Get Involved: FOOTBALL
Men's Olympic football may play second fiddle to the World Cup in the international pecking order but since the introduction of professional players in 1984, the tournament has been taken increasingly seriously.
It has carved a niche in the football calendar, with a maximum of three over-age players strengthening under-23 teams.
In the Beijing Olympics four years ago, Barcelona superstar Lionel Messi and Manchester City striker Sergio Aguero (then playing for Atletico Madrid) were the key players as Argentina won the men's gold.
A British entry for London 2012 has been riddled with controversy for many years and arguments about its make-up continue to rumble on.
The Scottish, Welsh and Northern Irish associations have been vehemently opposed to letting their players take part in a unified British team as they fear their independence in world football would be compromised if they united with England at the Olympics.
Why is it good for you?
Football provides a great variety of physical exercise as in a game a player will have to run, kick, dodge, sprint and jump. It helps increase endurance, promote agility, develop physical coordination and build muscle strength.
Players remain in constant motion, with about five miles typically run in a 90-minute, 11-a-side game. This effort burns approximately 630 calories.
A study by the University of Copenhagen found that playing football on a regular basis boosted cardiovascular fitness, aided fat loss and reduced blood pressure.
As it is a team game, it is an excellent way to develop communication skills and learn to work effectively with other people. Football clubs also offer a variety of social events beyond simply playing the sport.
More than 250m people are believed to play football regularly in over 200 countries. A further 3.5 billion are believed to be fans, making it the most popular sport in the world.
Football is a fast moving and simple sport that is open to people of all abilities and ages. There are almost five million players in the United Kingdom playing the game in more than 50,000 clubs.
Unlike other sports, a casual game of football is incredibly easy to set up. All that is needed is a ball, makeshift goals and varying numbers of competing players.
For safety, shin pads should always be worn whether playing on grass, astro turf or indoors.
People from beginners to experts, amateurs to professionals, can take part in a variety of formats. Traditional 11-a-side leagues are run throughout the country, with five-a-side competitions also available.
Programmes can also be found by those who want to get into the sport by becoming coaches and referees.
Thousands of grassroots training schemes take place each year in parks, sport centres, schools, universities, gyms and colleges.
Want to get involved with sport in your local community? Why not Join In ?
'Join In Local Sport' aims to get as many people as possible to turn up and take part in activities at their local sports facilities on 18/19 August, 2012 - the first weekend between the Olympic and Paralympic Games.
The aim of the initiative is for every sports club and community group in the UK to put on a special event in a bid to encourage more people to get involved as members, supporters or volunteers.
More than 4,000 local sports clubs will be opening their doors to host events and show people just how they can get involved.
As well as tips on playing sport there will be information on coaching, supporting and how to help out.
Find an event near you.
The competition format at London 2012
- From Wednesday 25 July to Saturday 11 August, 504 footballers (288 men, 216 women) will compete in the men's and women's football tournaments.
- The City of Coventry Stadium, (Coventry), Hampden Park (Glasgow), Millennium Stadium (Cardiff), Old Trafford (Manchester), Sports Direct Arena (Newcastle) and Wembley Stadium (London) will host the matches.
- Due to the amount of games that need to be played, the competition actually kicks off two days before the opening ceremony.
- The men's competition consists of 16 teams split into four groups.
- The women's has 12 teams drawn into three groups.
- In the men's, the top two from each group will progress to the quarter-finals. In the women's, the top two from each group, plus the two best third-placed teams, will advance.
- The semi-final winners play in the final for gold and silver, with the semi-final losers competing for bronze in a third-place play-off.
The rules at London 2012
Olympic football is played on an 11-a-side basis over 90 minutes.
In the knockout stages only, matches that are level after 90 minutes are resolved by two 15-minute periods of extra time, which is followed by a penalty shootout if necessary.
There are five initial penalty takers per team. If no winner is decided then, a sudden death competition ensues.
In the group stages, teams receive three points for a win, one point for a draw and nothing for a loss.
In the men's tournament, each 18-member squad must include at least 15 athletes below 23 years old, with no age limit for the remaining three. There are no age restrictions for the women's tournament.
A referee and two assistants decide on infringements during the game. Indirect free-kicks, direct free-kicks and penalties are awarded depending on what type and where the foul is committed on the pitch.
Ones to watch
Great Britain are entering a men's team for the first time since 1960 and the women's team are making their Olympic bow.
Stuart Pearce's men have been drawn against Uruguay, Senegal and the UAE., while the women's team were also seeded but Brazil were drawn in their group. England's women reached the quarter-finals of the 2011 World Cup.
Spain, the European under-21 champions, and Brazil are the favourites in the men's competition. Argentina, the 2004 and 2008 gold medallists, failed to qualify.
Japan come into the women's event as holders of the World Cup after beating USA in the final last year. The USA have won three of the four Olympic titles on offer.
Football has its roots in ancient China and the streets of medieval England, and first appeared on the Olympic programme in Paris in 1900.
Men's football was introduced as a demonstration sport at the 1896 Olympics and was one of the first team sports to be introduced to the Games. It became an official Olympic sport in 1908 but was dropped from the Games in 1932 following the inaugural Fifa World Cup.
It returned in 1936 but the growth of professional football after the Second World War meant the best players were ineligible to take part - unless they lived in Communist countries, resulting in dominance for Eastern Bloc nations.
In 1984 some professionals were allowed to compete, but European and South American nations were restricted to using players who had not yet featured at a World Cup. In 1992 all professionals were eligible, provided they were under 23 years old.
At the 1996 Games in Atlanta, teams were allowed to field three over-age players in the final tournament and women's football was introduced with no age restrictions.
Europe had dominated until that tournament, since when African and South American teams have won all the gold medals. The women's competition was introduced then as well, with the USA taking three of the four gold medals to date.