Height Restriction

A Height Restriction is a balancing mechanic in Street Fighter that affects attacks that the opponent can only use when they are in the air.

Description
In Street Fighter games many attacks, both Unique Attacks and Special Attacks and even occassionally Target Combos can only use their attacks when the performer of the attack is jumping. Height restrictions are a certain point in the jump that a character can perform their attack. Trying to use the attack before the character reaches that point will either have the character perform another action or the game will wait for the character to reach the point of activation then continue as usual.

Balancing
As Street Fighter games try to balance characters, Height Restrictions are used on a per character basis to keep a certain character from being overpowered. In Street Fighter IV Since Rufus's Falcon Kick is so central to his gameplay Falcon Kick does not have a height restriction to help ensure he can use it to punish low attacks, Crouch Techs and grab attempts, as a tradeoff Falcon Kick does not have a very dominating hitbox, meaning it can barely trade with other attacks, let alone beat other hitboxes. Cammy's EX Cannon Spike doesn't have a height restriction either, while her regular version does. The tradeoff here is that Cammy needs to use Meter for her attack.