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The UEFA injury study: 11-year data concerning 346 MCL injuries and time to return to play

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  • Institute of Clinical Science

Abstract and Figures

Background Medial collateral ligament (MCL) injury is the most common knee ligament injury in professional football. Aim To investigate the rate and circumstances of MCL injuries and development over the past decade. Methods Prospective cohort study, in which 27 professional European teams were followed over 11 seasons (2001/2002 to 2011/2012). Team medical staffs recorded player exposure and time loss injuries. MCL injuries were classified into four severity categories. Injury rate was defined as the number of injuries per 1000 player-hours. Results 346 MCL injuries occurred during 1 057 201 h (rate 0.33/1000 h). The match injury rate was nine times higher than the training injury rate (1.31 vs 0.14/1000 h, rate ratio 9.3, 95% CI 7.5 to 11.6, p<0.001). There was a significant average annual decrease of approximately 7% (p=0.023). The average lay-off was 23 days, and there was no difference in median lay-off between index injuries and reinjuries (18 vs 13, p=0.20). Almost 70% of all MCL injuries were contact-related, and there was no difference in median lay-off between contact and non-contact injuries (16 vs 16, p=0.74). Conclusions This largest series of MCL injuries in professional football suggests that the time loss from football for MCL injury is 23 days. Also, the MCL injury rate decreased significantly during the 11-year study period.
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The UEFA injury study: 11-year data concerning
346 MCL injuries and time to return to play
Matilda Lundblad,
1,2
Markus Waldén,
1,2
Henrik Magnusson,
2,3
Jón Karlsson,
4
Jan Ekstrand
1,2,5
1
Division of Community
Medicine, Department of
Medical and Health Sciences,
Linköping University,
Linköping, Sweden
2
Football Research Group,
Linköping University,
Linköping, Sweden
3
Division of Physiotherapy,
Department of Medical and
Health Sciences, Linköping
University, Linköping, Sweden
4
Department of Orthopaedics,
Sahlgrenska University,
Gothenburg, Sweden
5
UEFA Medical Committee,
Nyon, Switzerland
Correspondence to
Professor Jan Ekstrand,
Football Research Group
Solstigen 3, Linköping
University, Linköping S-589 43,
Sweden; Jan.ekstrand@telia.
com
Accepted 29 March 2013
Published Online First
26 April 2013
To cite: Lundblad M,
Waldén M, Magnusson H,
et al.Br J Sports Med
2013;47:759762.
ABSTRACT
Background Medial collateral ligament (MCL) injury is
the most common knee ligament injury in professional
football.
Aim To investigate the rate and circumstances
of MCL injuries and development over the past decade.
Methods Prospective cohort study, in which
27 professional European teams were followed over
11 seasons (2001/2002 to 2011/2012). Team medical
staffs recorded player exposure and time loss injuries.
MCL injuries were classied into four severity categories.
Injury rate was dened as the number of injuries per
1000 player-hours.
Results 346 MCL injuries occurred during 1 057 201 h
(rate 0.33/1000 h). The match injury rate was nine times
higher than the training injury rate (1.31 vs 0.14/1000 h,
rate ratio 9.3, 95% CI 7.5 to 11.6, p<0.001). There was
a signicant average annual decrease of approximately
7% (p=0.023). The average lay-off was 23 days, and
there was no difference in median lay-off between index
injuries and reinjuries (18 vs 13, p=0.20). Almost 70% of
all MCL injuries were contact-related, and there was no
difference in median lay-off between contact and non-
contact injuries (16 vs 16, p=0.74).
Conclusions This largest series of MCL injuries in
professional football suggests that the time loss from
football for MCL injury is 23 days. Also, the MCL injury
rate decreased signicantly during the 11-year study
period.
INTRODUCTION
The overall injury rate of professional footballers is
approximately 1000 times higher than that of
typical industrial occupations, generally regarded as
high risk.
1
Several studies have investigated the
injury epidemiology in high-level football,
28
but
few have reported the data on medial collateral
ligament (MCL) injuries. After hamstring injury,
MCL injury is the most common severe injury
subtype.
2
The objective of this study was to investigate the
rate and circumstances of MCL injuries and their
development over the past decade. The hypotheses
of this study were that the MCL injury rate
decreased during the study period and that MCL
injuries are more frequently caused by contact
mechanisms.
MATERIAL AND METHODS
A prospective cohort study of professional mens
football in Europe has been carried out since 2001
in collaboration with the Union of European
Football Associations (UEFA): the UEFA
Champions League study.
2
For the purpose of this
study, 27 European teams (1743 players) were fol-
lowed for 11 seasons from 2001 to 2012.
3
All con-
tracted players in the rst teams were invited to
participate in the study. The mean squad size was
25 players.
3
Study design and denitions
The full methodology and the development of the
study design have been reported elsewhere.
9
The
study design followed the consensus on denitions
and data collection procedures in studies of football
injuries.
10
Specically for this study, MCL injury
was dened as a traumatic distraction injury to the
supercial MCL (sMCL), deep MCL (dMCL) and
the posterior oblique ligament (POL) leading to a
player being unable to participate fully in training
or match play. General denitions are given in
table 1.
Data collection
Player baseline data were collected once a year at
player inclusion. Individual player exposure in
training and matches was registered by the clubs on
a standard exposure form sent to the study group
on a monthly basis. The teamsmedical staff
recorded injuries on a standard injury form that
was also sent to the study group each month. The
injury form provided the information about the
diagnosis, nature and circumstances of injury occur-
rence, for example. All injuries resulting in a player
being unable to participate fully in training or
match play (ie, time loss injuries) were recorded.
The player was regarded as injured until the team
medical staff allowed full participation in training
and availability for match selection. All injuries
were followed until the nal day of rehabilitation.
Contact/non-contact was recorded on the injury
form from 2004 to 2005, match minute of injury
from 2005 to 2006 and injury mechanisms from
2008 to 2009.
Statistical analyses
Lay-off time is presented as the mean±SD and the
corresponding median and quartiles (Q
1
=25
th
per-
centile and Q
3
=75
th
percentile). Owing to skewed
distribution in lay-off time, group differences were
analysed using the Mann-Whitney U test. Pearsons
χ
2
test was used to analyse the association between
categorical variables. Injury rate was reported as the
number of injuries per 1000 player-hours and
injury burden was calculated as the number of
lay-off days per 1000 player-hours. The rate ratio
(RR) with a 95% CI was used for group compari-
sons of injury rates and injury burden, while signi-
cance was tested using z-statistics.
11
Seasonal trend,
Lundblad M, et al.Br J Sports Med 2013;47:759762. doi:10.1136/bjsports-2013-092305 1 of 5
Original article
expressed as the average annual percentage of change, was ana-
lysed using linear regression with log-transformed injury rates as
the dependent variable. A 2-year moving average approach, by
summarising two consecutive seasons, was also used to smooth
out large seasonal variation. A one-sample proportional z-test
was used to analyse the differences between 15 min periods in
matches. All tests were two-sided and the signicance level was
set at p<0.05.
RESULTS
In all, 10 57 201 h of exposure (8 88 249 h of training and
1 68 952 h of match play) were registered. In overall terms, 8029
injuries were documented, 346 (4.3%) of which were MCL injuries.
The total MCL injury rate was 0.33/1000 h (table 2); a team of 25
players can therefore expect roughly two MCL injuries every
season. The match injury rate was nine times higher than the train-
ing injury rate (1.31 vs 0.14/1000 h, RR 9.3, 95% CI 7.5 to 11.6,
p<0.001).
Between-season and within-season variation
The MCL injury rate uctuated between 0.19 and 0.57/1000 h
over the 11 seasons; the lowest was in 2008/2009 and the
highest in 2004/2005. The crude injury rate and the 2-year
moving average injury rate are illustrated in gure 1. The
moving average approach indicated an average annual decrease
of 3%, while the log-transformed regression model indicated a
signicant annual average decrease of approximately 7%
(R
2
=0.46, b=0.069, 95% CI 0.125 to 0.012, p=0.023).
No signicant differences could be found within the seasons.
Lay-off time
The mean lay-off time in MCL injuries was 23±23
(median=16, Q
1
=8, Q
3
=31) days. The mean lay-off time in
other knee ligament injuries such as anterior cruciate ligament
(ACL), posterior cruciate ligament (PCL) and lateral collateral
ligament (LCL) was 194±75 (median=194, Q
1
=166, Q
3
=228)
days, 52±57 (median=31, Q
1
=12, Q
3
=85) days and 23±26
(median=12, Q
1
=6, Q
3
=27) days, respectively. Sixty per cent
of the MCL injuries affected the dominant leg. There was no
difference in lay-off time between MCL injuries to the dominant
leg compared with the non-dominant leg (median=19, Q
1
=7,
Q
3
=33 vs median=15, Q
1
=8, Q
3
=28, p=0.39).
Circumstances and mechanism
Almost 70% (182/264) of all MCL injuries were due to contact
with another player or an object, which could be compared
with 37% (21/57) among ACL injuries, 70% (7/10) among PCL
injuries and 57% (24/42) among LCL injuries. There was a sig-
nicant association between the distribution of contact/non-
contact injuries and the type of knee ligament injury
(p<0.001). The most common mechanisms of contact injuries
were collision (26%), being tackled (25%) and being blocked
Table 2 Medial collateral ligament injuries of the knee in
professional football
MCL injuries, n (% of total no. of injuries) 346 (4.3)
Reinjuries, n (%) 37 (10.8)
Lay-off days, mean±SD 23±23
Index injury 24±24
Reinjury 18±15
Dominant leg injury 24±22
Non-dominant leg injury 23±26
Contact injury 23±24
Non-contact injury 21±18
Lay-off days, median (Q
1
Q
3
)16(831)
Index injury 18 (832)
Reinjury 13 (725)
Dominant leg injury 19 (733)
Non-dominant leg injury 15 (828)
Contact injury 16 (829)
Non-contact injury 16 (730)
Injury rate* (95% CI) 0.33 (0.29 to 0.36)
Training injury rate 0.14 (0.12 to 0.17)
Match injury rate 1.31 (1.15 to 1.49)
Dominant leg injury rate 0.20 (0.17 to 0.22)
Non-dominant leg injury rate 0.13 (0.11 to 0.15)
Contact injury rate 0.21 (0.18 to 0.24)
Non-contact injury rate 0.10 (0.08 to 0.12)
Injury severity, n (%)
Slight/minimal (03 days) 32 (9.2)
Mild (47 days) 54 (15.6)
Moderate (828 days) 162 (46.8)
Severe (>28 days) 98 (28.3)
Injury burden(95% CI) 7.6 (7.5 to 7.8)
Lay-off days/player/season, mean±SD 1.8±9.6
*Injury rate expressed as number of injuries/1000 player-hours.
Injury burden expressed as number of lay-off days/1000 player-hours (injury
rate×mean lay-off).
MCL, medial collateral ligament; Q
1
, 25th percentile; Q
3
, 75th percentile.
Table 1 Operational definitions used in the study
Training session Team training that involved physical activity under the
supervision of the coaching staff
Match Competitive or friendly match against another team
Injury Injury resulting from playing football and leading to a
player being unable to participate fully in future training
or match play (ie, time-loss injury)
Rehabilitation A player was considered to be injured until team medical
staff allowed full participation in training and availability
for match selection
Reinjury Injury of the same type and at the same site as an index
injury occurring no more than 2 months after a players
return to full participation from the index injury
MCL injury A traumatic injury to the superficial MCL, deep MCL and
the posterior oblique ligament leading to a player being
unable to participate fully in training or match play
Slight/minimal injury Injury causing lay-off of 03 days from training and
match play
Mild injury Injury causing lay-off of 47 days from training and
match play.
Moderate injury Injury causing lay-off of 828 days from training and
match play
Severe injury Injury causing lay-off of more than 28 days from training
and match play
Traumatic injury Injury with sudden onset and known cause
Overuse injury Injury with insidious onset and no known trauma
Non-contact injury Injury occurring without contact with another player or
object
Dominant leg Preferred kicking leg
Foul play Violation of the laws of the game according to the match
referee
Injury rate Number of injuries per 1000 player-hours ((Σinjuries/Σ
exposure hours)×1000)
Injury burden Number of lay-off days per 1000 player-hours ((Σlay-off
days/Σexposure hours)×1000)
MCL, medial collateral ligament.
2 of 5 Lundblad M, et al.Br J Sports Med 2013;47:759762. doi:10.1136/bjsports-2013-092305
Original article
(15%). Thirty-eight per cent of the non-contact injuries, repre-
senting a small fraction of the data, were the consequence of
twisting/turning. No difference in lay-off times between contact
(median=16, Q
1
=8, Q
3
=29) and non-contact (median=16,
Q
1
=7, Q
3
=30) injuries was detected (p=0.74).
Foul play
A higher percentage of foul play injuries were found in MCL
contact injuries compared with other contact injuries during
match play (24% vs 18%, p=0.015).
Variation of injury risk during matches
Approximately 43% (53/123) of the MCL match injuries
occurred during the last 15 min of the rst or second half of the
game (see gure 2). This nding is signicantly higher than
would be expected (1/3) of the injuries in each quarter of an
hour (p=0.022). No difference was found in the quarterly dis-
tribution between the rst and second halves (p=0.76).
Reinjuries
Eleven per cent of all MCL injuries were classied as reinjuries,
which is approximately the same as the reported recurrence rate
for other injuries in the study cohort (12%). There were no dif-
ferences in lay-off time between index injuries (median=18,
Q
1
=8, Q
3
=32) and reinjuries (median=13, Q
1
=7, Q
3
=25;
p=0.20).
Playing position
A signicantly higher injury rate was found among outelders
compared with goalkeepers (0.33 vs 0.17/1 000 h, RR 2.1, 95%
CI 1.3 to 3.2, p=0.001).
DISCUSSION
The principal nding in this study was that MCL injury causes
an average lay-off from professional football for slightly more
than 3 weeks. Another important nding was that MCL injuries
were more frequently caused by contact than non-contact situa-
tions, but, interestingly, lay-off times do not differ signicantly
between these two mechanisms. Also, the MCL injury rate
decreased signicantly over the 11-year study period.
Injury epidemiology
A professional football team with a typical 25-player squad can
expect around two MCL injuries every season. In spite of a
somewhat uctuating rate over the seasons, the MCL injury rate
has decreased slightly over time. It is possible to speculate about
whether this is a consequence of (1) less contact between
players during matches and training nowadays, (2) because of
the development of football into a more technically skilled
game or (3) the referees being stricter and more observant of
dangerous contact situations. Another plausible explanation is
that radiological imaging is used more frequently nowadays
compared with the beginning of the study period; there may
have been clinical overdiagnosishistorically. There is, however,
no study showing that the use of radiological imaging reduces
injury rates, shortens lay-off times or reduces injury recurrence.
Figure 1 Seasonal variation in injury
rates for medial collateral ligament
injuries in professional football.
Figure 2 Distribution of medial
collateral ligament injuries during
15 min periods of match play in
professional football.
Lundblad M, et al.Br J Sports Med 2013;47:759762. doi:10.1136/bjsports-2013-092305 3 of 5
Original article
Injury circumstances
Almost 70% of all MCL injuries were due to contact with
another player or object. Interestingly, the proportion of
contact-related MCL injuries is thus of approximately the same
percentage as that of non-contact ACL injuries reported in this
study (63%) and in another similar study of elite football.
12
It
therefore appears that the typical injury mechanisms differ
between MCL and ACL injuries, and it is reasonable to believe
that many MCL injuries are the result of a collision or tackle
with physical impact on the outside of the lower part of the
thigh or the upper part of the lower leg. We speculate that, if
the referees are even stricter while judging these situations, the
injury rate may decrease further.
Increased injury rate towards the last 15 minutes
A signicant number of MCL match injuries occurred during
the last 15 minutes of the rst or second half of the game. It is
possible to speculate that the players are more fatigued towards
the last 15 minutes and therefore fail to react and tackle with
the same precision and speed in their technique as in the rst
30 min of the halves. Another possible explanation is that the
players are aware that the halves of the match are about to end
and they perform with greater intensity and more contact in
order to change the outcome of the game in their favour.
MCL injury severity related to lay-off
The ability to predict lay-off is very important for the injured
player, as well as the coaching staff. It appears logical that the
severity of the injury is correlated to the subgrouping of MCL
injuries, if the aim is to predict injury lay-off. In the present study,
16 days was the median value for the lay-off from football after an
MCL injury. Compared with other ligament injuries in the knee,
MCL injury has a rather short lay-off, and can therefore, together
with LCL injury, be regarded as a fairly mild knee ligament injury.
The median lay-off was 194 days for ACL injuries, 31 days for
PCL injuries and 12 days for LCL injuries.
Eleven per cent of all MCL injuries were reinjuries, which is in
line with other injuries in the cohort (12%). There was no signi-
cant difference in the lay-off time specically for MCL index
injury and reinjuries. In previous studies, in professional football,
reinjuries have caused longer lay-off than index injuries,
26
but
these studies refer to overall injuries.
Methodological considerations
There are some important methodological issues and limitations
to consider with this study. First, 75% of the MCL injuries were
moderate or severe (ie, >7 lay-off days), and these two groups
could thus be argued to be more relevant to football than slight/
minimal injuries due to their longer lay-off time and greater
recurrence rate. The number of slight/minimal injuries might be
underestimated because, even if the player is seeking medical
attention and has some time loss, it is most probably difcult
for the medical team in many occasions to differentiate
between, for example, a contusion on the medial aspect of the
distal femur and an actual slight MCL sprain if the player com-
pletes a match and is able to train fully within a few days after
the event. Second, the injury form did not include mandatory
information about the clinical or radiological grading of MCL
injury or whether the injury was partial or complete.
Additionally, no information was available on the injury form
about which part of the MCL was damaged (sMCL, dMCL and
POL) or any associated injuries (eg, an MCL injury with a long
lay-off could be associated with occult meniscus or cartilage
lesions). Third, only the main diagnosis is reported on the
injury form, which means that some associated MCL injuries
are missed (eg, in an ACL injury with concomitant MCL injury
only the ACL injury is typically recorded on the general injury
card). Fourth, no systematic information about the treatment
was collected.
What are the new ndings?
Medial collateral ligament (MCL) injury rates appear to have
decreased during the last decade.
MCL injury is more commonly caused by contact than
non-contact situations and more frequently caused by foul
play than non-foul play.
There were no differences in return to play between index
MCL injury and reinjury.
How might it impact on clinical practice?
The nding that medial collateral ligament injuries were
more frequently caused by contact and foul play warrants
discussion in the referee sections of the international
governing bodies.
Acknowledgements The authors would like to thank the participating clubs,
medical staff and players. Martin Hägglund is acknowledged for help with data
collection and Christoffer Thomeé for technical assistance.
Contributors ML, MW, JK and JE were responsible for the study concept and
design. JE was responsible for data collection monitoring and co-ordinated the
study. HM was responsible for database management and, together with ML,
conducted all the analyses that were planned and checked with MW, JK and JE. ML
wrote the rst draft of the manuscript. All the authors had full access to all data
and contributed to the interpretation of the ndings and critical revision of the
manuscript. JE is the study guarantor.
Funding This study was supported by grants from UEFA, the Swedish Centre for
Research in Sports and Praktikertjänst AB.
Competing interests JE is the rst vice chairman of the UEFA Medical
Committee.
Patient consent Obtained.
Ethics approval The study design was approved by the UEFA Medical Committee
and the UEFA Football Development Division.
Provenance and peer review Not commissioned; externally reviewed.
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... Owing to the requirements of the game, elite soccer athletes are particularly prone to knee injuries, including medial collateral ligament (MCL) injuries. 26 MCL injuries generally occur when a valgus stress is applied to the knee through direct contact, with tackling and being tackled being the most commonly reported injury mechanisms in soccer athletes. 25 As such, the MCL is the most commonly injured knee ligament, with a reported injury rate of 0.33 per 1000 player-hours. ...
... 25 As such, the MCL is the most commonly injured knee ligament, with a reported injury rate of 0.33 per 1000 player-hours. 4,26 Although the majority of MCL injuries are treated nonoperatively with physical therapy and bracing, 3 MCL injuries represent the most common traumatic knee injury resulting in time lost in professional soccer. 25 The incidence of MCL injuries in male soccer athletes has been reported to be twice that of female athletes, 38 resulting in a mean of 23 to 24 days lost from play. ...
... 25 The incidence of MCL injuries in male soccer athletes has been reported to be twice that of female athletes, 38 resulting in a mean of 23 to 24 days lost from play. 25,26 However, the effect of MCL injuries on future athletic performance after recovery is largely unknown. As elite soccer athletes are at high risk for sustaining MCL injuries, it is important to better understand the effect of MCL injuries on time lost and the potential consequences on subsequent performance after return to play (RTP). ...
Article
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Background Participation in elite-level soccer predisposes athletes to injuries of the medial collateral ligament (MCL), resulting in variable durations of time lost from sport. Purpose To (1) determine the rate of return to play (RTP) and timing after MCL injuries, (2) investigate MCL reinjury incidence after RTP, and (3) evaluate the long-term effects of MCL injury on future performance. Study Design Descriptive epidemiology study. Methods Using publicly available records, we identified athletes who had sustained MCL injury between 2000 and 2016 across the 5 major European soccer leagues (English Premier League, Bundesliga, La Liga, Ligue 1, and Serie A). Injured athletes were matched to controls using demographic characteristics and performance metrics from the season before injury. We recorded injury severity, RTP rate, reinjury incidence, player characteristics associated with RTP within 2 seasons of injury, player availability, field time, and performance metrics during the 4 seasons after injury. Results A total of 59 athletes sustained 61 MCL injuries, with 86% (51/59) of injuries classified as moderate to severe and surgical intervention performed in 14% (8/59) of athletes. After injury, athletes missed a median of 33 days (range, 3-259 days) and 4 games (range, 1-30 games). Overall, 71% (42/59) of athletes returned successfully at the same level, with multivariable regression demonstrating no athlete characteristic predictive of RTP. MCL reinjury was reported in 3% (2/59) of athletes. Midfielders demonstrated decreased field time after RTP when compared with controls ( P < .05). No significant differences in player performance for any position were identified out to 4 seasons after injury. Injured athletes had a significantly higher rate of long-term retention ( P < .001). Conclusion MCL injuries resulted in a median loss of 33 days in elite European soccer athletes, with the majority of injuries treated nonoperatively. RTP remained high, and few athletes experienced reinjury. While midfielders demonstrated a significant decrease in field time after RTP, player performance and long-term retention were not compromised. Future studies are warranted to better understand athlete-specific and external variables predictive of MCL injury and reinjury, while evaluating treatment and rehabilitation protocols to minimize time lost and to optimize athlete safety and health.
... For instance, American football players present with some of the highest rates of MCL and ACL damage. [16,17] Ice hockey players are also at great risk for MCL tears, [18,19] as 60% of all injuries to the knee involve trauma to this ligament. ...
... [44] Taken further, some researchers have even investigated whether altering playing surfaces can help mitigate the risk of developing collateral ligament injuries. As American football players experience some of the highest rates of MCL injury, [16,17] Powell and Schootman [45] investigated the incidence of injuries experienced by NFL players on AstroTurf surfaces. The authors discovered that this surface was associated with high number of ACL sprains and other injuries. ...
... A retrospective review of the patients medical and rehabilitation records was then carried out to collect the following information : age, gender, type of injury, number and timing of injections, technique used, content of injection, other injuries, other treatments, reinjury rate and return to play information. All players were considered 'injured' until club medical staff allowed full participation in training and availability for match selection (9,10,17). Re-injury was defined according to the concept of early recurrences (9), and any re-injury was documented. A literature review was carried out to identify the RTP times for conservative and surgical treatments of ATFL and AITFL injuries to allow comparisons with prolotherapy treatments to be made. ...
... Of the cohort of athletes two had medial ligament injuries and were therefore excluded from the study. The mean age for the lateral ligament athletes was 23.7 years (range, [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. and the number of prolotherapy injections ranged between one and three with each one being one week apart (Table 1). ...
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Injuries to the lateral ankle ligaments are among the most common sustained in professional football. The return to elite level sport within a predictable timeframe after injury is a key aim of the medical team managing professional athletes. Prolotherapy involves injection of dextrose/sucrose injection into injured tissues which is presumed to stimulate the body's self-healing mechanisms, leading to the re-establishment of structural integrity and improved function. This study reports on the results of prolotherapy used to treat anterior talofibular ligament (ATFL) and anterior inferior tibiofibular ligament (AITFL) injuries in elite level athletes and describes the time to return to play (RTP) and rate of reinjury. Patients who had undergone prolotherapy treatment since February 2014 under the care of three specialist sports musculoskeletal radiologists for ankle sprains were identified using the patient database. A retrospective review of the patients medical and rehabilitation records was then carried out. A literature review was carried out to identify the RTP times for conservative and surgical treatments of ATFL and AITFL injuries to allow comparisons with prolotherapy treatments to be made. Standard rehabilitation protocols were then followed and managed by the clubs. Nine elite athletes where treated with prolotherapy for isolated lateral ankle ligament tears since February 2014. Mean age was 23.7 years. Grade III ATFL RTP mean duration was 62 days and AITFL Grade IIa RTP was also 62 days. Importantly there were no reinjuries in any of the prolotherapy groups. To our knowledge this is the first study investigating prolotherapy treatment of ATFL/AITFL in elite athletes. Prolotherapy is safe and appears effective as no re-injuries were identified. However our results have not demonstrated any improvement in RTP when compared to similar injuries treated conservatively without prolotherapy. Level of Evidence : IV
... MCL sprains were the third most common injury behind muscle strains and ankle sprains in professional European soccer players from 2001 through 2008, with 23 days being the average time lost playing because of MCL injury. [1][2][3] A study tracking injuries for 1 season in 8 Division I collegiate men's hockey teams found that only concussions occurred more frequently than MCL injuries. 4 Football and skiing also have a high incidence of MCL sprains. ...
... [5][6][7][8][9] Approximately one quarter of all MCL injuries are isolated, with MCL injuries frequently occurring with patellar instability events or collateral ligament injuries. 2,3 Anterior cruciate ligament injuries, especially in females, are more commonly seen in sports that involve vertical landing/loading, but MCL injuries are also common in both basketball and volleyball. 10,11 The majority of MCL injuries respond well to nonoperative treatment, although notable exceptions include chronic injury, multiligamentous injury, and acute grade 3 tibial sided tears. ...
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Purpose The purpose of this study was to assess the ability of 2 commonly used knee braces to control knee valgus motion and subsequent strain on the medial collateral ligament (MCL) in a laboratory-controlled environment. Methods Twenty healthy individuals (6 male, 14 female; mean age, 23 ± 3 years) with no history of knee injury or brace use performed a jump landing task while wearing either no brace or 1 of 2 braces: the Playmaker and Total Range of Motion . Three-dimensional joint kinematics and kinetics were measured in our biomechanics laboratory. Results Significantly less knee dynamic valgus angulation was noted when using either brace (−0.51° ± 3.9° and −1.3° ± 3.2°) compared no brace (4.8° ± 3.0°). Dynamic valgus angulation did not differ significantly between the 2 braces tested, which were both not statistically different from baseline alignment. There were significant differences seen in peak knee flexion angle between each brace (77.9° ± 8.8°and 83.1° ± 8.4°), as well as between both braces and no brace (90.6° ± 11.1°). There was no significant difference in knee frontal plane moment or peak vertical ground reaction force loading among all 3 testing conditions. Conclusions Compared to no brace, both braces allowed significantly less dynamic valgus angulation of the knee under physiological vertical loads but were not significantly different from one another. Clinical Relevance Knee braces are commonly used to protect the MCL when placed under physiological loads. It is important to know which braces effectively reduce valgus stress to provide the best outcomes.
... Muscles, tendons, and ligaments are usually injured during eccentric contractions [1,2]. The overall injury rate of professional soccer players is approximately 1000 times higher than that of typical industrial occupations that are generally regarded as high risk [3]. Hamstring muscle injuries are the most common type of injury in sports in which fast running and repeated sprints are the basic movement patterns [4]. ...
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The hamstring muscle group is the most frequently injured muscle group in non-contact muscle injuries in sports involving high-speed running. A total of 84% of hamstring injuries affect the biceps femoris (BF) muscle. Clinical assessments and magnetic resonance imaging (MRI) are routinely used for diagnosis and plan management. MRI-negative scans for clinically diagnosed hamstring injuries range from 14% to 45%. We tested the hypothesis that the functional differences between injured and non-injured BF assessed by tensiomyography can be used for diagnostic and classification purposes. We compared an injured group of 53 international-level soccer players and sprinters with 53 non-injured international-level soccer players and sprinters of both sexes. Comparing the injured vs. non-injured athletes and the left vs. right side in all of the athletes, we used the percentage of absolute differences in the BF contraction time (Tc) to classify non-injured and injured BF muscles. The receiver operating characteristic (ROC) curve and the area under the curve (AUC) and the precision–recall curve (PRC) were used to measure the classification accuracy and to identify cut-off limits using the Tc differences. There was a very high ROC AUC value of 0.981 (SE = 0.009, p < 0.000), with 98.11% of the injured muscles being correctly classified (cut-off point 12.50% on Tc differences), and an AUPRC value of 0.981, with association classification criteria at >9.87. Tensiomyography has a high predictive ability to discriminate between injured and non-injured BF non-invasively and functionally.
... However, it is important to note that in our multivariate logistic regression model (when all significant predictors were simultaneously included in the model), playing time actually diminished the influence of age on injury occurrence. In other words, older (i.e., more experienced) players spend more time playing in games and play more matches, which naturally increases their likelihood of being injured [12,[40][41][42]. ...
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Agility is an important factor in football (soccer), but studies have rarely examined the influences of different agility components on the likelihood of being injured in football. This study aimed to prospectively evaluate the possible influences of sporting factors, i.e., flexibility, reactive agility (RAG), and change of direction speed (CODS), on injury occurrence over one competitive half-season, in professional football players. Participants were 129 football professional players (all males, 24.4 ± 4.7 years), who underwent anthropometrics, flexibility, and RAG and CODS (both evaluated on non-dominant and dominant side) at the beginning of second half-season 2019/20 (predictors). Over the following half-season, occurrence of injury was registered (outcome). To identify the differences between groups based on injury occurrence, t-test was used. Univariate and multivariate logistic regressions were calculated to identify the associations between predictors and outcome. Results showed incidence of 1.3 injuries per 1000 hours of training/game per player, with higher likelihood for injury occurrence during game than during training (Odds Ratio (OR) = 3.1, 95%CI: 1.63-5.88) Univariate logistic regression showed significant associations between players' age (OR = 1.65, 95%CI: 1.25-2.22), playing time (OR = 2.01, 95%CI: 1.560-2.58), and RAG (OR = 1.21, 95%CI: 1.09-1.35, and OR = 1.18, 95%CI: 1.04-1.33 for RAG on dominant-and non-dominant side, respectively), and injury occurrence. The multivariate logistic regression model identified higher risk for injury in those players with longer playing times (OR = 1.81, 95%CI: 1.55-2.11), and poorer results for RAG for the non-dominant side (OR = 1.15, 95%CI: 1.02-1.28). To target those players who are more at risk of injury, special attention should be paid to players who are more involved in games, and those who with poorer RAG. Development of RAG on the non-dominant side should be beneficial for reducing the risk of injury in this sport.
... 16 It has been speculated that this decrease is an effect of successful implementation of preventive measures and changes in training philosophy, including more low-risk training sessions such as strengthening, conditioning and recovery sessions. [14][15][16] Since no long-term analyses of injury patterns in South American professional football are available, one can only speculate if similar trends exist in South America. It could be argued that the difference in ligament injury incidence between the South American and European cohorts that were observed in this present study might indicate that there has not been a similar decreasing trend of the frequency of ligament injuries in South American football over the last decades. ...
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Objective To describe the injury epidemiology in professional football in South America and compare it with European professional football. Methods Data about football exposures and injury occurrences were registered in Six teams participating in Copa Libertadores in 2016. These teams’ exposure and injury data were compared with teams participating in the UEFA Elite Club Injury Study during the 2015/2016 and 2016/2017 seasons. Results A total of 271 injuries were reported in the South American cohort representing a training injury incidence of 3.2 (95% CI=2.7 to 3.7) injuries/1000 hours of training exposure and 20.9 (95% CI=17.3 to 25.1) injuries/1000 hours of match exposure. While no differences in muscle injury incidence were observed between South American and European teams, the ligament injury incidence in training among South American teams was significantly higher than European teams (0.6 vs 0.3, RR 1.87, 95% CI 1.21 to 2.87). In addition, a significantly higher proportion of all reported injuries among South American teams than European teams occurred in training. Conclusions A larger proportion of injuries occur in training in South American compared with European professional football. Specifically, ligament injuries in training were more frequent among South American teams.
... Epidemiologic studies have reported the prevalence of isolated ACL and sMCL injuries and their combination as approximately 20%, 8%, and 2%, respectively, of all knee injuries undergoing specialist treatment [3]. Secondary to sports activities of young individuals that involve contact or cutting maneuvers, excessive valgus stress is the most common mechanism of injury [4,5]. Timely and correct diagnosis is essential to correctly identify the grade of injury and to plan treatment accordingly, both in the case of isolated and combined sMCL injuries [6,7]. ...
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Standard clinical MRI techniques provide morphologic insights into knee joint pathologies, yet do not allow evaluation of ligament functionality or joint instability. We aimed to study valgus stress MRI, combined with sophisticated image post-processing, in a graded model of medial knee joint injury. To this end, eleven human cadaveric knee joint specimens were subjected to sequential injuries to the superficial medial collateral ligament (sMCL) and the anterior cruciate ligament (ACL). Specimens were imaged in 30° of flexion in the unloaded and loaded configurations (15 kp) and in the intact, partially sMCL-deficient, completely sMCL-deficient, and sMCL- and ACL-deficient conditions using morphologic sequences and a dedicated pressure-controlled loading device. Based on manual segmentations, sophisticated 3D joint models were generated to compute subchondral cortical distances for each condition and configuration. Statistical analysis included appropriate parametric tests. The medial compartment opened gradually as a function of loading and injury, especially anteriorly. Corresponding manual reference measurements by two readers confirmed these findings. Once validated in clinical trials, valgus stress MRI may comprehensively quantify medial compartment opening as a functional imaging surrogate of medial knee joint instability and qualify as an adjunct diagnostic tool in the differential diagnosis, therapeutic decision-making, and monitoring of treatment outcomes.
Article
Background A “Stener-like” lesion of the knee is defined as a distal avulsion of the superficial medial collateral ligament (sMCL) with interposition of the pes anserinus between the ligament and its tibial insertion—a displacement impeding anatomic healing. Because of the scarcity of these injuries, the literature is limited to case reports and small case series. Purpose To assess the effect of surgical repair of acute Stener-like lesions of the sMCL on the following outcomes: return to preinjury level of sporting function; time to return to preinjury level of sporting function; functional performance; injury recurrence; and any other complications. Study Design Case series: Level of evidence, 4. Methods This prospective single–surgeon study included 23 elite athletes with a mean age of 27.2 years (range, 19-37 years). Of the participants, 20 were men (87%) and 3 were women (13%). The mean body mass index was 23.1 ± 2.3. A total of 16 athletes were soccer players (70%) and 7 were rugby players (30%), with isolated acute, traumatic Stener-like lesions of the sMCL of the knee confirmed on preoperative magnetic resonance imaging. Surgical repair was undertaken with primary suture anchor repair with ligament repair or reconstruction system (LARS) augmentation. Predefined outcomes were recorded at regular intervals after surgery. The minimum follow–up time was 24 months (range, 24-108 months) from the date of surgery. Results The mean time from injury to surgical intervention was 9 days (range, 3-28 days). Overall, 15 (65%) athletes had isolated distal sMCL injuries requiring anatomic suture anchor repair at the distal tibial insertion site only, and 8 (35%) athletes had concomitant injuries of the proximal and distal sMCL and required anatomic suture anchor repair at the proximal and distal attachment sites. Ten athletes required LARS augmentation at the time of the index operation. All study patients returned to their preinjury level of sporting activity in professional soccer or rugby. The mean time from surgical intervention to return to full sporting activity was 16.8 ± 2.7 weeks. At 6 and 24 months’ follow–up, all patients had Tegner scores of 10. At a 2–year follow–up, all study patients were still participating at their preinjury level of sporting activity. Three patients developed complications around the LARS that required further surgery to remove synthetic material; however, this did not affect function. Conclusion Surgical repair of acute Stener-like lesions of the sMCL is associated with a high return to preinjury level of sporting function, excellent functional performance, and a low risk of recurrence at short–term follow-up in elite athletes.
Chapter
Soccer is one of the world’s most popular sports, but is physically demanding and acute and overuse injuries occur rather frequently. It is a typical low-extremity sport, with the lower limb region most frequently injured. Through a structured approach focused on injury epidemiology, relevant anatomy, mechanism, and appearance on medical imaging, the radiologist can gain familiarity with the common and important injuries experienced by soccer players and in turn assist the player and referring clinician towards the goal of appropriate treatment and timely return to play. This chapter reviews the most commonly observed and most important injuries in soccer players.
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Limited information is available on the variation in injury rates over multiple seasons of professional football. To analyse time-trends in injury characteristics of male professional football players over 11 consecutive seasons. A total of 1743 players comprising 27 teams from 10 countries were followed prospectively between 2001 and 2012. Team medical staff recorded individual player exposure and time loss injuries. A total of 8029 time loss injuries were recorded. The match unavailability due to injury was 14% and constant over the study period. On average, a player sustained two injuries per season, resulting in approximately 50 injuries per team and season. The ligament injury rate decreased during the study period (R(2)=0.608, b=-0.040, 95% CI -0.065 to -0.016, p=0.005), whereas the rate of muscle injury (R(2)=0.228, b=-0.013, 95% CI -0.032 to 0.005, p=0.138) and severe injury (R(2)=0.141, b=0.015, 95% CI -0.013 to 0.043, p=0.255) did not change over the study period. In addition, no changes in injury rates over the 11-year period were found for either training (R(2)=0.000, b=0.000, 95% CI -0.035 to 0.034, p=0.988) or match play (R(2)=0.282, b=-0.015, 95% CI -0.032 to 0.003, p=0.093). The injury rate has decreased for ligament injuries over the last 11 years, but overall training, match injury rates and the rates of muscle injury and severe injury remain high.
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Anterior cruciate ligament (ACL) injury causes long lay-off time and is often complicated with subsequent new knee injury and osteoarthritis. Female gender is associated with an increased ACL injury risk, but few studies have adjusted for gender-related differences in age although female players are often younger when sustaining their ACL injury. The objective of this three-cohort study was to describe ACL injury characteristics in teams from the Swedish men's and women's first leagues and from several European men's professional first leagues. Over a varying number of seasons from 2001 to 2009, 57 clubs (2,329 players) were followed prospectively and during this period 78 ACL injuries occurred (five partial). Mean age at ACL injury was lower in women compared to men (20.6 ± 2.2 vs. 25.2 ± 4.5 years, P = 0.0002). Using a Cox regression, the female-to-male hazard ratio (HR) was 2.6 (95% CI 1.4-4.6) in all three cohorts studied and 2.6 (95% CI 1.3-5.3) in the Swedish cohorts; adjusted for age, the HR was reduced to 2.4 (95% CI 1.3-4.2) and 2.1 (95% CI 1.0-4.2), respectively. Match play was associated with a higher ACL injury risk with a match-to-training ratio of 20.8 (95% CI 12.4-34.8) and 45 ACL injuries (58%) occurred due to non-contact mechanisms. Hamstrings grafts were used more often in Sweden than in Europe (67 vs. 34%, P = 0.028), and there were no differences in time to return to play after ACL reconstruction between the cohorts or different grafts. In conclusion, this study showed that the ACL injury incidence in female elite footballers was more than doubled compared to their male counterparts, but also that they were significantly younger at ACL injury than males. These findings suggest that future preventive research primarily should address the young female football player.
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Groin injury is a common injury in football and a complicated area when it comes to diagnosis and therapy. There is a lack of comprehensive epidemiological data on groin injuries in professional football. To investigate the incidence, pattern and severity of hip and groin injuries in professional footballers over seven consecutive seasons. Prospective cohort study. European professional football. During the 2001/2 to 2007/8 seasons, between nine and 17 clubs per season (23 clubs in total) were investigated, accounting for 88 club seasons in total. Time loss injuries and individual exposure during club and national team training sessions and matches were recorded. Injury incidence. A total of 628 hip/groin injuries were recorded, accounting for 12-16% of all injuries per season. The total injury incidence was 1.1/1000 h (3.5/1000 match hours vs 0.6/1000 training hours, p<0.001) and was consistent over the seasons studied. Eighteen different diagnostic entities were registered, adductor (n = 399) and iliopsoas (n = 52) related injuries being the most common. More than half of the injuries (53%) were classified as moderate or severe (absence of more than a week), the mean absence per injury being 15 days. Reinjuries accounted for 15% of all registered injuries. In the 2005/6 to 2007/8 seasons, 41% of all diagnoses relied solely on clinical examination. Hip/groin injuries are common in professional football, and the incidence over consecutive seasons is consistent. Hip/groin injuries are associated with long absences. Many hip/groin diagnoses are based only on clinical examination.
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To study the injury characteristics in professional football and to follow the variation of injury incidence during a match, during a season and over consecutive seasons. Prospective cohort study where teams were followed for seven consecutive seasons. Team medical staff recorded individual player exposure and time-loss injuries from 2001 to 2008. European professional men's football. The first team squads of 23 teams selected by the Union of European Football Associations as belonging to the 50 best European teams. Injury incidence. 4483 injuries occurred during 566 000 h of exposure, giving an injury incidence of 8.0 injuries/1000 h. The injury incidence during matches was higher than in training (27.5 vs 4.1, p<0.0001). A player sustained on average 2.0 injuries per season, and a team with typically 25 players can thus expect about 50 injuries each season. The single most common injury subtype was thigh strain, representing 17% of all injuries. Re-injuries constituted 12% of all injuries, and they caused longer absences than non re-injuries (24 vs 18 days, p<0.0001). The incidence of match injuries showed an increasing injury tendency over time in both the first and second halves (p<0.0001). Traumatic injuries and hamstring strains were more frequent during the competitive season, while overuse injuries were common during the preseason. Training and match injury incidences were stable over the period with no significant differences between seasons. The training and match injury incidences were stable over seven seasons. The risk of injury increased with time in each half of matches.
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All injuries occurring over a 7-week period at a local indoor soccer arena were documented for analysis of incidence rates. All injury rates were calculated per 100 player-hours. The overall injury rates for male and female players were similar, 5.04 and 5.03, respectively. The lowest injury rate was found among the 19- to 24-year-old athletes and the highest injury rate was found among the oldest age group (> or = 25 years). Collision with another player was the most common activity at the time of injury, accounting for 31% of all injuries. The most common injury types were sprains and muscle contusions, both occurring at a rate of 1.1 injuries per 100 player-hours. Male players suffered a significantly higher rate of ankle ligament injuries compared with female players (1.24 versus 0.43, P < 0.05), while female players suffered a significantly higher rate of knee ligament injuries (0.87 versus 0.29, P < 0.01). Goalkeepers had injury rates (4.2) similar to players in nongoalkeeper positions (4.5).
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Variations in definitions and methodologies have created differences in the results and conclusions obtained from studies of football (soccer) injuries, making interstudy comparisons difficult. Therefore an Injury Consensus Group was established under the auspices of Fédération Internationale de Football Association Medical Assessment and Research Centre. A nominal group consensus model approach was used. A working document on definitions, methodology, and implementation was discussed by the group. Iterative draft statements were prepared and circulated to members of the group for comment before the final consensus statement was produced. Definitions of injury, recurrent injury, severity, and training and match exposures in football together with criteria for classifying injuries in terms of location, type, diagnosis, and causation are proposed. Proforma for recording players’ baseline information, injuries, and training and match exposures are presented. Recommendations are made on how the incidence of match and training injuries should be reported and a checklist of issues and information that should be included in published reports of studies of football injuries is presented.
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All 12 female football clubs (228 players) and 11 of 14 male clubs (239 players) in the Swedish premier league were followed prospectively during the 2005 season. Individual exposure (playing time), injuries (time loss), and injury severity (days lost due to injury) were recorded by the team medical staffs. Injury incidence was higher for male players during both training (4.7 vs 3.8 injuries/1000 h, P=0.018) and match play (28.1 vs 16.1, P<0.001). However, no difference was found in the incidence of severe injury (absence >4 weeks) (0.7/1000 h in both groups). The thigh, especially the hamstrings, was the overall most commonly injured region in both sexes, while the hip/groin was more commonly injured in male players and the knee in female players. Knee ligament injuries accounted for 31% and 37% of the total time lost from football for male and female players, respectively. In conclusion, male elite players had a higher injury incidence than their female counterparts although no difference was observed in the incidence of moderate to severe injury. We recommend that preventive measures should be focused on hamstring and knee ligament injury in order to reduce the overall injury burden.
Article
We investigated the frequency, cause and location of injuries in Icelandic elite soccer in 1991. The incidence of injuries for the individual player was 34.8 +/- 5.7 per 1000 game-hours and 5.9 +/- 1.1 per 1000 practice-hours. The most common types of injuries were muscle strains (29%), ligament sprains (22%), contusions (20%), and other injuries (29%). The frequency of reinjury was markedly high, where 44% of the strains and 58% of the sprains were registered as reinjuries. Strains occurred mainly during sprinting, sprains by tackling, and contusion during other contact. Significantly more injuries occurred on artificial turf than on grass or gravel in correlation to number of hours in games and practices. Teams who had the longest pre-season preparation period obtained significantly fewer injuries during the season.
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To define the causes of injuries to players in English professional football during competition and training. Lost time injuries to professional and youth players were prospectively recorded by physiotherapists at four English League clubs over the period 1994 to 1997. Data recorded included information related to the injury, date and place of occurrence, type of activity, and extrinsic Playing factors. In all, 67% of all injuries occurred during competition. The overall injury frequency rate (IFR) was 8.5 injuries/1000 hours, with the IFR during competitions (27.7) being significantly (p < 0.01) higher than that during training (3.5). The IFRs for youth players were found to increase over the second half of the season, whereas they decreased for professional players. There were no significant differences in IFRs for professional and youth players during training. There were significantly (p < 0.01) injuries in competition in the 15 minute periods at the end of each half. Strains (41%), sprains (20%), and contusions (20%) represented the major types of injury. The thigh (23%), the ankle (17%), knee (14%), and lower leg (13%) represented the major locations of injury, with significantly (p < 0.01) more injuries to the dominant body side. Reinjury counted for 22% of all injuries. Only 12% of all injuries were caused by a breach of the rules of football, although player to player contact was involved in 41% of all injuries. The overall level of injury to professional footballers has been showed to be around 1000 times higher times higher than for industrial occupations generally regarded as high risk. The high level of muscle strains, in particular, indicates possible weakness in fitness training programmes and use of warming up and cooling down procedures by clubs and the need for benchmarking players' levels of fitness and performance. Increasing levels of injury to youth players as a season progresses emphasizes the importance of controlling the exposure of young players to high levels of competition.
Article
To undertake a prospective epidemiological study of the injuries sustained in English professional football over two competitive seasons. Player injuries were annotated by club medical staff at 91 professional football clubs. A specific injury audit questionnaire was used together with a weekly form that documented each club's current injury status. A total of 6,030 injuries were reported over the two seasons with an average of 1.3 injuries per player per season. The mean (SD) number of days absent for each injury was 24.2 (40.2), with 78% of the injuries leading to a minimum of one competitive match being missed. The injury incidence varied throughout the season, with training injuries peaking during July (p<0.05) and match injuries peaking during August (p<0.05). Competition injuries represented 63% of those reported, significantly (p<0.01) more of these injuries occurring towards the end of both halves. Strains (37%) and sprains (19%) were the major injury types, the lower extremity being the site of 87% of the injuries reported. Most injury mechanisms were classified as being non-contact (58%). Re-injuries accounted for 7% of all injuries, 66% of these being classified as either a strain or a sprain. The severity of re-injuries was greater than the initial injury (p<0.01). Professional football players are exposed to a high risk of injury and there is a need to investigate ways of reducing this risk. Areas that warrant attention include the training programmes implemented by clubs during various stages of the season, the factors contributing to the pattern of injuries during matches with respect to time, and the rehabilitation protocols employed by clubs.