This form of onside kick is still legal in Canadian football, just as in rugby. A player of the kicking team (at any kick, not just a free kick) who is "onside" may recover the ball and retain possession for his team. This includes the kicker himself and anyone else behind the ball at the time it was kicked, other than the holder for a place kick. The form of onside kick available at a free kick in American football (see below) is also available in Canadian football for a kickoff as well; however, the kick may well be chipped high instead of bounced, because the players of the receiving team have no particular first right to the ball as in American football—both sides may play the ball equally, even in the air.
"Onside kick" is now reserved in modern usage for a free kick intentionally attempted in such a manner as to maximize the possibility of recovery by the kicking team. Kicks not attempted in such a way that yet happen to be muffed or fumbled by the receiving team are not referred to as onside kicks.
Once the ball has hit the ground there is no chance of a catch and hence no possibility of interference. Thus the kicking team generally attempts to make the ball bounce early and be available around 10 yards in front of the spot of the kick. One technique, useful especially on a hard field such as one with an artificial surface, is to kick the ball in a way that it spins end-over-end very near the ground and makes a sudden bounce high in the air. The oblong shape of an American football can make it bounce off the ground and players in very unpredictable ways. This unpredictability has the additional benefit for the kicking team of increasing the probability that the receiving team will muff the kick.
An onside kick from a free kick is usually a desperation technique used for a kickoff by a team trailing in the score with little time left in the game, in order to gain another possession of the ball and to hopefully allow scoring again. The risk is that if the receiving team does get possession of the ball — as they usually do — they will have much better field position, meaning they will have less distance of the field that they need to move the ball in order to score. For this reason, this play is typically only attempted with very little time on the clock, when the field position advantage of the receiving team is not very important because they are already ahead and will simply focus on running the clock out and ending the game regardless of their initial field position.
Occasionally, football coaches will attempt surprise onside kicks in an effort to catch their opponent's players off guard, when they are less likely to have the putative "hands team" on the field. For instance, in Super Bowl XXX, Pittsburgh Steelers coach Bill Cowher called an onside kick early in the fourth quarter when trailing 20-10 which was successfully recovered.
In 2004 in the NFL, 23% of onside kicks were successful (12 out of 52).
One such version, Arena football, is current. American football for approximately a decade in the 1910s and 1920s allowed all players of the kicking team except the kicker to recover the ball once it hit the ground beyond the neutral zone; after two years that was modified to require it be at least 20 yards downfield. The XFL of 2001 revived that rule, changing the minimum to 25 yards.
The idea of the early 20th century, XFL, and Arena rules allowing kicking side recovery on grounded balls was generally to force the receiving team to play the ball, encourage quick (i.e. surprise) kicking, and thereby loosen the defense. However, kicks have rarely been employed as offensive tactics even when these rules were present; the forward pass remains the more effective tactic to loosen and surprise the defense.