Hockey’s origins go back to ancient times. Records indicate that a rudimentary form of the discipline was played in Egypt 4,000 years ago, and in Ethiopia around 1,000 BC, as well as by the Romans, Greeks and Aztecs. However, the modern form of the sport arose in the mid-18th century in the schools of England.

Despite modern hockey's English roots, one of the theories about its name is that it comes from the French word hocquet, which means 'stick'. The first amateur hockey association was established in London in 1886, and the sport’s influence soon spread not just across Great Britain, but in all British colonies – which is the reason why countries such as India and Pakistan have strong traditions in the sport.

Hockey’s popularity within the British Empire meant that it made its Olympic debut at the London 1908 Games, as a demonstration sport. After this, however, hockey entered and left the Olympic programme several times, reappearing at the Stockholm 1912 and Antwerp 1920 Games.

It was not played at the 1924 Games in Paris, due to the fact that no organisation existed to regulate the sport throughout the world. At the time, the nearest thing that existed was an agreement between Great Britain, Belgium and France to standardise the rules. In the same year, the International Hockey Federation (known by French acronym FIH) was established.

At the Amsterdam 1928 Games, hockey returned definitively, and medals were awarded for it. Over the years, the sport has gone through changes that have made it even more popular: the number of countries affiliated to the FIH increased and, as of 1976, natural turf hockey pitches began to be replaced by artificial surfaces, making the game faster. Women first played in the Olympic Games at Moscow 1980.

Hockey pitches measure 91.4 x 55 metres – a little smaller than football pitches – and games have traditionally consisted of two halves of 35 minutes. However, a change in the regulations at the end of 2014 means that at major events, including the Rio 2016 Games, matches will be now disputed in four periods of 15 minutes, called quarters, with automatic 40-second time-outs each time the referee awards a penalty corner or a goal is scored.

Players use a stick, generally made from carbon fibre, Kevlar and fibreglass (composed of 90, five and five per cent of each material, respectively). The stick weighs between 350 and 700 grams, and may not exceed five centimetres in diameter. The ball is made from plastic and cork, weighs around 160g, and is three centimetres in diameter.

Each team has 11 players, including the goalkeeper, who defends a goal 2.14m high and 3.66m wide. The aim is to score as many goals as possible - although they are only valid if scored inside the shooting circle, which has a 14.63m radius drawn from the middle of the end line towards the centre of the field.

Hockey competitions at the Olympic Games have the following format: the 12 participating countries in each event (men's and women's) are divided into two groups of six, in which everyone faces each other. The four best teams in each group go through to the quater-finals, the winners of which contest the semi-finals. The semi-final winners play for gold, while the losers compete for bronze.

In the semi-finals and finals, games that end up drawn after the regular length of play have an extension with two halves of seven and a half minutes, and whichever team scores first wins. If there is still a tie at the end of extra time, the match is decided by a penalty shoot-out of five shots per team. Each player starts with the ball on the 23m line and has eight seconds to score, with only the goalkeeper to beat. If the scores are still tied, the match is decided by sudden-death penalties.