Overuse Injuries In Runners Research Articles

Effects of Running Speeds and Exhaustion on Iliotibial Band Strain during Running.

Iliotibial band syndrome (ITBS) is one of the most prevalent overuse injuries in runners. The strain rate in the iliotibial band (ITB) has been theorized to be the primary causative factor in the development of ITBS. Running speed and exhaustion might lead to an alteration in the biomechanics that influence the strain rate in the iliotibial band. To identify how exhaustion states and running speeds affect the ITB strain and strain rate. A total of 26 healthy runners (including 16 males and 10 females) ran at a normal preferred speed and a fast speed. Then, participants performed a 30 min exhaustive treadmill run at a self-selected speed. Afterward, participants were required to run at similar speeds to those of the pre-exhaustion state. Both the exhaustion and running speeds were revealed to have significant influences on the ITB strain rate. After exhaustion, an increase of approximately 3% in the ITB strain rate was observed for both the normal speed (p = 0.001) and the fast speed (p = 0.008). Additionally, a rapid increase in the running speed could lead to an increase in the ITB strain rate for both the pre- (9.71%, p = 0.000) and post-exhaustion (9.87%, p = 0.000) states. It should be noted that an exhaustion state could lead to an increase in the ITB strain rate. In addition, a rapid increase in running speed might cause a higher ITB strain rate, which is proposed to be the primary cause of ITBS. The risk of injury should also be considered due to the rapid increase in the training load involved. Running at a normal speed in a non-exhaustive state might be beneficial for the prevention and treatment of ITBS.

Comparing Functional Motor Control Exercises With Therapeutic Exercise in Wrestlers With Iliotibial Band Syndrome.

Iliotibial band syndrome (ITBS) is a common overuse injury in runners with parallels to our findings of overuse in Greco Roman wrestlers. Despite research indicating coordination and movement-based factors about the hip, no studies were found using functional motor control (FMC) in runners or wrestlers with ITBS. Thus, we compared FMC exercises and therapeutic exercises (TEs) on pain, function, muscle strength, and range of motion (ROM) in national-level Greco Roman wrestlers with ITBS. Controlled laboratory study. Sixty national-level Greco Roman wrestlers diagnosed with ITBS were randomly assigned to 8weeks of FMC exercises, TE, and a control group (20 individuals for each group). Pain (visual analog scale), function (triple hop test for distance, single-leg vertical jump test, and agility T test), muscle strength (handheld dynamometer), and ROM (goniometer) were measured at baseline and 8weeks after intervention as posttest. Although both interventions significantly reduced pain (P < .001, η2 = .87), improved function (triple hop test P = .004, η2 = .94; single-leg vertical jump P = .002, η2 = .93; and T test P < .001, η2 = .93) and strength (hip abduction (P < .001, η2 = .52), hip external rotation (P = .02, η2 = .95), knee flexion (P ≤ .001, η2 = .94), and knee extension (P < .001, η2 = .91) compared with the control group, FMC showed more significant improvements in comparison with TE. Significant differences (P = .001) were observed between FMC and TE compared with the control group in ROM outcome. However, TE was more effective than FMC in improving ROM hip abduction (P < .001, η2 = .93), hip adduction (P = .000, η2 = .92), hip internal rotation (P < .001, η2 = .92), and hip external rotation (P < .001, η2 = .93). FMC exercises were superior to TE in terms of pain, function, and muscle strength, whereas TE was more effective for improving ROM. FMC exercise is suggested as an effective intervention for improvement of the outcomes related to ITBS in national-level Greco Roman wrestlers.

Changes Of Bone Metabolism Markers In Japanese Male Long Distance Runners During In-season

Stress fracture is one of the most common overuse injuries in runners and there are many risk factors that predispose to this injury. Previous studies have focused on bone metabolism and the correlation between stress fractures and bone metabolism has been reported. However, most studies are on female athletes, and little is known on male athletes. Moreover, long-term bone metabolic process in athletes is unknown. PURPOSE: To investigate changes bone metabolism markers in male long distance runners during in-season METHODS: Twenty-five male long distance runners participated in this study, and total of 11 athletes were qualified for analysis (24 ± 4.3 yrs, 170.4 ± 5.0 cm, 55.9 ± 3.7 kg) after excluding those who were injured and/or were not able to run more than 200 km per month. Blood samples were collected from 9 am to 11 am during pre-season (PRs), post-track season (PTs), and road-race season(RRs). Athletes were instructed to refrain from training prior to blood collection. To assess bone metabolism bone-specific alkaline phosphatase(BAP) and tartrate-resistant acid phosphatase-5b(TRACP-5b) were measured. In addition, athletes reported their monthly training volume of one month prior the first measurement. Changes of bone metabolic markers were assessed by one-way ANOVA with repeated measures and correlations between training volume and both markers were made using Spearman’s rank correlation coefficient. RESULTS: BAP in PTs (14.98 ± 3.11 vs. 16.62 ± 3.76 p = 0.004) and RRs (14.85 ± 3.68 vs. 16.62 ± 3.76 p = 0.004) were significantly lower than that of PRs. There were no statistically significant changes in TRACP-5b. Moreover, there were not any correlations between monthly training volume and both bone metabolism markers. CONCLUSIONS: We found that BAP lower than PRs from the latter half of track season to the road race season.

Research protocol to evaluate the effectiveness of shockwave therapy, photobiomodulation and physical therapy in the management of non-insertional Achilles tendinopathy in runners: a randomised control trial with elective cross-over design

BackgroundAchilles tendinopathy (AT) is a common overuse injury in runners. While the mainstay of treatment for AT is tendon loading exercises (physical therapy and exercise programme (EXER)), some patients have...

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.

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.

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.

Radiographic Pattern to Recognize Overuse Injury in Runners: The Ipsilateral Pubic Ramus and Sacral Bone Stress Injury.

Radiographic Pattern to Recognize Overuse Injury in Runners: The Ipsilateral Pubic Ramus and Sacral Bone Stress Injury.

A Multifactorial Approach to Overuse Running Injuries: A 1-Year Prospective Study.

Because of the complex and multifaceted nature of running injuries, a multifactorial approach when investigating running injuries is required. Compared with uninjured runners, injured runners would exhibit different running biomechanics, display more fatigue changes, and would run a greater weekly running volume; more injured runners would also report having a previous injury. Prospective cohort study. Level 4. At commencement of the study, data were collected on demographics, anthropometrics, training history, previous injury history, and center-of-mass accelerations during a long-distance overground run. Participants completed weekly training diaries and were monitored for 1 year for an injury. A total of 76 runners completed the study, with 39 (22 male; 17 female) reporting an injury. Compared with male uninjured runners, male injured runners were heavier and ran a greater weekly distance. Male runners (injured and uninjured) exhibited increases in mediolateral center-of-mass accelerations during the run. Compared with female uninjured runners, female injured runners were heavier, ran with longer flight times and lower step frequencies, and more of them had reported an injury in the previous year and had increased speed training in the weeks prior to injury. Over 60% of male injured runners and over 50% of female injured runners had increased their weekly running distance by >30% between consecutive weeks at least once in the 4 weeks prior to injury. Factors that may be related to injury for male runners include being heavier, running a greater weekly distance, and exhibiting fatigue changes in mediolateral center-of-mass accelerations. Factors that may be related to injury for female runners include being heavier, having an injury in the previous year, running with longer flight times and lower step frequencies, and increasing speed training prior to injury. Increases in weekly running distance in 1 consecutive week (particularly >30%) needs to be monitored in training, and this along with the other factors found may have contributed to injury development. This study found that multiple factors are related to running injuries and that some factors are sex specific. The findings can aid in injury prevention and management.

Controlled trial to compare the Achilles tendon load during running in flatfeet participants using a customized arch support orthoses vs an orthotic heel lift

BackgroundAchilles tendinopathy is one of the most common overuse injuries in running, and forefoot pronation, seen in flatfeet participants, has been proposed to cause additional loading across the Achilles tendon. Foot orthoses are one of the common and effective conservative treatment prescribed for Achilles tendinopathy, it works by correcting the biomechanical malalignment and reducing tendon load. Previous studies have shown reduction of Achilles Tendon load (ATL) during running by using customized arch support orthosis (CASO) or an orthotic heel lift (HL). However, there are still little biomechanical evidence and comparative studies to guide orthotic prescriptions for Achilles tendinopathy management. Therefore, this study seeks to investigate the two currently employed orthotic treatment options for Achilles tendinopathy: CASO and HL for the reduction of ATL and Achilles tendon loading rate (ATLR) in recreational runners with flatfeet.MethodsTwelve participants were recruited and run along the runway in the laboratory for three conditions: (1) without orthoses, (2) with CASO (3) with HL. Kinematic and kinetic data were recorded by 3D motion capturing system and force platform. Ankle joint moments and ATL were computed and compared within the three conditions.ResultsParticipants who ran with CASO (p = 0.001, d = 0.43) or HL (p = 0.001, d = 0.48) associated with a significant reduction in ATL when compared to without orthotics while there was no significant difference between the two types of orthoses, the mean peak ATL of CASO was slightly lower than HL. Regarding the ATLR, both orthoses, CASO (p = 0.003, d = 0.93) and HL (p = 0.004, d = 0.78), exhibited significant lower value than the control but similarly, no significant difference was noted between them in which the use of CASO yielded a slightly lower loading rate than that of HL.ConclusionsBoth CASO and HL were able to cause a significant reduction in peak ATL and ATLR comparing to without orthotics condition. There were subtle but no statistically significant differences in the biomechanical effects between the two types of orthoses. The findings help to quantify the effect of CASO and HL on load reduction of Achilles tendon and suggests that foot orthoses may serve to prevent the incidence of Achilles tendon pathologies.Trial registrationNCT04003870 on clinicaltrials.gov 1 July 2019.

A Randomized Study of a Strength Training Program to Prevent Injuries in Runners of the New York City Marathon.

Lower extremity overuse injuries are common among runners, especially first-time marathoners. Hip abductor and quadriceps strengthening is often recommended to reduce running-related injuries. A 12-week strength training program would decrease the rate of overuse injuries resulting in marathon noncompletion and improve race finishing time. Randomized trial. Level 2. Twelve weeks before the New York City Marathon, first-time marathon runners age 18 years and older were randomized into a strength training group or an observation group. The strength training group was instructed to perform a 10-minute program 3 times weekly using written and video instruction. This program targeted the quadriceps, hip abductor, and core muscle groups. Injuries were self-reported through biweekly surveys, with major injuries being those that resulted in marathon noncompletion and minor injuries being those that impaired training or race performance. A total of 720 runners were enrolled (mean age, 35.9 ± 9.4 years; 69.4% female), of whom 583 runners started the marathon and 579 completed it. The incidence of major injury was 8.9% and minor injury was 48.5%. Fifty two of 64 major injuries were overuse, of which 20 were bone stress injuries. The incidence of overuse injury resulting in marathon noncompletion was 7.1% in the strength training group and 7.3% in the observation group (risk ratio, 0.97; 95% CI, 0.57-1.63; P = 0.90). The mean finishing time was 5 hours 1 ± 60 minutes in the strength training group and 4 hours 58 ± 55 minutes in the observation group (P = 0.35). There is a high prevalence of injury among first-time marathon runners, but this self-directed strength training program did not decrease overuse injury incidence resulting in marathon noncompletion. Prevention strategies such as strength training need to be developed and evaluated through clinical trials to reduce the high prevalence of overuse injuries in runners, especially for high-risk populations such as first-time marathon runners.

Association Between Temporal Spatial Parameters and Overuse Injury History in Runners: A Systematic Review and Meta-analysis.

Temporal spatial parameters during running are measurable outside of clinical and laboratory environments using wearable technology. Data from wearable technology may be useful for injury prevention, however the association of temporal spatial parameters with overuse injury in runners remains unclear. To identify the association between overuse injury and temporal spatial parameters during running. Electronic databases were searched using keywords related to temporal spatial parameters, running, and overuse injury, and authors' personal article collections through hand search. Articles included in this systematic review contained original data, and analytically compared at least one temporal spatial parameter (e.g. cadence) between uninjured and retrospectively or prospectively injured groups of runners. Articles were excluded from this review if they did not meet these criteria or measured temporal spatial parameters via survey. The internal validity of each article was assessed using the National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Meta-analyses were conducted for temporal spatial parameters if data existed from at least three separate cohorts of the same prospective or retrospective design. Data were pooled and analyzed using an inverse variance fixed-effect model. Thirteen articles which tested a total of 24 temporal spatial parameters during running were included in the review. Meta-analyses were conducted on four temporal spatial parameters using data from eleven retrospective studies. Healthy runners and those with a history of overuse injury had a similar average stride time (mean difference: 0.00 s, 95% CI - 0.01 to 0.01 s), contact time (mean difference: 0.00 s, 95% CI 0.00 to 0.01 s), cadence (mean difference: 0.3 steps per minute (spm), 95% CI - 1.8 to 2.5 spm), and stride length (mean difference 0.00 m, 95% CI - 0.05 to 0.05 m) during running. Data pooled for meta-analyses were limited to retrospective design studies. Studies included in the systematic review had low methodological consistency. Based on pooled results from multiple studies, stride time, contact time, cadence, and stride length averages are not distinguishable between runners either with or without a history of overuse injury. More prospective studies are required to determine the association of temporal spatial parameters with overuse injury development in runners. CRD42018112290.

Ankle Joint Kinetics in Runners with Medial Tibial Stress Syndrome

Medial tibial stress syndrome (MTSS) is a common overuse running injury. While numerous studies have reported abnormal ankle kinematics in runners with MTSS, to date, no studies have evaluated ankle kinetics in this population. PURPOSE: To compare ankle kinetics in runners with and without MTSS. METHODS: Participants included eight runners with MTSS (sex: 7M/1F; age: 35 ± 11.3 years) and eight matched controls (CON; sex: 7M/1F; age: 35 ± 8.7 years). Kinematics and ground reaction forces were recorded while participants ran overground. Sagittal plane kinetics were calculated about an axis connecting the malleoli while frontal plane kinetics were calculated about an axis approximating the 23° medially deviated and 42° inclined orientation of the subtalar joint. Joint work was calculated by integrating the joint power curves. Paired t-tests were used to compare peak moments, powers, and work between MTSS and CON groups. RESULTS: Neither peak plantar flexor (MTSS: 2.14 ± 0.53, CON: 2.24 ± 0.57 Nm/kg) nor peak invertor (MTSS: 1.04 ± 0.34, CON: 1.16 ± 0.32 Nm/kg) moments were different between groups (p = .720, p = .472, respectively). There were no differences in sagittal plane powers or work between groups. In the frontal plane, the MTSS group demonstrated lower peak positive power (MTSS: 1.97 ± 0.38, CON: 3.05 ± 1.12 W/kg, p = .021), and performed less negative (MTSS: -0.09 ± 0.02, CON: -0.16 ± 0.07 J/kg, p = .032), positive (MTSS: 0.14 ± 0.03, CON: 0.22 ± 0.07 J/kg, p = .039), and total (MTSS: 0.23 ± 0.06, CON: 0.37 ± 0.15 J/kg, p = .032) work. CONCLUSIONS: Compared to healthy individuals, runners with MTSS are not able to generate as much energy to invert their foot during late stance. This may explain why previous studies have observed runners with MTSS have prolonged rearfoot eversion during stance.Figure 1: Frontal plane joint moments (A) and powers (B). The solid line represents the CON group and the dotted line represents the MTSS group. Error bars show one standard deviation above and below the mean curve for the CON group.

Overuse injuries in runners of different abilities—a one-year prospective study

ABSTRACT The aim of this prospective study was to investigate differences in participant characteristics, previous injury, running dynamics during a long-distance run, and training between injured and uninjured runners in runners of different abilities. Center-of-mass acceleration data were collected during a long-distance overground run. Runners were then divided into four groups (elite, advanced, intermediate and slow) based on their finishing time. Participants completed training diaries and were monitored for 1 year. Seventy-six runners completed the prospective study with 39 (51.3%) sustaining a running injury (44% elite, 42% advanced, 54% intermediate, 59% slow). Differences between injured and uninjured runners within each group related to injury included: (1) elite injured runners ran with longer contact times and (2) more slow injured runners reported an injury in previous year, were heavier, had higher body mass and body mass index, ran with lower step frequencies, and ran a greater weekly distance. Advanced injured runners exhibited fatigue changes in step regularity and peak braking during the run that may be related to injury. These findings suggest that runners of different abilities may have different factors related to injury however due to the small sample sizes in the groups this needs to be explored further.

Interaction between body composition and impact-related parameters in male and female heel-toe runners

BackgroundBone fatigue resistance and more generally the ability to dissipate the stress sustained in dynamic tasks are partly affected by tissue properties. Men and women demonstrate substantial differences in body composition. Research questionTo assess whether gender, as a function of body composition, affects impact-related parameters in running. MethodsA qualitative study has been conducted. Twelve females and eighteen males performed four 2-min running trials at 2.8 m∙s−1, 3.3 m∙s−1, 3.9 m∙s−1, and 4.4 m∙s−1 while recording axial and transverse tibial acceleration. Peak acceleration and power spectral density within the impact-related frequency range (vibration content) were measured. Bone mineral content, fat mass, lean mass, and muscle mass were assessed using an impedance meter. Two-way (gender × speed) ANOVAs were computed. Multiple linear regressions were then used to assess the magnitude of the effect of body composition indicators on impact-related parameters. ResultsSignificant gender and speed effects were observed. Females and high running speeds were associated with greater peak acceleration and vibration content at the tibia. Small interactions were observed between muscle mass and axial peak acceleration and vibration content, and between bone mineral content and transverse peak acceleration and vibration content, and axial vibration content. SignificanceWomen demonstrated greater mechanical stress than men during running. High mechanical stress was associated with low bone mineral content and muscle mass. These findings may have implications in the prevention and management of bone overuse injuries in runners.

Segment Coordination Variability Differs by Years of Running Experience.

The purpose of this study was to determine if less-experienced runners have different segment coordination and lower segment coordination variability compared with their more-experienced peers. This retrospective analysis included 20 more-experienced (≥10 yr running) and 21 less-experienced (≤2 yr running) runners. Sagittal thigh versus shank and shank versus foot segment coordination and coordination variability were calculated using a modified vector coding approach as individuals ran on a treadmill at preferred pace. Coordination and its variability were compared between groups during terminal swing and early, mid, and late stance for both segment couples. Segment coordination was similar between less- and more-experienced runners. Less-experienced runners had lower segment coordination variability compared with more-experienced runners for both the thigh versus shank and shank versus foot couples. This lower variability occurred during early and mid stance. Runners appeared to attain stable segment coordination patterns within 2 yr of consistent running, but had lower coordination variability compared with individuals who had been running for 10 or more years. These results suggest that assessment of movement patterns and their flexibility may help inform injury prevention or treatment strategies for less-experienced runners.

Hip Taping Positively Alters Running Kinematics in Asymptomatic Females.

Greater functional knee valgus (FKV) is thought to contribute to a greater risk of sustaining overuse running injuries. The hip is commonly implicated in greater functional knee valgus, but no studies have investigated the effects of hip taping on running kinematics. The present study investigated whether or not hip taping altered hip and knee kinematics compared to sham and no taping in female runners demonstrating excessive functional knee valgus. Lower limb stance-phase kinematics were collected from 23 female runners using three-dimensional motion capture. Participants performed over ground running at 3.5 m/s and 5.0 m/s. Three taping conditions (no tape; sham tape; hip tape) were tested. Statistical inference was performed using Statistical Parametric Mapping Hotelling's paired t-tests, with post-hoc paired t-tests. Hip taping significantly decreased hip adduction and internal rotation angles throughout stance phase by up to 7°, compared to sham and no taping. Hip taping significantly increased knee adduction, internal rotation, flexion, and reduced peak knee flexion angles, compared to no tape. Hip taping reduced excessive hip motion by clinically meaningful magnitudes, and also benefited knee frontal and transverse plane kinematics at the slower running speed. Hip taping may provide an immediate solution in correcting FKV in running.

A 2-Year Prospective Cohort Study of Overuse Running Injuries: The Runners and Injury Longitudinal Study (TRAILS)

Background: The National Center for Injury Prevention and Control, noting flaws in previous running injury research, called for more rigorous prospective designs and comprehensive analyses to define the origin of running injuries. Purpose: To determine the risk factors that differentiate recreational runners who remain uninjured from those diagnosed with an overuse running injury during a 2-year observational period. Study Design: Cohort study; Level of evidence, 2. Methods: Inclusion criteria were running a minimum of 5 miles per week and being injury free for at least the past 6 months. Data were collected at baseline on training, medical and injury histories, demographics, anthropometrics, strength, gait biomechanics, and psychosocial variables. Injuries occurring over the 2-year observation period were diagnosed by an orthopaedic surgeon on the basis of predetermined definitions. Results: Of the 300 runners who entered the study, 199 (66%) sustained at least 1 injury, including 73% of women and 62% of men. Of the injured runners, 111 (56%) sustained injuries more than once. In bivariate analyses, significant (P ≤ .05) factors at baseline that predicted injury were as follows: Short Form Health Survey–12 mental component score (lower mental health–related quality of life), Positive and Negative Affect Scale negative affect score (more negative emotions), sex (higher percentage of women were injured), and knee stiffness (greater stiffness was associated with injury); subsequently, knee stiffness was the lone significant predictor of injury (odds ratio = 1.18) in a multivariable analysis. Flexibility, quadriceps angle, arch height, rearfoot motion, strength, footwear, and previous injury were not significant risk factors for injury. Conclusion: The results of this study indicate the following: (1) among recreational runners, women sustain injuries at a higher rate than men; (2) greater knee stiffness, more common in runners with higher body weights (≥80 kg), significantly increases the odds of sustaining an overuse running injury; and (3) contrary to several long-held beliefs, flexibility, arch height, quadriceps angle, rearfoot motion, lower extremity strength, weekly mileage, footwear, and previous injury are not significant etiologic factors across all overuse running injuries.

Influence of outdoor running fatigue and medial tibial stress syndrome on accelerometer-based loading and stability

Medial tibial stress syndrome (MTSS) is a common overuse running injury with pathomechanics likely to be exaggerated by fatigue. Wearable accelerometry provides a novel alternative to assess biomechanical parameters continuously while running in more ecologically valid settings. The purpose of this study was to determine the influence of outdoor running fatigue and MTSS on both dynamic loading and dynamic stability derived from trunk and tibial accelerometery. Runners with (n=14) and without (n=16) history of MTSS performed an outdoor fatigue run of 3200m. Accelerometer-based measures averaged per lap included dynamic loading of the trunk and tibia (i.e. axial peak positive acceleration, signal power magnitude, and shock attenuation) as well as dynamic trunk stability (i.e. tri-axial root mean square ratio, step and stride regularity, and sample entropy). Regression coefficients from generalised estimating equations were used to evaluate group by fatigue interactions. No evidence could be found for dynamic loading being higher with fatigue in runners with MTSS history (all measures p>0.05). One significant group by running fatigue interaction effect was detected for dynamic stability. Specifically, in MTSS only, decreases mediolateral sample entropy i.e. loss of complexity was associated with running fatigue (p<0.01). The current results indicate that entire acceleration waveform signals reflecting mediolateral trunk control is related to MTSS history, a compensation that went undetected in the non-fatigued running state. We suggest that a practical outdoor running fatigue protocol that concurrently captures trunk accelerometry-based movement complexity warrants further prospective investigation as an in-situ screening tool for MTSS individuals.

Exertion and pain do not alter coordination variability in runners with iliotibial band syndrome

BackgroundIliotibial band syndrome is a common overuse running injury which results in altered mechanics. While injuries alter discrete mechanics, they may also cause a change in coordination variability, the stride-to-stride organization of runners' movement patterns. Uninjured and injured runners may experience a change in coordination variability during a run to exertion due to fatigue, pain, or a combination of these factors. The aim of the current study was to determine if runners with iliotibial band syndrome and uninjured runners display different segment coordination variability across the course of a run to exertion. Methods3D kinematics were collected as 13 uninjured runners and 12 runners with iliotibial band syndrome ran on a treadmill. A modified vector coding technique was used to calculate coordination variability during stance for segment couples of interest. Coordination variability was compared between uninjured and injured runners at the beginning and end of the run. The influence of pain on coordination variability was also examined. FindingsThere were no differences in coordination variability at the beginning or end of the run between uninjured runners and those with iliotibial band syndrome. The change in coordination variability due to the run was not different between uninjured runners, injured runners who experienced no change in pain, and injured runners who did experience a change in pain. InterpretationRunners do not constrain the patterns of segment motion they use in response to exertion nor does it appear that occurrence of pain during running results in a differential change in coordination variability.