In football, an onside kick is a type of kickoff in which the kicking team attempts to recover the football after kicking the ball. For the kicking team to recover the ball, the ball must travel at least ten yards from the spot of the kick before the kicking team is allowed to touch the ball. If the kicking team touches the ball before it travels ten yards, it is a penalty and the receiving team is awarded possession of the football.
For an onside kick to be successful, the kicking team must recover the ball. This is not easy, and it's a big risk. If the receiving team recovers the ball, they are more likely to score since they're getting the ball near the 50 yard line.
The kicking team will disguise an onside kick to look like a normal kickoff. The place kicker will make the onside kick difficult to catch, so that it gives players on the kicking team a chance to recover it.
The onside kick is used as a desperation tactic, usually by a team that is trailing in a game with very little time left. The chance of success of an onside kick is very low, but increases if the receiving team is not expecting it. Teams employ one of two strategies when performing an onside kick: kicking the ball low and kicking the ball high. By kicking the ball low, the kicking team hopes the ball bounces off the ground and high enough into the air to create a jump ball for both teams. By kicking the ball high, the kicking team hopes the create the same scenario, though accurately kicking the ball high into the air is difficult. If the ball goes out of bounds during the kick, the receiving team is awarded possession.