Risk factors for recurrent hamstring injuries

Original article
Br J Sports Med 2012;46:124–130. doi:10.1136/bjsports-2011-090317124
ABSTRACT
Background Although recurrent hamstring injury is a
frequent problem with a significant impact on athletes,
data on factors determining the risk for a recurrent
hamstring injury are scarce.
Objective To systematically review the literature and
provide an overview of risk factors for re-injury of acute
hamstring muscle injuries.
Study design Prospective studies on risk factors
for re-injury following acute hamstring injuries were
systematically reviewed. Medical databases and
reference lists of the included articles were searched.
Two reviewers independently selected potential studies
and assessed methodological quality; one reviewer
extracted the data. A best-evidence synthesis of all
studied risk factors was performed.
Results Of the 131 articles identified, five prospective
follow-up studies fulfilled our inclusion criteria. These
studies reported a recurrence incidence of 13.9–63.3%
in the same playing season up to 2 years after initial
injury. Limited evidence for three risk factors and one
protective factor for recurrent hamstring injury was
found; patients with a recurrent hamstring injury had
an initial injury with a larger volume size as measured
on MRI (47.03 vs 12.42 cm3), more often had a Grade 1
initial trauma (Grade 0: 0–30.4%; Grade 1: 60.9–100%;
Grade 2: 8.7%) and more often had a previous ipsilateral
anterior cruciate ligament (ACL) reconstruction (66.6%
vs 17.1%) independent of graft selection. Athletes in
a rehabilitation programme with agility/stabilisation
exercises rather than strength/stretching exercises had
a lower risk for re-injury (7.7% vs 70%). No significant
relationship with re-injury was found for 11 related
determinants. There was conflicting evidence that a
larger cross-sectional area is a risk factor for recurrent
hamstring injury.
Conclusions There is limited evidence that athletes
with a larger volume size of initial trauma, a Grade
1 hamstring injury and a previous ipsilateral ACL
reconstruction are at increased risk for recurrent
hamstring injury. Athletes seem to be at lower risk for
re-injury when following agility/stabilisation exercises.
INTRODUCTION
Hamstring injuries account for 12–15% of the
total injuries in different sports and mostly occur
in high-speed running or activities requiring
extremes in a range of motion.1–3 Moreover, the
re-injury rate is 12–41%1 4 with the second ham-
string injury usually more severe than the first,
and the time away from sport generally twice as
long.5 Hamstring injuries are not only problematic
for the athlete but also for their trainer(s) and club,
because of the time lost before return to sport.1 4
Although many protocols have been examined
for optimal treatment and rehabilitation after a
hamstring injury in different sports,6 few stud-
ies have adequately addressed patient factors and
injury characteristics that help determine the risk
for a recurrent hamstring injury and the moment
for return to sport. Systematic reviews of risk fac-
tors for initial hamstring strain injuries have been
published; a systematic review of risk for recur-
rent injury is yet to be completed.7
To classify the severity of injury, the classifica-
tion described by Peetrons combines the clinical
spectrum of symptoms with imaging, ranging
from clinical symptoms without imaging signs
of injury (Grade 0) to complete rupture of the
hamstring muscle (Grade 3)8 (table 1). Moreover,
a higher classification of injury will take longer
to rehabilitate due to the extent of damage to the
tissue.6 The rehabilitation period before return to
sport ranges from 1 week for Grade 0 injuries9 10
up to 6 months for Grade 3 injuries.11
The exact moment of return to sport after a ham-
string injury is difficult to determine. Not only the
well-being of the patient, but also factors such as
sports competition and financial interests play a
role in an athlete’s return to sports.12 Therefore,
identification of factors that determine the risk of
recurrent hamstring injuries will help determine
the exact moment for return to sport activities. For
athletes at increased risk of recurrent hamstring
injuries, a specific or a longer rehabilitation pro-
gramme can be recommended, which can lead to
a decrease in recurrent hamstring injuries, with
less time lost from sports.5
To address these items, this study provides a
systematic review of the currently reported risk
factors for recurrent hamstring injury.
METHODS
Search strategy
A systematic search was performed to identify
relevant studies in PubMed, EMBASE, CINAHL
and Web of Science since their inception up to
April 2011. Figure 1 presents an overview of the
complete search strategy.
Inclusion criteria
Papers were considered eligible for inclusion if
they fulfilled all of the following criteria:
(1) Study participants diagnosed with an acute
initial hamstring injury by physical examina-
tion, classified as Grades 1–3 (table 1; Peetrons),8
or classified as Grades 0–3 (Peetrons)8 when an
additional MRI or sonography was performed.
If the classification by Peetrons was not applied,
Department of Orthopaedic
Surgery, Erasmus University
Medical Center, Rotterdam,
The Netherlands
Correspondence to
Pieter K. Bos, Department
of Orthopaedics, Erasmus
University Medical Center,
PO Box 2040, 3000 CA
Rotterdam, The Netherlands;
p.k.bos@erasmusmc.nl
Received 16 June 2011
Accepted 8 September 2011
Published Online First
19 October 2011
Risk factors of recurrent hamstring injuries:
a systematic review
HM de Visser, M Reijman, MP Heijboer, PK Bos
group.bmj.comon October 10, 2012 - Published bybjsm.bmj.comDownloaded from

Original article
Br J Sports Med 2012;46:124–130. doi:10.1136/bjsports-2011-090317 125
then the characteristics of the injury were sufficiently well
described to enable the authors to classify the injury of each
participant according to the classification of Peetrons.8
(2) Prospective studies with a minimal follow-up period of
2 weeks after return to sport.
(3) Full text of the article was available.
(4) The article was written in English, German or Dutch; if
a subset of the total patients included in a study met our inclu-
sion criteria, the study was included only if the outcomes of
the subset were assessed and reported separately.
Information concerning the severity of initial injury should
be reported in the studies because this could probably influ-
ence the rehabilitation, timing of return to sport and conse-
quently be a potential risk factor for recurrent injury.
Study selection
Two reviewers (HMV and PKB) independently applied the inclu-
sion criteria to select potential studies. A consensus method was
used to solve any disagreements concerning the inclusion of the
studies. A third reviewer (MR) was consulted when disagree-
ment persisted. Disagreements were solved in a single consen-
sus meeting, without the help of the third reviewer.
Assessment of methodological quality
Two reviewers (HMV and MR) independently assessed
the methodological quality on the external and internal
validity of each included study, using questions of existing
quality assessment tools.13 14 Table 2 lists the five quality
criteria; each item was scored as a ‘yes, ‘no’ or ‘unable to
determine’. Disagreements were solved in a single consen-
sus meeting.
Studies were classified as high quality when minimally three
criteria scored a ‘yes’ and when the question ‘Was there ade-
quate adjustment for confounding in the analysis from which
the main findings were drawn?’ also scored ‘yes’. Adjustment
had to be made for ‘age’ and ‘gender’.
Data extraction
One author (HMV) extracted the data. Information was col-
lected on the study population, diagnostic test used, determi-
nants measured and the definition of re-injury.
Data synthesis
Because the studies were considered heterogeneous with
regard to the outcome measures or determinants studied,
and the methodological quality, we refrained from statistical
data pooling and performed a best-evidence synthesis.15 16
The level of evidence was ranked and divided into the fol-
lowing levels:
Strong evidence: provided by two or more studies with1.
high quality (=quality assessment ≥3 and adjustment for
confounders) and by generally consistent findings in all
studies (>75% of the studies reported consistent findings).
Moderate evidence: provided by one high-quality study2.
and two or more low-quality studies and by generally con-
sistent findings in all studies (>75%).
Limited evidence: provided by low-quality studies or in3.
one high-quality study and by generally consistent findings
(>75%).
Conflicting evidence: provided by conflicting findings4.
(<75% of the studies reported consistent findings).
No evidence: provided when no studies could be found.5.
RESULTS
Included studies
The initial search yielded 131 records (29 from PubMed, 41
from EMBASE, 33 from Web of Science and 28 from CINAHL).
After duplicates were removed, 75 remained. Finally, five
studies met our inclusion criteria, and were included in this
review9 10 17–19 (figure 2).
The included studies reported a recurrence incidence of 13.9–
63.3%inthesameplayingseasonupto2yearsafterinitialinjury.
Athletes from different sports were included (most of them par-
ticipating in Australian Rules football) and were mainly men
(73.8%). The study by Malliaropoulos et al,10 with 165 subjects,
had the largest study population. The remaining four studies
Table 1 Classification according to Peetrons8
Grade 0 Lack of any lesion using MRI* or US, despite clinical diagnosis of
posterior thigh muscle injury.
Grade 1 Minimal elongations with less than 5% of the muscle involved.
Grade 2 Partial muscle ruptures. They correspond to lesions involving from
5% to 50% of the muscle volume or cross-sectional diameter.
Grade 3 Complete muscle tears with complete retraction. Usually, these
lesions are clinically evident because the muscle belly forms a real
mass and because a gap can be palpated between the retracted
ends of the muscle.
*This classification is originally described for ultrasound; Davis26 described the
same classification for MRI.
US, ultrasound.
Table 2 Methodological quality criteria
Item Judgement
External validity
Were the subjects asked to participate in the
study representative of the entire population
from which they were recruited?
Yes/No/Unable to determine
Internal validity
Were the determinants measured used
accurate?
Were the statistical tests used to assess the
main outcomes appropriate?
Were losses of patients to follow-up taken into
account?
Was there adequate adjustment for confounding
in the analysis from which the main findings
were drawn?
Figure 1 Search strategy in Medline.

Original article
included 24–41 subjects. None of the studies included athletes
with a complete rupture of the hamstring (Grade 3) (table 3).
Methodological quality
The two reviewers had four disagreements that were solved in
a single consensus meeting. The methodological quality of the
included studies ranged from 1 to 4 points (table 4). Because
none of the ﬁve studies corrected the relationship for known
confounders (such as age and gender), none of the evaluated
determinants could be judged as strong or moderate evidence
in the best-evidence synthesis.
Determinants related to re-injury
Table 5 presents an overview of the levels of evidence.
Limited evidence for three risk factors of re-injury was
found: two studies found that athletes with a re-injury more
often had a Grade 1 hamstring injury at initial trauma, com-
pared with Grade 0 and Grade 2 injuries (Grade 0: 0–9.3%,
Grade 1: 24.1–35%, Grade 2: 6.3%).9 10
Koulouris et al reported that athletes with a previous ipsi-
lateral anterior cruciate ligament (ACL) reconstruction had an
increased risk of a hamstring re-injury compared with ath-
letes without a previous ACL reconstruction (66.6% vs 17.1%,
respectively); the risk for a re-injury was independent of graft
selection (hamstring or bone patellar-tendon bone).17 Verrall
et al18 reported that athletes with a re-injury had a larger
volume size of the initial trauma as measured on MRI com-
pared with athletes without a re-injury (47.03 vs 12.42 cm3,
respectively).
Limited evidence for a lower risk of re-injury was found for
athletes who followed a rehabilitation programme with ‘agil-
ity and stabilisation’ exercises compared with ‘stretching and
strengthening’ exercises (7.7% vs 70%, respectively).19
Figure 2 Study election.

Original article
Limited evidence for no relationship with re-injury was
found for age, height, weight, length of injury, time to return to
sports, muscle involved, location of trauma in the hamstring,
pain severity score (VAS) 12–18 h after the initial injury, pres-
ence of a haematoma, dominant leg injured and the outcome
of functional tests performed on the day of return to sports
from athletes with a re-injury compared with those with a
single injury.9 10 17–19
Conflicting evidence was found for the cross-sectional
area as a risk factor for re-injury. This is the ratio of the area
(cross-section) of muscle abnormality to the area of the entire
muscle at the same level. Three studies found no relation to
re-injury, and Verrall et al found that athletes with a re-injury
had a larger cross-sectional area of the initial trauma com-
pared with athletes without a re-injury (54.47% vs 32.27%,
respectively).9 10 17 18
DISCUSSION
This systematic review aimed to provide an overview of the
current evidence for known risk factors of recurrent hamstring
injuries. Our search strategy yielded five relevant studies in
which a recurrence incidence of 13.9–63.3% was reported.
None of these studies corrected the relationship for known
confounders and, consequently, none of the determinants
could be judged as having strong or moderate evidence. Limited
evidence was found for a larger volume size of the initial injury
as measured on MRI, Grade 1 injuries and a previous ipsilateral
ACL reconstruction to be risk factors for recurrent injury. Also,
limited evidence was found that athletes who followed a reha-
bilitation programme focusing on ‘agility and stability’ had a
decreased risk of a recurrent hamstring injury compared with
a ‘stretching and strength’ protocol.
For all other determinants, no evidence was found for a rela-
tionship with a recurrent hamstring injury.
It is noteworthy that the reported incidence of recurrent
hamstring injuries ranged from 13.9% to 63.3%.9 10 17–19 A
possible explanation for this wide range might be the fol-
low-up period used; that is, with a longer follow-up, more
re-injuries can be reported. However, the highest and low-
est recurrences were reported in studies with a similar fol-
low-up period of 2 years,10 18 indicating that the follow-up
had no specific relationship with the differences in re-injury
rates. The characteristics of the included studies were sim-
ilar regarding age, gender, number of subjects and level of
sports. This indicates that differences in the study popula-
tion are not solely responsible for the difference in re-injury
incidence.
The severity of the initial trauma of the study popula-
tions also differed; two studies included athletes with Grade
0 injuries and both reported the lowest recurrence rate of all
studies.9 10 Thus, it seems that re-injury rates decrease when
patients with less severe initial trauma are included. The time
until return to sports may also influence re-injury rates, that
is, without a complete recovery, there may be a higher risk
to suffer a re-injury. All the included studies used different
rehabilitation programmes and different criteria to determine
whether athletes were completely recovered. Therefore, it
seems that the differences in the rehabilitation programme
and the return to sport criteria might explain the differences
in re-injury rates.
In conclusion, the differences in the severity of the initial
trauma, the rehabilitation programme and the criteria used for
return to sports could be responsible for the differences in the
reported re-injury rates.
One study reported that a larger volume area is related
to re-injury.18 Nevertheless, another study reported that
Grade 1, compared with Grade 2 initial injuries, has a higher
risk for re-injury.10 Thus, there are some contradictions in
these findings. Malliaropoulos et al10 suggest that athletes
with more severe injuries experience a longer rehabilita-
tion time and will, therefore, have less re-injuries.10 Thus,
a possible explanation for this apparent contradiction is the
Table 3 Characteristics of the included studies
First author, year
of publication Study population
Number of
subjects* Diagnosed
Age (years)
mean±SD % Male Follow-up period
Number of
recurrences
Gibbs et al9 Elite Australian Rules football
athletes who sustained an acute
Grade 0–1 hamstring injury
(AFL club 1998–2002)
Total: 31 CE MRI 18–33† 100 The same playing
season‡
Total: 6 (19.4%)
Grade 0: 14 (45.2%)
Grade 1: 17 (54.8%) Grade 0: 0 (0%)
Grade 2: 0 Grade 1: 6 (35%)
Koulouris et al17 Elite Australian Rules football
athletes who sustained an acute
Grade 1–2 hamstring injury
(AFL 2002)
Total: 41 MRI 24±3.8 (Single injury) 100 The same playing
season‡
Total: 10 (24.4%)
Grades: NA 25.5±3.8 (Re-injury)
Malliaropoulos et al10 Elite track and field athletes
with acute, first-time unilateral
Grade 0–2 hamstring strain
(1999–2007)
Total: 165 CE 18–24† 57.7 2 Years after injury Total: 23 (13.9%)
Grade 0: 75 (45.4%) Grade 0: 7 (9.3%)
Grade 1: 58 (35.2%) Sonography Grade 1: 14 (24.1%)
Grade 2: 32 (19.4%) Grade 2: 2 (6.3%)
Sherry and Best19 24 Athletes of various sports
with an acute Grade 1–2
hamstring strain
Total: 24 CE 24.3±12.4 (STSS) 75 1 Year after return
to sports
Total: 8 (33.3%)
Grade 0: 0
Grade 1: 12 (50%) 23.2±11.1 (PATS) Grades: NA
Grade 2: 12 (50%)
Verrall et al18 1 of 3 Elite Australian Rules
football athletes who sustained
an acute Grade 1–2 hamstring
injury (AFL)
Total: 30 CE 23.6±3.2 100 The same and
subsequent playing
season
Total: 19 (63.3%)
Grades: NA MRI
*Number of subjects are those athletes who sustained a hamstring injury based on our inclusion criteria.
†Age range of subjects.
‡Hamstring injuries that occurred prior to the end of the season break period, which could not be monitored during rehabilitation, were excluded.
AFL, Australian Football League; CE, clinical examination; NA, not available; PATS, progressive agility and trunk stabilisation; STSS, stretching and strengthening.

Original article
difference in the time to return to sport. Malliaropoulos et
al10 reported a mean time of return to sport of 29.5 days for
Grade 2 injuries, and Verrall et al18 reported a mean time of
return to sport of 29.1 days but did not differentiate between
grades of injury. Despite the similar mean time to return to
sport in both these studies, the recurrence incidence was
higher in the study of Verrall et al.18 Unfortunately, these
authors did not report the rehabilitation periods for differ-
ent grades of initial injury. Also, both studies used differ-
ent study populations. Malliaropoulos et al included 165
track and field athletes with an age range of 18–24 years and
57.7% male athletes. The rehabilitation protocol focused on
normalisation of gait, regaining pain-free range of motion,
return to running activities, sport-specific training and agil-
ity drills; return to full athletic activities was allowed when
three clinical tests were successfully passed.10 Verrall et al
included 30 male Australian Rules football athletes with
a mean age of 23.6±3.2 years; the rehabilitation protocol
focused on pain-free walking, passive hamstring stretches to
point of pain, speed running without rapid acceleration and
active hamstring stretches when pain-free.18 Return to full
athletic activities was allowed when 1 full week of training
was achieved.18 Because both studies used the same length
of follow-up, the period of rehabilitation could not explain
the differences between these two studies. The differences
might be explained by the characteristics of the studies,
especially the study population, rehabilitation protocol and
return to sport criteria used.
There is no consensus on the definition of a recurrent ham-
string injury, and several studies used different definitions.
We followed the definition as described in a previous review,
which defined a recurrent hamstring injury as an injury of the
same type and location.20 A specific time frame in which the re-
injury should take place was not defined.
In our opinion, the best way to document a recurrent
injury should be a confirmed trauma on the same location
as the initial injury on MRI or on sonography. The actual
presence of an initial Grade 0 hamstring injury exists even
though it remains speculative, because no abnormality is
detected on MRI or on sonography. Therefore, we consider
a recurrent hamstring injury to be a confirmed injury on the
same location as the initial injury after full return to sport
activity. Moreover, we suggest that future studies could anal-
yse their findings with Grade 0 injuries and without Grade 0
hamstring injuries.
A possible limitation of MRI assessment is that all muscle
injuries have associated oedema and haemorrhage, which
cause elongation of the T1 and T2 relaxation times of the
injured muscle.21 Although MRI techniques are still evolving,
the images may be misinterpreted, leading to an overestima-
tion of the actual muscle tear volume. Therefore, it is difficult
to determine whether the extent of reported injuries presented
in this review match with the actual lesion.
By identifying determinants related to re-injury, athletes
at increased risk can be identified. For these athletes, a more
careful approach in their rehabilitation programme and better
timing for return to sports can be recommended. Moreover,
Table 4 Quality assessment
External validity Internal validity Total
Author
Subjects
representative?
Determinants
accurate?
Statistical
test
appropriate?
Losses to
follow-up
taken into
account?
Adjustment for
confounding?
High
quality
Gibbs et al9 Unable to determine* Yes Yes Yes No 3
Koulouris et al17 Yes Yes Yes Yes No 4
Malliaropoulos et al10 Yes Yes Yes Yes No 4
Sherry and Best19 No Unable to
determine†
Yes No No 1
Verrall et al18 Yes Yes Yes Yes No 4
*Study does not report the source population from where the patients were selected.
†Determinants measured were the rehabilitation programme and functional tests; it was unable to determine whether this
was performed accurately.
Table 5 Determinants for recurrent hamstring injuries
Determinants
Study reference
number Best-evidence synthesis
Age 2, 5 Limited evidence
Height 2, 5 Limited evidence
Weight 2, 5 Limited evidence
Time to return to sports All Limited evidence
Size of the initial injury 1, 2 Limited evidence
Cross-sectional area of the
initial injury
1, 2, 3, 5↑ Conflicting evidence
Volume of the initial injury 5↑ Limited evidence
Grade 1 injuries according to
Peetrons
1↑, 3↑ Limited evidence
Muscle involved 2, 3, 5 Limited evidence
Location in the muscle* 2, 3, 5 Limited evidence
Pain severity score (VAS)
12–18 h after the initial injury
5 Limited evidence
Presence of a haematoma 3 Limited evidence
Dominant leg injured 5 Limited evidence
Previous hamstring injury† 2 Limited evidence
Previous ACL reconstruction 2↑ Limited evidence
Rehabilitation ‘agility and
stabilisation’‡
4↓ Limited evidence
Outcome functional tests§ 4 Limited evidence
1=Gibbs et al9; 2=Koulouris et al17; 3=Malliaropoulos et al10; 4=Sherry and
Best19; 5=Verrall et al18
↑=Risk factor for re-injury.
↓=Protective factor for re-injury.
*Location in the muscle: upper, middle or lower thigh. Or musculotendinous
junction compared with myofascial.
†Positive for a history of a hamstring injury before the first injury during the
competition.
‡Rehabilitation programme of ‘agility and stabilisation’ compared with a
programme of ‘strengthening and eccentric stretching’ exercises.
§Functional tests performed: hop for height, hop for distance, 4 hop crossover
test, 40 yard sprint.
ACL, anterior cruciate ligament; VAS, visual analogue scale.

Original article
a specific rehabilitation programme can be designed when
modifiable determinants of recurrent hamstring injuries are
known. We could trace one modifiable determinant of re-
injury, namely a specific rehabilitation programme.19 Hence,
athletes with a larger volume size of initial injury as measured
on MRI, a Grade 1 injury or a previous ipsilateral ACL recon-
struction should be advised to take a more careful approach
to their rehabilitation and return to sports. Exercises of agil-
ity and stabilisation can be added to the rehabilitation pro-
gramme; also a longer rehabilitation time can be realised. Both
adaptations may lead to a complete recovery of the injury and
a decrease of re-injuries.
Several studies reporting on determinants of hamstring
re-injury were excluded based on our strict inclusion/exclu-
sion criteria.1 4 22–25 In these latter studies, the initial type
of hamstring injury was self-reported but not clinically clas-
sified by physical examination or additionally diagnosed on
MRI/ultrasound; these studies are presented in appendix A.
The results should be interpreted with caution, due to uncer-
tainty about the presence of the initial hamstring injury. A
recurrence incidence of 11.9–25% in soccer players and of
15–40.6% in Australian Rules football athletes was reported
in these studies.1 4 22–25 A hamstring injury before the ini-
tial trauma and age were reported to be related to re-injury.4
22 23 25 If these data are added to the results of the present
review, higher age would change from limited evidence for
no relationship into conflicting evidence as a risk factor for
re-injury.
Applying our search strategy and the inclusion/exclusion
criteria, only five studies were included. Because none of
these studies corrected the risk estimate of the determinant
for known confounders, all studies were considered to be of
low quality. We used the correction of confounders as impor-
tant quality criteria, because we were interested in the inde-
pendent relationship between determinants and recurrent
injury. Eventually, the confounders did not seem to be related
to recurrent hamstring injury. Thus, it is doubtful whether it
was appropriate to expect the included studies to correct for
the confounders chosen in advance. However, because none of
the included studies corrected for any possible confounder, the
independent relationship between determinants and recurrent
injury could not be proven. Thus, we still consider our included
studies to be of low quality and with limited evidence as the
best level of evidence.
In conclusion, based on the best available evidence pre-
sented in this review, it seems that clinicians can identify
those athletes at increased risk for a hamstring re-injury.
Patients with a previous ACL reconstruction, a Grade 1 ini-
tial injury and a larger initial injury volume size as measured
on MRI should be treated with caution with regard to both
rehabilitation and return to sport. It seems that ‘agility and
stabilisation’ exercises should be added to the rehabilitation
programme.
More high-quality prospective follow-up studies are needed,
using the state-of-the-art imaging and standardised and vali-
dated clinical tests. Especially, studies with adjustment for
known confounders are needed to identify the risk factors for
recurrent hamstring injuries.
Competing interests None.
Provenance and peer review Not commissioned; externally peer reviewed.
REFERENCES
1. Woods C, Hawkins RD, Maltby S, et al. The Football Association Medical
Research Programme: an audit of injuries in professional football–analysis of
hamstring injuries. Br J Sports Med 2004;38:36–41.
2. Orchard J, Seward H. Epidemiology of injuries in the Australian Football League,
seasons 1997-2000. Br J Sports Med 2002;36:39–44.
3. Malliaropoulos N, Papacostas E, Kiritsi O, et al. Posterior thigh muscle injuries
in elite track and field athletes. Am J Sports Med 2010;38:1813–9.
4. Verrall GM, Slavotinek JP, Barnes PG, et al. Clinical risk factors for hamstring
muscle strain injury: a prospective study with correlation of injury by magnetic
resonance imaging. Br J Sports Med 2001;35:435–9; discussion 440.
5. Heiderscheit BC, Sherry MA, Silder A, et al. Hamstring strain injuries:
recommendations for diagnosis, rehabilitation, and injury prevention.
J Orthop Sports Phys Ther 2010;40:67–81.
6. Mason DL, Dickens V, Vail A. Rehabilitation for hamstring injuries.
Cochrane Database Syst Rev 2007;24:CD004575.
7. Foreman TK, Addy T, Baker S, et al. Prospective studies into the causation
of hamstring injuries in sport: a systematic review. Physical Therapy in Sport
2006;7:101–9.
8. Peetrons P. Ultrasound of muscles. Eur Radiol 2002;12:35–43.
9. Gibbs NJ, Cross TM, Cameron M, et al. The accuracy of MRI in predicting
recovery and recurrence of acute grade one hamstring muscle strains within the
same season in Australian Rules football players. J Sci Med Sport 2004;7:248–58.
10. Malliaropoulos N, Isinkaye T, Tsitas K, et al. Reinjury after acute posterior thigh
muscle injuries in elite track and field athletes. Am J Sports Med 2011;39:304–10.
11. Klingele KE, Sallay PI. Surgical repair of complete proximal hamstring tendon
rupture. Am J Sports Med 2002;30:742–7.
12. Koulouris G, Connell D. Hamstring muscle complex: an imaging review.
Radiographics 2005;25:571–86.
13. Slim K, Nini E, Forestier D, et al. Methodological index for non-randomized
studies (minors): development and validation of a new instrument. ANZ J Surg
2003;73:712–6.
14. Downs SH, Black N. The feasibility of creating a checklist for the assessment of
the methodological quality both of randomised and non-randomised studies of
health care interventions. J Epidemiol Community Health 1998;52:377–84.
15. Slavin RE. Best evidence synthesis: an intelligent alternative to meta-analysis.
J Clin Epidemiol 1995;48:9–18.
16. Guyatt GH, Sackett DL, Sinclair JC, et al. Users’ guides to the medical literature.
IX. A method for grading health care recommendations. Evidence-Based
Medicine Working Group. JAMA 1995;274:1800–4.
17. Koulouris G, Connell DA, Brukner P, et al. Magnetic resonance imaging
parameters for assessing risk of recurrent hamstring injuries in elite athletes.
Am J Sports Med 2007;35:1500–6.
18. Verrall GM, Slavotinek JP, Barnes PG, et al. Assessment of physical examination
and magnetic resonance imaging findings of hamstring injury as predictors for
recurrent injury. J Orthop Sports Phys Ther 2006;36:215–24.
19. Sherry MA, Best TM. A comparison of 2 rehabilitation programs in the treatment
of acute hamstring strains. J Orthop Sports Phys Ther 2004;34:116–25.
20. Hägglund M, Waldén M, Bahr R, et al. Methods for epidemiological study of
injuries to professional football players: developing the UEFA model. Br J Sports
Med 2005;39:340–6.
21. Gielen JL, Robinson P, van Dyck P. Muscle injuries. In: Vanhoenacker FM,
M Maas, JL Gielen, ed. Imaging Of Orthopedic Sports Injuries. Berlin: Springer
2007:22–3.
22. Engebretsen AH, Myklebust G, Holme I, et al. Intrinsic risk factors for hamstring
injuries among male soccer players: a prospective cohort study. Am J Sports Med
2010;38:1147–53.
23. Gabbe BJ, Bennell KL, Finch CF, et al. Predictors of hamstring injury at the elite
level of Australian football. Scand J Med Sci Sports 2006;16:7–13.
24. Petersen J, Thorborg K, Nielsen MB, et al. Acute hamstring injuries in Danish
elite football: a 12-month prospective registration study among 374 players.
Scand J Med Sci Sports 2010;20:588–92.
25. Warren P, Gabbe BJ, Schneider-Kolsky M, et al. Clinical predictors of time
to return to competition and of recurrence following hamstring strain in elite
Australian footballers. Br J Sports Med 2010;44:415–9.
26. Davis KW. Imaging of the hamstrings. Semin Musculoskelet Radiol
2008;12:28–41.

Original article
Appendix A Characteristics of the excluded studies with previously described hamstring injury
First author, year
of publication Study population
No. of
subjects* Deﬁnition of previous injury
Age (years)
(mean±SD) % Male
No. of
recurrences
Risk factors for
recurrence
Engebretsen et al22 Norwegian elite soccer
players with recorded
hamstring injury
61 Questionnaire: number,
severity, nature and number of
months since the most recent
hamstring injury
24.8±0.6 100% 10 (16.4%) Previous hamstring
injury, OR=2.19
(1.19–4.03), p=0.01
Gabbe et al23 Elite Australian Rules football
athletes with hamstring
injury resulting in at least one
missed match
31 Questionnaire: hamstring injury
sustained during the previous
12 months
21.8 (17.6–37.1) 100% 10 (32.3%) Previous hamstring
injury, OR=4.30
(1.66–11.15), p=0.003
Age, OR=4.04
(1.24–13.11),
‡p=0.020
Petersen et al24 Danish elite soccer players
with an hamstring injury
32 Recalled hamstring injury in the
last year before this study
17–35† 100% 8 (25%)
Verrall et al4 Elite Australian Rules football
athletes who sustained an
acute Grade 1–3 hamstring
32 Injury occurred within the
last two playing seasons and
resulted in at least one missed
match
20.5±3.4
21.6±3.4
100% 13 (40.6%) Previous hamstring
injury, OR=4.9
(1.6–15.1), p=0.006
Woods et al1 English elite soccer players
with a reported hamstring
injury by their Club medical
staff
749 Sustained during training or
competition that prevented the
injured player from participating
for more than 48 h
17–35† 100% 89 (11.9%)
Warren et al25 Elite Australian Rules football
Athletes with a hamstring
injury resulting in at least one
missed match
59 Clinically diagnosed by medical
personnel and missed at least
one missed match
24 (17–33) 100% 9 (15%) Previous hamstring
injury past
12 months, AOR=16.9
(1.5–261.1), p=0.025
*Number of subjects are those athletes who sustained a hamstring injury.
†Age range of subjects included in the study.
‡Age≥25 years.
AOR, adjusted odds ratio.

doi: 10.1136/bjsports-2011-090317
19, 2011
2012 46: 124-130 originally published online OctoberBr J Sports Med
HM de Visser, M Reijman, MP Heijboer, et al.
a systematic review
Risk factors of recurrent hamstring injuries:
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