Frequency of Self-Reported Concussion Amongst Professional and Semi-Professional Footballers in Ireland During the 2014 Season: a Cross-Sectional Study
Coffey et al. Sports Medicine - Open
Frequency of Self-Reported Concussion Amongst Professional and Semi-Professional Footballers in Ireland During the 2014 Season: a Cross-Sectional Study
Nicola Coffey 0
Martin Lawless 0
Seamus Kelly 1
Conor Buggy 0
0 UCD Centre for Safety and Health at Work, School of Public Health , Physiotherapy and Sports Science , University College Dublin , Dublin , Ireland
1 UCD Centre for Sports Studies, School of Public Health , Physiotherapy and Sports Science , University College Dublin , Dublin , Ireland
Background: This paper examines the occupational risk of concussion amongst professional and semi-professional footballers in Ireland during the 2014 League of Ireland season. As part of a broader nationally representative study examining occupational safety and health (OSH) awareness amongst professional footballers, this empirical quantitative study, utilising a convenience sample is the first and largest investigation of the frequency of, and attitudes towards, concussion and concussion reporting amongst Irish senior professional and semiprofessional footballers. Methods: A census survey using an anonymous questionnaire was provided to available League of Ireland clubs between March and May 2015. Permission to access players was provided by the Professional Footballers Association of Ireland. This convenience sample was determined by club availability in relation to match fixtures. Participation by the footballers was voluntary. At the time, there were 250 professional and semi-professional players within the League available to participate. Results: A total of 149 footballers participated in the study. Sixty percent of the participants were employed on a semi-professional basis and the majority of all participants were aged between 18 and 30. 15.7% of the participants reported having received a concussion in the 2014 season with semi-professional players having a noticeably higher (though not significant) reporting rate. Analysis indicated that there was a significant association between playing position and concussion reporting with defenders having the greater odds of reporting a concussion than other playing positions. Professional and semi-professional footballers have a relatively equal risk of receiving a concussion. Conclusion: This research is the first major investigation of the self-reported frequency of, and attitudes towards, concussion amongst Irish senior professional and semi-professional footballers. The results have important implications for coaches, clinicians, parents, players and national governing bodies. Further research is needed to ascertain whether professional footballers perceive concussion as an occupational risk, and whether they appreciate that accepting such risks can have long-term implications for health.
Concussion; Occupational risk; Occupational injury; Safety awareness; Professional football
There is no association between self-reported
concussion with professional status.
Defenders are more likely to self-report a concussion.
Sixteen percent of footballers that reported concussive
symptoms were officially diagnosed as having received
In 2013, the American National Football League agreed
to pay $765 million in compensation to more than 4500
former professional players due to concussions and head
injuries sustained during their careers [
]. In 2015, this
compensation was increased to $914 million and
extended to 5000 former professionals [
]. In 2002, a
verdict of death by industrial disease was returned
following an inquest into the death of former England
professional footballer Jeff Astle. This inquest identified
a type of dementia that was consistent with heading the
ball. Consequently, considerable media attention drew
the general public’s attention to the potential dangers
and long-term consequences of sports-related
concussion. Head trauma and concussion are everyday
occupational risks for professional and semi-professional
athletes competing in contact sports. However, these
risks are not limited to elite athletes. In a quantitative
epidemiological study of the general population of New
], it was found that 21% of all traumatic brain
injuries were sustained during sports-related activities.
Despite increased public awareness and growth in
concussion-related research, a number of concerns and
important gaps in our knowledge still exist.
The 5th International Conference on Concussion in
Sport (Berlin 2016), defined sports-related concussion as
“a traumatic brain injury induced by biomechanical
]. In the USA [
], between 1.6 and 3.8 million
athletes participating in a sporting activity suffer a
concussion. However, the true figure is likely to be much
higher, owing to many injuries not being recognised or
]. While this has been a recognised player
safety and health issue for over a decade [
progress has been made in reporting practice. Moreover,
while many instances of sports-related concussion
may be deemed clinically mild, there is evidence
emerging that an athlete’s ability to fully recover from a
concussion may be impaired and that the effects of
repeated concussions are more severe than previously
In recent years, there has been a growth in research
examining concussion in football [
], with national
football associations [
], national football leagues [
] and in
countries such as the Netherlands [
] and Italy [
Studies of high-school [
], university-level [
] football players exist. However, the
significance of parameters such as player age and playing
position remains unclear . Moreover, despite a
growth in studies examining concussion-reporting rates
and practices with professional rugby players in Ireland
] studies examining the occupational risks
associated with concussion amongst Irish semi-professional
and professional footballers are lacking. Finally, research
examining personal safety awareness and the frequency
of concussion reporting amongst professional athletes
has been limited. In response, the purpose of this study
was to investigate the safety awareness and
concussionreporting frequencies of a cohort of Irish professional
and semi-professional footballers.
The study cohort consisted of professional and
semiprofessional football players playing in the top two
divisions of the League of Ireland, which is run by the
Football Association of Ireland (FAI, the governing body for
football in the Republic of Ireland). Players may be
classified by a number of factors such as age, gender and
level of play (youth, university, amateur and
]. Semi-professional football players typically
get paid and sign a semi-professional contract but may
have other employment. Amateur players, regardless of
age or playing level, do not get paid. At the
commencement of the study in March 2015, it was indicated that
there was a total of 250 professional (100) and
semiprofessional (150) footballers registered with the
Professional Footballers Association of Ireland (PFAI). All were
male and ranged in age from 18 to 39. These footballers
had received educational information regarding
concussion during the interval between the 2013 and 2014
seasons. In order to assess occupational safety awareness in
League of Ireland footballers, certain inclusion and
exclusion criteria were taken into consideration when
evaluating the eligibility of potential applicants. The
inclusion criteria were that each participant had to be
registered with a League of Ireland football club, in receipt
of remuneration for playing for the club, to be a member
of the PFAI, and to have played professionally or
semiprofessionally for at least one season prior to 2014.
Exclusion criteria were that players under 18 years of age,
players that had not played professionally prior to the
2014 season and players on loan from non-League of
Ireland clubs were excluded from the study.
A census survey utilising an anonymous questionnaire
was considered as the preferred method for obtaining
safety awareness and self-reported concussion
information. Permission was sought from and granted by the
FAI to access their cohort of players to participate in the
survey. Ethical exemption was granted by the University
College Dublin Human Research Ethics Committee in
advance of the study (no vulnerable groups, sensitive
topics or conflicts of interest were identified). The survey
was in the format of a questionnaire that was adapted
from four appropriate and validated questionnaires
identified: the Occupational Safety Climate Questionnaire [
the Organisational Practices Questionnaire [
Questionnaire Measuring Perception of Workplace Safety [
and the Questionnaire on Occurrence of Concussion and
Knowledge in Italian Soccer [
]. The latter questionnaire
was based on the McCrea et al.’s Standardised Assessment
of Concussion (SAC) [
]. For this study, the following
questions were asked, based on that survey:
During the 2014 season, did you experience any of
the concussive symptoms, or have a concussion
playing football, even if you did not tell anyone?
How many concussions can you recall you received
during the 2014 season?
If you received a concussion, how many days did
you have the symptoms, did you report your injury
to anyone and how many days did you sit out due
to the injury? [This question was asked for each
If you reported a concussion, to whom did you
If you did not report a concussion, what was your
reason for not reporting it?
Due to population access permission restrictions, no
questions were asked regarding; actions or inaction by
management or support staff, attitudes towards
management or support staff, attitudes towards or actions of
peers in relation to safety and concussion or recall of
specific concussion symptoms. Players were provided
with a definition of concussion and a list of concussive
symptoms for reference in answering the questions
regarding their reporting. The questionnaire was piloted in
advance on eight former professional footballers. Players
could choose not to participate as it was entirely
voluntary and anonymous and in no way could any individual
be subsequently identified from the data gathered. By
completing the questionnaire, participants implied
consent for their responses to be included in the analysis
and subsequent reporting.
Originally, the questionnaire was distributed via the
online tool, Survey Monkey, for ease of completion. A link
to the survey was emailed to the PFAI administration
staff, along with the participant information sheet, in
mid-March 2015. The link and participant information
sheet were then forwarded to all members of the
association. However, after 3 weeks, the response rate was low,
rendering the study infeasible. Consequently, and in
recognition of the importance of minimising the period of
recall, it was determined that face-to-face distribution of
the survey in hardcopy to the participants before
training sessions would improve the response rate. Due to
time constraints (all data was required to be gathered by
mid-June 2015), a convenience sample of willing and
available league clubs was utilised to expedite the
completion of the data collection process. Hardcopy
questionnaires were distributed between April and June 2015
(5 months after the conclusion of the 2014 season) at
times convenient for the participating clubs. This
method of convenience sampling while the most
efficient to gain access to as many players as possible in a
limited time, is acknowledged as a limitation to this
research as discussed later. The questionnaires were
filled out prior to training sessions. An additional
question was added to hardcopy questionnaires, asking
participants to confirm that they had not already completed
the questionnaire online. In total, 68 footballers
participated online while 81 footballers participated via the
hardcopy questionnaire, giving a total of 149 participants
and a response rate of 60%.
Descriptive statistics were used to determine the
population’s demographic profile, playing positions, frequency
of concussions reported and reasons for non-reporting.
Statistical analysis was conducted using SPSS with
Pearson Chi-Square with Yates Correction and Fishers Exact
utilised for testing. Odds ratios (OR) were also reported.
Pearson Chi-square tests were used to compare the
frequencies of self-reported concussion between groups for
categorical variables such as age group (i.e. 18-29 years
and 30–39 years), level of play (i.e. professional and
semi-professional), and playing position (i.e. defenders,
midfielders, and attackers). Pearson chi-square was
utilised for initial significance testing and this was followed
by or checking using a Yates correction and Fishers
Exact tests as necessary. Fisher’s exact test was used
when the chi-square criterion of a minimum cell
number of five was not achievable. Any results of p < 0.05 at
the 95%CI were deemed significant. Some comments
were added based on the merit of the 90%CI results in
Just over one third of the participants of the study (n = 54)
were professional footballers, with the remaining
participants designated as semi-professional (n = 95). The
majority of both professional footballers and
semiprofessional footballers were aged (years = a) between 18a
and 29a; n = 35 (64.8%) and n = 80 (84.3%) respectively.
34 participants were aged between 30a and 39a, the
majority of which were professional footballers; n = 19
(55.8%). Significantly more players from the 18a to 29a
age category participated in the study as indicated by a
Pearson chi-sq test (p = 0.007, OR 2.9 (1.3–6.4))
reinforced by a Fishers exact test (0.013) and the Yates
correction (0.012) all to the 95% CI.
15.7% of the total population reported having officially
received a verified concussion in the 2014 season (N.B.
127 out of 149 participants answered this question).
There was no significant difference between professional
and semi-professional players regarding self-reporting a
concussion. This was confirmed via a Pearson chi-sq
(p = 0.43, OR 1.5 (0.5–4.5)) and supported by a Fishers
exact (0.6) and Yates correction (0.6).
Table 1 provides a breakdown of self-reported
concussion based on playing position. Some players designated
themselves as playing in multiple positions. Amongst the
defenders, there was a significant difference between
professional and semi-professional players as regards the
frequency of self-reported concussion. Table 1 shows
significance within the defender group reporting
concussion with a Pearson chi-square result (p = 0.04, OR 5.0
(1.0-36.9)). The Fishers exact was less significant for this
group (0.09) and the Yates correction reinforces this
(0.09) although when one looks at the analysis at the
90%CI both Fishers (0.05) and Yates (0.05) show
significance at that level indicating that there is some merit in
the result. None of the other playing positions show any
material significance and this is backed up by both the
Fishers and Yates analysis.
Further statistical analysis indicated that when
considering the defenders as a single group (n = 44, 35%)
versus the rest of the players (n = 83; 65%) irrespective of
professional status, there was a greater likelihood of
selfreported concussion. 12 defenders self-reported
concussion as opposed to 8 other players (Pearson chi-square
p = 0.009, OR 3.5 (1.3–9.7)). This was further reinforced
with the Fishers exact test (0.02) and the Yates
correction (0.02) at the 95%CI.
Players can report concussive symptoms to a wide
range of individuals within their support network,
including teammates and club employees. Table 2
indicates to whom players reported their symptoms. There
were no significant differences between professional or
semi-professional players in this regard.
Few players admitted to suffering concussive
symptoms but failing to report them. As Table 3 shows, no
significant differences were reported between
professional and semi-professional players in this regard,
however the semi-pro players had the higher level of
nonreporting concussive symptoms.
Of those whose concussion was verified after they
reported concussive symptoms, only 60% (12 out of 20)
reported being prevented from playing or training as a
consequence. Table 4 indicates that there was no
significant difference between professional and
semiprofessional players in this regard.
Of the 127 players who responded to the questions
regarding concussion within this broader study, 68
reported concussive symptoms to individuals within their
support network. Of these 68 players, 20 (15.7%) were
officially diagnosed with concussion. This figure is
considerably higher (> 10%) than that of a similar
representative study conducted with Italian footballers, which
found that 5% of the population had suffered a
concussion in the previous season [
]. Globally, footballers’
risk of concussion is considered to be substantial,
accounting for a quarter of all injuries amongst elite male
]. Factors impacting football players’
selfreporting, or under-reporting, of concussion include the
importance of a particular match, an eagerness to return
to play for big games, the possibility of being prevented
from playing and the availability of quality substitutes
. However, the higher levels of recognition of
concussive symptoms and of self-reported concussion for
League of Ireland players in the 2014 season could be
attributed to a number of factors. While concussion
research was previously focussed on the validation of
concussion assessment tools, more recent studies have
emphasised the need for improved concussion education
for stakeholders in football [
]. There has also been
significant mainstream media interest in concussion
in sport over the last few years. Consequently, it is
argued that players are now more aware of
concussion (types, symptoms, sources, diagnosis, treatment
etc.) in general [
], and of the need to report it to
relevant personnel in particular [
]—and indeed, are
more likely to do so [
This higher levels of reporting are of interest because,
while increased concussion incidence and reporting by
players may impact team selection in the short term, the
potential recurrence of concussion can impact career
opportunities and trajectory in the long term. A career
in professional football is characterised by chronic
insecurity and uncertainty [
]. For professional footballers,
missing a game through injury can have considerable
short-term consequences in terms of getting back into
the team as well as more significant long-term
implications in terms of securing of a professional contract [
Furthermore, the threat of deselection is more
significant for professional footballers and players may hide
injuries, not impacting performance, from medical staff
and managers [
]. The moderately higher reporting
levels of semi-professional footballers in this study could
be due, in part, to this cohort possessing alternative
occupations, employment opportunities and sources of
income. In contrast to the findings of recent research in
professional football in England [
semiprofessional footballers may be less risk averse, may
connect their personal actions with the risk and may be
more aware of the long-term impact of concussion.
Thus, while concussion education has improved
considerably recently, changing the culture of underreporting
will require ongoing efforts over many years [
]. As we
know, concussion injuries may have an associated
stigma, viewed as a ‘less serious injury than a leg break’
(15:201). In this regard, there is a need for further player
and manager education linking the short-term decision
to ignore concussion symptoms with the long-term
This study’s results indicate that certain playing
positions have a greater likelihood of receiving a concussion
than others. These results are similar to those of studies
carried out with professional rugby league players, in
which it was noted that the ball carrier (attacker) was
found to be at greater risk of sustaining a concussion
than the tacklers (defender), probably because rugby
league is a full contact sport [
]. An Irish study carried
out with rugby union players came to a similar
conclusion, with a higher proportion of concussions being
sustained by attacking players; however, interestingly, the
severity of concussions was greater for defending players
]. Regarding the age ranges of both the professional
and semi-professional players in this study, the
professional players had an older age range and their
experiences with concussion over their careers may be
influencing the reporting practices of the younger
members of their teams.
Despite semi-professional footballers accounting for
over two thirds of the concussions reported in the study,
professional status does not appear to have an
association with concussion. While professional sport is
a unique ‘work’ environment, legislation to protect
workers is still applicable, depending on the jurisdiction.
When considering concussion as an occupational injury
for professional athletes, comparison with other
occupational sectors can give an insight into how injuries are
perceived in professional sport. Across the EU,
concussion accounted for 17% of all workplace injuries in 2013
]. In contrast, the Irish Central Statistics Office
(CSO) noted that concussion, grouped with several other
occupational injuries (including amputation, internal
injury, burn, scald or frostbite) made up only 7% of all
workplace injuries in 2013 [
]. While it is not possible
to obtain an exact figure for the number of workplace
concussions, it is worth noting that the total number of
injuries in this group nationally was 1300. Consequently,
20 concussions could be considered high for professional
and semi-professional footballers as one defined
occupational group. Given that concussion in professional sport
can be considered an occupational risk, it is imperative
that professional athletes’ awareness of this risk should
be evaluated more rigorously [
There are a number of issues to bear in mind when
interpreting the results of the current study. One
methodological limitation is the sample size. In this regard, it
must be noted that gaining access to professional
football players and clubs normally presents difficulties for
researchers, as professional football clubs are often quite
wary of social science researchers [
] and when
exploring sensitive issues such as concussion in particular.
Moreover, it is often difficult to secure the cooperation
of professional leagues, professional football associations
and governing bodies. Consequently, concussion-related
research in football utilising professional football players,
though growing [
11, 15, 16
], is limited. A second
limitation concerns recall error. Asking athletes to recall
symptoms from the previous year when they may not
have been able to recognise them or were unwilling to
report them can lead to bias, which has implications for
the internal validity of the study [
]. However, this
study occurred immediately after the preceding season
when the players had returned to pre-season training,
thus minimising recall duration . Despite its
limitations, retrospective recall does ‘allow an athlete the
opportunity to reveal symptoms that may not have been
identified prospectively’ (14: 337). However, mitigating
measures to enhance validity and minimise self-report
limitations such as miscomprehension, measurement
error and conscious bias [
] were adopted. For
instance, participants were provided with clear instructions
and an overview of the rationale of the study. It was also
assumed that participants were ‘honest in their
responses without a societal response bias’ (15: 202).
Situational limitations, such as confidentiality , were
addressed by excluding coaches, managers and support
staff. This, coupled with the anonymous nature of the
survey, allowed the players to participate and answer
truthfully without fear of and potential negative
]. This could be a factor in the higher
reporting levels evidenced in this study.
This research is the first and largest investigation of the
self-reported frequency of, and attitudes towards,
concussion amongst Irish senior professional and
semiprofessional footballers. This study has indicated that
professional status does not have a significant bearing on
the likelihood of recognising concussive symptoms or of
reporting a concussion. Further research is needed to
ascertain whether professional footballers perceive
concussion as an occupational risk, and whether they appreciate
that accepting such risks can have long-term implications
for health (i.e. that cumulative sporting injuries can
potentially lead to debilitating health conditions). As a
questionnaire may not be an effective tool for exploring attitudes
towards concussion, it has been argued that
understanding player’ views on self-reporting concussion would
require qualitative research [
The research team wish to acknowledge Mr. Stephen McGuinness (General
Secretary of the Professional Footballers Association of Ireland) and Mr. Fran
Gavin (Director of the SSE Airtricity League of Ireland) for granting access to
their footballers for this study, and to the footballers who participated in the
Ms. Nicola Coffey completed this research as part of her academic
requirements for her MSc in Occupational Safety and Health (2014–2016) and
is the first author of this paper accordingly. Dr. Conor Buggy supervised the
research project and compiled this paper based on Ms. Coffey’s research thesis
with input from her and fellow authors. Dr. Martin Lawless provided input for
all statistical analysis and Dr. Seamus Kelly provided detailed input on sport and
No research funding was involved in this project. Ms. Nicola Coffey
conducted the research as part of her MSc in Occupational Safety and
Health and no external or internal financial assistance was provided.
Availability of data and materials
The dataset generated and analysed during this study are not publicly available
due to permission criteria to access the population from the Professional
Footballers Association of Ireland (PFAI). Data is available from the corresponding
author on reasonable request and with permission of the PFAI.
NC conceived the research and approached CB as her MSc research
supervisor. CB, in consultation with SK, advised NC on the initial literature
review, methods, timeline and ethical approval process while supervising NC.
NC administered the survey and collated the data into a database which was
checked by ML and CB. ML advised NC on initial statistical analysis. CB
advised ML to conduct a range of analysis for the paper. CB wrote the paper
with input from SK throughout. All authors read and approved the final
Ms. Nicola Coffey is a MSc Researcher, Centre for Safety and Health at Work,
School of Public Health, Physiotherapy and Sports Science, University College
Dublin, Dublin 4, Ireland.
Dr. Martin Lawless is a PhD Researcher, Centre for Safety and Health at Work,
School of Public Health, Physiotherapy and Sports Science, University College
Dublin, Dublin 4, Ireland.
Dr. Seamus Kelly is an Assistant Professor, Centre for Sports Studies, School
of Public Health, Physiotherapy and Sports Science, University College
Dublin, Dublin 4, Ireland.
Dr. Conor Buggy is an Assistant Professor, Centre for Safety and Health at
Work, School of Public Health, Physiotherapy and Sports Science, University
College Dublin, Dublin 4, Ireland.
Ethics approval and consent to participate
The authors of this paper declare that there is no conflict of interest or
commercial interest in relation to this research. Each author has completed a
Conflict of Interest Disclosure Form. This research was conducted with
ethical exemption granted by the University College Dublin Human Research
Ethics Committee and access to the population was granted by the
Professional Footballers Association of Ireland. The data presented has not
been published elsewhere. Players could choose not to participate in the
study as it was entirely voluntary and anonymous and in no way could any
individual be subsequently identified from the data gathered. By completing
the questionnaire, participants implied consent for their responses to be
included in the analysis and subsequent reporting.
Consent for publication
The authors grant the right to Sports Medicine Open to publish this research paper.
There are no competing interests identified in relation to this research. The
authors; Nicola Coffey, Martin Lawless, Seamus Kelly and Conor Buggy
declare that they have no conflict of interest. There is no financial, copyright,
trademark or patent implications arising from this research and no
organisation has any vested interest in this research.
Springer Nature remains neutral with regard to jurisdictional claims in
published maps and institutional affiliations.
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