SYSTEMATIC REVIEW
Incidence of Running-Related Injuries Per 1000 h of running
in Different Types of Runners: A Systematic Review
and Meta-Analysis
Solvej Videbæk1,2 • Andreas Moeballe Bueno3 •
Rasmus Oestergaard Nielsen3 • Sten Rasmussen1,2
Published online: 8 May 2015
 The Author(s) 2015. This article is published with open access at Springerlink.com
Abstract
Background
No systematic review has identiﬁed the in-
cidence of running-related injuries per 1000 h of running in
different types of runners.
Objective
The purpose of the present review was to
systematically search the literature for the incidence of
running-related injuries per 1000 h of running in different
types of runners, and to include the data in meta-analyses.
Data Sources
A search of the PubMed, Scopus, SPOR-
TDiscus, PEDro and Web of Science databases was conducted.
Study Selection
Titles, abstracts, and full-text articles
were screened by two blinded reviewers to identify
prospective cohort studies and randomized controlled trials
reporting the incidence of running-related injuries in
novice runners, recreational runners, ultra-marathon run-
ners, and track and ﬁeld athletes.
Study Appraisal and Synthesis Methods
Data were ex-
tracted from all studies and comprised for further analysis.
An adapted scale was applied to assess the risk of bias.
Results
After screening 815 abstracts, 13 original articles
were included in the main analysis. Running-related injuries
per 1000 h of running ranged from a minimum of 2.5 in a
study of long-distance track and ﬁeld athletes to a maximum
of 33.0 in a study of novice runners. The meta-analyses
revealed a weighted injury incidence of 17.8 (95 % conﬁ-
dence interval [CI] 16.7–19.1) in novice runners and 7.7
(95 % CI 6.9–8.7) in recreational runners.
Limitations
Heterogeneity in deﬁnitions of injury, deﬁni-
tion of type of runner, and outcome measures in the included
full-text articles challenged comparison across studies.
Conclusion
Novice runners seem to face a signiﬁcantly
greater risk of injury per 1000 h of running than recre-
ational runners.
Key Points
‘Injuries per 1000 h of running’ is an important and
useful measure of association that enables
comparison of the risk of injury across studies.
Novice runners are at signiﬁcantly higher risk of
injury 17.8 (95 % CI 16.7–19.1) than recreational
runners, who sustained 7.7 (95 % CI 6.9–8.7)
running-related injuries per 1000 h of running.
More studies on ultra-marathon runners and track
and ﬁeld athletes are needed in order to calculate
weighted estimates.
1 Introduction
Running is one of the most popular and accessible sport
activities worldwide [1, 2]. It can be performed with
minimal equipment, and by a broad variety of people in
Electronic supplementary material
The online version of this
article (doi:10.1007/s40279-015-0333-8) contains supplementary
material, which is available to authorized users.
& Solvej Videbæk
solvejandersen@hotmail.com
1
Department of Orthopaedic Surgery Research Unit, Science
and Innovation Center, Aalborg University Hospital, Aarhus
University, 18–22 Hobrovej, 9000 Aarhus, Denmark
2
Department of Clinical Medicine, Aalborg University,
Aalborg, Denmark
3
Section of Sport Science, Department of Public Health,
Faculty of Health Science, Aarhus University, Room 438,
Dalgas Avenue 4, 8000 Aarhus, Denmark
123
Sports Med (2015) 45:1017–1026
DOI 10.1007/s40279-015-0333-8
almost every part of the world. In the US, more than
40,000,000 people run [2], and in Denmark and The
Netherlands approximately 25 and 12.5 % of the popula-
tion, respectively, run on a regular basis [3, 4].
Running-related injuries affect many runners. Unfortu-
nately, the exact number of injuries is hard to identify
because various studies have provided results on the
prevalence and incidence of running-related injuries using
different measures of association [5, 6]. To name a few,
injuries have been reported as the number of injuries per
1000 km [7, 8]; proportion of injuries in a population [9];
number of injured runners per 100 runners [10]; and
number of injured runners per 1000 h of running [11, 12].
The inconsistent use of such measures in the literature
makes comparison of injury data difﬁcult across studies.
Injuries per 1000 h of running was highlighted by
Jakobsen et al. [12] as an important measure of association.
They stated that the risk of injury must be related to the
time spent running, in order to make the results from dif-
ferent studies comparable. This is supported in a review
from 2012 by Lopes et al. [13], who emphasize that stan-
dardization of the number of injuries per hour of exposure
is highly needed in running-related injury research.
In a review from 1992, van Mechelen [10] compared the
incidence rates of running-related injuries across a few
studies presenting such results. The results revealed an
injury incidence of 2.5–12.5 injuries per 1000 h of running.
Since then, many studies have reported information on
running-related injuries in different types of runners per
1000 h of running—for instance, novice runners, recre-
ational runners, ultra-marathon runners, and track and ﬁeld
athletes. However, no review has been published which
systematically searched the literature for studies with in-
formation on the incidence of running-related injuries in
different types of runners per 1000 h of running.
The purpose of the present review was to systematically
review the literature for the incidence of running-related
injuries in novice runners, recreational runners, ultra-
marathon runners, and track and ﬁeld athletes per 1000 h of
running. A secondary objective was to compare the injury
rates across different types of runners per 1000 h of run-
ning and include the data in meta-analyses.
2 Methods
2.1 Search Strategy
Five databases (PubMed, Scopus, SPORTDiscus, PEDro
and Web of Science) were searched electronically, without
restriction on date of publication, to identify studies that
included data regarding running-related injury incidences
per 1000 h of running. The search was performed in
collaboration with a certiﬁed librarian at Aarhus University
Library, Denmark. Full details of the electronic search
strategy for PubMed are provided in the electronic sup-
plementary material (ESM) Appendix S1. Additional
studies and trials were identiﬁed by checking references of
included full-text articles and published reviews within the
running injury thematic. Full-text articles, which were not
included after searching the databases, were included
afterwards if they, to the authors’ knowledge, had infor-
mation about injuries per 1000 h of running.
2.2 Study Selection
The screening of eligible studies was performed by two
reviewers (SV and AMB), in two steps. In step 1, all ab-
stracts were evaluated according to pre-speciﬁed inclusion
and exclusion criteria. Inclusion criteria for abstracts con-
sisted of the following: subjects were children, novice
runners, recreational runners, elite runners, cross-country
runners, orienteers, and/or triathletes; the study was based
on original research (prospective cohort studies and ran-
domized controlled trials); the article was written in Eng-
lish or Danish; and the abstract included data regarding
running-related injuries per 1000 h of running, or indicated
that such data might be available in the full-text article.
Exclusion criteria included the following: subjects were
military or army recruits; studies in which participants
were predominantly exposed to different types of sports
other than running; original study designs consisted of
cross-sectional studies, case–control studies, case series
and case reports; and studies did not include original re-
search, for instance reviews.
All abstracts were evaluated independently by each of
the two reviewers and either included or excluded. In cases
of disagreement between the two blinded reviewers (SV
and AMB), a third reviewer (RON) made the ﬁnal decision
of selection.
In step 2, the two reviewers (SV and AMB) read all full
texts included in step 1 as well as the full texts of the
additional articles identiﬁed in the reference lists. The
following criteria were used to ﬁnally include or exclude
full-text articles. Inclusion criteria for full-text articles:
must include ﬁndings from which it is possible to extract
data on running-related injuries per 1000 h of running;
articles without data on injuries per 1000 h of running, but
containing data on the incidence of injuries per 1000 km.
Exclusion criteria: studies in which participants were pre-
dominantly exposed to different types of sports other than
running and, consequently, running-related injuries could
not be distinguished from other sport injuries; if injuries
per 1000 h were estimated per leg and not per individual;
and data on injuries per 1000 h of running were missing,
data on number of events and time at risk were unavailable,
1018
S. Videbæk et al.
123
and the corresponding author was unable to provide these
data after being contacted by e-mail.
Each reviewer (SV and AMB) processed the articles
individually and, in cases of disagreement, they followed a
consensus decision-making process. In cases where they
did not reach a consensus, a third reviewer (RON) made the
ﬁnal judgment.
2.3 Data Collection
The study characteristics of the included full-text articles
were described to gain insight into the homogeneity of the
study populations and deﬁnitions of running-related injuries.
The following data were collected: author and year of pub-
lication; study design; type of runners; sample size used in
the analysis; description of the study population; and
deﬁnition of the running-related injury (Table 1). Estimates
of the incidence of running-related injuries per 1000 h and
per kilometres were extracted from all studies for further
analysis. Three studies provided estimates of running-related
injuries per 1000 h without 95 % conﬁdence intervals (CIs)
and without presenting the raw data needed to calculate these
[12, 14, 15]. The corresponding authors were contacted and
data were received from two of them [14, 15], which enabled
the inclusion of these results in the meta-analyses.
The study populations of the included studies were
categorized into one of four types of runners: novice run-
ners; recreational runners; ultra-marathon runners; and
track and ﬁeld athletes. This categorization was made to
enable comparison of results across studies.
Some studies reported the incidence of running-related
injuries per 1000 miles [7, 8, 16] but these results were
converted into running-related injuries per 1000 km using
an online converter [17].
2.4 Risk of Bias Assessment
The tool used for assessing risk of bias of the included
studies was chosen after thorough consideration of the ad-
vantages and disadvantages of the available methods for
evaluating bias. The studies included both prospective co-
hort studies and randomised controlled trials. The main
purpose of this review was to measure the incidence of
running-related injuries per 1000 h of running. The causes
of running-related injuries were not of interest, thus
minimizing the importance of methods of randomization for
the quality of outcome. Quality assessment by one single
tool was therefore possible for both designs. The tool used
to assess the risk of bias of the included studies was a
version of the Newcastle Ottawa Scale, a tool modiﬁed by
Saragiotto et al. [18] to evaluate studies undertaking re-
search on runners. The tool contains 11 criteria designed to
assess the risk of bias, and uses a star rating system to
indicate the quality of a study (see ESM Appendix S2 for a
description of each criterion in the original version of the
quality assessment tool modiﬁed for runners [18]). Certain
modiﬁcations were applied to specify the tool used to assess
the risk of bias on the parameter of concern in our review—
the incidence of running-related injuries. Three of the 11
criteria were excluded. Item 4 was excluded because an
exposed versus non-exposed cohort was irrelevant as long
as the total study population was exposed to running; item 7
was excluded because it was linked to item 4; and item 11
concerned the risk of association and was removed because
these measures relate to research on associations. In item 3
the wording ‘average runners in the community’ was re-
worded to ‘average type of runners researched’, meaning
that the article received a star if the study population were
representative of the type of runner (novice runners,
recreational runners, ultra-marathon runners, or track and
ﬁeld athletes) described according to item 1. The criteria
adopted to assess risk of bias were (1) description of runners
or type of runner; (2) deﬁnition of the running-related in-
jury; (3) representativeness of the exposed cohort; (4)
ascertainment of exposure; (5) demonstration that outcome
of interest was not present at the start of the study; (6)
assessment of outcome; (7) was follow-up long enough for
outcomes to occur; and (8) adequacy of follow-up of co-
horts. The risk of bias assessment was carried out by two
researchers (SV and AMB) in a blinded process and, in
cases of disagreement, they went through a consensus-
making process. Only studies with estimates on injury in-
cidence per 1000 h were quality scored since this outcome
represented the main analysis.
3 Results
A total of 3172 articles were identiﬁed through the data-
base searches. Among these articles, 2357 were duplicates,
as determined by the reference program RefWorks. Next,
815 titles and abstracts were evaluated in step one of the
selection process. Of these, 69 full-text articles were in-
cluded and evaluated according to the inclusion and ex-
clusion criteria in step two of the selection process, of
which 58 were excluded. In Fig. 1, the selection process is
visualised in a ﬂowchart. By checking reference lists, one
additional study was included [14]. In addition, the authors
knew of one article that was not included in the search but
in which the relevant information was incorporated [26].
This article was also included. Finally, 13 articles that
presented data on running-related injuries per 1000 h of
running were included—eight prospective cohort studies
and ﬁve randomized controlled trials. Overall, ten studies
provided estimates on running-related injuries per 1000 km
and these were used for a subanalysis.
Incidence of Running-Related Injuries
1019
123
Table 1 Description of studies
References,
country of origin
Study design (follow-
up)
Study population
Baseline characteristics
Musculoskeletal injury deﬁnition
Novice runners
Bovens et al.
[25], The
Netherlands
Prospective cohort
study (81 weeks)
73 Novice runners with little or no running
experience
Age above 20 years. Only volunteers without
persisting injuries were accepted. (58 men and 15
women)
Any physical complaint developed in relation with
running activities and causing restriction in running
distance, speed, duration or frequency
Bredeweg et al.
[24], The
Netherlands
Randomised
controlled trial
(9 weeks plus
additional 4 weeks
for 211 runners)
362 (171?191) All participants had not been
running on a regular basis in the previous
12 months
Age range 18–65 years. No injury of the lower
extremity within the preceding 3 months
Any musculoskeletal complaint of the lower extremity
or lower back causing restriction of running for at
least a week
Buist et al. [11],
The
Netherlands
Prospective cohort
study (8 weeks)
629 Runners who had signed up for 4-mile
running event. 474 novice runners who
either restarted running or had no running
experience. 155 recreational runners
Age above 18 years
Any musculoskeletal pain of the lower limb or back
causing a restriction of running for at least 1 day
Buist et al. [20],
The
Netherlands
Randomized
controlled trial (8
and 13 weeks)
486 Novice runners who had not been
running on a regular basis in the previous
12 monthsa
Age range 18–65 years. No injury of the lower
extremity within the preceding 3 months
Any self-reported running-related musculoskeletal pain
of the lower extremity or back causing a restriction of
running for at least 1 week (three scheduled
trainings)
Nielsen et al.
[26],
Denmark
Prospective cohort
study (12 months)
930 Novice runners who had not been
running on a regular basis in the previous
12 monthsa
Healthy novice runners age range 18–65 years with
no injury in the lower extremities or back 3 months
preceding baseline investigation. Not participating
in other sports for more than 4 h/week
Any musculoskeletal complaint of the lower extremity
or back causing a restriction of running for at least
1 week
Recreational runners
Jakobsen et al.
[12],
Denmark
Randomised
controlled trial
(12 months)
41 Recreational long-distance runners. Had
all taken part in marathon races and
intended to take part in at least two
marathons during the year of investigation
19 Men and 2 women aged 24–56. No runner had any
symptoms or objective signs of overuse injury at the
start of the investigation
Any injury to the musculoskeletal system that was
sustained during running and prevented training or
competition
Malisoux
et al. [14],
Luxembourg
Prospective cohort
study (22 weeks)
264 Recreational runners. Mean regularity of
runningc in the last 12 months = 9.4–10.8
Healthy participants above 18 years old with any
level of ﬁtness
A physical pain or complaint located at the lower limbs
or lower back region, sustained during or as a result
of running practice and impeding planned running
activity for at least 1 day
Theisen
et al. [15],
Luxembourg
Randomised
controlled trial
(5 months)
247 Recreational runners
Healthy and uninjured leisure-time runners, aged
above 18 years. Participants having more than 6
accumulated months of regular trainingb
Any ﬁrst-time pain sustained during or as a result of
running practice and impeding normal running
activity for at least 1 day
Van Mechelen
et al. [28],
The
Netherlands
Randomised
controlled trial
(16 weeks)
421 Recreational runners running at least
10 km/week all year-round
Healthy, no current injury, not home from work at
sick leave, not performing sport as a part of their
profession
Any injury that occurred as a result of running and
caused one or more of the following: (1) the subject
had to stop running, (2) the subject could not run on
the next occasion, (3) the subject could not go to
work the next day, (4) the subject needed medical
attention, or (5) the subject suffered from pain or
stiffness during 10 subsequent days while running
1020
S. Videbæk et al.
123
Table 1 continued
References,
country of origin
Study design (follow-
up)
Study population
Baseline characteristics
Musculoskeletal injury deﬁnition
Wen et al. [23],
USA
Prospective cohort
study (32 weeks)
MH group:108 recreational runners
previously running a mean of 24.94 km/
weekb. However 8.3 % of these were
novice runners with no running experience
Members of a running group with the purpose to
prepare its members to run a marathon
Answering yes to having had ‘‘injury or pain’’ to an
anatomic part; answering yes to having had to stop
training, slow pace, stop intervals, or otherwise
having had to modify training; and a ‘‘gradual,’’
versus ‘‘immediate’’, onset of the injury or a self-
reported diagnosis that is generally considered an
overuse injury
Ultra marathon runners
Krabak et al.
[21], USA
Prospective cohort
study (7 days)
396 Experienced runners who have
completed marathon or ultraendurance
events
Age range 18–64 years
A disability sustained by a study participant during the
race, resulting in a medical encounter by the medical
staff
Track and ﬁeld athletes
Bennell et al.
[22],
Australia
Prospective cohort
study (12 months)
95 Competitive track and ﬁeld athletes
(throwers and walkers excluded)
Age range 17–26 years. Training at least three times a
week, when uninjured
Any musculoskeletal pain or injury that resulted from
athletic training and caused alteration of normal
training mode, duration, intensity or frequency for
1 week or more
Lysholm et al.
[19], Sweden
Prospective cohort
study (12 months)
60 Track and ﬁeld athletes. Sprinters,
middle-distance runners and
longdistance/marathon runners running in
club and competing
Previous experience of training (7 h per week or
more) varied between 1 and 32 years
Any injuries that markedly hampered training or
competition for at least 1 week
MH mileage-hours
a 10km total in all training sessions in the previous 12 months
b Miles were converted to km [17]
c Regular training (at least once a week)
Incidence of Running-Related Injuries
1021
123
The year of publication for the included studies ranged
from 1987 to 2014, and the studies represented populations
in
Australia,
Denmark,
Luxembourg,
Sweden,
The
Netherlands, and the USA. The follow-up periods ranged
from 7 days to 81 weeks. Eight studies used a time-loss
deﬁnition of injury; one study deﬁned an injury as a need
for medical attention; and the remaining four studies used a
mixture of time loss, physical pain, and the need for
medical attention in the deﬁnition of injury.
Across studies, the primary purpose was to compare the
incidence of running-related injuries per 1000 h of running.
Five studies reported this estimate in novice runners; ﬁve
studies in recreational runners; one study in ultra-marathon
runners; and two studies in track and ﬁeld athletes. The
estimates ranged from 2.5 [19] to 33.0 [20] running-related
injuries per 1000 h of running. Two meta-analyses were
performed on the estimates of novice runners and recre-
ational runners, respectively. As one article [12] did not
provide data to calculate 95 % CIs, estimates from nine
studies were included in these quantitative analyses
(Fig. 2). The weighted estimates revealed novice runners
faced a signiﬁcantly greater injury rate of 17.8 (95 % CI
16.7–19.1) than recreational runners, who sustained 7.7
(95 % CI 6.9–8.7) running-related injuries per 1000 h of
running.
Ten studies provided estimates of running-related in-
juries per 1000 km of running, and these results were
pooled in a subanalysis (Table 2). The weighted estimate
revealed an injury incidence of 1.07 (95 % CI 1.01–1.13)
per 1000 km of running.
The risk of bias was assessed for each of the 13 studies
presenting an estimate of the incidence of running-related
Fig. 1 Flowchart visualizing
the selection process of studies
in the systematic review
1022
S. Videbæk et al.
123
injuries per 1000 h of running (Table 3). The criteria most
frequently awarded with a star were description of runners
or type of runners (13/13) and deﬁnition of running-related
injury (13/13). The criteria with the least stars awarded
comprised ascertainment of exposure (6/13) and assess-
ment of outcome (8/13). The average stars awarded to the
articles assessed for risk of bias was 6 out of a total of 8
stars, with a maximum of 8 and a minimum of 3.
4 Discussion
The present review is the ﬁrst to systematically review the
literature on the incidence rate of running-related injuries
in different types of runners. The weighted estimate of 17.8
(95 % CI 16.7–19.1) running-related injuries per 1000 h of
running in novice runners was signiﬁcantly greater than the
incidence rate of 7.7 (95 % CI 6.9–8.7) in recreational
runners. One study reported the incidence of running-
Fig. 2 Meta-analysis performed on the estimates of running-related
injuries per 1000 h in novice runners and recreational runners. aData
on standard error or 95 % conﬁdence limits were not reported and the
study was therefore not included in the meta-analysis. bData on
standard error or 95 % conﬁdence limits were not reported and
therefore no meta-analysis was performed on track and ﬁeld athletes.
CI conﬁdence intervals
Table 2 Running-related injuries per 1000 km of running
References
Runners
(n)
Injuries
(n)
Estimate
(RRI per
1000 km)
95 % CI
Bennell et al. [22]
95
130
0.58
0.5, 0.7
Bovens et al. [25]
73
174
0.86
0.7, 1.0
Fields et al. [7]
40
17
0.18
0.1, 0.3
Gerlach et al. [8]
86
47
0.22
0.2, 0.3
Jakobsen et al. [12]
41
50
0.62
0.4, 0.9
Krabak et al. [21]
396
217
2.28
2.0, 2.6
Nielsen et al. [27]
58
13
2.85
1.7, 4.9
Nielsen et al. [26]
930
294
1.64
1.5, 1.8
Van Mechelen et al.
[28]
421
49
0.44
0.3, 0.6
Wen et al. [23]
108
49
0.76
0.6, 0.9
Weighted estimate
2248
1040
1.07
1.01,
1.13
RRI running-related injuries, km kilometres, CI conﬁdence interval
Incidence of Running-Related Injuries
1023
123
related injuries in ultra-marathon runners as 7.2 per 1000 h
[21]. In track and ﬁeld athletes, two studies reported the
incidences of running-related injuries from 2.5 to 26.3 per
1000 h [19, 22]. In the latter, track and ﬁeld athletes were
subdivided into sprinters, middle-distance runners, and
long-distance runners, which may be relevant as the re-
ported running-related injury incidence per 1000 h was
greater in sprinters and middle-distance runners than in
long-distance runners [19].
In Fig. 2, a summary of the results in different types of
runners is presented. The healthy participant effect may
play a role when grouping novice versus recreational run-
ners [23]. In novice runners, the ﬁve studies are heteroge-
neous since the estimates reported by three of the studies
[11, 20, 24] range from 30.1 to 33 and are signiﬁcantly
higher than those reported by the two remaining studies [25,
26]. A possible explanation for the discrepancy is the fol-
low-up time in the respective studies. The non-injured
runners accumulate relatively more exposure time in studies
with a long follow-up, while the injured runners are
censored. This will mathematically explain the overall de-
crease in running-related injuries per 1000 h of running in
studies with longer follow-up amongst novice runners. The
two studies with the lowest incidence of running-related
injuries per 1000 h of running had 81 and 52 weeks of
follow-up, while the three studies with the greatest injury
incidence had follow-up periods of 8–13 weeks (Table 1).
The link between a relatively short follow-up time and a
high incidence rate of running-related injuries versus long
follow-up time and a lower incidence rate of running-re-
lated injuries indicates the possibility that runners classiﬁed
as novice runners at the beginning of a study may rea-
sonably be classiﬁed as recreational runners as time passes.
If novice runners exceed 8–13 weeks without injury, they
may well have adapted to running and face a lower injury
risk after this period, even though they may spend more
time running. Novice runners exceeding 8–13 weeks’ fol-
low-up may then be considered as recreational runners
instead. Based on this, it may be appropriate to identify a
cut-off distinguishing a novice runner from a recreational
runner.
In contrast, the injury incidences are homogeneous in
recreational runners and the weighted estimate is unaf-
fected by bias.
The strengths of the present review are mainly the sys-
tematic search of the literature and the use of meta-analyses
to compare the injury incidences. The searches were per-
formed thoroughly in ﬁve databases, in cooperation with a
certiﬁed librarian. Moreover, all reference lists of the in-
cluded full-text articles were checked for additional studies
and, to the authors’ knowledge, one article [26] was also
able to be included for analysis, although it was not indexed
in any of the ﬁve databases searched. Evaluation of the
quality of all articles presenting estimates of running-re-
lated injuries per 1000 h was accomplished and meta-ana-
lyses on these data were conducted. Thus, the present
systematic review and meta-analyses represent rigorous
evaluations and provide estimates of running-related injury
incidences in novice runners, recreational runners, ultra-
marathon runners, and track and ﬁeld athletes.
The present study has a number of limitations, including
differences in deﬁnitions of injury, deﬁnition of type of
runner, and outcome measures used. First, deﬁnition of
injury varies considerably across studies. Eight studies
used time-loss deﬁnitions, but even within this deﬁnition
there is a lack of consensus of the amount of time needed to
classify time loss from running as a running-related injury.
One study did not deﬁne the amount of time [12], some
studies used 1 day in their deﬁnition [11, 14, 15], while
other studies used 1 week [19, 20, 22, 24]. The only study
[21] solely deﬁning injury as the need for medical attention
was reporting on ultra-marathon runners, and as these data
were collected in real time while the runners participated in
Table 3 Risk of bias assessment
Criteria for assessing risk of bias
1
2
3
4
5
6
7
8
Novice runners
Bovens et al. [25]
*
*
*
0
*
*
*
*
Bredeweg et al. [24] RCT
*
*
*
0
*
0
0
0
Buist et al. [11]
*
*
*
0
0
0
0
0
Buist et al. [20] RCT
*
*
*
0
0
0
0
*
Nielsen et al. [26]
*
*
*
*
*
*
*
*
Recreational runners
Jakobsen et al. [12] RCT
*
*
*
0
*
*
*
0
Malisoux et al. [14]
*
*
*
*
*
0
*
*
Theisen et al. [15] RCT
*
*
0
*
*
*
*
*
Van Mechelen et al. [28] RCT
*
*
*
0
*
*
*
0
Wen et al. [23]
*
*
*
0
0
0
*
*
Ultra-marathoners
Krabak et al. [21]
*
*
*
*
0
*
0
*
Track and ﬁeld athletes
Bennell et al. [22]
*
*
*
*
*
*
*
*
Lysholm et al. [19]
*
*
*
*
0
*
*
0
Only studies providing estimates of the incidence of running-related
injuries per 1000 h were assessed for risk of bias. The criteria adopted
to assess risk of bias were: (1) description of runners or type of
runner; (2) deﬁnition of the running-related injury; (3) representa-
tiveness of the exposed cohort; (4) ascertainment of exposure; (5)
demonstration that outcome of interest was not present at start of
study; (6) assessment of outcome; (7) was follow-up long enough for
outcomes to occur?; (8) adequacy of follow-up of cohorts
RCT randomised controlled trial
* A study was awarded a star for every criterion it fulﬁlled. The more
stars the higher quality
1024
S. Videbæk et al.
123
the ultra-marathon, this method was reasonable. No studies
exclusively deﬁned a running-related injury as physical
pain alone, but, in four studies, physical pain was incor-
porated as part of the injury deﬁnition [16, 22, 25, 28].
Second, runners from the included studies were classiﬁed
into four groups according to the type of runner, enabling
relevant intergroup comparison. No exact deﬁnition of each
category was made, but the baseline characteristics leading
to grouping in one of the four types of runners are listed in
Table 1. Third, the method of gathering data on exposure
time may be questionable. In many studies, runners were
asked to self-report their training exposure in web-based
running diaries. This approach may lead to training hours
or distance being estimated wrongly, possibly because of
recall bias and time spent self-reporting [27]. The quality
assessment tool accounted for this, and awarded no star
when exposure was registered by written self-report (item
5). However, it is questionable whether the risk of bias was,
in reality, higher in the study by Bovens et al. [25], which
received no star in item 5 because running exposure was
collected in diaries, than in the study by Benell et al. [22],
in which a star was awarded for a retrospective personal
interview completed by one of the researchers at the end of
the 12 months of follow-up. Lack of agreement in the way
exposure time was calculated was another challenge. In
some studies [11, 14, 15, 19, 23–25, 28], exposure time was
calculated from the time a participant started the running
programme until the time they reported a running-related
injury (injured runners) or until the end of the programme
(non-injured runners). This way of calculating exposure
time was ideal due to that fact that the same runner could
only contribute exposure time as long as he had not been
injured. Thus, the risk of registering the same injury twice,
if re-occurring, was avoided. Additionally, an injured
person could not add exposure time after the injury oc-
curred, and the number of injuries would be the same as the
number of injured runners. Other studies did not mention
whether study participants were censored if an injury oc-
curred [12, 20, 26]. Further, some studies speciﬁed the
premise that the same runner was included and was con-
tributing exposure time, if running was resumed after an
injury occurrence [21, 22]. Due to the varying ways of
calculating exposure time in the included studies, the most
appropriate comparison of the incidence of running-related
injuries across all included studies was to use the total
number of registered injuries instead of the total number of
injured runners. This approach made it possible for one
runner to ﬁgure twice or more in the pooled count of in-
juries. However, it would have been preferable if all studies
had used the ideal method of calculating exposure time
since this would have meant that one single runner could
not accumulate exposure time after a ﬁrst-time injury and
have a recurrent injury counted twice.
Of the 13 studies providing estimates on running-related
injuries per 1000 h of running, not all provided raw data on
exact exposure time or 95 % CIs of the reported estimates.
Corresponding authors from the respective articles [12, 14,
15, 26] were contacted, and data were received from
Malisoux et al. [14], Theisen et al. [15] and Nielsen et al.
[26]. Moreover, the estimate of 30.1 running-related in-
juries per 1000 h used in the meta-analysis relating to
novice runners derives from the complete study population
of runners in the prospective study of Buist et al. [11].
Overall, 155 of these 629 runners were described as run-
ners already participating in running at baseline, running a
mean of 1.2 h per week. Unfortunately, we were unable to
obtain data that allowed us to calculate estimates for each
of the groups of runners separately. Consequently, we de-
cided to include the estimate of 30.1 running-related in-
juries per 1000 h in the category of novice runners;
therefore, the true incidence of running-related injuries in
novice runners might be even higher.
The present study constitutes a thorough and fully up-
dated literature review presenting data regarding the inci-
dence rates of running-related injuries, and outlining
relevant key issues, which limit the comparison of studies
in running-related injury research. The included meta-
analyses form new estimates showing variations in the
incidence rates of running-related injuries among different
types of runners, and can be used as a starting point in
future running-related injury research.
5 Conclusions
The reported weighted analysis of running-related injury
incidence per 1000 h of running revealed that novice run-
ners face a signiﬁcantly greater risk of injury 17.8 (95 % CI
16.7–19.1) than their recreational peers 7.7 (95 % CI
6.9–8.7). Caution is advisable when comparing estimates
on the incidence of running-related injuries across studies
because of differences in the deﬁnition of injury. Only a
few studies reported injury incidences of ultra-marathon
runners and track and ﬁeld athletes, and no weighted es-
timates were calculated.
Acknowledgments
No sources of funding were used to assist in the
preparation of this review. Solvej Videbæk, Andreas Moeballe
Bueno, Rasmus Oestergaard Nielsen and Sten Rasmussen have no
potential conﬂicts of interest that are directly relevant to the content
of this review.
Open Access
This article is distributed under the terms of the
Creative Commons Attribution 4.0 International License (http://
creativecommons.org/licenses/by/4.0/), which permits unrestricted
use, distribution, and reproduction in any medium, provided you give
appropriate credit to the original author(s) and the source, provide a
link to the Creative Commons license, and indicate if changes were
made.
Incidence of Running-Related Injuries
1025
123
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Incidence of Running-Related Injuries Per 1000 h of running in Different Types of Runners: A Systematic Review and Meta-Analysis.
Videbæk, Solvej,Bueno, Andreas Moeballe,Nielsen, Rasmus Oestergaard,Rasmussen, Sten