Crouch jumping is especially prominent in the Half-Life series
and other games running on Valve
's game engines, since there it actually makes the player jump higher and reach places they wouldn't be able to reach with regular jumping.
The mechanics of the crouch
jump are such that when crouching, the player character does not actually hunch down lower, but instead pulls his feet up towards this body, allowing for greater clearance.
Crouch jumping initially was born as an elite skill for dedicated players, but came full circle in Mirror's Edge
, the first person free running game. Mirror's Edge allocated a specific button command for tucking the player's feet up against her body to allow for greater clearance while jumping.
Aside from Mirror's Edge, crouch jumping actually works due to odd game physics. A similar example comes from Tony Hawk's Pro Skater
, in which the player could perform flip tricks while in mid air. Each trick, rather than pushing the board down, actually lifted the player higher above the board, allowing players to gain jump height through repeatedly tricking.
A famous example of crouch jumping comes from Halo: Combat Evolved
, where skilled players could crouch jump to retrieve the active camo power up in the multiplayer map Hang 'Em High.
"Crouch jumping" as defined here is not to be confused with jumping while crouched, such as was possible in many 80's and 90's side-scrolling games, e.g. the Super Mario franchise. In these cases, jumping while crouched was used to reach elevated areas with low clearance, or to take advantage of game bugs, sometimes passing level areas, or even dropping "behind" the level.