It seems there is nothing haphazard about football injuries, according to a study conducted by the Sahlgrenska Academy at the University of Gothenburg. Working together with FIFA, the Swedish researchers analysed injury data from three World Cups (2002, 2006 and 2010), concluding that incidents are closely linked to various events on the pitch. These events affect the emotional and physical state of the players and thus determine the risk and frequency of injuries.
According to the study report, which has been published in the British Journal of Sports Medicine, injury frequency depends on the power balance in the game. This means that footballers in the winning team are more likely to get injured. According to study contributor Jaakko Ryynanen, this may have to do with the fact that players on the opposing side get more aggressive. The research also established a direct connection between free kicks and injuries: the more free kicks there are in a match, the higher the frequency of injuries. It appears that yellow and red cards also have a part to play in determining injury frequency, as the frequency rises in the five minutes after such an event, as well as after a goal and other injuries. The researchers theorise that this may be due to the loss of concentration after disruptive game breaks.
The position of a player also has relevance to injury risk, the frequency being highest among strikers. This could be related to the importance of these team members for the outcome of the game.
The researchers were surprised to find that the number of injuries during a World Cup match went up after a longer break between matches. According to one theory, longer breaks may affect the focus of players. It is also possible that they play more intensely after a few days´ break.