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Training guidelines for novice runners are needed to reduce the risk of injury. The purpose of this study was to investigate whether the risk of injury varied in obese and non‐obese individuals initiating a running program at different weekly distances.
A volunteer sample of 749 of 1532 eligible healthy novice runners was included in a 3‐week observational explorative prospective cohort study. Runners were categorized into one of six strata based on their body mass index (BMI) (≤30=low; >30=high) and running distance after 1 week (<3 km = low; 3 to 6 km = medium; >6 km = high). Data was collected for three weeks for the six strata. The main outcome measure was running‐related injury.
Fifty‐six runners sustained a running‐related injury during the 3‐week data collection. A significantly greater number of individuals with BMI>30 sustained injuries if they ran between 3 to 6 km (cumulative risk difference (CRD) = 14.3% [95%CI: 3.3% to 25.3%], p<0.01) or more than 6 km (CRD = 16.2% [95%CI: 4.4% to 28.0%], p<0.01) the first week than individuals in the reference group (low distance and low BMI). The effect‐measure modification between high running distance and BMI on additive scale was positive (11.7% [‐3.6% to 27.0%], p=0.13). The number of obese individuals needed to change their running distance from high to low to avoid one injury was 8.5 [95%CI: 4.6 to 52].
Obese individuals were at greater risk of injury if they exceeded 3 km during the first week of their running program. Because of a considerable injury risk compared with their non‐obese peers, individuals with a BMI>30 may be well advised to begin running training with an initial running distance of less than 3 km (1.9 miles) the first week of their running regime. Large‐scale trials are needed to further describe and document this relationship.
Level of Evidence:
Level 2b
PMCID: PMC4060311  PMID: 24944852
Body mass index; distance; injury risk; Running
Background and Purpose:
Many researchers acknowledge the importance of “training errors” as the main cause of running‐related injuries. The purpose of this clinical commentary is to present a theoretical framework for the assumption that some running‐related injuries among rear‐foot strikers develop due to rapidly changing running volume, while others develop due to rapidly changing running pace.
Description of Topic with Related Evidence:
Evidence from clinical and experimental studies is presented to support the assertion that rapid change in running volume may lead to the development of patellofemoral pain syndrome, iliotibial band syndrome, and patellar tendinopathy, while change in running pace may be associated with the development of achilles tendinopathy, gastrocnemius injuries, and plantar fasciitis.
Discussion/Relation to Clinical Practice:
If this assertion is correct, bias may be prevented in future studies by categorizing injuries into volume or pacing injuries. However, more work is needed to provide further evidence in support of this approach. Future investigations of the link between training patterns and injury development should be designed as large‐scale prospective studies using objective methods to quantify training patterns.
Level of evidence:
PMCID: PMC3625796  PMID: 23593555
Etiology; running pace; running‐related injury; training volume
3.  Predictors of Running-Related Injuries Among 930 Novice Runners 
Orthopaedic Journal of Sports Medicine  2013;1(1):2325967113487316.
To identify persons at high risk of sustaining running-related injuries, an evidence-based understanding of the risk factors associated with injury is needed.
To identify demographic and behavioral risk factors associated with running-related injuries.
Study Design:
Observational prospective cohort study with a 1-year follow-up.
Exposures including sex, age, body mass index (BMI), behavior (Type A Self-Rating Inventory [TASRI]), running experience, other sports activity, previous running-related injuries, and other injuries not related to running were assessed prior to or at baseline. The outcome of interest was a running-related injury, defined as any musculoskeletal complaint of the lower extremity or back caused by running that restricted the amount of running (volume, duration, pace, or frequency) for at least 1 week. All participants quantified their running volume by global positioning system (GPS) and used a neutral running shoe. Time to first injury for each exposure variable was analyzed using a generalized linear model, with cumulative kilometers of the training sessions as the time scale.
A total of 930 individuals were included in the study, of which 254 sustained a running-related injury during a total of 155.318 km of running. By calculating the cumulative injury risk differences (cIRDs) [95% confidence intervals] after 500 km of running, the TASRI Type B behavior (cIRD, 11.9% [−0.5%; 23.3%]; P = .04) was found to be a significant predictor of injury, while age between 45 and 65 years (cIRD, 14.7% [−2.1%; 31.5%]; P = .08) and previous injuries not related to running (cIRD, 11.1% [−0.2%; 22.4%]; P = .05) were considered clinically interesting, although not statistically significant. In addition, χ2 test results across 4 BMI groups also revealed a borderline significant relationship (P = .06). No significant or clinically relevant relationships were found for sex (P = .42), previous running-related injury (P = .47), running experience (P = .30), and other sports activities (P = .30).
The findings of the present study suggest BMI >30 kg/m2, age between 45 and 65 years, noncompetitive behavior, and previous injuries not related to running are associated with increased risk of injury among novice runners, while BMI <20 kg/m2 was protective. Still, the role of the risk factors in the causal mechanism leading to injury needs to be investigated.
PMCID: PMC4555503  PMID: 26535228
running-related injury; novice; BMI; behavior; age
The purpose of this systematic review was to examine the link between training characteristics (volume, duration, frequency, and intensity) and running related injuries.
A systematic search was performed in PubMed, Web of Science, Embase, and SportDiscus. Studies were included if they examined novice, recreational, or elite runners between the ages of 18 and 65. Exposure variables were training characteristics defined as volume, distance or mileage, time or duration, frequency, intensity, speed or pace, or similar terms. The outcome of interest was Running Related Injuries (RRI) in general or specific RRI in the lower extremity or lower back. Methodological quality was evaluated using quality assessment tools of 11 to 16 items.
After examining 4561 titles and abstracts, 63 articles were identified as potentially relevant. Finally, nine retrospective cohort studies, 13 prospective cohort studies, six case-control studies, and three randomized controlled trials were included. The mean quality score was 44.1%. Conflicting results were reported on the relationships between volume, duration, intensity, and frequency and RRI.
It was not possible to identify which training errors were related to running related injuries. Still, well supported data on which training errors relate to or cause running related injuries is highly important for determining proper prevention strategies. If methodological limitations in measuring training variables can be resolved, more work can be conducted to define training and the interactions between different training variables, create several hypotheses, test the hypotheses in a large scale prospective study, and explore cause and effect relationships in randomized controlled trials.
Level of evidence:
PMCID: PMC3290924  PMID: 22389869
Duration; frequency; injuries; intensity; running; training; volume
5.  The design of the run Clever randomized trial: running volume, −intensity and running-related injuries 
Injury incidence and prevalence in running populations have been investigated and documented in several studies. However, knowledge about injury etiology and prevention is needed. Training errors in running are modifiable risk factors and people engaged in recreational running need evidence-based running schedules to minimize the risk of injury. The existing literature on running volume and running intensity and the development of injuries show conflicting results. This may be related to previously applied study designs, methods used to quantify the performed running and the statistical analysis of the collected data. The aim of the Run Clever trial is to investigate if a focus on running intensity compared with a focus on running volume in a running schedule influences the overall injury risk differently.
The Run Clever trial is a randomized trial with a 24-week follow-up. Healthy recreational runners between 18 and 65 years and with an average of 1–3 running sessions per week the past 6 months are included. Participants are randomized into two intervention groups: Running schedule-I and Schedule-V. Schedule-I emphasizes a progression in running intensity by increasing the weekly volume of running at a hard pace, while Schedule-V emphasizes a progression in running volume, by increasing the weekly overall volume. Data on the running performed is collected by GPS. Participants who sustain running-related injuries are diagnosed by a diagnostic team of physiotherapists using standardized diagnostic criteria. The members of the diagnostic team are blinded. The study design, procedures and informed consent were approved by the Ethics Committee Northern Denmark Region (N-20140069).
The Run Clever trial will provide insight into possible differences in injury risk between running schedules emphasizing either running intensity or running volume. The risk of sustaining volume- and intensity-related injuries will be compared in the two intervention groups using a competing risks approach. The trial will hopefully result in a better understanding of the relationship between the running performed and possible differences in running-related injury risk and the injuries developed.
Trial registration
Clinical Trials NCT02349373 – January 23, 2015.
PMCID: PMC4842282  PMID: 27107810
Running; Musculoskeletal pain; Leg injuries; Athletic injuries; Recreational runners; Running schedule; Injury prevention; Running-related Injuries; Running volume; Running intensity
6.  Collagen content in the vastus lateralis and the soleus muscle following a 90-day bed rest period with or without resistance exercises 
spaceflight seems associated with deterioration of the function of the skeletal muscles. Since muscle collagen is critical for muscle function, an improved understanding of the content of the muscle collagen during long-term inactivity seems important. Bed-rest with in-bed resistance training serves as a proxy for the conditions in space. Therefore, ground-based studies may improve the understanding of the consequences of long-term inactivity.
the purpose is to compare the change in collagen protein in the vastus lateralis (VL) and the soleus (SOL) muscle amongst persons exposed to a 90-day bed rest with or without resistance exercise.
an explorative analysis was completed based on data from a randomized, controlled trial. The intervention group (BRE, SOL n=4, VL n=8) performed supine-based squat exercises, whereas the controls (BE, SOL n=6, VL n=12) remained inactive during follow-up. Muscle biopsies from vastus lateralis and soleus were taken at baseline (pre) and after 90-days’ follow-up (post). Muscle collagen (μg collagen/mg protein) was quantified. Two-way repeated measurements ANOVA was used to compare the interaction between the intervention (BRE/BR) and time (pre/post) for each muscle.
the collagen content of VL was similar between pre and post in the BRE group (−3.8 μg collagen/mg protein [95% CI: −22.0; 14.4], p=0.68) while it rose amongst individuals in the BR group (14.9 μg collagen/mg protein [95% CI: −0.01; 29.7], p=0.05). The difference of 18.66 [95% CI: −6.5; 43.9] between BRE and BR across time was, however, not significant (p=0.14). No significant reduction in SOL muscle collagen content was observed from pre to post in the BR group (−9.3 μg collagen/mg protein [95% CI: −24.9; 6.4], p=0.25) or in the BRE group (−6.5 μg collagen/mg protein [95% CI: −25.6; 12.6], p=0.50). There was no difference in the effect of BR versus BRE over time (mean difference −2.78 μg collagen/mg protein [95% CI: −29.7; 24.1], p=0.82).
muscle collagen content in the VL or SOL muscle does not seem to differ after a 90-day bed rest period with or without squat exercises.
PMCID: PMC4762644  PMID: 26958541
exercise; bed rest; spaceflight; collagen; muscle
Disc golf is rapidly increasing in popularity and more than two million people are estimated to regularly participate in disc golf activities. Despite this popularity, the epidemiology of injuries in disc golf remains under reported.
The purpose of the present study was to investigate the prevalence and anatomic distribution of injuries acquired through disc-golf participation in Danish disc golf players.
The study was a cross-sectional study conducted on Danish disc-golf players. In May 2015, invitations to complete a web-based questionnaire were spread online via social media, and around disc-golf courses in Denmark. The questionnaire included questions regarding disc-golf participation and the characteristics of injuries acquired through disc golf participation. The data was analyzed descriptively.
An injury prevalence of 13.3% (95% CI: 6.7% to 19.9%) was reported amongst the 105 disc-golf players who completed the questionnaire. The anatomical locations most commonly affected by injury were the shoulder (31%) and the elbow (20%). Injuries affecting the players at the time of completion of the questionnaire had a median duration of 240 days (IQR 1410 days), and the majority (93%) had a gradual onset.
A 13.3% point prevalence of injury was reported. Most injuries occurred in the shoulder and elbow regions, and were gradual in onset. Injuries affecting the players at the time of data collection had median symptomatic duration of 240 days.
Levels of Evidence
PMCID: PMC4739042  PMID: 26900508
Disc golf; epidemiology; frisbee golf; injury; overuse
8.  Incidence of Running-Related Injuries Per 1000 h of running in Different Types of Runners: A Systematic Review and Meta-Analysis 
Sports Medicine (Auckland, N.z.)  2015;45(7):1017-1026.
No systematic review has identified the incidence of running-related injuries per 1000 h of running in different types of runners.
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, SPORTDiscus, 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 runners, and track and field athletes.
Study Appraisal and Synthesis Methods
Data were extracted from all studies and comprised for further analysis. An adapted scale was applied to assess the risk of bias.
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 % confidence interval [CI] 16.7–19.1) in novice runners and 7.7 (95 % CI 6.9–8.7) in recreational runners.
Heterogeneity in definitions of injury, definition of type of runner, and outcome measures in the included full-text articles challenged comparison across studies.
Novice runners seem to face a significantly greater risk of injury per 1000 h of running than recreational runners.
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.
PMCID: PMC4473093  PMID: 25951917
In clinical practice, joint kinematics during running are primarily quantified by two‐dimensional (2D) video recordings and motion‐analysis software. The applicability of this approach depends on the clinicians’ ability to quantify kinematics in a reliable manner. The reliability of quantifying knee‐ and hip angles at foot strike is uninvestigated.
To investigate the intra‐ and inter‐rater reliability within and between days of clinicians’ ability to quantify the knee‐ and hip angles at foot strike during running.
Eighteen recreational runners were recorded twice using a clinical 2D video setup during treadmill running. Two blinded raters quantified joint angles on each video twice with freeware motion analysis software (Kinovea 0.8.15)
The range from the lower prediction limit to the upper prediction limit of the 95% prediction interval varied three to eight degrees (within day) and nine to 14 degrees (between day) for the knee angles. Similarly, the hip angles varied three to seven degrees (within day) and nine to 11 degrees (between day).
The intra‐ and inter rater reliability of within and between day quantifications of the knee‐ and hip angle based on a clinical 2D video setup is sufficient to encourage clinicians to keep using 2D motion analysis techniques in clinical practice to quantify the knee‐ and hip angles in healthy runners. However, the interpretation should include critical evaluation of the physical set‐up of the 2D motion analysis system prior to the recordings and conclusions should take measurement variations (3‐8 degrees and 9‐14 degrees for within and between day, respectively) into account.
Level of evidence:
PMCID: PMC4387722  PMID: 25883863
kinematics; knee‐ and hip angles; motion‐analysis software; reliability; running
10.  A Prospective Study on Time to Recovery in 254 Injured Novice Runners 
PLoS ONE  2014;9(6):e99877.
Describe the diagnoses and the time to recovery of running-related injuries in novice runners.
Prospective cohort study on injured runners.
This paper is a secondary data analysis of a 933-person cohort study (DANO-RUN) aimed at characterizing risk factors for injury in novice runners. Among those sustaining running-related injuries, the types of injuries and time to recovery is described in the present paper. All injured runners were diagnosed after a thorough clinical examination and then followed prospectively during their recovery. If they recovered completely from injury, time to recovery of each injury was registered.
A total of 254 runners were injured. The proportion of runners diagnosed with medial tibial stress syndrome was 15%, 10% for patellofemoral pain, 9% for medial meniscal injury, 7% for Achilles tendinopathy and 5% for plantar fasciitis. Among the 220 runners (87%) recovering from their injury, the median time to recovery was 71 days (minimum  = 9 days, maximum  = 617 days).
Medial tibial stress syndrome was the most common injury followed by patellofemoral pain, medial meniscal injury and Achilles tendinopathy. Half of the injured runners were unable to run 2×500 meters without pain after 10 weeks. Almost 5% of the injured runners received surgical treatment.
PMCID: PMC4055729  PMID: 24923269
The purpose of this study was to investigate if the risk of injury declines with increasing weekly running volume before a marathon race.
The study was a retrospective cohort study on marathon finishers. Following a marathon, participants completed a web‐based questionnaire. The outcome of interest was a self‐reported running‐related injury. The injury had to be severe enough to cause a reduction in distance, speed, duration or frequency of running for at least 14 days. Primary exposure was self‐reported average weekly volume of running before the marathon categorized into below 30 km/week, 30 to 60 km/week, and above 60 km/week.
A total of 68 of the 662 respondents sustained an injury. When adjusting for previous injury and previous marathons, the relative risk (RR) of suffering an injury rose by 2.02 [95% CI: 1.26; 3.24], p < 0.01, among runners with an average weekly training volume below 30 km/week compared with runners with an average weekly training volume of 30‐60 km/week. No significant differences were found between runners exceeding 60 km/week and runners running 30‐60 km/week (RR=1.13 [0.5;2.8], p=0.80).
Runners may be advised to run a minimum of 30 km/week before a marathon to reduce their risk of running‐related injury.
Level of Evidence:
PMCID: PMC3625790  PMID: 23593549
Running‐related injury; marathon; risk factors; running volume.
12.  Classification of the height and flexibility of the medial longitudinal arch of the foot 
The risk of developing injuries during standing work may vary between persons with different foot types. High arched and low arched feet, as well as rigid and flexible feet, are considered to have different injury profiles, while those with normal arches may sustain fewer injuries. However, the cut-off values for maximum values (subtalar position during weight-bearing) and range of motion (ROM) values (difference between subtalar neutral and subtalar resting position in a weight-bearing condition) for the medial longitudinal arch (MLA) are largely unknown. The purpose of this study was to identify cut-off values for maximum values and ROM of the MLA of the foot during static tests and to identify factors influencing foot posture.
The participants consisted of 254 volunteers from Central and Northern Denmark (198 m/56 f; age 39.0 ± 11.7 years; BMI 27.3 ± 4.7 kg/m2). Navicular height (NH), longitudinal arch angle (LAA) and Feiss line (FL) were measured for either the left or the right foot in a subtalar neutral position and subtalar resting position. Maximum values and ROM were calculated for each test. The 95% and 68% prediction intervals were used as cut-off limits. Multiple regression analysis was used to detect influencing factors on foot posture.
The 68% cut-off values for maximum MLA values and MLA ROM for NH were 3.6 to 5.5 cm and 0.6 to 1.8 cm, respectively, without taking into account the influence of other variables. Normal maximum LAA values were between 131 and 152° and normal LAA ROM was between -1 and 13°. Normal maximum FL values were between -2.6 and -1.2 cm and normal FL ROM was between -0.1 and 0.9 cm. Results from the multivariate linear regression revealed an association between foot size with FL, LAA, and navicular drop.
The cut-off values presented in this study can be used to categorize people performing standing work into groups of different foot arch types. The results of this study are important for investigating a possible link between arch height and arch movement and the development of injuries.
PMCID: PMC3354337  PMID: 22340625
Medial longitudinal arch; Longitudinal arch angle; Navicular drop; Feiss line
Lower limb injuries are a large problem in athletes. However, there is a paucity of knowledge on the relationship between alignment of the medial longitudinal arch (MLA) of the foot and development of such injuries. A reliable and valid test to quantify foot type is needed to be able to investigate the relationship between arch type and injury likelihood. Feiss Line is a valid clinical measure of the MLA. However, no study has investigated the reliability of the test.
The purpose was to describe a modified version of the Feiss Line test and to determine the intra- and inter-tester reliability of this new foot alignment test. To emphasize the purpose of the modified test, the authors have named it The Navicular Position Test.
Intra- and inter-tester reliability were evaluated of The Navicular Position Test with the use of ICC (interclass correlation coefficient) and Bland-Altman limits of agreement on 43 healthy, young, subjects.
Inter-tester mean difference -0.35 degrees [–1.32; 0.62] p = 0.47. Bland-Altman limits of agreement –6.55 to 5.85 degrees, ICC = 0.94. Intra-tester mean difference 0.47 degrees [–0.57; 1.50] p = 0.37. Bland-Altman limits of agreement –6.15 to 7.08 degrees, ICC = 0.91.
The present data support The Navicular Position Test as a reliable test of the navicular bone position during rest and loading measured in a simple test set-up.
The Navicular Position Test was shown to have a high intraday-, intra- and inter-tester reliability. When cut off values to categorize the MLA into planus, rectus, or cavus feet, has been determined and presented, the test could be used in prospective observational studies investigating the role of the arch type on the development of various lower limb injuries.
PMCID: PMC3163999  PMID: 21904698
Foot; Feiss Line; reliability; alignment; pronation

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