling height using trapdoors or by sprinting on ice.
 * A similar effect occurs if you sprint and rapidly hit jump at the same time on a set of stairs.