In 2002, France and Arsenal star Robert Pires damaged the anterior cruciate ligament (ACL) in his right knee. Pires and the French national team coach Roger Lemerre have both blamed fatigue as a contributory factor in the injury. Lemerre has been deprived of the services of one of the worlds top midfield players for the World Cup in Japan and South Korea and the manager was critical of the high number of games his English based players have to play in a season. Speaking from the French Football Federation HQ at Clarefontaine he said, We know that the players who are playing loads of games during the season become very fragile and we think that Pires' injury is due to the accumulation of games.
Lemerre seemed most concerned about the welfare of his players based at Arsenal, who have been involved in the Champions League, FA Cup and Premiership. The French coach added, Pires and (Thierry) Henry are the two players who have played the most this season. They have played around 45 or 47 games. After a certain limit, it becomes very dangerous. They play at a very high level. The competition and the pressures are very high, and it can have serious consequences on their health.
Pires damaged his knee when landing awkwardly trying to avoid a tackle from Newcastle Uniteds Nicos Dabizas. The players right foot was planted in the turf as his knee twisted under the players momentum - a common method of damaging the cruciate ligaments without the need for a collision with an opponent. After the diagnosis had been confirmed, by Professor Jean-Henri Jaeger in Strasbourg, Pires himself reflected on his circumstances, admitting, I am very tired and the succession of games was probably too high, even if I like playing every three to four days. My injury does not make me change my opinion on that. In all jobs there are risks. Maybe I have not been careful enough, when I see the video it was a lack of concentration.
There is scientific evidence to support Lemerres theory that playing too many games is the major reason he will not have the services of Pires in Japan and South Korea. Although we all know what we mean when we refer to fatigue, it is a difficult concept to define from a scientific viewpoint. Many definitions exist, but the simplest is the inability to maintain work output. This can manifest itself in several ways. Mental fatigue is a subjective experience that can lead to a lack of concentration. Alternatively, physiological fatigue can be defined objectively as a decline in work output when a task is measured or timed and results from changes in the nervous system, or in the muscle tissue, which adversely affect the athletes performance and ability to avoid injury.
In order to understand how physiological fatigue can contribute to knee ligament injuries, it is necessary to understand the way the nervous system and muscles interact to contribute to joint stability.