Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review * COMMENTARY

Abstract

The purpose of this study was to present a systematic overview of published reports on the incidence and associated potential risk factors of lower extremity running injuries in long distance runners. An electronic database search was conducted using the PubMed-Medline database. Two observers independently assessed the quality of the studies and a best evidence synthesis was used to summarise the results. The incidence of lower extremity running injuries ranged from 19.4% to 79.3%. The predominant site of these injuries was the knee. There was strong evidence that a long training distance per week in male runners and a history of previous injuries were risk factors for injuries, and that an increase in training distance per week was a protective factor for knee injuries.

Full text

REVIEW
Incidence and determinants of lower extremity running injuries
in long distance runners: a systematic review
R N van Gent, D Siem, M van Middelkoop, A G van Os, S M A Bierma-Zeinstra, B W Koes
...................................................................................................................................
Br J Sports Med 2007;41:469–480. doi: 10.1136/bjsm.2006.033548
The purpose of this study was to present a systematic overview
of published reports on the incidence and associated potential
risk factors of lower extremity running injuries in long distance
runners. An electronic database search was conducted using
the PubMed–Medline database. Two observers independently
assessed the quality of the studies and a best evidence synthesis
was used to summarise the results. The incidence of lower
extremity running injuries ranged from 19.4% to 79.3%. The
predominant site of these injuries was the knee. There was
strong evidence that a long training distance per week in male
runners and a history of previous injuries were risk factors for
injuries, and that an increase in training distance per week was
a protective factor for knee injuries.
.............................................................................
See end of article for
authors’ affiliations
........................
Correspondence to:
Marienke van Middelkoop,
Erasmus MC Rotterdam,
Dr Molewaterplein 50,
Rotterdam, Netherlands;
m.vanmiddelkoop@
erasmusmc.nl
Accepted 13 March 2007
Published Online First
1 May 2007
........................
S
ports activities and exercises are known to
have a positive influence on a person’s
physical fitness, as well as to reduce the
incidence of obesity, cardiovascular disease, and
many other chronic health problems.
1–4
Because of
its easy accessibility, long distance running is
practised by many people and along with the
growing interest in disease prevention it continues
to increase in popularity. However, running may
also cause injuries, especially to the lower extre-
mities. Various studies have reported on the
prevalence and incidence of running injuries
occurring in long distance runners during training
or races.
235
Risk factors contributing to these
injuries have also been reported.
256
To help prevent such injuries it is necessary to
summarise knowledge about potential risk factors.
Thus the primary purpose of this study was to
present an overview of published reports describ-
ing the incidence of various running injuries of the
lower extremities in long distance runners. Our
second aim was to identify risk factors associated
with these running injuries.
METHODS
Search
The PubMed–Medline database, available through
the NCBI (National Center for Biotechnology
Information), was consulted up to January 2006
using search items concerning running injuries
combined with the anatomical sites at which these
injuries occur, and search items excluding specific
publication types in which we were not interested.
The search strategy is specified in the appendix.
Additionally, all references in the articles included
were screened according to the criteria described
below.
Relevant review publications and randomised
controlled trials in Pubmed were searched from
the beginning of the database up to May 2006.
Study criteria
Abstracts
The search in PubMed–Medline produced a group
of abstracts which were screened using the
following criteria:
N
The subject of the study was running injuries to
the lower extremities occurring in long distance
runners. We included only studies where sub-
jects ran >5 km per training or race, or both.
N
The runners were recreational or competitive
runners, but not belonged to the elite group
(which presumably can rely on a better medical
support).
N
The study described epidemiology (prevalence,
incidence) or aetiology (determinants) of lower
extremity running injuries, or both.
N
The study included a study population of at least
10 individuals (cross sectional studies, prospective
cohort studies, retrospective cohort studies, case–
control studies, case series and clinical trials).
N
The study was written in English, Dutch,
German, French, Spanish, Italian, Danish,
Norwegian, Swedish, Icelandic or Indonesian.
Full text articles
Based on this first screening a selection of articles
was made, which was further narrowed down
using the following criteria after reading the full
text of the articles:
Inclusion criteria: prospective cohort studies, cross
sectional studies, retrospective cohort studies with
a follow up period of maximum one month, and
randomised clinical trials.
Exclusion criteria: studies in which the participants
were predominantly exposed to types of sporting
activity other than running (such as triathlon,
military training programmes, and so on), and
studies describing populations, which only take
part in cross country running.
Quality scoring
To analyse the quality of the selected studies we used
the following list of questions: (1) a clear definition
of inclusion criteria; (2) description of demographic
characteristics; (3) use of a prospective study design;
(4) follow up of at least 80% of the included subjects;
(5) information of withdrawals describing their
demographic characteristics.
469
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To examine risk factors appropriately we sought: (6)
measurement of determinants at baseline or independently
from injuries (blinding); (7) presentation of data and statistical
significance (percentages, odds ratios (ORs), relative risks
(RRs), p values); (8) the use of multivariate analysis to adjust
for other risk factors and confounding variables.
The quality score was calculated for each study, based on the
sum of the eight items specified above and scored as positive. It
could therefore range from 0 to 8. Articles were judged as high
quality studies when they had a quality score of 4 or more
(>50% of the maximum attainable score). Two observers
(RNvG and DS) obtained the quality scores of the studies
independently, so that k values could be calculated to describe
the interobserver agreement. The k values both for the
interobserver agreement in studies describing the incidence or
prevalence of lower extremity running injuries (in this
calculation questions 6, 7, and 8 were left out of consideration)
and for the interobserver agreement in studies describing
determinants for these injuries (in this calculation all eight
questions were included) were calculated separately. A k value
of .0.7 indicates a high level of agreement between assessors, a
value between 0.5 and 0.7 a moderate level of agreement, and a
value ,0.5 a poor level of agreement.
7
In case of disagreement,
a final decision was made by a third observer (SMAB-Z).
Analysis
SPSS 10.1 was used to calculate k values of the quality score.
For the determinants of injuries, we calculated some ORs that
were not given in the reports but could be obtained from the
raw data. To summarise ORs and RRs, a best evidence synthesis
was used, because clinical and statistical homogeneity across
the studies was absent. The level of evidence was ranked based
on the guidelines of Van Tulder et al
8
and was divided in the
following levels:
N
Strong evidence: consistent findings (in >75% of the studies)
among multiple (>2) high quality studies.
N
Moderate evidence: consistent findings (in >75% of the
studies) among one high quality study and multiple low
quality studies.
N
Limited evidence: consistent findings (in >75% of the studies)
among multiple low quality studies or one high quality
study.
N
Conflicting evidence: provided by conflicting findings (fewer
than 75% of the studies reported consistent findings).
Only statistically significant associations were considered as
associated factors.
RESULTS
After examining the 1113 titles and abstracts, 172 articles were
identified as potentially relevant. The full texts of 166 of these
articles were retrieved (this was not possible for six), and were
subsequently evaluated by both observers. Review of the
complete texts excluded 155 articles, because they did not
meet our criteria; thus 11 articles were selected in our study. In
addition to this selection, we included six more articles after
searching through the references of these 11 selected articles.
Therefore our final selection comprised 17 articles (1.5%). Most
of these were published in English, but there were two foreign
language publications (one German and one Norwegian).
Description of the studies
Thirteen prospective cohort studies
9–21
and four retrospective
cohort studies
22–25
were included. The study characteristics of
the selected studies were described to obtain insight into the
homogeneity of the study populations (table 1).
The follow up period in the studies ranged from 1 day to
18 months. The studies contained runners participating in
specific training programmes or races from 4 km to a full
marathon. Two studies included runners who were followed
during one season of training and race participation.
913
In one
of the studies, runners wished to be notified of upcoming road
races, but their exact training programme or race attendance
was unknown.
14
The proportions of subjects analysed ranged
from 41.8% to 100%. Both the population characteristics and
the injury definition differed between the various reports. The
quality score of the studies ranged from 2 to 7 (table 2).
Four studies were judged as of low quality.
11 18 22 24
The
interobserver agreement in studies describing the incidence or
prevalence, or both, of lower extremity running injuries was
moderate, with a k value of 0.60 (agreement in 83% of the
questions), whereas in studies describing determinants for
these injuries the k value of 0.58 showed a moderate level of
agreement (agreement in 82% of the questions). Disagreements
were especially seen in items 2, 4, and 5, whereas in only two
studies were more than two disagreements found.
10 21
Incidence of injuries
The overall incidence of lower extremity injuries found in the
17 studies varied from 19.4% to 79.3%.
9 12 14 19 21–24
In other
studies in which non-lower-extremity injuries were also
described and included in the overall incidence number, the
reported incidence for injuries varied from 26.0% to
92.4%.
10 11 13 17 18 20 25
The predominant site of lower extremity
injuries was the knee, for which the location specific incidence
ranged from 7.2% to 50.0%. Injuries of the lower leg (shin,
Achilles tendon, calf, and heel), foot (also toes), and upper leg
(hamstring, thigh, and quadriceps) were common, ranging
from 9.0% to 32.2%, 5.7% to 39.3%, and 3.4% to 38.1%,
respectively. Less common sites of lower extremity injuries were
the ankle and the hip/pelvis (also groin), ranging from 3.9% to
16.6% and 3.3% to 11.5%, respectively (table 3).
9 10 12–14 16 18–22 24
Only five studies described incidence figures for specific types
of injuries (table 4).
11 15 16 22 25
Two studies also reported the incidence numbers of injuries
presented at medical aid posts during a race: 6.2%
16
and 17.9%
15
of runners participating in a marathon and 3.6% of runners
participating in a half marathon.
15
Determinants of injuries
We divided the determinants into four categories: systemic
factors (table 5), running/training related factors (table 6),
health factors (table 7), and lifestyle factors (table 8). Based on
the large heterogeneity in the studies, pooling of the results was
not possible, leaving us to present a best evidence synthesis.
Systemic factors
Greater age was reported to be a significant risk factor for
incurring running injuries in four high quality studies.
15 17 19 21
However, in two high quality studies greater age was reported
to be a significant protective factor.
17 25
Therefore there is
conflicting evidence over whether greater age is a risk factor for
overall lower extremity running injuries. There was, however,
limited evidence that greater age was positively associated with
front thigh injuries but protective against calf injuries.
17
The only significant association for overall lower extremity
running injuries showed a positive relation with female sex.
15
There was also limited evidence that female runners were more
prone to incur hip injuries, and limited evidence that male
runners were at greater risk of getting hamstring or calf
injuries.
17
There was limited evidence that a lower leg length difference
was associated with overall lower extremity running injuries,
and that a higher left tubercle–sulcus angle or a greater knee
470 van Gent, Siem, van Middelkoop, et al
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Table 1 Study characteristics
Author, year
of publication
Study design
(follow up period) Running type No included/analysed (%) Description of population Injury definition
Quality score
of study
Taunton et al,
2003
19
Prospective cohort Recreational runners, registered
in training clinics, interested in
either completing a 10 km race
or improving their existing race
time.
1020/844 (82.7%) 24.4% M: 75.6% F Experiencing pain only after exercise (grade 1); pain
during exercise (grade 2); pain during exercise and
restricting distance or speed (grade 3); pain
preventing all running (grade 4).
6
(12–13 wk) M, age (y): 12.3% ,30, 51.5% 31–49,
19.1% 50–55, 17.2% .56.
M, BMI: 1.0% ,19, 55.1% 20–26, 41.0%
.26
F, age (y): 18.6% ,30, 63.6% 31–49,
11.5% 50–55, 6.3% .56.
F, BMI: 4.3% ,19, 69.8% 20–26, 16.7%
.26
Lun et al,
2004
12
Prospective cohort Recreational runners, running
more than 20 km/week.
153/87 (56.8%) 50.6% M: 49.4% F Any musculoskeletal symptom of the lower limb that
required a reduction or stoppage of a runners’
normal training.
6
38.0 y
Steinacker
et al, 2001
18
Prospective cohort
(6 months)
58 runners in training for a
marathon, of whom 42 did
participate in a marathon.
58/58 (100%) of whom
42 ran a marathon.
62.1% M: 37.9% F Injuries and having had to skip training. 3
M: 43.6 y, 76.3 kg, BMI 23.1
F: 45.5 y, 61.7 kg, BMI 23.3
Satterthwaite
et al, 1999
17
Prospective cohort
(1 week)
Runners participating in a
marathon.
1054/875* (83.0%) Age (y): 5.7% ,25, 12.5% 25–29, 17.4%
30–34, 21.3% 35–39, 43.2% >40
(1) Injuries and other health problems sustained by
runners attending the medical aid posts.
6
Satterthwaite
et al, 1996
16
1054/916 (86.9%) 80.3% M: 19.7% F` (2) Specific health problems using a matrix of 13
body sites and 11 problem types sustained both
during or immediately after the marathon and in
the seven days following the marathon.
7
38.6¡9.8 y (range 19–74 y)
Wen et al,
1998
21
Prospective cohort
(32 wk)
Runners participating in a
training programme for a
marathon.
355/255 (71.8%) 42.0% M: 58.0% F Answering yes to having had ‘‘injury or pain’’ to an
anatomical part; answering yes to having had to stop
training, slow pace, stop intervals, or otherwise having
had to modify training; and a ‘‘gradual’’ v
‘‘immediate’’ onset of the injury or a self reported
diagnosis that is generally considered an overuse injury.
6
41.8¡10.8 y
M: 176.8¡6.3 cm, 79.3¡11.7 kg
F: 164.3¡7.3 cm, 64.1¡12.3 kg
Bennell et al,
1996
9
Prospective cohort
(12 months)
Track and field athletes
during one season.
111/95 (85.6%) of whom
21 were long distance
runners.
52.3% M: 47.7% F` (1) Stress fracture (diagnosis on a bone or CT scan
was made using a blinded protocol)
6
M: 20.3¡2.0 y, 179.3¡6.1 cm,
70.3¡7.8 kg
(2) An injury was defined as any musculoskeletal pain
or injury that resulted from athletic training and
caused alteration of normal training in mode, duration,
intensity, or frequency for one week or more.
F: 20.5¡2.2 y, 167.4¡6.1 cm,
59.0¡5.6 kg
Macera et al,
1989
14
Prospective cohort
(12 months)
Runners wishing to be notified
of road races.
966/583 (60.4%) 83.2% M: 16.8% F A self-reported ‘‘muscle, joint or bone
problem/injury’’ of the lower extremities (foot, ankle,
Achilles tendon, calf, shin, knee, thigh or hip) that
the participant attributed to running. The problem had
to be severe enough to cause a reduction in weekly
distance, a visit to a health professional, or the use
of medication.
6
M: 41.6¡9.5 y (range 13–75 y),
178.6¡6.5 cm (range 154.9–195.6 cm),
73.6¡8.7 kg (range 39.6–104.6 kg), BMI
23.0¡2.2 (range16.5–31.0)
F: 36.1¡8.2 y (range 22–64 y),
164.3¡6.0 cm (range 149.9–180.3 cm),
54.5¡6.1 kg (range 40.9–76.4 kg), BMI
25.8¡2.4 (range 20.2–34.6)
Walter et al,
1989
20
Prospective cohort
(12 months)
Runners participating in a 4,
5.6, 16, or 22.4 km race
and all adult members of the
organizing clubs.
1680/1288 (76.6%) 76.5% M: 23.5% F Injuries, defined as ‘‘severe enough to reduce the
number of miles run, take medicine, or see a health
professional.
7
M, age (y): 9.8% 14–19, 19.0% 20–29,
38.7% 30–39, 24.4% 40–49, 8.1% >50
F, age (y): 16.2% 14–19, 28.4% 20–29,
41.3% 30–39, 10.2% 40–49, 4.0% >50
Bovens et al,
1989
10
Prospective cohort
(18 months)
Runners participating in a
training programme for a
marathon with three phases
(finished with a 15, 25, and
42 km race, respectively).
115/73 (63.5%) 79.5% M: 20.5% F Any physical complaint developed in relation to
running activities and causing restriction in running
distance, speed, duration, or frequency was
considered to be an injury.
7
M: 35.2¡7.9 y, 178.1¡5.7 cm,
71.9¡6.4 kg
F: 33.5¡6.7 y, 165.6¡5.1 cm,
57.5¡5.0 kg
Lower extremity running injuries 471
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Author, year
of publication
Study design
(follow up period) Running type No included/analysed (%) Description of population Injury definition
Quality score
of study
Lysholm &
Wiklander,
1987
13
Prospective cohort
(12 months)
Competitive athletes of two
track and field athletes during
one season.
60/60 (100%) of whom
28 were long distance
runners.
28 M long distance/marathon runners Any injuries that markedly hampered training or
competition for at least one week.
5
34.5¡7.4 y
Kretsch et al,
1984
11
Prospective cohort
(1 day)
Runners participating in a
marathon.
1098/459 (41.8%) 75.8% M: 24.2% F (1) Injuries occurring immediately before the race;
medical problems experienced during the race; pains
or ‘‘unusual’’ symptoms developing after the race.
4
(2) A description of the principal symptoms and any
other symptoms present at a first aid station.
Nicholl &
Williams,
1982
15
Prospective cohort
(1 day)
Runners participating in a
marathon.
3462/3429 (99.0%) of
whom 1140 ran a half
marathon and 2289 ran
a full marathon.
93.8% M: 6.2% F1 Clinical details of all contacts made by runners with
any of the 12 first aid posts.
6
Macera et al,
1991
23
Retrospective cohort
(1 month)
Runners participating in a 5 or
10 km race, or in a marathon.
534/509 (95.3%) of whom
347 ran a 5 or 10 km race
and 162 ran a marathon.
77.0% M: 23.0% F Musculoskeletal problems: development of problems
in foot, ankle, Achilles tendon, calf or shin, knee,
thigh, or hip, regardless of cause, that required a
consultation with a physician or reduction in usual
running mileage. These problems may or may not
be due to running.
4
M marathon (37.2%): 36 y, 69.0%,45 y
F 5 & 10 km (62.8%): 80.0% ,45 y
M marathon (13.7%): 33 y, 94.0% ,45 y
F 5 and 10 km (86.3%): 87.0% ,45 y
Jakobsen et al,
1989
22
Retrospective cohort
(1 day)
Runners participating in a half
or a full marathon.
831/831 (100%) 88.0% M: 12.0% F Injuries: ankle sprains; overuse/stress injuries of feet,
ankle, lower leg, knee, or thigh; blisters.
3
34.6¡9.75 y
Maughan &
Miller, 1983
24
Retrospective cohort
(1 week)
Runners participating in a
marathon.
497/449 (90.3%) 95.0% M: 5.0% F Injuries incurred during training and the race itself. 3
32¡8y`
Nicholl &
Williams,
1982
25
Retrospective cohort
(10 days)
Runners participating in a half
or a full marathon.
614/557 (90.7%) of whom
242 ran a half marathon
and 312 ran a full marathon.
83.2% M: 16.8% F Medical problems in the week after the race. 6
Half marathon: 73.6% M, 26.4% F, 74.4%
,40 y, 25.6% >40 y
Full marathon: 90.7% M, 9.3% F,
76.6% ,40 y, 23.4% >40 y
*This population was used to determine risk factors.
This group was selected from the 1219 runners who are known to have started the marathon.
`Description of population concerned all included subjects.
1Description of population concerned the 4559 entrants of the marathon, not the 3462 registered starters; significantly more over-40 s (82%) were registered than younger entrants (75%) (p,0.05).
The injury definition was extracted from the results section in the article, while this is normally obtained from the materials and methods section.
BMI, body mass index (kg/m
2
); CT, computed tomography; F, female; M, male; y, years.
Table 1 Continued
472 van Gent, Siem, van Middelkoop, et al
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varus were risk factors for shin injuries.
21
Additionally, there
was limited evidence that a higher heel valgus was protective
against knee and foot injuries, while a lower heel valgus and a
higher right arch index were protective factors only for knee
injuries.
21
There was limited evidence that static biomechanical
lower limb alignment was not related to lower limb injuries.
12
Male runners whose height was 1.70 metres or more were
reported to be at a significantly greater risk of suffering new
injuries.
20
Thus there was limited evidence for the positive
association between male runners of greater height and lower
extremity running injuries.
There was limited evidence that greater weight was
protective against foot injuries,
21
and there was also limited
evidence that a body mass index of .26 kg/m
2
protected male
runners from overall lower extremity running injuries.
19
Running/training related factors
Only one high quality study reported that male runners were at
statistically significant greater risk when running more than
two days a week,
20
whereas conflicting evidence was found for
female runners for this association.
19 20
Running a whole year
through without a break from training was reported to be a
significant risk factor for incurring a lower extremity running
injury. As there was only one study that reported this
association, there was limited evidence for the association.
20
There was conflicting evidence for an association between an
increase of training and overall lower extremity running
injuries.
17 21
An increase of training distance per week was
reported as a significant protective factor against knee injuries
in two high quality studies, which means there is strong
evidence for this association.
17 21
There was limited evidence
that an increase in days of training per week was a risk factor
for incurring front thigh injuries,
17
that an increase of training
distance per week was a risk factor for hamstring injuries,
17
and
that an increase of hours training per week was a protective
factor for knee as well as foot injuries.
21
Two high quality studies reported training for more than
64 km/week as a significant risk factor for male runners
incurring lower extremity running injuries,
14 20
while in female
runners this association was only reported in one high quality
study.
20
Thus there was stronger evidence for an association
between higher training distance for male runners than for
female runners. There was no evidence for an association
between training less than 60 km in the last three months
before a marathon and overall lower extremity running
injuries, because this association was only significant in one
low quality study.
11
Lower extremity injuries in one high quality study were
associated with longer race distances (marathon races com-
pared with 5 and 10 km races).
23
Thus there was limited
evidence that participating in races of greater distance was a
risk factor for incurring these injuries.
There was conflicting evidence for an association between
inexperience in running and overall lower extremity inju-
ries.
14 15 17 21 25
An association between hamstring or knee
injuries and participation in a marathon for the first time was
reported in one high quality study,
17
while foot injuries were
associated with more experienced runners in another high
quality study.[32] Thus there was limited evidence for
inexperience as a risk factor for hamstring or knee injuries or
as a risk factor for foot injuries.
Two high quality studies reported no significant associations
between the use of a warm up and lower extremity injuries,
implying that there is no such association.
14 20
There was limited evidence for an association between female
runners running on concrete surfaces and lower extremity
injuries.
14
There was no significant association between male
runners running on a specific surface and lower extremity
injuries and between training on hilly terrain, or running in the
dark or in the morning and these injuries, implying that there is
no association between these determinants and lower extremity
running injuries.
14
For an association between competitive running and lower
extremity running injuries there was limited evidence for male
runners only.
20
There was limited evidence for an association between shin
injuries and the use of a greater number of shoes for running.
21
There was limited evidence that a shoe age of four to six
months was a protective factor for lower extremity running
injuries in male runners, but was a risk factor in female
runners.
19
No significant association between pace and lower extremity
running injuries was reported, implying that there is no
association.
21 22
Health factors
A history of previous injuries was reported to be a significant
risk factor for injuries in multiple high quality studies.
14 20 21 23
Table 2 Quality scores of the articles selected
Articles
Questions
OutcomeDefinition Demographics
Prospective
design
80%
follow up Withdrawals Blinding
Data
presentation
Multivariate
analysis
Taunton et al, 2003
19
++ + +––++6
Lun et al, 2004
12
++ + – +++–6
Satterthwaite et al, 1999
17
++ + +––++6
Wen et al, 1998
21
++ + – ++++7
Bennell et al, 1996
9
++ + +– ++ –6
Macera et al, 1991
23
++ – + ––++5
Macera et al, 1989
14
++ + – + – ++6
Walter et al, 1989
20
++ + – +++–6
Jakobsen et al, 1989
22
++ ––– –+ –3
Kretsch et al, 1984
11
+ – + –– –+ –3
Nicholl & Williams, 1982
15
++ + +– ++ –6
Nicholl & Williams, 1982
25
++ – + – ++ –5
Steinacker et al,2001
18
– ++– – na na na 2
Satterthwaite et al, 1996
16
++ + +–nanana4
Bovens et al, 1989
10
++ + – + na na na 4
Lysholm & Wiklander, 1987
13
++ + +–nanana4
Maughan & Miller, 1983
24
++ ––– nanana2
Questions that could be answered with yes are ‘‘+’’; those answered with no or unknown are ‘‘2’’; ‘‘+’’ scores 1 and ‘‘–’’ scores 0.
na, not applicable.
Lower extremity running injuries 473
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Table 3 Overall and location specific incidence of injuries
Author, year of
publication
Incidence of injuries Location specific incidence of injuries
Overall Men (%) Women (%) Foot (%) Ankle (%)
Lower
leg (%) Knee (%)
Upper
leg (%)
Hip/pelvis
(%)
LEX, not
stated (%)
Other sites,
not LEX (%)
Other sites,
not stated (%)
Taunton et al, 2003
19
28.0% (236 injuries by 236/840 runners) 26.3 28.7 14.0 11.0 26.7 35.2 3.4 9.7
Steinacker et al, 2001
18
46.6% (injuries by 27/58 runners)* during training 41.6 54.5 16.6 50.0 11.1 11.1 11.2
43.9% (injuries by 18/41 runners)* during marathon 38.5 53.3 11.1 16.7 33.4 16.6 22.2
Lun et al, 2004
12
79.3% (injuries by 69/87 runners) 79.5 79.1 15.0 3.9 9.0 7.2 9.0 5.0 3.9
Wen et al, 1998
21
32.9% (84 injuries by 84/255 runners) 16.7 10.7 32.1 31.0 3.6 5.9
Bennell et al, 1996
9
31.6% (9 injuries by 6/19 runners) 20.0 44.4 100
Satterthwaite et al,
1996
16
92.4% (2671 injuries by 846/916 runners) during
or immediately after marathon
22.6 16.0 8.8 28.9 23.7
78.9% (1905 injuries by 723/916 runners) in the
7 days following the marathon
14.8 20.5 12.7 38.1 13.9
Macera et al, 1989
14
51.5% (injuries by 300/583 runners)* 52.0 49.0 22.0 24.0 54.0
Walter et al, 1989
20
48.4% (747 new+ recurrent injuries by 620/1281
runners)
49.3 45.5 15.7 15.0 12.0 26.6 7.2 8.8 10.6 4.0
26.0% (427 new injuries by 333/1281 runners) 26.8 23.3 18.5 16.6 14.8 25.5 8.2 8.7 5.4 2.3
Bovens et al, 1989
10
84.9% (174 injuries by 62/73 runners) 5.7 12.1 32.2 24.7 6.3 11.5 7.5
58.0% in 15 km phase
60.0% in 25 km phase
67.0% in 42 km phase
Lysholm & Wiklander,
1987
13
57.1% (18 injuries by 16/28 runners) 33.3 66.6%
Kretsch et al, 1984
11
92.0% (injuries by 422/459 runners)* of whom 11%
had injuries for more than 1 day after the marathon
Macera et al, 1991
23
21.6% (injuries by 75/347 runners)* in 5 and 10 km
race
24.0 15.8
35.2% (injuries by 57/162 runners)* in the marathon 34.2 43.8
26.1% (injuries by 133/509 runners)* in both races 28.1 19.7
Jakobsen et al, 1989
22
19.4% (193 injuries by 161/831 runners) 6.9 10.8 16.6 26.9 11.4 27.4`
Maughan & Miller,
1983
24
27.2% (122 injuries by 122/449 runners) 39.3 4.9 13.1 32.0 7.4 3.3
Nicholl & Williams,
1982
25
40.1% (injuries by 97/242 runners)* in half marathon 39.3 42.2
65.1% (injuries by 203/312 runners)* in marathon 65.7 58.6
*Total number of injuries is unknown.
Overall incidence of stress fractures obtained in this study; the injuries in this study are all stress fractures.
`These are all blisters; the exact location of the blisters was not given.
LEX, lower extremity.
474 van Gent, Siem, van Middelkoop, et al
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Thus there was strong evidence for an association between a
history of previous injuries and lower extremity running
injuries. For an association between a positive medical history
and these injuries there was only limited evidence.
17
Lifestyle factors
There was limited evidence that drinking alcohol was a risk
factor for incurring blisters or front thigh injuries and that
participation in cycling and aerobics were risk factors for,
respectively, front thigh and hamstring injuries.
17
There was,
however, some evidence that smoking was a protective factor
against blisters.
17
DISCUSSION
Three reviews on running injuries were published more than a
decade ago.
25–27
New studies on running injuries since those
reviews have been incorporated into this systematic review.
Further, in contrast to the methods used in those reviews, we
undertook a systematic search strategy. We also evaluated the
quality of the studies included and carried out a best evidence
synthesis for determinants of lower extremity running injuries.
Thus our review is a rigorous update of earlier reviews and
provides evidence of risk factors for these injuries.
Incidence of injuries
The reported overall incidence of lower extremity running
injuries showed a large range (19.4% to 79.3%). An increase in
the incidence range is mainly seen in studies that also included
non-lower-extremity injuries in their incidence numbers
(19.4% to 92.4%), although higher incidences may partly reflect
higher rate of lower extremity injury. Previous reviews reported
ranges of 24% to 83%,
26
33% to 85%,
27
and 24% to 77%.
28
The most common site of lower extremity injuries was the
knee (7.2% to 50.0%), followed by the lower leg (9.0% to
32.2%), the foot (5.7% to 39.3%), and the upper leg (3.4% to
38.1%). Less common sites of lower extremity injuries were the
ankle (3.9% to 16.6%) and the hip/pelvis (3.3% to 11.5%). Our
results supports Van Mechelen’s conclusion
28
that most of
running injuries are located in the knee.
Determinants of injuries
Only limited evidence was found for some of the systemic,
lifestyle, and health factors as risk factors for running injuries.
These included greater age (a clear cut off point for greater age
could not be observed), sex, lower leg length difference, greater
left tubercle–sulcus angle and greater knee varus, greater height
in male runners, drinking alcohol, participation in cycling and
aerobics, and a positive medical history. We found strong
evidence for a greater training distance per week in male
runners and a history of previous injuries as a risk factor for
both male and female runners. There was also strong evidence
that increased training distance per week was a protective
factor, although only for knee injuries. It remains unclear why
increasing weekly distance is protective for knee injuries.
However, the relation between distance and injury may not
be simple and there may be a fine balance between overuse and
underconditioning among long distance runners. For several
other training/running related factors we only found limited
evidence that they were risk factors (greater training frequency
in male runners, running the whole year through, greater
training distance in female runners, participation in races of
greater distance, women running on concrete surfaces, compe-
titive male runners, increase in days of training per week,
increase in training distance per week, level of experience in
running, use of more shoes for running, and shoe age).
Although limited evidence was found that greater weight and
a body mass index of .26 kg/m
2
were protective factors, this
Table 4 Incidence of injury by specific injury type
Author, year of
publication Group characteristic
Types specific incidence of injuries
Skin lesions
(%)
Pain/stiffness
(%)
Overuse/stress
injuries (%)
Cramps
(%)
Haematomas
(%)
Ankle
sprains (%)
Joint
problems (%)
Tendonitis
(%)
Other, not running
injuries (%)
Other injuries,
not stated (%)
Satterthwaite et al,
1996
16
At medical aid post* 14.5 19.7 14.5 6.6 21.1 23.7
During or immediately
after a marathon
14.9 61.3 8.7 1.0 14.1
In the 7 days following
a marathon
7.6 80.3 2.5 1.8 7.8
Kretsch et al, 1984
11
After a marathon 7.9 44.4 14.5 33.2
Nicholl & Williams
1982
15
During full marathon at
first aid station
15.6 57.6 25.3 1.5
Jakobsen et al,
1989
22
During a half and a full
marathon
27.4 67.5 5.1
Nicholl & Williams,
1982
25
During a half and a full
marathon
10.5 54.1 22.4 13.0
*Type specific distribution of injuries in the 1219 runners who are known to have started the marathon.
Lower extremity running injuries 475
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association may be caused by the fact that in these groups of
runners less training activity is being undertaken.
Limitations
Because of the specific search definition and because the
language restriction we used to identify studies in the PubMed–
Medline database, we may have found fewer studies on
running related injuries than are available. In the studies
identified there was a lack of standard definition of injury. In
some studies running injuries were defined as running related
injuries to the lower extremities, but other studies also included
non-lower-extremity injuries and even problems such as
headache, dehydration, fatigue, and others. Further, different
study designs, differing data collection methods, and differing
methods of determining the denominator might have affected
the incidence rates of the studies. Also, the type of runners
selected for each study varied—usually a specific selection of
runners was made (for example, male runners, recreational
runners, runners in training programmes, race participants).
All these factors may have influenced the final incidence rates
of injuries and the odds ratios and relative risks for the
determinants.
We decided only to include studies that investigated long
distance runners. The studies of Bennell et al
9
and Lysholm and
Wiklander
13
both described a group of track and field athletes;
however, they also described a separate group of long distance/
Table 5 Systemic factors for lower extremity injuries
Determinant Author Injury Specification of determinant Outcome (95% CI)
Age Taunton et al, 2003
19
Overall injuries* F Age .50 y RR = 1.92 (1.11 to 3.33)
New injuries* F Age ,31 y RR = 0.58 (0.34 to 0.97)
Satterthwaite et al, 1999
17
Stiffness and/or pain in front thigh Age 25–29 y (ref ,25 y) OR = 1.42 (0.79 to 2.53)
Stiffness and/or pain in front thigh Age 30–34 y (ref ,25 y) OR = 1.83 (1.04 to 3.22)
Stiffness and/or pain in front thigh Age 35–39 y (ref ,25 y) OR = 1.34 (0.77 to 2.31)
Stiffness and/or pain in front thigh Age >40 y (ref ,25 y) OR = 0.96 (0.56 to 1.63)
Stiffness and/or pain in calf Age 25–29 y (ref ,25 y) OR = 0.60 (0.32 to 1.13)
Stiffness and/or pain in calf Age 30–34 y (ref ,25 y) OR = 0.43 (0.23 to 0.78)
Stiffness and/or pain in calf Age 35–39 y (ref ,25 y) OR = 0.56 (0.31 to 1.01)
Stiffness and/or pain in calf Age >40 y (ref ,25 y) OR = 0.40 (0.23 to 0.73)
Wen et al, 1998
21
Knee injuries Higher age` RR = 2.09 (0.95 to 4.58)
Overall injuries* Higher age (miles)1 RR = 1.08 (0.99 to 1.17)
Lower age (miles)1 RR = 0.39 (0.15 to 0.97)
Macera et al, 1989
14
Lower extremity injuries M, higher age OR = 1.0 (1.0 to 1.0)
M, higher age OR = 1.0 (0.9 to 1.0)
Kretsch et al, 1984
11
Overall injuries* Age 14–20 y (ref >41 y) p,0.025
Nicholl & Williams, 1982
15
Overall injuries* Age 40+ yp,0.05
Macera et al, 1991
23
Lower extremity musculoskeletal
problems
M, higher age OR = 1.0 (1.0 to 1.0)
F, higher age OR = 1.0 (0.9 to 1.1)
Jakobsen et al, 1989
22
Overall injuries Lower age p,0.01
Nicholl & Williams, 1982
25
Overall injuries* Age ,40 y (half marathon) OR = 2.12 (1.13 to 3.98)
Age ,40 y (marathon) OR = 1.31 (0.76 to 2.25)
Sex Satterthwaite et al, 1999
17
Stiffness and/or pain in hamstring M OR = 1.60 (1.04 to 2.47)
Stiffness and/or pain in hip F OR = 1.88 (1.15 to 3.06)
Stiffness and/or pain in calf M OR = 1.86 (1.29 to 2.68)
Bennell et al,1996
9
Stress fractures F OR = 3.20 (0.42 to 24.42)
Macera et al, 1989
14
Lower extremity injuries F OR = 0.89 (0.58 to 1.37)
Nicholl & Williams, 1982
15
Overall injuries* Fp,0.05
Macera et al, 1991
23
Lower extremity musculoskeletal
problems
F (marathon) OR = 1.49 (0.53 to 4.25)
F (5 and 10 km) OR = 0.60 (0.32 to 1.10)
Jakobsen et al, 1989
22
Overall injuries F p.0.05
Nicholl & Williams, 1982
25
Overall injuries* F (half marathon) OR = 1.13 (0.63 to 2.01)
F (marathon) OR = 0.74 (0.34 to 1.61)
Height Walter et al, 1989
20
New injuries* M 170–179 cm (average) (ref ,170) OR = 2.04 (1.15 to 3.46)
M >180 cm (tallest) (ref ,170) OR = 2.30 (1.29 to 3.90)
F 160–169 cm (average) (ref ,160) OR = 1.29 (0.65 to 2.48)
F >170 cm (tallest) (ref ,160) OR = 0.78 (0.32 to 1.97)
Weight Wen et al, 1998
21
Foot injuries Higher weight` RR = 0.94 (0.89 to 0.99)
BMI Taunton et al, 2003
19
Overall injury* M, BMI .26 RR = 0.41 (0.21 to 0.79)
Macera et al, 1989
14
Lower extremity injuries M, BMI (.74th centile) OR = 0.7 (0.5 to 1.2)
M, BMI (,26th centile) OR = 1.2 (0.7 to 1.9)
F, BMI (.74th centile) OR = 3.0 (0.5 to 18.8)
F, BMI (,26th centile) OR = 2.0 (0.6 to 6.6)
Alignment Lun et al, 2004
12
Overall injuries Left subtalar varus CI = 0.2 to 4.2
Wen et al, 1998
21
Overall injuries* Lower leg length difference (h)1 RR = 1.96 (1.07 to 3.58)
Knee injuries Higher arch index (h)1 RR = 0 (0 to 0.37)
Shin injuries Lower heel valgus (miles)1 RR = 0.08 (0.01 to 0.74)
Foot injuries Higher heel valgus (miles)1 RR = 0.09 (0.01 to 0.81)
Higher right arch index (h)1 RR = 0.11 (0.01 to 0.90)
Lower right arch index (h)1 RR = 0.25 (0.05 to 1.20)
Higher left tubercle–sulcus angle (miles)1 RR = 11.02 (2.00 to 60.86)
Higher knee varus (miles)1 RR = 1.09 (1.03 to 1.15)
Higher arch index (h)1 RR = 0 (0 to 8.21)
Higher heel valgus (miles)1 RR = 0.76 (0.58 to 0.98)
Higher heel valgus (h) 1 RR = 0.74 (0.58 to 0.94)
*Not-running injuries and running injuries not involving the lower extremity were included, to establish the outcome.
Represents adjusted OR or RR.
`RRs were calculated dividing the number of injured runners by the total number of runner-weeks accumulated (relative incidence ratios).
1RRs were obtained from special subgroups in which information on distances run (miles) and time spent running (hours) was measured.
BMI, body mass index; CI, confidence interval; F, female; M, male; OR, odds ratio; ref, reference; RR, relative risk; y, years.
476 van Gent, Siem, van Middelkoop, et al
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Table 6 Running/training related factors for lower extremity injury
Determinant Author Injury Specification of determinant Outcome (95% CI)
Training
frequency
Taunton et al, 2003
19
Overall injuries* F, running frequency 1 d/wk RR = 3.68 (1.08 to 12.30)
Macera et al, 1989
14
Lower extremity injuries M, run 6 or 7 d/wk OR = 1.4 (0.8 to 2.5)
Walter et al, 1989
20
New injuries* F, run 6 or 7 d/wk OR = 0.5 (0.1 to 2.1)
M, 3 d running/wk (ref 0–2) OR = 2.93 (1.27 to 6.20)
M, 4 d running/wk (ref 0–2) OR = 2.49 (1.08 to 5.26)
M, 5 d running/wk (ref 0–2) OR = 3.13 (1.38 to 6.46)
M, 6 d running/wk (ref 0–2) OR = 3.66 (1.62 to 7.50)
M, 7 d running/wk (ref 0–2) OR = 5.92 (2.49 to 12.75)
F, 3 d running/wk (ref 0–2) OR = 0.59 (0.15 to 2.22)
F, 4 d running/wk (ref 0–2) OR = 1.91 (0.56 to 5.65)
F, 5 d running/wk (ref 0–2) OR = 1.25 (0.36 to 3.82)
F, 6 d running/wk (ref 0–2) OR = 2.11 (0.62 to 6.12)
F, 7 d running/wk (ref 0–2) OR = 5.50 (1.44 to 17.39)
M, running year round OR = 1.64 (1.12 to 2.35)
F, running year round OR = 2.00 (1.01 to 3.75)
Jakobsen et al, 1989
22
Overall injuries Fewer months training p.0.05
Fewer h/wk p,0.05
Training
alteration
Satterthwaite et al,
1999
17
Stiffness and/or pain in front
thigh
Increase in training of 1 d/wk OR = 1.19 (1.05 to 1.34)
Stiffness and/or pain in
hamstring
Increase in training of 10 km/wk OR = 1.07 (1.02 to 1.13)
Stiffness and/or pain in knee Decrease in training of 10 km/wk OR = 1.13 (1.04 to 1.23)
Wen et al, 1998
21
Overall injuries* Increased h/wk (miles)` RR = 0.57 (0.42 to 0.78)
Increased h/wk (h)` RR = 0.58 (0.45 to 0.73)
Knee injuries Increased miles/wk (miles)` RR = 0.90 (0.82 to 0.99)
Increased h/wk (h)` RR = 0.49 (0.30 to 0.80)
Foot injuries Increased h/wk (miles)` RR = 0.31 (0.15 to 0.63)
Increased h/wk (h)` RR = 0.21 (0.10 to 0.44)
Macera et al, 1991
23
Lower extremity musculoskeletal
problems
M, increased mileage in month before
the race
OR = 1.1 (0.7 to 1.8)
F, increased mileage in month before
the race
OR = 1.6 (0.6 to 4.6)
Training
distance
Macera et al, 1989
14
Lower extremity injuries M, 16.0–31.8 km/wk for preceding 3 m OR = 1.6 (0.8 to 3.0)
M, 32.0–47.8 km/wk for preceding 3 m OR = 1.6 (0.8 to 3.2)
M, 48.0–63.8 km/wk for preceding 3 m OR = 1.7 (0.8 to 3.6)
M, 64.0+ km/wk for preceding 3 m OR = 2.9 (1.1 to 7.5)
F, 16.0–31.8 km/wk for preceding 3 m OR = 2.1 (0.5 to 9.7)
F, 32.0–47.8 km/wk for preceding 3 m OR = 4.2 (0.8 to 21.7)
F, 48.0–63.4 km/wk for preceding 3 m OR = 7.4 (0.9 to 60.3)
F, 64.0+ km/wk for preceding 3 m OR = 3.0 (0.3 to 27.5)
Walter et al, 1989
20
New injuries* M, longest run each wk .8 km OR = 2.49 (1.64 to 3.71)
F, longest run each wk .8 km OR = 1.78 (0.99 to 3.13)
M, 16–30.4 km/wk (ref ,16) OR = 0.88 (0.40 to 1.58)
M, 32–46.4 km/wk (ref ,16) OR = 1.36 (0.77 to 2.35)
M, 48–62.4 km/wk (ref ,16) OR = 1.27 (0.70 to 2.27)
M, >64 km/wk (ref , 16) OR = 2.22 (1.30 to 3.68)
F, 16–30.4 km/wk (ref ,16) OR = 0.98 (0.43 to 2.21)
F, 32–46.4 km/wk (ref ,16) OR = 1.37 (0.58 to 3.23)
F, 48–62.4 km/wk (ref ,16) OR = 1.97 (0.97 to 4.80)
F, >64 km/wk (ref ,16) OR = 3.42 (1.42 to 7.85)
Kretsch et al, 1984
11
Overall injuries* ,60 km/wk in 3 m before marathon p,0.025
Jakobsen et al, 1989
22
Overall injuries More km/wk p,0.01
Race distance Macera et al, 1991
23
Lower extremity musculoskeletal
problems
M, marathon OR = 1.7 (1.0 to 2.8)
F, marathon OR = 4.7 (1.2 to 17.4)
Experience Satterthwaite et al,
1999
17
Stiffness and/or pain in
hamstring
Participation in marathon for first time OR = 1.55 (1.08 to 2.22)
Stiffness and/or pain in knee Participation in marathon for first time OR = 1.66 (1.16 to 2.38)
Wen et al, 1998
21
Overall injuries* Higher experience1 RR = 1.88 (1.16 to 3.05)
Foot injuries Higher experience1 RR = 1.09 (1.03 to 1.15)
Macera et al, 1989
14
Lower extremity injuries M, 0–2 years running experience OR = 2.2 (1.5 to 3.3)
M, 10+ years running experience OR = 1.2 (0.8 to 1.9)
F, 0–2 years running experience OR = 1.4 (0.3 to 6.4)
F, 10+ years running experience OR = 1.7 (0.5 to 6.1)
M, run a marathon during preceding 12 m OR = 1.3 (0.7 to 2.2)
F, run a marathon during preceding 12 m OR = 4.3 (0.7 to 27.0)
Nicholl & Williams,
1982
15
Overall injuries* Any previous experience of running a half
and/or a full marathon
p,0.05
Jakobsen et al, 1989
22
Overall injuries ,5 Years experience p.0.05
Nicholl & Williams,
1982
25
Overall injuries* No previous experience of running a half
and/or a full marathon (half marathon)
OR = 1.66 (0.99 to 2.80)
No previous experience of running a half
and/or a full marathon (marathon)
OR = 1.75 (1.10 to 2.81)
Lower extremity running injuries 477
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marathon runners. Both these studies were included in our
review because they described the results of the long distance
runners separately from the whole track and field athletes
group; thus only the results for the long distance runners were
included in this study.
The results could also be biased by a self selection process of
healthy runners participating in running events or training
programmes in the studies included, or by injured runners not
responding to questionnaires or overreporting of injuries
because of the self reporting nature of some studies.
For some subgroups reported here, there was low power. This
might have influenced our conclusions, based on the best
evidence synthesis. For example, associations were found for
male but not female runners, while the estimate of the
Determinant Author Injury Specification of determinant Outcome (95% CI)
Warm up Macera et al, 1989
14
Lower extremity injuries M, stretch before running OR = 1.1 (0.8 to 5.9)
F, stretch before running OR = 1.6 (0.7 to 3.5)
Walter et al, 1989
20
New injuries* M, usually using stretching (ref always) OR = 0.80 (0.55 to 1.17)
M, sometimes using stretching (ref always) OR = 1.56 (1.10 to 2.21)
M, never using stretching (ref always) OR = 0.87 (0.50 to 1.57)
M, usually using warm up (ref always) OR = 1.03 (0.73 to 1.44)
M, sometimes using warm up (ref always) OR = 1.30 (0.87 to 1.93)
M, never using warm up (ref always) OR = 0.37 (0.19 to 0.81)
F, usually using stretching (ref always) OR = 0.95 (0.48 to 1.96)
F Sometimes using stretching (ref always) OR = 1.78 (0.91 to 3.53)
F, never using stretching (ref always) OR = 0.85 (0.27 to 3.22)
F, usually using warm up (ref always) OR= 0.82 (0.42 to 1.60)
F, sometimes using warm up (ref always) OR = 0.95 (0.47 to 1.96)
F, never using warm up (ref always) OR = 0.55 (0.22 to 1.51)
Circumstances
of training
Macera et al, 1989
14
Lower extremity injuries M, hilly terrain OR = 1.1 (0.7 to 1.6)
M, asphalt surface OR = 1.2 (0.8 to 1.7)
M, run in dark OR = 0.9 (0.6 to 1.3)
M, run in morning OR = 1.1 (0.7 to 1.7)
F, hilly terrain OR = 1.0 (0.4 to 2.5)
F, asphalt surface OR = 1.8 (0.8 to 4.2)
F, run in dark OR = 1.0 (0.4 to 2.7)
F, run in morning OR = 1.4 (0.6 to 3.2)
M, concrete surface OR = 1.4 (0.8 to 2.5)
M, concrete surface OR = 5.6 (1.1 to 29.3)
Type of runner Walter et al, 1989
20
New injuries* M, recreational runner (ref fitness runner) OR = 1.18 (0.84 to 1.66)
M, competitive runner (ref fitness runner) OR = 1.73 (1.21 to 2.49)
F, recreational runner (ref fitness runner) OR = 0.71 (0.37 to 1.40)
F, competitive runner (ref fitness runner) OR = 1.93 (0.97 to 3.89)
Shoe use Taunton et al, 2003
19
Overall injuries* M, running shoe age 4–6 m RR = 0.36 (0.15 to 0.83)
New injuries F, running shoe age 4–6 m RR = 1.74 (1.10 to 2.98)
F, running shoe age 1–3 m RR = 0.61 (0.38 to 0.99)
Wen et al, 1998
21
Shin injuries Higher number of shoes (h)` RR = 6.91 (1.36 to 35.15)
Pace Wen et al, 1998
21
Shin injuries More intervals1 RR = 14.89 (0.50 to 147.33)
Jakobsen et al, 1989
22
Overall injuries Lower pace p = 0.06
*Not-running injuries and running, but not lower extremity, injuries were included to establish the outcome.
Represents adjusted OR or RR.
`RRs were obtained from special subgroups in which information on distances run (miles) and time spent running (hours) was measured.
1RRs were calculated dividing the number of injured runners by the total number of runner-weeks accumulated (relative incidence ratios).
CI, confidence interval; F, female; m, months; M, male; OR, odds ratio; ref, reference; RR, relative risk; wk, week.
Table 6 Continued
Table 7 Health factors for lower extremity injury
Determinant Author Injury Specification of determinant Outcome (95% CI)
History of previous
injuries
Wen et al, 1998
21
Overall injuries* History of previous injuries RR = 2.02 (1.27 to 3.21)`
Shin injuries History of old shin injuries RR = 7.24 (2.40 to 21.82)`
Macera et al, 1989
14
Lower extremity injuries M, new lower extremity injury during the
previous 12 m
OR = 2.7 (2.6 to 2.7)`
F, new lower extremity injury during the
previous 12 m
OR = 1.9 (0.7 to 4.9)`
Walter et al, 1989
20
New injuries* M, injured in previous year OR = 1.69 (1.27 to 2.25)`
F, injured in previous year OR = 2.35 (1.33 to 4.07)`
Kretsch et al, 1984
11
Overall injuries* Number of medical or physical problems
experienced during training
p.0.05
Macera et al, 1991
23
Lower extremity
musculoskeletal problems
M, previous musculoskeletal problems in the
past year
OR = 6.3 (3.7 to 10.8)`
F, previous musculoskeletal problems in the
past year
OR = 7.6 (2.0 to 28.4)`
Medical history Satterthwaite et al,
1999
17
Stiffness and/or pain in
knee
Current medication use OR = 1.56 (1.02 to 2.32)`
Being unwell in last 2 wk before marathon OR = 1.42 (1.03 to 1.95)`
Kretsch et al, 1984
11
Overall injuries* Positive medical history p,0.025
*Not-running injuries and running, but not lower extremity, injuries were included to establish the outcome.
RRs were calculated dividing the number of injured runners by the total number of runner-weeks accumulated (relative incidence ratios).
`Represents adjusted OR or RR.
CI, confidence interval; m, months; OR, odds ratio; RR, relative risk; wk, week.
478 van Gent, Siem, van Middelkoop, et al
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association in both sexes was the same. This probably reflects a
reduced statistical power in the female subgroup.
Fortunately, 12 studies reported the sites where the lower
extremity running injuries occurred. Specific diagnoses, how-
ever, were discussed in only three studies and not even for all
injured runners.
10 11 20
Also the impact of these running injuries
was rarely reported. Very little information was provided on the
duration and severity of these injuries, and there was a lack of
information about health care visits (for example, to general
practitioner, physiotherapist, orthopaedic specialist) or the
treatment used (drugs, rest, operation, other).
Implications
The presence of associations between determinants and
running injuries suggests that advice and education may still
be necessary. An unmodifiable risk factor is a history of
previous injuries. Runners with this risk factor should pay extra
attention to signs of injuries, avoid other determinants of
injuries, and take time to recover fully from their injuries. The
training distance per week is a modifiable risk factor and
therefore runners should preferably not exceed 64 km/week.
Further investigation is necessary, because the incidence of
running injuries in long distance runners is not clear and
knowledge of the specific determinants of these injuries is still
unsatisfactory. Future studies should clearly define the type of
runners included (sprinters, middle distance, or long distance
runners) and also specifically report information about training
characteristics and race participation, so that the results can be
applied on the correct group of runners. Also investigators
should try to use a universal definition of running injury, so
that results can easily be compared.
Likewise the length of observation period needs to be equal in
different studies and the incidence numbers need to be
expressed in comparable units.
Finally, to obtain information on the clinical consequences of
running injuries, details on the duration and severity of these
injuries, as well as information on the use of professional
medical advice and the chosen treatment, is required.
CONCLUSIONS
The reported incidence of running injuries to the lower
extremities in long distance runners varied from 19.4% to
92.4%. The most common site of lower extremity running
injuries was the knee. There is strong evidence that a greater
training distance per week in male runners and a history of
previous injuries are risk factors for lower extremity running
injuries. We recommend further well designed studies on risk
factors for running injuries for male and female runners.
Authors’ affiliations
.......................
R N van Gent, D Siem, M van Middelkoop, A G van Os, S M A Bierma-
Zeinstra, B W Koes, Erasmus MC Rotterdam, Netherlands
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Table 8 Lifestyle factors
Determinant Author Injury Specification of determinant Outcome (95% CI)
Drinking alcohol Satterthwaite et al, 1999
17
Blisters Drinking alcohol >1/m OR = 1.44 (1.01 to 2.05)*
Stiffness and/or pain in front thigh Drinking alcohol >1/m OR = 1.38 (1.01 to 1.88)*
Smoking Satterthwaite et al, 1999
17
Blisters Smoking OR = 0.39 (0.17 to 0.88)*
Participation in other
sports
Satterthwaite et al, 1999
17
Stiffness and/or pain in front thigh Cycling OR = 1.53 (1.13 to 2.06)*
Stiffness and/or pain in hamstring Aerobics OR = 1.74 (1.05 to 2.89)*
*Represents adjusted OR or RR.
CI, confidence interval; m, months; OR, odds ratio.
What is already known on this topic?
N
Besides its positive heath effects, running may also cause
injuries, especially to the lower extremities. Various
studies have reported on the prevalence and incidence
of running injuries occurring in long distance runners
during training or races. Risk factors contributing to the
occurrence of these injuries have also been reported.
What this study adds
N
The incidence of lower extremity running injuries in
published reports ranges from 20% to 79%.
N
The predominant site of these injuries is the knee.
N
There is strong evidence that a long training distance per
week in male runners and a history of previous injuries
are risk factors for running injuries.
Lower extremity running injuries 479
www.bjsportmed.com

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Sports Med 1992;14:320–35.
APPENDIX
SPECIFICATION OF THE SEARCH STRATEGY USED IN
THE PUBMED-MEDLINE DATABASE
(runn*) AND (injur* OR syndrome* OR tend* OR fract* OR
pain* OR fasciitis OR bursitis OR splint* OR tear* OR sprain* OR
strain* OR entrapment* OR ostei* OR osteop* OR osteom* OR
osteoc* OR osteoa* OR rupture* OR arthro* OR arthri* OR
lipoma OR sciatica OR lumbago OR laceration* OR split* OR
tenosynovitis OR blister* OR cramp* OR corn OR callus* OR
edema* OR sesamoiditis OR ganglion* OR rhabdomyolisis OR
hernia* OR muscle soreness OR delayed onset muscle soreness
OR hemorrh* OR ischi* OR neurom* OR abrasion OR wart* OR
mold* OR dislocation* OR damage OR trauma OR displacement
OR periostitis) AND (patell* OR knee* OR tibial* OR fibular* OR
spinal OR lumbar OR plantar OR calcaneal OR achilles* OR
hamstring* OR ligament* OR ankle* OR foot* OR infrapatellar
OR hip OR back OR adductor* OR tigh* OR pubi* OR menisc*
OR toe* OR lower extremity OR shin OR calve* OR neck OR
shoulder OR groin OR ischia* OR sacral OR metatars* OR tars*)
NOT (‘‘addresses’’[Publication Type] OR
‘‘bibliography’’[Publication Type] OR ‘‘biography’’[Publication
Type] OR ‘‘case reports’’[Publication Type] OR ‘‘clinical
conference’’[Publication Type] OR ‘‘comment’’[Publication
Type] OR ‘‘congresses’’[Publication Type] OR
‘‘dictionary’’[Publication Type] OR ‘‘directory’’[Publication
Type] OR ‘‘editorial’’[Publication Type] OR
‘‘festschrift’’[Publication Type] OR ‘‘government
publications’’[Publication Type] OR ‘‘interview’’[Publication
Type] OR ‘‘lectures’’[Publication Type] OR ‘‘legal
cases’’[Publication Type] OR ‘‘legislation’’[Publication Type]
OR ‘‘letter’’[Publication Type] OR ‘‘news’’[Publication Type]
OR ‘‘newspaper article’’[Publication Type] OR ‘‘retracted
publication’’[Publication Type] OR ‘‘retraction of
publication’’[Publication Type] OR ‘‘review’’[Publication
Type] OR ‘‘review literature’’[Publication Type] OR ‘‘review of
reported cases’’[Publication Type] OR ‘‘review,
academic’’[Publication Type] OR ‘‘review,
multicase’’[Publication Type] OR ‘‘review,
tutorial’’[Publication Type] OR ‘‘scientific integrity
review’’[Publication Type] OR ‘‘technical report’’[Publication
Type] OR ‘‘twin study’’[Publication Type] OR ‘‘validation
studies’’[Publication Type]). Limits: Human.
BNF for Children 2006, second annual edition
In a single resource:
N
guidance on drug management of common childhood conditions
N
hands-on information on prescribing, monitoring and administering medicines to children
N
comprehensive guidance covering neonates to adolescents
For more information please go to bnfc.org
...............
COMMENTARY
...............
This is a high quality review which is long overdue. The authors
have included an excellent evaluation of the quality of papers
selected for review process and very good criteria of selected
variables. It is surprising that there is no inclusion of the
strength of either core or hip abduction such as iliotibial band
(ITB) injuries, knee injuries or possibly achilles injuries. The
study allowed evaluation of location but not specific diagnosis.
There is a good discussion of age and gender but not much on
the role of downhill running, which is often attributed to knee
injury (ITB, patellofemoral pain syndrome (PFPS) and patellar
tendinosis). There is also a good discussion of previous injury,
which has been highlighted recently, but not the degree of
rehabilitation from previous injury. Recent biomechanical
analysis points to a synchronous coupling of the lower
extremity, related to the shoe and orthotic—that is, a loss of
variability and capability to adapt to the surface as a factor in
PFPS. See Ryan, MacLean and Taunton’s latest review in Int
Sports Med J.
1
Jack E Taunton
University of British Columbia, Vancouver, BC, Canada;
jtaunton@interchange.ubc.ca
REFERENCE
1 Ryan M, MacLean C, Taunton J. A review of anthropometric, biomechanical,
neuromuscular and training factors associated with injury in runners. Int Sport
Med J 2006;7(2). http://www.ismj.com/default.asp?pageID=562698171&
article=548095859 (accessed 3 July 2007).
480 van Gent, Siem, van Middelkoop, et al
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