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Increased risk of injury following red and
yellow cards, injuries and goals in FIFA
World Cups
Jaakko Ryynänen, Jiri Dvorak, Lars Peterson, et al.
Br J Sports Med 2013 47: 970-973 originally published online July 23,
2013
doi: 10.1136/bjsports-2013-092487
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Original article
Increased risk of injury following red and yellow
cards, injuries and goals in FIFA World Cups
Jaakko Ryynänen,1,2 Jiri Dvorak,3,4,5 Lars Peterson,2,3,5 Hannu Kautiainen,6,7,8
Jón Karlsson,2 Astrid Junge,3,4 Mats Börjesson9,10
1
University of Helsinki,
Helsinki, Finland
Department of Orthopaedics,
Sahlgrenska University
Hospital, Institute of Clinical
Sciences, Sahlgrenska
Academy, Gothenburg
University, Gothenburg,
Sweden
3
FIFA Medical Assessment and
Research Centre (F-MARC),
Zurich, Switzerland
4
FIFA Medical Centre of
Excellence, Schulthess Clinic,
Zurich, Switzerland
5
Fédération Internationale de
Football Association (FIFA),
Zurich, Switzerland
6
Unit of Primary Health Care,
Helsinki University Central
Hospital, Helsinki, Finland
7
Department of General
Practice, University of Helsinki,
Helsinki, Finland
8
Unit of Primary Health Care,
Turku University Hospital,
Turku, Finland
9
Swedish School of Sport and
Health Sciences, Stockholm,
Sweden
10
Department of Cardiology,
Karolinska University Hospital,
Stockholm, Sweden
2
Correspondence to
Jaakko Ryynänen,
Tarkk’ampujankatu 4 A
10, 00140 Helsinki, Finland;
jaakko.ryynanen@helsinki.fi
Accepted 24 June 2013
Published Online First
23 July 2013
ABSTRACT
Objective To study the relationship between
potentially game-disrupting incidents (PGDIs; red and
yellow cards, goals and injuries) and the injury incidence
in football.
Design Prospective injury surveillance during three FIFA
World Cups in 2002, 2006 and 2010. Official match
statistics were obtained for all the matches played in the
three tournaments.
Setting 2002, 2006 and 2010 FIFA World Cups.
Participants Team physicians at the 2002, 2006 and
2010 FIFA World Cups.
Main outcome measures Injury incidences and
incidence rate ratios (IRRs).
Results The injury incidence was significantly higher
during match periods within the minute of, or during a
five-minute period following a yellow card, red card,
another injury or a goal (PGDIs) than during other match
periods (76.7/1000 match hours; 95% CI (66.6 to 87.9)
vs 54.0/1000 match hours (46.9 to 61.9), p<0.001).
There were significant differences in injury incidence
between different match periods, with the highest injury
incidence seen in the last 15 min of the first half
( p<0.001). The PGDIs (other than injury) had a
tendency to increase towards the end of the game and
the most frequent PGDI was a yellow card. There was a
risk ratio of 1.17 (95% CI 1.08 to 1.26) for injury, per
PGDI (other injuries excluded) ( p<0.001), and 1.15
(95% CI 1.06 to 1.24) after adjusted match time
( p<0.001).
Conclusions The injury incidence is high within the
five minutes following a PGDI. For both team
management and players, being aware of the increased
risk of injury directly after a PGDI may be of clinical
relevance, as it may enable them to take precautions in
order to prevent injuries. There are significant differences
in injury incidence between different match periods and
game-related factors, such as PGDIs, appear partly to
contribute to this variation.
INTRODUCTION
To cite: Ryynänen J,
Dvorak J, Peterson L, et al.
Br J Sports Med
2013;47:970–973.
Owing to the huge popularity of the game of football, which unfortunately is not free of injury,
research into the epidemiology of football injuries,
their treatment and the potential for prevention is
important. FIFA Medical Assessment and Research
Centre (F-MARC) has therefore developed an
injury surveillance system that has been successfully
implemented at all FIFA tournaments since
1998.1 2
One important part of this epidemiological
research has been directed at identifying risk
factors for injuries in football. The risk factors are
often divided into two subgroups, that is, intrinsic
Ryynänen J, et al. Br J Sports Med 2013;47:970–973. doi:10.1136/bjsports-2013-092676
and extrinsic factors, related to the individual characteristics of a player and to environmental variables, respectively.3 The most important extrinsic
factor in professional and international football
appears to be foul play, which is involved in 12–
61% of all injuries.2–10 Other extrinsic factors that
have been studied include player exposure, match
period, type of competition, match venue, current
score and final result, among others.2 4 7 10–15
Psychological factors may also play a role and have
probably long been underestimated.16
A study of the psychological and sport-specific
characteristics of football players found that 90%
of footballers are ready to commit a professional
foul if required, depending on the score and
importance of the match.17 Athletes concentration
has been shown to be negatively affected by
aroused, angry behaviour and by a social environmental setting of considerable complexity and
stress.18 Moreover, watching pictures of players
being hurt or severely injured has been shown to
evoke emotional and physiological responses in
players from the same sport.19 This suggests that
game events could change the players’ mentality
within a game, possibly increasing the risk of
injury. In the past, the changes in injury occurrence
within a match have mainly focused on differences
in individual time periods of the match or comparing the injury frequencies between the two
halves.1 6–8 11 12 20 Studies of player performance
and the physiology of football players, however,
show that there are periods and situations of highintensity activity, followed by periods with a lower
intensity, within a football match.21 22 It has been
estimated that high-intensity activities in football
account for 10–20% of match time.23
To the best of our knowledge, no previous
studies have taken account of the possible effect of
game events that form an essential and inevitable
part of the game (goals, injuries, as well as red and
yellow cards) on the injuries in football. The
hypothesis in the present study was that these specific game events that affect the course of the game
could be seen as potentially game-disrupting incidents (PGDIs), subsequently affecting the players’
attitudes, concentration and team strategies within
a game and, accordingly, the occurrence of injuries.
The aim of the present study was to investigate
the possible relationship between PGDIs and injuries in international top-level male football.
MATERIALS AND METHODS
The study material consisted of all injury reports
with information about match play injuries in the
men’s FIFA World Cup in 2002 (Korea–Japan),
1 of 5
Original article
Table 1 Characteristics of FIFA World Cups 2002–2010
Tournaments
2002 FIFA
World Cup
2006 FIFA
World Cup
2010 FIFA
World Cup
Number of
Number of
Number of
Number of
Number of
Number of
Number of
64
32
736
271
17
161
171
64
32
736
345
28
147
145
64
32
736
261
17
145
125
matches
teams
players
yellow cards
red cards
goals
injuries
2006 (Germany) and 2010 (South Africa), as well as match statistics for all the games in these tournaments provided by FIFA’s
official internet website.24 The material included information on
441 match-play injuries reported on FIFA injury report
forms,7 9 20 as well as match statistics relating to all 192 games
played during these three tournaments. Table 1 shows the baseline data.
The match statistics were assessed, using FIFA’s official
website,24 and they included the time and total number of goals
and the time and total number of red and yellow cards.
Combining the data from match statistics and injury report
forms enabled additional factors to be included in order to
analyse all injury circumstances. The injury report forms and
the data collection methods are described in previous publications1 7 9 20 and followed the consensus statement on injury
definitions and data collection procedures in studies of football
injuries.25 The injury reports contain details of the type and
location of the injury, the time when the injury occurred, the
circumstances (non-contact, contact, foul play) and consequences (referees’ sanction, treatment) of injury, as well as an
estimate of the absence from training and/or playing football,
resulting from the injury. An injury was defined as any physical
symptom that occurred during the match that received medical
attention from the team physician, regardless of the consequences with respect to absence from the match or subsequent
training.1 7 9 20 25
PGDIs were defined as yellow or red cards, injuries and goals.
The factors included in the definition of PGDIs were chosen
according to two main criteria: (1) the total numbers and
minutes when they occurred had to be documented and (2) they
had to have a potential impact on the following course of the
match that could potentially affect several players simultaneously.
Injury incidence following a PGDI
The timing (minutes) of yellow cards, red cards and goals, as
well as injuries from all games, was obtained from the official
match statistics and the injury reports, respectively. The match
was divided into two periods: (1) minutes played during the
minutes of PGDIs or within the following 5 min and (2) other
match periods. If there were two or more PGDIs within the
same 5 min game period, only the minutes before the subsequent PGDI were calculated for the prior PGDI. The 5 min
period was chosen, based on the finding that a football match is
characterised by 5 min periods of high-intensity running, followed by 5 min periods with lower intensity running, compared
with the average level during matches.22 According to the
minutes of injury, obtained from the injury reports, the injuries
were grouped into the corresponding match periods (1–5 min
following PGDIs vs other match periods). The incidence of
2 of 5
injury was then calculated for both match periods. Minutes of
additional time were not taken into account.
Time of PGDIs in relation to the time of injuries during
different match periods
The match was divided into six 15 min periods and extra time
(when played). The PGDIs (injuries excluded) were grouped
according to the minute they occurred, based on the match
periods. The same was performed separately for all injuries
based on the team physicians’ reports. The injury incidence and
the mean numbers of other PGDIs were calculated for the different game periods separately. The relationship between PGDIs
and injury incidence was assessed.
Statistical analysis
The incidence of injury was calculated using the formula:
(number of injuries × 1000 match hours)/((minutes of exposure/60) × N players exposed) and expressed as the number of
injuries per 1000 match hours.25
Injury incidence rates ( per 1000 match-hours) with 95% CI
were calculated assuming a Poisson distribution. Incidence rate
ratios (IRR) and the test for a significant trend in injury incidence rates across the different groups were calculated using
Poisson regression models. The 95% CIs for numbers of PGDIs
per match period were obtained by bias-corrected bootstrapping
(5000 replications). The level of significance was set at p values
of <0.05. The STATA 12.1, StataCorp LP (College Station,
Texas, USA) statistical package was used for the analyses.
RESULTS
Injury incidence following a PGDI compared
with the rest of the match
The total injury incidence was 67.8/1000 match-hours (95% CI
61.7 to 74.5). For 412 injuries (93.4%) the time (minute) of
injury was reported on the injury report forms and only these
were included in the study.
On average, there were 9.5 PGDIs (SD 3.8) per match. The
most frequent PGDI was a yellow card, with an average of 4.6
yellow cards a match (SD 2.6), followed by goals (2.5; SD 1.6),
injuries (2.3; SD 1.7) and red cards (0.3 SD 0.6). The total
match exposure was 2686 player hours for match periods from
the minutes of PGDIs to the following 5 min, and 3815 player
hours for other match periods. Two hundred and six injuries
(50%) occurred during match periods at the minutes of PGDIs
or within the following 5 min, giving an injury incidence of
76.7/1000 match-hours (95% CI 66.6 to 87.9), which was significantly higher compared with other match periods (54.0/
1000 match-hours; 95% CI 46.9 to 61.9) (IRR 1.42; (1.17 to
1.72), p<0.001).
Time of PGDIs in relation to the time of injuries during
different match periods
The lower part of figure 1 shows the variation in injury incidence across different match periods. The differences in the
injury incidence between the match periods were statistically significant ( p<0.001), with the highest injury incidence calculated
for the last 15 min of the first half (90/1000 match-hours; 95%
CI 72.8 to 110) and the lowest for the initial 15 min period of
the match (33.1/1000 match-hours; 95% CI 23.1 to 46.1). The
upper part of figure 1 shows the means of PGDIs (injuries not
included) during the different match periods. There was a risk
ratio of 1.17 (95% CI 1.08 to 1.26) for an injury per PGDI
(other than injury) ( p<0.001) and 1.15 (95% CI 1.06 to 1.24)
after adjusted match time ( p<0.001).
Ryynänen J, et al. Br J Sports Med 2013;47:970–973. doi:10.1136/bjsports-2013-092676
Original article
Figure 1 Average incidence of injury and number of other potentially
game-disruptive incidents during the course of the match.
DISCUSSION
The most important finding in the present study was that the
injury incidence is high during a 5 min period following a PDGI
(ie, goal, injury to another player, as well as red or yellow
cards).
The hypothesis in the present study was that red and yellow
cards, injuries and goals could disrupt the normal course of the
game, evoke responses from both players and teams, at both a
strategic and a psychological level, leading to an increased injury
risk. With the exception of foul play, essential and inevitable
game events within a game have not been studied as possible
extrinsic risk factors for injuries. Contact between players
accounts for between 63% and 86% of the injuries in international football tournaments.1 7 9 10 20 Foul play and the possible subsequent yellow and/or red cards may provoke
aggression and, in the worst cases, even action involving elements of revenge among the players of the team against which
the foul was committed. Moreover, injuries resulting from
contact, even when they do not involve foul play, may provoke
aggression among the injured player’s team-mates. Players’ concentration on the game and awareness may be affected by
PGDIs and fouls in a disadvantageous way, leading to an
Ryynänen J, et al. Br J Sports Med 2013;47:970–973. doi:10.1136/bjsports-2013-092676
increased risk of injury. The results of a study assessing the
effect of behavioural and situational factors on concentration
and skill performance in sports suggest that concentration is
negatively affected by aroused, angry behaviour and by a social
environmental setting of considerable complexity and stress.19
Psychological stressors and situation-dependent emotional states
seem to have an effect on athletes’ risk of injury.16 Stanger
et al18 found greater physiological responses (blink responses,
heart-rate deceleration, P300 and slow-wave potentials) when
athletes were looking at unpleasant sport-specific pictures
(players being hurt by another player or players being badly
injured) compared with neutral or pleasant pictures. The participants in the study by Stanger et al were both male and female
football, rugby and field hockey players. These findings present
possible underlying factors for altered emotional states and subsequent physiological responses resulting from some of the
PGDIs, perhaps affecting the injury risk. However, we found no
studies showing a relationship between these physiological
responses and sports injuries in the literature.
Changes in the score (goals) can also affect player attitudes,
awareness and team strategies. Junge et al17 found that 90% of
football players were ready to commit an intentional (‘professional’) foul if required, depending on the score and importance
of the match. The FIFA World Cup is one of the most followed
and valued sports tournaments and the relatively small number
of matches per team during the tournament highlights the
importance of each match. Significant variation in the injury
incidence depending on the current score has been shown in
FIFA World Cup matches.13
It has been shown that the total incidence of injury (without
taking into account injury or player specific factors) increases
towards the ends of each half and this has generally been
attributed to increasing fatigue of the players, which does
indeed appear to play an essential role.4 11 26 However, previous research also shows that the amounts of high-intensity
running and distance covered by sprinting are similar in the
last 15 min of the first half and the first 15 min of the second
half22 and this is somewhat contradictory in relation to the
fatigue hypothesis. The present study found the highest injury
incidence in the matches during the last 15 min of the first
half, and a tendency for the incidence to decrease during the
last 15 min of the game (figure 1), when fatigue supposedly
accumulates.22 A comparison of the variation in injury incidence and the mean numbers of PGDIs (injuries not included)
in figure 1 reveals a similarity in the increased injury incidence
of injury, towards the end of each half and the increasing
numbers of other PGDIs, with the exception of the last 15 min
of the match and extra time. It could be claimed that the accumulating fatigue towards the end of the game, resulting in
lower levels of high-intensity running and sprinting,22 with a
subsequent reduction in potential trauma energy, might reduce
the incidence of injury.
Video analysis could possibly have reduced the bias of possible incorrectly reported injury minutes. However, previous
research demonstrates that it incorporates other sources of bias.
First and foremost, not all injuries are identified on video
recordings.27–30 Second, a larger percentage of contact injuries
compared to non-contact injuries are identified on video material.28–30 Fuller et al31 avoided this bias by analysing the injuries
resulting from tackles only. Tscholl et al27 analysed the injuries
in six women’s top-level tournaments from video recordings,
and discussed wrong selections of video recordings as a possible
reason for a lack of concordance between injury report data and
the data obtained by video analysis.
3 of 5
Original article
Study limitations
One possible limitation could be inaccurate minutes of injuries
in the injury reports. As the team doctors filled in the injury
reports after the matches, it is possible that some reported
injury times are merely approximations rather than exact
minutes. The half-time break was not taken into account. A halftime break may, however, have a transitory calming effect on the
game and, if a PGDI had occurred in the last minutes of the
first half, the following half-time break might reduce the intensity following one of these incidents. It has been shown for both
halves of the match that fewer injuries tend to occur during the
first parts of the half compared with the last minutes,6 7 9 26 32
and the findings in the present study are in line with this. The
exclusion of minutes of additional time from the analysis may
also have been a source of bias. Further limitations were the
exclusion of other interruptions (goal kicks, substitutions, free
kicks and so on) from the analysis; they too, may have a
calming effect on the game, as they may allow the players to
take a short break. Differences between injury types, locations
or the severity of injuries were not taken into account and individual player exposures were not recorded. Differences between
the effects of the different factors included in the definition of
PGDI on injury incidence were not taken into account.
The definition of PGDIs applied in the present study may be
regarded as strength and a limitation. The match events defined
as PDGIs were chosen because of their potentially major effect
on players’ attitudes and concentration, teams’ strategies and,
accordingly, the subsequent course of the match. There might
be numerous other factors, such as aggressive or insulting comments by players or fans, personal frustrations, referees’ mistakes and rejected goals, among perhaps countless others, that
affect the players’ concentration that have similar effects.
However, data on all of these may be impossible to obtain, and
therefore their significance difficult to assess. Whether or not all
reported injuries should have been included in the definition of
PGDIs is controversial. It might be argued that only acute injuries that result in a clear interruption of the game should be
included, as some other injuries (or their symptoms) may occur
by gradual onset (ie, some overuse injuries) and not reach the
consciousness of many players simultaneously and have a more
moderate impact on the match. However, there is to our knowledge no reliable tool available for assessing which particular
injuries the players, team management and referees become
aware of at the specific moment of injury, and furthermore,
whether some injuries affect the subsequent course of the match
more than others. Therefore, all reported injuries were included
in the present study.
Clinical implications
Recognising the significance of the proximity of PGDIs and
injuries, opportunities for sanctions, including temporary expulsion from a game for players committing violent fouls, could be
considered. A few minutes’ absence for the player violating the
rules could theoretically help to re-establish the players’ concentration on the game more rapidly. For both team management
and players, being aware of the increased risk of injury directly
after a PGDI may be of clinical relevance. It may be useful for
coaches to take this into account when discussing team tactics in
order to prevent injuries.
4 of 5
What are the new findings?
▸ The incidence of injury within a 5 min period following
potentially game-disruptive incidents (PGDIs) was
significantly higher than during other match periods.
▸ There were on average 9.5 PGDIs per match, and the most
frequent PGDI was a yellow card.
▸ The frequency of PGDIs increased towards the end of each
half.
How might it impact on clinical practice in the near
future?
▸ The findings may help to improve the planning of medical
services and injury prevention during major football
tournaments.
▸ The teams may be able to reduce the risk of injuries through
interaction between players, team medical staff and team
management.
▸ The findings may be of use to referees in order to protect
the players by sanctioning foul play, especially during game
periods with a high risk of injury.
Acknowledgements The authors gratefully acknowledge FIFA (Fédération
Internationale de Football Association) for funding this study. We also greatly
appreciate the cooperation of all the team physicians who provided the injury data.
We express our gratitude to Professor Ilkka Kiviranta (University of Helsinki) whose
initiative was essential for this project to be realised.
Contributors JR coordinated the study, collected part of the data, conducted the
statistical analysis, together with HK and wrote the major part of the final
manuscript. All authors participated in the study design through revision and by
partly writing the research plan, as well as all versions of the manuscript. AJ, JD and
LP played a key role in the collection of injury data. AJ prepared the anonymous
injury data files. JK supervised and took part in all the phases of the study since its
conception, as well as revision and writing of all versions of the manuscript. MB
participated in revision and writing of the research plan, the first draft as well as the
final manuscript.
Funding FIFA (Fédération Internationale de Football Association).
Competing interests None.
Ethics approval The ethics approval for injury surveillance has been obtained
before by F-MARC. This approval covers the data of the present study and articles
based on these data have been published before (i.e. Br J Sports Med
2007;41:578-581 doi:10.1136/bjsm.2006.034579).
Provenance and peer review Not commissioned; externally peer reviewed.
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