Injury rates in the Olympic sports

The overall rate of injury in the Sochi Games was similar to those in Beijing 2008, Vancouver 2010 and in London 2012 (12% of all athletes injured in Sochi vs 11% in Vancouver and London, and 10% in Beijing).12 ,13 Compared to their Vancouver Winter Games counterparts, higher injury rates were found in the Sochi Games athletes competing in aerial skiing (49% vs 19% of the athletes injured), alpine skiing (21% vs 15%), biathlon (7% vs 1%), cross-country skiing (8% vs 3%), curling (12% vs 4%), luge (8% vs 2%), moguls skiing (25% vs 2%), skeleton (11% vs 6%), snowboard halfpipe (18% vs 13%), and snowboard slalom (14% vs 7%). Conversely, lower injury rates were found among the Sochi Games athletes competing in ice hockey (11% vs 18%), short track (9% vs 18%) and ski cross (14% vs 19%). In general, our findings on the sports-specific injury rates in Sochi are corroborated by a large body of research from the Fédération Internationale de Ski (FIS) World Cup, where snowboard cross and halfpipe,47 aerial and halfpipe skiing and ski cross,42 as well as particularly downhill of the alpine skiing events41 ,46 have been identified as disciplines with a higher rate of injury.

A change in injury incidence can be the result of changes in the composition of the Olympic Games programme (eg, 12 new events introduced in Sochi), environmental factors, such as weather, snow or ice conditions, venue or track design, competition rules, in equipment or other factors. Changes in injury rates can also follow an increased or reduced awareness among the athletes and their medical staff in recognising and reporting even minor incidents (broad injury and illness definition applied in IOC surveillance studies). In certain sports, changes may also be attributable to more comprehensive and accurate data reporting by team physicians who over time have been trained as injury and illness recorders through the implementation of surveillance systems by their own Federation. Also, rate differences (lower or higher) may simply be the result of a natural fluctuation/variability of athlete’s exposure to risk, an observation that emphasises the value of on-going surveillance to monitor trends over time, for example, the effect of venue design, rule or equipment changes in the period between major sports events.

Severity, location and type of injuries

In major sports events, like the Olympic Games, injuries or illnesses of even minor severity and time loss have the potential to be participation-limiting and performance-inhibiting, and thus prevent athletes from reaching their life-time achievement. In the Sochi Games, 61% of the injuries were reported to lead to no absence from competition or training, whereas 39% were estimated to result in time loss of at least 1 day. However, 16% of the injuries were estimated to encompass time loss greater than 7 days. This may indicate a shift from the Vancouver Games, where 23% of the injuries were expected to entail a time loss of at least 1 day, and just 4% a time loss of more than 7 days; however, this is uncertain, as there was a high percentage of missing data on injury severity in Vancouver.12 These results warrant a more extensive recording and detailed analysis of injury risk factors and mechanisms, to improve injury prevention in the future.

The risk of concussion is a recurrent concern in certain sports, and its diagnosis, prevention, treatment and return-to-play guidelines have been addressed in recent consensus meetings.53 ,54 Eleven concussions were recorded in Sochi (0.4% of the athletes) which is half of the 20 concussions (0.8%) reported in Vancouver. This is higher than the rates reported from the Summer Olympics in London (n=6, 0.06% of athletes) and Beijing (n=12, 0.11%), although these rates are not directly comparable due to the different nature of the sports and events.

Causes, mechanisms and circumstances of injury

The causes, mechanisms and circumstances of injuries in competition and training differed significantly between the different sports. With 63% of the injuries occurring during training and only 35% in competition, the findings differ from those in the Vancouver Games, where the distribution was relatively even (54% vs 46%, respectively).12

It can, however, be hypothesised that winter sports athletes suffer a slightly higher proportion of injuries in training, whereas their summer sports counterparts sustain more injuries in competition, but more data is needed to confirm this.13 ,22 ,36–38 ,42 ,47 ,52 Ice hockey was the only sport on the Sochi Olympic programme in which the majority of injuries occurred in competition, an effect which was even greater when including only the injuries estimated to result in more than 7 days of time loss. These results correspond with earlier epidemiological findings.55–59 Ice hockey is a team and contact sport, where the intensity, speed of play, number of body checks and fatigue are considerably higher in games—where more is at stake—than in training, where a significant amount of time is used for recovery and training drills of lower intensity.

The majority of injuries in Sochi were reported to be acute, whereas overuse injuries with either a gradual or sudden onset accounted for about one-fifth of the injuries. Similar distributions have been reported from the summer and winter Olympic Games previously12 ,13 ,52; however, these numbers should be interpreted with caution, due to the current limitations in the recording of overuse injuries.60–63

Illness risk during the Olympics

The rate of illness in the Sochi Games was similar to those reported in the Vancouver Games and London Games (8% of all athletes affected in Sochi vs 7% in Vancouver and London).12 ,13 Also consistent with the Vancouver and London data is the difference in the incidence of illnesses between female and male athletes, with female athletes in Sochi contracting 50% more illnesses than male athletes. The same disproportion has previously been reported in the 2009 athletics37 and aquatics39 world championships, but not in the 2011 athletics world championships,38 in the 1994–2009 US Open tennis championships,64 or in the Summer Paralympic Games.14

The high incidence of respiratory infections mirrors data from other elite sport events.14 ,15 ,22 ,37–39 ,64–69 Predominant risk factors are mechanical and dehydration stresses generated within the airways and the level of airborne pollutants, irritants and allergens inhaled by the athlete under high ventilatory exercise conditions.70 Earlier it has been reported that airway hyper-responsiveness/asthma is one of the most common chronic medical conditions in winter and summer elite sports, especially among endurance athletes.71 Team physicians can anticipate that athletes travelling intercontinentally are at higher risk of illness,67 but that these illnesses can be mitigated through careful planning and diagnostic work prior to the Games.72

Methodological considerations

In studies on sports injury, it is usually recommended to express incidences using a measure of time exposed to risk as the denominator.14 ,15 ,35 ,73 ,74 However, considering the inherent complexity and size of the Olympic Games, this was not feasible in the present study. Instead, we expressed the incidence of injury or illnesses by means of absolute risk: the number of new cases per 100 registered athletes. This approach erroneously assumes that the frequencies and lengths of exposure are identical in all sports and that the number of athletes at risk in each NOC is constant throughout the Games, and interpretation of differences in injury incidences or patterns should therefore be made with caution.

In the current study we defined injuries and illnesses as new or recurring injuries or illnesses receiving medical attention, regardless of the consequences with respect to absence from competition or training. By using such a definition, predominantly the moderate and severe acute injuries will be recorded. The less serious injuries may be overlooked, since such injuries do not always require medical attention,75 ,76 albeit our results show that the majority of reported injuries were not estimated to involve any absence from the sport. In the Olympic Games, all athletes can get healthcare through the athletes’ village polyclinic and the venue medical clinics. However, the availability, size and quality of the NOCs own medical teams vary between countries, meaning that not all athletes benefit from identical healthcare, which may bias the injury and illness recording.

Throughout the 18 days of data collection in the Olympic Games, we collected 99.7% of all the NOC injury and illness report forms. This is the highest NOC response rate to date in the Olympic Games injury and illness surveillance, a result which can be attributed to favourably disposed NOC medical staff, an informational meeting with all NOCs the day before the Games’ opening, the preparation of report forms in seven languages and an instructional booklet on how to fill in the forms, and a dedicated and increasingly experienced research team which conducted frequent follow-up visits to boost NOCs’ compliance. However, although the NOC response rate was excellent, we did not test the accuracy and internal validity of their reported data. Thus, we cannot evaluate the extent to which the NOC data match the actual circumstances of the occurred injury or illness. Furthermore, it has been documented earlier in professional alpine skiing43 and male elite football77 that prospective injury surveillance by team medical staff underestimates the incidence of injuries and time-loss injuries. Our results support these findings, as the NOC medical teams failed to report 34% and 30% of the total reported injuries and illnesses, respectively.

The same result demonstrates how recording data both among NOC medical staff and in the organising committee's medical stations is absolutely vital to the scientific quality of the surveillance study. A mere 17% of the injuries and 2% of the illnesses were captured by both recorder groups. Our study also shows that in particular athletes from smaller NOCs benefit from diagnosis and treatment from the local organising committee's medical staff, whereas the majority of athletes from larger NOCs are seen by their own NOC medical staff. More importantly, we identified an inverse relationship between NOC size and the risk of health problems, with athletes from the smallest NOCs experiencing an almost threefold injury rate and twofold illness rate compared with the largest NOCs. It is difficult not to see this finding in light of distinct differences in resources available to the NOC. Large delegations usually come from countries with well-developed exercise physiology and sports medicine communities, and are generally able to offer their athletes more comprehensive healthcare and closer medical follow-up in the lead up to and during the Games, potentially giving them a competitive advantage.

Practical implications

The epidemiology of injuries in the Sochi and Vancouver Olympic Games12 and the FIS World Cup42 ,44 ,47 ,49 has demonstrated a high risk of severe injuries in many of the snowboarding and freestyle skiing events. Likewise, in recreational freestyle skiing and snowboarding, it has been found that the rate of severe injuries, in the form of spine and head injuries, is double inside terrain parks compared with outside.78 Furthermore, it has recently been demonstrated that a preponderance of the injuries occur in jumps, kickers and the halfpipe, in other words, in features that facilitate aerial manoeuvers.45 ,48 ,79 ,80 In order to mitigate the risk of these injuries, we need more refined data on their sport-specific risk factors and mechanisms. Our data, although crude, show that a large proportion of the injuries are caused by contact with the ground (or other stationary objects attached to it).12 It has been shown that the magnitude of impact risk can be characterised by the equivalent fall height, a measure of jumper impact velocity normal to the slope.81 ,82 By employing jump design algorithms taking the equivalent fall height into account, the landing impact from aerial manoeuvers and thus the risk of injury can be minimised.82–86

The IOC is currently developing a customised electronic medical record (EMR) for the Rio 2016 Games and beyond to replace the medical encounter system used by the local organising committees since the Barcelona 1992 Games. The implementation of the EMR will not only improve the healthcare provision in the Olympic and Paralympic Games, but also provide a number of new opportunities for recording of injuries and illnesses in a confidential manner. With time, NOC physicians and physiotherapists will be able to record their daily injury and illness data, feeding into the same EMR database, possibly rendering the IOC paper record forms obsolete. Data privacy will evidently be of high importance, with data accessible strictly to authorised users. In the long term, our aim is to invite NOCs to use the same EMR in their daily medical follow-up of their athletes in between the Games. An electronic injury and illness surveillance will also facilitate advances in the quality and usefulness of the data that we capture. For example, one will be able to record risk factors and mechanisms that are specific to each sport and event, which will significantly improve our ability to subsequently ideate and tailor injury prevention initiatives.

The continuously accumulating evidence that injury and illness rates vary substantially between sports demonstrates the need for tailoring preventive measures to the specific context of each sport. Sport bodies such as the IOC, International Paralympic Committee (IPC), IFs and NOCs have the responsibility to protect the health of their athletes. The Olympic Movement Medical Code encourages all stakeholders to take measures to ensure that sport is practised with minimal risks of physical injury and illness or psychological harm.87 For IFs, a critical component of this responsibility is the implementation of a scientifically sound injury and illness surveillance system in all major events. Some sports federations, such as FIFA (Fédération Internationale de Football Association), FINA (Fédération Internationale de Natation), FIS, FIVB (Fédération Internationale de Volleyball), IAAF (International Association of Athletics Federations), IIHF (International Ice Hockey Federation), WR (World Rugby) and UEFA (Union of European Football Associations) have put increasing effort into working systematically and scientifically to protect their athletes’ health. We encourage other IFs and sports organisations to follow their example.