Running Injuries Research Articles

Running Injury Paradigms and Their Influence on Footwear Design Features and Runner Assessment Methods: A Focused Review to Advance Evidence-Based Practice for Running Medicine Clinicians.

Many runners seek health professional advice regarding footwear recommendations to reduce injury risk. Unfortunately, many clinicians, as well as runners, have ideas about how to select running footwear that are not scientifically supported. This is likely because much of the research on running footwear has not been highly accessible outside of the technical footwear research circle. Therefore, the purpose of this narrative review is to update clinical readers on the state of the science for assessing runners and recommending running footwear that facilitate the goals of the runner. We begin with a review of basic footwear construction and the features thought to influence biomechanics relevant to the running medicine practitioner. Subsequently, we review the four main paradigms that have driven footwear design and recommendation with respect to injury risk reduction: Pronation Control, Impact Force Modification, Habitual Joint (Motion) Path, and Comfort Filter. We find that evidence in support of any paradigm is generally limited. In the absence of a clearly supported paradigm, we propose that in general clinicians should recommend footwear that is lightweight, comfortable, and has minimal pronation control technology. We further encourage clinicians to arm themselves with the basic understanding of the known effects of specific footwear features on biomechanics in order to better recommend footwear on a patient-by-patient basis.

The Effectiveness of Gait Retraining on Running Kinematics, Kinetics, Performance, Pain, and Injury in Distance Runners: A Systematic Review With Meta-analysis.

To evaluate the effectiveness of running gait retraining on kinematics, kinetics, performance, pain, and injury in distance runners. Intervention systematic review with meta-analysis. Seven electronic databases from inception to March 2021. Randomized controlled trials that (1) evaluated running gait retraining compared to no intervention, usual training, placebo, or standard care and (2) reported biomechanical, physiological, performance, or clinical outcomes. Random-effects metaanalyses were completed, and the certainty of evidence was judged using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria. We categorized interventions into step rate, non-rearfoot footstrike, impact, ground contact time, and multiparameter subgroups. We included 19 trials (673 participants). Moderate-certainty evidence indicated step rate gait retraining increased step rate (SMD 1.03 [95% confidence interval {CI}: 0.63, 1.44]; number of trials (N): 4; I2: 0%) and reduced average vertical loading rate (SMD -0.57 [95% CI, -1.05 to -0.09], N: 3; I2: 0%). Low-certainty evidence indicated non-rearfoot footstrike retraining increased knee flexion at initial contact (SMD 0.74 [95% CI, 0.11 to 1.37]; N: 2; I2: 0%), but did not alter running economy (SMD 0.21 [95% CI, -1.11 to 1.52]; N: 3; I2: 19%).). Low-certainty evidence indicated multiparameter retraining did not alter running economy (SMD 0.32 [-0.39, 1.02]; N: 3; I2: 19%) or performance (SMD 0.14 [95% CI, -4.87 to 4.58]; N: 2; I2: 18%). Insufficient trials reported on pain outcomes. Two trials demonstrated reduced 1-year injury incidence following gait retraining. Gait retraining interventions altered step rate and knee kinematics, lowered vertical loading rates, and did not affect running performance. J Orthop Sports Phys Ther 2022;52(4):192-206. Epub 05 Feb 2022. doi:10.2519/jospt.2022.10585.

Spatiotemporal and Ground-Reaction Force Characteristics as Risk Factors for Running-Related Injury: A Secondary Analysis of a Randomized Trial Including 800+ Recreational Runners

Background: Running biomechanics may play a role in running-related injury development, but to date, only a few modifiable factors have been prospectively associated with injury risk. Purpose: To identify risk factors among spatiotemporal and ground-reaction force characteristics in recreational runners and to investigate whether shoe cushioning modifies the association between running biomechanics and injury risk. Study Design: Case-control study; Level of evidence, 3. Methods: Recreational runners (N = 848) were tested on an instrumented treadmill at their preferred running speed in randomly allocated, standardized running shoes (with either hard or soft cushioning). Typical kinetic and spatiotemporal metrics were derived from ground-reaction force recordings. Participants were subsequently followed up for 6 months regarding running activity and injury. Cox regression models for competing risk were used to investigate the association between biomechanical risk factors and injury risk, including stratified analyses by shoe version. Results: In the crude analysis, greater injury risk was found for greater step length (subhazard rate ratio [SHR], 1.01; 95% CI, 1.00-1.02; P = .038), longer flight time (SHR, 1.00; 95% CI, 1.00-1.01; P = .028), shorter contact time (SHR, 0.99; 95% CI, 0.99-1.00; P = .030), and lower duty factor (defined as the ratio between contact time and stride time; SHR, 0.95; 95% CI, 0.91-0.98; P = .005). In the stratified analyses by shoe version, adjusted for previous injury and running speed, lower duty factor was associated with greater injury risk in those using the soft shoes (SHR, 0.92; 95% CI, 0.85-0.99; P = .042) but not in those using the hard shoes (SHR, 0.97; 95% CI, 0.91-1.04; P = .348). Conclusion: Lower duty factor is an injury risk factor, especially for softer shoe use. Contrary to widespread beliefs, vertical impact peak, loading rate, and step rate were not injury risk factors in recreational runners. Registration: NCT03115437 (ClinicalTrials.gov identifier).

Role of Antigravity Training in Rehabilitation and Return to Sport After Running Injuries

AbstractAnti-gravity treadmill training is a therapeutic option to help recovering runners return to activity after injury. This current concept paper provides a synopsis of the latest evidence of the biomechanical and metabolic changes that occur with body weight support (BWS) treadmill training, effects of antigravity treadmill training on clinical outcomes and clinical case studies in injured runners. Literature searches identified studies with descriptive, experimental and interventional designs and case studies that examined acute and chronic use of antigravity treadmills in runners and relevant populations. Laboratory-based studies were included to provide technical considerations for rehabilitation programming. Antigravity treadmills use causes reductions in cadence, ground reaction forces (GRF), GRF impulses, knee and ankle range of motion, and vertical stiffness, with elevations in stride duration, flight time, ground contact time, and plantarflexion. Antigravity treadmills appear useful across a spectrum of injuries in runners, including postsurgical repair of osteochondral defect, stress reactions (medial tibia, pelvis), and lumbar disc herniation. Runners may preserve aerobic fitness, muscle activation patterns, and muscle mass during recovery compared to traditional rehabilitation protocols. Technical considerations for accurate loading include treadmill frame adjustment to appropriate height to ensure accuracy of level of BWS while running, and monitoring for fast cadence to ensure impact loading rates remain low. Speed or grade can be increased to maintain metabolic demand and fitness while minimizing bone and tissue loading. Monitoring for symptom provocation will guide protocol adjustments to BWS and prescriptions. Once able to run pain-free (sustained or interval) >95% BWS for >30 min, the runner is likely ready to safely transition to ground running. Antigravity treadmill training can be considered when available to facilitate smooth transition back to ground running in a conditioned state.

Injury Prevention, Safe Training Techniques, Rehabilitation, and Return to Sport in Trail Runners

AbstractThis current concept, narrative review provides the latest integrated evidence of the musculoskeletal injuries involved with trail running and therapeutic strategies to prevent injury and promote safe participation. Running activities that comprise any form of off-road running (trail running, orienteering, short-long distance, different terrain, and climate) are relevant to this review. Literature searches were conducted to 1) identify types and mechanisms of acute and chronic/overuse musculoskeletal injuries in trail runners, 2) injury prevention techniques most relevant to running trails, 3) safe methods of participation and rehabilitation timelines in the sport. The majority of acute and chronic trail running-related musculoskeletal injuries in trail running occur in the lower leg, primarily in the knee and ankle. More than 70% are due to overuse, and ankle sprains are the most common acute injury. Key mechanisms underlying injury and injury progression include inadequate neuromotor control-balance-coordination, running through fatigue, and abnormal kinematics on variable terrain. Complete kinetic chain prehabilitation programs consisting of dynamic flexibility, neuromotor strength and balance, and plyometrics exercise can foster stable, controlled movement on trails. Patient education about early musculoskeletal pain symptoms and training adjustment can help prevent injury from progressing to serious overuse injuries. Real-time adjustments to cadence, step length, and knee flexion on the trail may also mitigate impact-related risk for injury. After injury occurs, rehabilitation will involve similar exercise components, but it will also incorporate rest and active rest based on the type of injury. Multicomponent prehabilitation can help prevent musculoskeletal injuries in trail runners through movement control and fatigue resistance.

Effects of Forefoot Shoe on Knee and Ankle Loading during Running in Male Recreational Runners

Objectives: Although overuse running injury risks for the ankle and knee are high, the effect of different shoe designs on Achilles tendon force (ATF) and Patellofemoral joint contact force (PTF) loading rates are unclear. Therefore, the primary objective of this study was to compare the ATF at the ankle and the PTF and Patellofemoral joint stress force (PP) at the knee using different running shoe designs (forefoot shoes vs. normal shoes). Methods: Fourteen healthy recreational male runners were recruited to run over a force plate under two shoe conditions (forefoot shoes vs. normal shoes). Sagittal plane ankle and knee kinematics and ground reaction forces were simultaneously recorded. Ankle joint mechanics (ankle joint angle, velocity, moment and power) and the ATF were calculated. Knee joint mechanics (knee joint angle velocity, moment and power) and the PTF and PP were also calculated. Results: No significant differences were observed in the PTF, ankle plantarflexion angle, ankle dorsiflexion power, peak vertical active force, contact time and PTF between the two shoe conditions. Compared to wearing normal shoes, wearing the forefoot shoes demonstrated that the ankle dorsiflexion angle, knee flexion velocity, ankle dorsiflexion moment extension, knee extension moment, knee extension power, knee flexion power and the peak patellofemoral contact stress were significantly reduced. However, the ankle dorsiflexion velocity, ankle plantarflexion velocity, ankle plantarflexion moment and Achilles tendons force increased significantly. Conclusions: These findings suggest that wearing forefoot shoes significantly decreases the patellofemoral joint stress by reducing the moment of knee extension, however the shoes increased the ankle plantarflexion moment and ATF force. The forefoot shoes effectively reduced the load on the patellofemoral joint during the stance phase of running. However, it is not recommended for new and novice runners and patients with Achilles tendon injuries to wear forefoot shoes.

Foot and Lower Limb Clinical and Structural Changes in Overuse Injured Recreational Runners Using Floating Heel Shoes: Preliminary Results of a Randomised Control Trial.

Foot-strike and the associated load rate are factors related to overuse injuries in runners. The purpose of this study was to analyse structural and functional changes in runners using floating heel running shoes, compared with runners using conventional footwear. A randomised control trial was conducted. Twenty runners with overuse injuries were followed over a 12-week gait retraining programme using floating heel running shoes or their conventional footwear. Pain was measured with pressure pain thresholds (PPTs), structural changes were measured with ultrasonography, and severity and impact of injury was scored on the Oslo Sports Trauma Research Centre Overuse Injury Questionnaire (OSTRC-O). Statistical differences were found between groups after the intervention (p < 0.001), with a medium size effect SE = 0.8, and the floating heel running shoes group reached higher PPTs values. Participants using floating heel running shoes showed higher OSTRC-O scores than those using their conventional footwear (p < 0.05), with higher scores after the intervention (p < 0.05). A 12-week gait retraining programme using floating heel running shoes had positive effects on the injury recovery process when compared to the use of conventional footwear, with significant differences in terms of pain and impact on sports activity.

Musculoskeletal overuse injuries in runners and heart rate variability: Is there a link?

Purpose: Running participation has increased over the past 15 years. Despite known health benefits of running, running related injuries (RRIs) are common and present a significant economic burden. Understanding RRIs is key to reducing prevalence. Changes in heart rate variability (HRV) may have the potential to objectify somatic tissue damage prior to onset of pain in overuse injury. This study aimed to test this hypothesis in regular, non-elite runners.

Identifying Running Deviations in Long Distance Runners Utilizing Gait Profile Analysis: A Case Control Study

Objective: The goal of this study was to utilize Gait Profile Score (GPS) and Gait Deviation Index (GDI), to assess its capability of differentiating between injured and non-injured runners. Design: In total, 45 long-distance runners (15 non-injured, 30 injured), diagnosed with one of the following running related injuries, patella femoral pain syndrome, iliotibial pain syndrome, and medial tibial stress syndrome, were recruited. Methods: Data were obtained from a running analysis gait laboratory equipped with eight infrared motion-capturing cameras and a conventional treadmill. Running kinematics were recorded according to the Plug-In Gait model, measuring running deviations of the pelvis and lower extremities at a sampling rate of 200 Hz. GPS and GDI were calculated integrating pelvis and lower limb kinematics. Movement Analysis Profile results were compared between injured and non-injured runners. The non-parametric two-sample Wilcoxson test determined whether significant kinematic differences were observed. Results: Total GPS score significantly differed between the injured and non-injured runners. Not all running kinematics expressed by GDI differed between groups. Conclusions: GPS score was capable of discriminating between the injured and non-injured runners’ groups. This new running assessment method makes it possible to identify running injuries using a single numerical value and evaluate movements in individual joints.

A comparison of plantarflexor musculotendon unit output between plyometric exercises and running

ObjectivesPlyometric exercises are used to prevent and rehabilitate plantarflexor running injuries. To facilitate exercise programming, this study compared plantarflexor musculotendon output during running to plyometric exercises. DesignExperimental study with cross-over. MethodsFourteen trained distance runners performed running, ankle bouncing, A-skips, bounding, and hurdle jumps. Three-dimensional motion capture and force plate data were collected and computational simulations used to calculate gastrocnemius lateralis and soleus musculotendon peak forces, strain, power generation and absorption, and total positive and negative work. Percentage difference and standardised mean differences were used to compare variables between plyometrics and running. Musculotendon units were classified as energy generators or absorbers according to their net mechanical work. ResultsBoth plantarflexors behaved as net energy generators during running. Plantarflexor peak force and power generation and absorption were lower in the A-skip and ankle bounce compared to running. Soleus behaved as a net energy absorber during hurdle jumps, with greater total negative work (16.5%; standardised mean difference 0.92) and higher peak strain (0.3%; standardised mean difference 0.28) during hurdle jumps than running. Gastrocnemius lateralis behaved as a net energy absorber during bounding, with greater total negative work (63.8%; standardised mean difference 0.81) and peak strain (0.4%; standardised mean difference 0.77) during bounding than running. ConclusionsThe ankle bounce and A-skip may be appropriate exercises when runners desire lower plantarflexor loads than running. Hurdle jumps elicited high soleus loads but low gastrocnemius lateralis loads, highlighting the disparate function of the plantarflexors. Bounding demanded high plantarflexor musculotendon output and may be suitable when eccentric overload is desired.

A Statistical Model for Prediction of Lower Limb Injury of Active Sportsperson

For an active sportsperson, running is the most common physical activity, but it carries a high risk of musculoskeletal injuries. Half of the running injuries are identified as overuse injuries, with the most affected areas being the lower limbs. Previous studies had revealed several factors responsible for the development of running-related lower-limb injuries of sportspersons. However, there have been few studies aiming at predicting them. Therefore, the present study aimed to develop a predictive model to predict lower limb injury of active sportsperson. The BTS G-WALK system synchronised with two GoPro Hero 6 cameras were used to conduct the study on seventy-five (N=75) healthy male subjects without any lower limb injury history. The BTS G-WALK system provided spatio-temporal parameters while Kinovea software was used to extract kinematic data from raw videos of treadmill running movement of the subjects. A prospective cohort study design was used to investigate how the difference in running gait kinematic affects the outcome of lower limb injury occurrences of active sportspersons. Further, a prediction model was developed using binary logistic regression, for which IBM® SPSS® version 25 was used. All statistical analyses were tested at 0.05 (p = 0.05) level of significance. The model indicated that Range of Pelvic Obliquity (RPO) and Maximum Toe Out (MTO) were positively and Symmetry Index (SI) was negatively associated with an increased likelihood of exhibiting lower limb injury. The model explained 85.7% variance and correctly classified 93.3% cases of lower limb injury of an active sportsperson. The risk factors for lower limb injuries of a sportsperson can be identified and prediction of lower limb injury of a sportsperson is theoretically possible. To generalize the model for practical implications, the researcher suggested further research with larger sample size.

Knee muscle strength in runners who have had knee surgery: differences between limbs and associations with functional performance

Introduction: Knee muscle weakness has been associated with an increased risk of various overuse injuries in runners and incident knee osteoarthritis; however, little is known about knee strength in runners, particularly those who are at high risk of osteoarthritis who have previously had knee surgery. The aim of this study was to explore differences in knee extensor and flexor strength between surgical and non-surgical limbs in runners with a history of knee surgery, and to explore if knee strength is associated with functional performance. Methods: A convenience sample of 38 runners (run ≥10km/week, ≥3 sessions/week) who had unilateral knee surgery (45% anterior cruciate ligament reconstruction) were recruited (33.2±6.8 years, 11 women). Three maximal voluntary isometric contractions of the knee extensors and flexors were performed at 60° knee flexion (Biodex dynamometer). The highest torque value (Nm) for the knee extensors and flexors for each leg was used for analysis. Functional performance was assessed via three trials of the hop for distance test, with the furthest distance hopped for each leg recorded. Paired t-tests were used to explore differences in knee strength between limbs (whole group and stratified by sex) and partial correlations were used to explore associations between knee strength and hop for distance, controlling for mass, age, and sex. Results: There was no significant difference in knee extensor strength between the surgical and non-surgical limbs (surgical=205.9±53.4Nm, non-surgical=215.5±57.9Nm; p=0.087, Cohen’s d=0.285). A significant difference was observed between limbs for knee flexor strength (surgical=103.6±24.1Nm, non-surgical=112.3±28.6Nm; p=0.001, Cohen’s d=0.576). When examining men only, the same results were found, but there were no significant differences between limbs for women. Small to moderate non-significant associations were observed between knee strength and hop for distance on both the surgical (knee extensor r=0.321, p=0.060; knee flexor r=0.333, p=0.051) and non-surgical limbs (knee extensor r=0.286, p=0.095; knee flexor r=0.093, p=0.596). Discussion: Runners who have had unilateral knee surgery demonstrate knee flexor weakness in the surgical limb, but not knee extensors, although differences may be sex specific. Small to moderate non-significant associations between knee strength and hop for distance indicate that factors other than knee strength may influence functional performance in runners who have had knee surgery. Conflict of interest statement: My co-authors and I acknowledge that we have no conflict of interest of relevance to the submission of this abstract.

The Effects of Flexibility and Relative Muscle Strength on Injury in Running

When exercising, physical injury is almost inevitable. Although there is a multitude of practices to avoid injury, a large portion of luck is required to minimize injury proneness. In this paper, with the aid of a public dataset gait kinetics and kinematics, flexibility and strength are tested against the Boolean value of injury to conduct a linear binary regression model.

Competitive and Recreational Running Kinematics Examined Using Principal Components Analysis.

Kinematics data are primary biomechanical parameters. A principal component analysis (PCA) of waveforms is a statistical approach used to explore patterns of variability in biomechanical curve datasets. Differences in experienced and recreational runners’ kinematic variables are still unclear. The purpose of the present study was to compare any differences in kinematics parameters for competitive runners and recreational runners using principal component analysis in the sagittal plane, frontal plane and transverse plane. Forty male runners were divided into two groups: twenty competitive runners and twenty recreational runners. A Vicon Motion System (Vicon Metrics Ltd., Oxford, UK) captured three-dimensional kinematics data during running at 3.3 m/s. The principal component analysis was used to determine the dominating variation in this model. Then, the principal component scores retained the first three principal components and were analyzed using independent t-tests. The recreational runners were found to have a smaller dorsiflexion angle, initial dorsiflexion contact angle, ankle inversion, knee adduction, range motion in the frontal knee plane and hip frontal plane. The running kinematics data were influenced by running experience. The findings from the study provide a better understanding of the kinematics variables for competitive and recreational runners. Thus, these findings might have implications for reducing running injury and improving running performance.

A prevalence of running-related injuries among professional endurance runners in the Rift Valley, Kenya.

Injuries related to endurance running have attracted attention as the sport has become more competitive, and as athletes seek to improve their performance. Consequently, endurance runners are increasingly becoming more susceptible to lower extremity running injuries. The aim of this study was to establish the prevalence of running-related injuries among professional endurance runners in the Rift Valley, Kenya. We used a cross-sectional survey design targeting professional endurance runners who had participated in both local and international running competitions. The sample size consisted of 209 respondents selected through stratified and simple random sampling techniques, of which 167 participated in the study. A self-administered questionnaire was used to collect data on the prevalence of injuries among the endurance runners. The data were analysed using descriptive statistics. The prevalence of running injuries was 63% (n=106). The prevalence among males (n=64; 69%) was higher in comparison with that of females (n=42; 57%). The posterior thigh was the most common site for injuries among the athletes (n=87; 52%), followed by the lower back (n=78; 47%) and ankle (n=63; 38%). The prevalence of running-related injuries was high among professional Kenyan endurance runners compared to other populations. These findings therefore form the basis of future research to explore the mechanisms behind the injuries and the feasibility of targeted injury prevention programmes.

Running-related injury: How long does it take? Feasibility, preliminary evaluation, and German translation of the University of Wisconsin running and recovery index

ObjectiveThe University of Wisconsin Running Injury and Recovery Index (UWRI) was developed as an evaluative patient-reported outcome measure of perceived running ability and recovery after running-related injuries. To date, the questionnaire was not translated into German language and studies on its clinical feasibility and validity are sparse. DesignProspective cohort study. SettingOutpatient sports medicine clinic. ParticipantsThe UWRI questionnaire was translated to German language using a state-of-the art back-translation method including three translators and two back-translators. Clinical feasibility and validation were assessed in 14 injured runners. Main outcome measuresUWRI total score, running volume. ResultsThe translation process was completed without major discrepancies. Feasibility and preliminary evaluation were demonstrated in a cohort of 14 injured runners. The UWRI total score significantly improved throughout 12 weeks of recovering from running-related injuries (p < 0.001). Relative running volume significantly correlated with UWRI score (p < 0.001). ConclusionThe University of Wisconsin Running Injury and Recovery Index was successfully translated into the German language. Its usage may hold promise for better rehabilitation surveillance following running-related injuries.

Interactions Between Running Volume and Running Pace and Injury Occurrence in Recreational Runners: A Secondary Analysis.

The combination of excessive increases in running pace and volume is essential to consider when investigating associations between running and running-related injury. To complete a secondary analysis, using a dataset from a randomized trial, to evaluate the interactions between relative or absolute weekly changes in running volume and running pace on the occurrence of running injuries among a cohort of injury-free recreational runners in Denmark. Prospective cohort study. Running volume and pace were collected during a 24-week follow-up using global positioning systems data. Training data were used to calculate relative and absolute weekly changes in running volume and pace. A total of 586 recreational runners were included in the analysis. All participants were injury free at baseline. Running-related injury was the outcome. Injury data were collected weekly using a modified version of the Oslo Sports Trauma Research Centre questionnaire. Risk difference (RD) was the measure of injury risk. A total of 133 runners sustained running-related injuries. A relative weekly change of progression >10% in running volume and progression in running pace (RD = 8.1%, 95% CI = -9.3%, 25.6%) and an absolute weekly change of progression >5 km in running volume and progression in running pace (RD = 5.2%, 95% CI = -12.0%, 22.5%) were not associated with a statistically significant positive interaction. Given that coaches, clinicians, and athletes may agree that excessive increases in running pace and running volume are important contributors to injury development, we analyzed the interaction between them. Although we did not identify a statistically significant positive interaction on an additive scale in runners who progressed both running pace and running volume, readers should be aware that an interaction is an important analytical approach that could be applied to other datasets in future publications.

Comprehensive Return to Competitive Distance Running: A Clinical Commentary.

Running injuries are very common, and there are well-established protocols for clinicians to manage specific musculoskeletal conditions in runners. However, competitive and elite runners may experience different injuries than the average recreational runner, due to differences in training load, biomechanics, and running experience. Additionally, injury-specific rehabilitation protocols do not consider the broader goal of return to competitive running, including the unique psychosocial and cardiorespiratory fitness needs of elite athletes. This review aims to suggest a guideline for running-specific progression as part of a comprehensive rehabilitation program for injured competitive runners. Tools to evaluate an athlete's psychosocial preparedness to return to competition are presented. Recommendations are also provided for monitoring cardiorespiratory fitness of injured runners, including the nuances of interpreting these data. Finally, a six-phase training paradigm is proposed to guide clinicians as they help competitive runners transition from the early stages of injury through a full return to competition.

Risk Factors for Injuries in Runners: A Systematic Review of Foot Strike Technique and Its Classification at Impact.

Background:It has been suggested that foot strike technique (FST) at initial contact is related to running-related injuries (RRIs).Purpose:To explore the relationship between FST and RRIs.Study Design:Systematic review; Level of evidence, 3.Methods:A systematic electronic search was performed using MEDLINE, PubMed, SPORTDiscus, Scopus, and Web of Science databases. Included were studies published in the English language that explored the relationship between FST and RRIs between January 1960 and November 2020. Results were extracted and collated. The Grading of Recommendations, Assessment, Development and Evaluation approach was applied to synthesize the quality of evidence.Results:We reviewed 13 studies exploring the relationship between FST and RRIs. Of these, 6 studies reported FST categorically (foot strike pattern [FSP]), and 7 reported continuous measures (foot contact angle, ankle flexion angle, and strike index). Three of the 6 studies looking at categorical FSP found rearfoot strikers have a significantly greater retrospective injury rate than do non– rearfoot strikers, with 1 other study noting a greater risk associated with midfoot and forefoot strike. Regarding the continuous measures of FST, only 1 of the 7 studies reported a significant relationship with RRIs.Conclusion:There was low evidence to suggest a relationship between FST (or its subcategories of categorical FSP and continuous measures) and RRIs. While two-thirds of the categorical studies found a relationship between FSP and RRIs, these studies were very low quality, with limitations such as retrospective study design, low participant numbers, and poor FSP assessment methods. More large-scale prospective studies are required.

Independent Risk Factors Predicting Gradual Onset Injury in 2824 Trail Running Race Entrants: SAFER XVIII Study.

Trail running is characterized by elevation changes, with uneven and varying running surfaces. Risk factors that may predict gradual-onset running-related injuries (GORRIs) in short-distance trail running have not been explored. The objective was to determine risk factors that predict GORRIs in trail running race entrants who entered mass community-based trail running events. In this descriptive cross-sectional study, data were collected prospectively from a prerace medical screening questionnaire over 4 trail run events held annually. Using a Poisson regression model, runner demographics, race distance, running training/racing variables, history of chronic diseases (number of chronic diseases reported as a cumulative "chronic disease composite score"), and allergies were investigated to determine factors predicting self-reported GORRI history in the previous 12 mo. This study included 2824 race entrants (80% of entrants). The retrospective annual incidence for GORRIs was 13%. Independent risk factors predicting GORRIs were longer race distance (P<0.0001), increasing chronic disease composite score (P=0.0012), and a history of allergies (P=0.0056). The lower limb (94%) was the main anatomic region of GORRIs, and soft tissue injuries accounted for most (83%) GORRIs. Common specific GORRIs were iliotibial band syndrome (22%), Achilles tendon injury (10%), and hamstring injury (9%). Independent risk factors predicting GORRIs among trail running entrants included longer race distance, a higher chronic disease composite score, and a history of allergies. This study has highlighted trail running race entrants at risk for sustaining GORRIs who could be targeted for future injury prevention interventions.