At any moment throughout the game, up to four interchange (reserve) players may be substituted for those on the field. These players are referred to as "on the bench" under Australian rules, which refers to a section of the sideline with a row of seats. The coach will often have several other spare players sitting in these seats, ready to come onto the field at a moments notice.
The number of substitutes allowed is one of the most flexible elements of the game. In fact, some senior football leagues allow two substitutes. This allows coaches the opportunity to play several young players who can be replaced if they get hurt or tire out. Other sports limit substitutions to replace one player with another who has the same physical ability categories (for example, one guard can be swapped for another guard). Under Australian rules, any player can be replaced by a substitute regardless of category so long as he is eligible to return to the field. A player who has been sent off (red carded) cannot be replaced and will therefore miss the next match.
In practice, most games feature only one substitute because adding more would slow down the game too much. However, it is possible to have two subs if you have enough room on your roster.
There is no limit on how many times a player can be substituted during a match, but most clubs choose not to use all their substitutes before the end of normal time.
Each team has four interchangeable substitutes to pick from, and they can enter the game at any moment. Most interchanges are tactical, but they can also come on for any player who has been injured and has been put to the blood bin. The maximum number of replacements per match is 14.
In English football, there are currently 80 divisions between the top professional club and the bottom amateur one. The Premier League is the highest level of play and consists of 20 teams. There are three points awarded for a win and one taken away if you lose so overall position is important. If two or more teams are equal on points at the end of the season then the team that has won most games will be ranked ahead of those who have won less.
In Spain's La Liga, there are currently 52 clubs divided into four categories based on their financial strength. The top division, known as "La Primera", has 18 teams while the other three have between nine and ten members each. They all operate under the same rules, with each team having four substitute players available during normal time periods. However, if a player suffers an injury that requires surgery, he/she will be out for several months and therefore unable to take part in matches.
The number of interchanges varies depending on how many players are unavailable due to injuries or suspensions.
Six players can be on the pitch at the same time, with up to eight replacements off the field. Reserves can be continually substituted from one side of the field at any moment. A try is scored by touching down on or behind the try-line. A try is worth one point. A penalty goal is worth three points.
The number of players on the field at any one time is called the lineup size. The term "full squad" is also used to describe a lineup that includes all members of the team available for selection. A "substituted lineup" is one in which some players have been removed from the field due to injury or otherwise unavailable and replacement players have entered the field during the game.
In American football, there are only eleven players per side on the field at any one time. In soccer, there are eighteen players (including the goalkeeper) on the field at any one time. In ice hockey, there are two fifteen-player teams on the ice at once; a coach can substitute any player on the bench for any player on the ice at any time.
In rugby, there are six players on the field at any one time plus a captain who is always one of them. A captain can replace any other player on the field without having to use a replacement player. However, if all the players except the captain are replaced, then a replacement player must be used.
In Australian rules football, there are 18 positions, not including four (occasionally six or eight) interchange players who can replace another player on the field at any moment during play. Because of the fluid character of the current game, football positions are not as rigorously defined as in sports such as rugby or American football. That being said, there are generally three types of positions: ruckmen, defenders and forwards.
The ruckman is the most important position in Australian rules football. The ruckman is responsible for taking opponents out of the game with powerful hits from his body and with forceful kicks to remove the ball from the play area. A popular saying in Australia is "there are no small roles in footy, just big men with bigger shoulders". The ruckman must have a strong upper body and be able to take strong tackles to the head and chest.
The second most important position is that of defender. Defenders are assigned to stop specific players from getting the ball; they may do this by physical force, by positioning themselves between the player and the ball, or by making aggressive challenges. They should have good speed and strength, and be able to handle hard tackles. In general, defenders are the hardest working players on the field. During a game, they may be required to cover more ground than others, which can lead to injury. However, because games are rarely played in succession, injuries usually only affect players for a few games.
Football played in Australia. Each side is allowed to have 18 players on the field at any given time, with an extra 4 players on an interchange bench (although this number often varies in exhibition and practice matches). The game requires very little equipment to play. A ball made of leather or synthetic materials is used in place of a soccer ball.
Australian rules football has been described as a contact sport, but it is not physically demanding like American football or rugby. An athlete's chance of being injured during a game is fairly high because there are multiple checks carried out by referees who will stop the game if necessary. In addition, some injuries may not be seen until later when the player returns to the field after being treated by a medical staff member.
In Australian rules football, you can be replaced by a substitute while you are still playing. This replacement allows teams to make changes without losing too much time, which is important because each team has a maximum number of timeouts per game. A team can use its first timeout after scoring a goal or winning the toss of possession. A second timeout is used after answering back against your opponent or forcing them to kick from their own half of the field. Teams can also use a third timeout if they believe that their opponent is about to score.
The substitution system is different in amateur and professional games.