There is an increasing body of evidence which shows that maintenance of aerobic capacity and skeletal muscle strength by lifelong physical activity delays biological ageing in most organs, and therefore has a direct link to the prevention of chronic disease such as high blood pressure, type II diabetes, obesity, cardiovascular disease and the metabolic syndrome.1^–9 This has been impressively documented in a supplement of the Journal of Sports Sciences in 2006 and also in the January 2009 issue of the British Journal of Sports Medicine. In a recent paper, Booth and Roberts link performance and chronic disease risk and urge not only the unfit population to start regular physical activity, but also encourage former athletes to continue their physical activity to prevent increased risk of chronic disease.2

If sports activities are considered as health enhancing leisure activities, the risk of sustaining injury caused by particular sports activities must be reduced to a minimum by implementing appropriate preventive measures.

Concussion is a common type of brain injury caused by impact forces to the head following intentional or unintentional collisions. All sports, be they team sports (eg, football, rugby and ice hockey), or individual sports (eg, horse riding, skiing or boxing) have a finite risk of concussion injury, which should be reduced as much as possible if the potential for long-term problems is to be avoided. Concussion must be recognised quickly and treated appropriately; however, the most important aspect of medical management is the timing of the return to play decision. The team physician is commonly under pressure from the team, the coach or the administration to get the athlete back in the game, particularly in high profile matches. On the other hand the physician has to take the ultimate responsibility for the decision on when the athlete can safely return to play or not.

To support all those physicians acting in the field by offering scientific evidence and expert consensus to facilitate the decision making was the main objective of the 3rd International Concussion Consensus Conference held in October 2008 in Zurich, Switzerland.

The first concussion symposium was held in November 2001 in Vienna as a joint venture of the International Ice Hockey Federation (IIHF), Federation International de Football Association (FIFA) and International Olympic Committee (IOC). The second symposium was held in Prague 2004. Both conferences produced a summary and agreement statement on concussion in sport.10 11 The Prague meeting offered as a recommendation, a simple sideline assessment tool called the Sports Concussion Assessment Tool (SCAT). The SCAT has been promoted by the major international sports federations within their educational courses in the respective sports and has been extremely helpful for the decision making process for return to play.

In football, concussion is a serious issue, particularly when it comes to the discussion of potential long-term brain damage. The FIFA Medical and Research Centre (F-MARC) initiated a series of biomechanical experiments to analyse the forces impacting on the head and brain, and also video analysis of incidents leading to concussion, identifying tackles with higher propensity to cause concussion. The results were presented in a 2005 supplement of the British Journal of Sports Medicine entitled “Head injuries in football”. The scientific evidence from these studies was presented to the International Football Association Board (IFAB), proposing to eliminate those incidents which lead to head and brain injuries (such as elbow to head contact in tackles). The IFAB decided to sanction offenders (through the red card send off mechanism); this rule change resulted in a significant decrease in head injuries in the FIFA World Cup 2006. This is an example of how medical science can work with game administrators and lawmakers to ensure that injury prevention is achieved.

Concussion is also a serious problem in ice hockey where rule change and enforcement have been utilised to reduce concussion risk. The IIHF and international member federations have adopted rule changes that disallow any hit to the head area from any part of the body and also penalise the use of the stick on an opponent’s body in all instances. To improve rule enforcement, the IIHF is using a two-referee system to enhance vigilance detecting fouls. In addition, there has also been an increasing emphasis on fair play and respect in all competitions around the world.

In rugby, the IRB has a training programme entitled RugbyReady that has been designed to educate, aid and support players, coaches, match officials and member unions on the importance of proper preparation for training and playing so that players enjoy rugby to the fullest while reducing the risk of injury. Within RugbyReady it is emphasised that padded clothing does not protect against concussion. The training programme also indicates safe practices when making contact with opposition players either as a ball carrier or as someone attempting to tackle the ball carrier which, if followed, should minimise injuries to the head and neck area.

The 3rd International Concussion Consensus Conference in Zurich was designed to follow the US National Institutes of Health consensus criteria as closely as possible; Professor Willem Meeuwisse, editor in chief of the Clinical Journal of Sports Medicine, provided leadership to ensure that this process was followed. The detail of the process is outlined in the consensus paper in this issue. In brief, topics and issues were identified in advance; individual panellists conducted reviews of the literature and provided reading material ahead of the meeting which comprised an open to the public conference followed by closed session with 27 invited experts who are well published and experienced in the field of head and brain injuries. The key papers presented at the consensus meeting are available as “flash lectures” via the medical commission link at http://www.olympic.org/medical or at http://www.FIFA.com/medical, or BJSM online http://bjsm.bmj.com. After extensive structured discussion, a consensus paper has been drafted and corrected until all involved authors and experts could reach full agreement. An integrated part of the consensus paper is the presentation of the SCAT2 assessment tool and “pocket SCAT” as an aid to sideline diagnosis as well as providing a complete medical examination for concussed athletes.

The 3rd International Concussion Consensus Conference has been held with the support of the IOC, FIFA, IIHF and the IRB (International Rugby Board). The current supplement is the result of almost 10 years of continuous scientific collaboration of the involved partners which has raised awareness in the international sports federations, stimulated research output and outlined the possible ways where research should be guided in future to be able to present scientifically proven and sound guidelines for return to play after sustained concussion. We commend this supplement to you.