Non-injured Runners Research Articles

The pop-up pain: reconceptualizing the perception of short-lived pain among non-injured recreational marathoners

Multiple forms of short-lived pain are common experiences among non-injured recreational marathoners, yet there remains little in-depth qualitative research on the lived experience regarding the sociology of transient pain. This study seeks to fill the lacuna by exploring the relationship between transient pain and its multifaceted consequences within the running social world. Drawing on Leder’s notion of the dys-appearing body, the study investigates how non-injured runners interpret and attribute context-dependent significance to transient pain due to their runs. An ethnographic research design of two years was implemented in two running groups, using participant observation and semi-structured interviews. Three categories of transient pain were identified: (1) “Pre-flow pain” - discomfort at the start of a run before easing into a relaxed state, (2) “Impromptu pain” - unexpected, sharp pain that occurs during the run and (3) “Resurgent pain” - an ache that manifests after the end of a running session as a result of lingering effects from prior injuries. The data presented suggest that transient pain cannot be approached as a self-evident phenomenon occurring in a vacuum. Instead, it should be viewed as a nuanced pain epistemology that encompasses the lived experience of bodily pain within the subjective perception.

The Association of Joint Power Kinetic Variables with Running Injuries: A Case-Control Study.

There is conflicting data on which kinetic variables are important to consider with running injuries. Furthermore, less is understood regarding differences in these variables when considering demographics such as age, sex, weight, and running speed. The primary question was what joint power kinetic variables were different between non-injured and injured runners. The purpose of this study was to identify if there were differences in joint power kinetic variables between non-injured runners and injured runners. Case-Control Study. Kinetic data were collected on 122 runners (26 non-injured and 96 injured) over three years with a Bertec force plated treadmill and Qualisys 3D motion capture. The subjects were considered eligible if they self-identified themselves as runners or had running as a key component of their activity. The subjects ran at a comfortable, self-selected pace while two 10-second trials of recordings were used to calculate the means of peak power generated at the hips, knees, and ankles of each gait cycle. Foot strike was categorized by kinematic data. Two sample T-tests were used to compare peak power variables at the hips, knees, and ankles between non-injured and injured runners. Logistic regression analyses examined how a combination of demographics and peak power variables were associated with injuries. No peak power variable at the hip, knee, or ankle was significantly different between injured and non-injured runners (p=0.07-0.87). However, higher hip power absorbed was found to be protective against injuries (odds ratio, .16; 95% CI .025-.88) when considering demographics using a logistic regression model including sex, foot strike, BMI, speed, age, and power variables from the hip, knee, and ankle. The area under the ROC curve was .74, which is acceptable discrimination. When controlling for age, sex, BMI, foot strike, and speed; higher hip power absorbed was found to be protective against injury. This could be due to the hip muscles' unique role in absorbing force during early stance phase. 3b©The Author(s).

Wearable technology assessing running biomechanics and prospective running-related injuries in Active Duty Soldiers

ABSTRACT The purpose of this study was to determine if running biomechanical variables measured by wearable technology were prospectively associated with running injuries in Active Duty Soldiers. A total of 171 Soldiers wore a shoe pod that collected data on running foot strike pattern, step rate, step length and contact time for 6 weeks. Running-related injuries were determined by medical record review 12 months post-study enrollment. Differences in running biomechanics between injured and non-injured runners were compared using independent t-tests or ANCOVA for continuous variables and chi-square analyses for the association of categorical variables. Kaplan–Meier survival curves were used to estimate the time to a running-related injury. Risk factors were carried forward to estimate hazard ratios using Cox proportional hazard regression models. Forty-one participants (24%) sustained a running-related injury. Injured participants had a lower step rate than non-injured participants, but step rate did not have a significant effect on time to injury. Participants with the longest contact time were at a 2.25 times greater risk for a running-related injury; they were also relatively slower, heavier, and older. Concomitant with known demographic risk factors for injury, contact time may be an additional indicator of a running-related injury risk in Active Duty Soldiers.

Inter-limb differences in in-vivo tendon behavior, kinematics, kinetics and muscle activation during running

Overloading of tendon tissue may result in overuse tendon injuries in runners. One possible cause of overloading could be the occurrence of biomechanical inter-limb differences during running. However, scarce information exists concerning the simultaneous analysis of inter-limb differences in external and internal loading-related variables in habitual runners. In this study ground reaction force, joint kinematics, triceps surae and tibialis anterior activations, and medial gastrocnemius muscle-tendon junction displacement were assessed bilaterally during treadmill running at 2.7 m.s−1 and 4.2 m.s−1. Statistical parametric t-tests and effect sizes were calculated to identify eventual inter-limb differences across the stance phase and stride cycle. Hip flexion angle was 9° greater (p = 0.03, ES = 0.30) in the non-preferred limb during the flight phase at 4.2 m.s−1. Hip extension velocity was 45 deg.s−1 greater (p = 0.04, ES = 0.41) during ground contact and 25 deg.s−1 greater (p = 0.02, ES = 0.41) immediately after toe-off in the non-preferred limb at 4.2 m.s−1. Hip extension velocity was also 40 deg.s−1 greater (p = 0.01, ES = 0.46) in the non-preferred limb prior to touch-down at 4.2 m.s−1. Brief inter-limb differences in joint kinematics were not accompanied by inter-limb differences in variables associated to internal loading, suggesting they are unlikely to be underlying factors leading to tendon overloading in healthy non-injured runners.

Anthropometric Factors Associated With Bone Stress Injuries in Collegiate Distance Runners: New Risk Metrics and Screening Tools?

Background:Lower limb bone stress injury (BSI) of the pelvis, femur, and tibia is prevalent in collegiate track and field distance runners. Bone mineral density (BMD), body composition (BComp), and anthropometric parameters before initial collegiate injury have not been compared between runners with BSI and their noninjured counterparts.Purpose:To characterize bone health in relation to BComp and anthropometric measurements from total-body dual x-ray absorptiometry (DXA) scans in collegiate male and female distance runners before BSI and develop BMD prediction models.Study Design:Case-control study; Level of evidence, 3.Methods:Distance runners (N = 79) from a single university track and field team were retrospectively enrolled into this study. The runners completed a DXA scan during the fall season (August-November) and participated in sport activities before the scan. Three months after scanning, electronic medical records were reviewed for the occurrence of BSI. An independent-sample t test was used to compare BMD (total and regional [spine, pelvis, and legs]), BComp (% body fat, fat mass, and lean mass), and anthropometric measurements (shoulder width and leg, arm, and trunk length) between runners with versus without BSI (included subgroup analysis by sex). Multiple linear regression with stepwise removal was used to determine variables most predictive of BMD.Results:Of the 79 enrolled participants (42 male, 37 female), 18 runners (22.8%; 11 female, 7 male) sustained a lower limb BSI. Compared with the noninjured group, injured runners had lower total and regional BMD (P < .001 for all) and shorter leg and arm lengths (P < .05 for both), whereas injured male runners had lower fat mass and injured female runners had lower lean mass in the legs (P < .05 for both). Injured runners’ age-matched total BMD Z score (-0.1 ± 0.6) was considered clinically normal. BComp and anthropometric measures were predictive of total and regional BMD (P < .05; R 2 = 0.64-0.80; percentage error = 3.8%-4.8%).Conclusion:The DXA scans of injured runners prior to incidence indicated lower BMD compared with noninjured runners. Shorter limb lengths, lower fat mass (male), and lower leg lean mass (female) may also be indicative of risk. Certain BComp and anthropometric measures were predictive of BMD.

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.

What Are the Main Risk Factors for Lower Extremity Running-Related Injuries? A Retrospective Survey Based on 3669 Respondents.

Background:Despite the many studies on running-related injuries (RRIs), risk factors for injury remain unclear in the literature.Purpose:To investigate the risk factors of RRIs.Study Design:Case-control study; Level of evidence, 3.Methods:An online survey was conducted among 3669 injured and noninjured runners. Injury was defined as pain of various kinds, without attention to its consequences on running practice. The survey included 41 questions on 5 main categories—personal characteristics, daily lifestyle, training and running characteristics, practice of other sporting activities, and prevention habits—as well as information about the occurrence of RRI over the previous 12 months. Continuous and qualitative variables were analyzed by Student t test and chi-square test, respectively. Sixteen variables were selected for multivariate binary logistic analysis.Results:Among the 3669 runners, 1852 (50.5%) reported at least 1 injury over the previous 12 months. Overuse injuries were largely represented (60.6%). The variables associated with RRIs that remained significant in the fully adjusted model were previous injury (odds ratio [OR], 1.62; 95% CI, 1.42-1.86), higher weight (OR, 1.006; 95% CI, 1.00-1.012), competitive running (OR, 1.53; 95% CI, 1.19-1.98), running >2 h/wk (OR, 1.28; 95% CI, 1.01-1.62), running >20 km/wk (OR, 1.25; 95% CI, 1.001-1.55), and stretching before running (OR, 1.46; 95% CI, 1.25-1.71).Conclusion:Previous injury remains the most relevant risk factor for RRIs according to the current study and previous data. Many training characteristics seem to be involved but still have to be confirmed in view of conflicting data in the literature. Further research would help clinicians better understand RRIs and how to prevent them.

IS STEP RATE ASSOCIATED WITH RUNNING INJURY INCIDENCE? AN OBSERVATIONAL STUDY WITH 9- MONTH FOLLOW UP

Several strategies have been proposed to reduce loading of the lower extremity while running including step rate manipulation. It is unclear however, whether step rate influences the incidence of lower extremity injuries. To examine the association between step rate and risk of injury in an adult recreational runner population. Prospective Cohort. A total of 381 runners were prospectively followed for an average of nine months. Two-dimensional video was used to assess preferred step rate during a timed two-mile run or a 5K race. Injury surveillance to record sub-clinical injuries (those for which medical treatment was not sought) was performed via semi-monthly email surveys over the course of one year. Injury surveillance for clinical injuries (those for which medical treatment was sought) was performed via a full medical record review using the Armed Forces Health Longitudinal Technology Application. Clinical, sub-clinical and combined clinical and sub-clinical injury incidence were assessed in separate analyses. Injury was operationally defined as seven or more days of reduced activity due to pain. To assess the predictive validity of running step rate, the step rate of participants who did not develop a musculoskeletal injury during the observation period were compared with the running step rate of participants who did develop an injury during the observation period. Out of 381 runners, 16 sustained a clinical overuse injury for which medical treatment was sought. Mean step rate for clinically un-injured runners was 172 steps/min and mean step rate for clinically injured runners was 173 steps/min which was not statistically significantly different (p = 0.77.) Out of 381 runners, 95 completed all four sub-clinical injury surveys (95/381 = 25%). Out of those 95 runners, 19 sustained a clinical (n=4) or sub-clinical injury (n=15). The step rate of sub-clinically injured and non-injured runners in this sub-sample was also not statistically significantly different (p = 0.08), with a mean of 174 steps/min for the uninjured group and a mean step rate of 170 steps/min for those in the sub-clinical injured group. Preferred step rate was not associated with lower extremity injury rates in this sample of DoD runners. Additional research is needed to justify preferred step rate manipulation as a means to reduce lower extremity injury risk. Level 3.

Comparisons of Running Mechanics Between Injured and Non-injured Cross-country Runners

PURPOSE: The purpose of this study was to compare ankle power, peak plantarflexion moment, and ankle range of motion (ROM) between injured and uninjured Division-I cross-country athletes. METHODS: Six Division-I female cross-country athletes (height 164.7 ± 4.1 cm; weight 52.0 ± 3.1 kg) reported prior to the start of the cross-country season. Upon providing informed consent, athletes completed 5 running trials at a preferred pace over a 15-m runway in a laboratory equipped with ten 3D motion capture infrared cameras. Kinetic data were collected using three embedded force platforms within a 15-m runway. Ankle ROM, peak plantarflexion moment, and average ankle plantarflexion power were calculated. Injury reports were obtained from the team’s certified athletic trainer at the end of the season. These reports allowed for the stratification of athletes into injured and uninjured groups. Data from six athletes were used for the current analysis, thus Hedges’ g measures were used to identify effect size. RESULTS: Three athletes sustained left foot injuries during the season. Injury status had a small effect prospectively on plantarflexor power (g=0.25) and ankle ROM (g=0.25), and a medium effect on peak plantarflexor moment (g=0.68) of the injured ankle. Injured athletes exhibited lower magnitudes of the variables of interest compared to uninjured athletes: average plantarflexor power (274.8 ± 53.5 and 306.1 ± 101.4 Nm/s respectively), less ankle ROM (41.5 ± 4.3 and 44.1 ± 8.3°), and lower peak plantarflexor moments (124.1 ± 12.3 and 140.0 ± 17.8 Nm). CONCLUSIONS: Based on the results of the current study, the measured variables, particularly peak plantarflexion moment, may be of interest when investigating foot injury risk. The athletes in the current study may already be altering their motion to protect the at-risk limb. Longitudinal studies with additional data points and robust sample sizes are necessary to determine changes in running gait which may indicate increased risk of injury. This information has the potential to inform pre-screening gait analyses and subsequent coaching and clinical interventions.

Biomechanical Risk Factors Associated with Running-Related Injuries: A Systematic Review.

Running is a popular form of physical activity with many health benefits. However, the incidence and prevalence of running-related injuries (RRIs) is high. Biomechanical factors may be related to the development of RRIs. This systematic review synthesizes biomechanical risk factors related to the development of RRIs in non-injured runners. PubMed, Web of Science, CINAHL, Embase, and SPORTDiscus were searched in July 2018 for original peer-reviewed prospective studies evaluating potential biomechanical factors associated with the development of RRIs. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Two reviewers independently assessed articles for inclusion and methodological quality. Due to methodological heterogeneity across studies, a narrative synthesis of findings was conducted, rather than a meta-analysis. Sixteen studies, including 13 of high quality and three of moderate quality, were included. A large number of biomechanical variables were evaluated, producing inconsistent evidence overall. Limited evidence indicated greater peak hip adduction in female runners developing patellofemoral pain and iliotibial band syndrome, but not for a mixed-sex population of cross-country runners sustaining an RRI. The relationship between vertical loading rate and RRIs was inconsistent. Other kinematic, kinetic and spatiotemporal factors were only studied to a limited extent. Current prospective evidence relating biomechanical variables to RRI risk is sparse and inconsistent, with findings largely dependent on the population and injuries being studied. Future research is needed to confirm these biomechanical risk factors and determine whether modification of these variables may assist in running injury prevention and management.

The Association Between Changes in Weekly Running Distance and Running-Related Injury: Preparing for a Half Marathon.

Sudden changes in training load may play a key role in the development of running-related injury (RRI). Because the injury mechanism depends on the runner's musculoskeletal load capacity, the running schedule followed prior to sudden change in training load may influence the amount of change that a runner can tolerate before the runner is at a higher risk of RRI. To investigate the association between change in weekly running distance and RRI, and to examine whether the association may be modified by the running schedule the runner follows. Two hundred sixty-one healthy (noninjured) runners were included in this prospective cohort study over a period of 14 weeks. Data on running activity were collected daily and objectively, using a global positioning system watch or smartphone. Instances of RRIs were collected using weekly e-mailed questionnaires. Primary exposure was defined as changes in weekly running distance. Data were analyzed with time-to-event models that produced cumulative risk difference as the measure of association. A total of 56 participants (21.5%) sustained an RRI during the 14-week study period. Twenty-one days into the study period, significantly more runners were injured when they increased their weekly running distance by 20% to 60% compared with those who increased their distance by less than 20% (risk difference, 22.6%; 95% confidence interval: 0.9%, 44.3%; P = .041). No significant difference was found after 56 and 98 days. No significant effect-measure modification by running schedule was found. Significantly more runners were injured 21 days into the study period when they increased their weekly running distances by 20% to 60% compared with those who increased their distances by less than 20%. Prognosis, level 1b. J Orthop Sports Phys Ther 2019;49(4):230-238. Epub 7 Dec 2018. doi:10.2519/jospt.2019.8541.

Textured insoles reduce vertical loading rate and increase subjective plantar sensation in overground running

The effect of textured insoles on kinetics and kinematics of overground running was assessed. 16 male injury-free-recreational runners attended a single visit (age 23 ± 5 yrs; stature 1.78 ± 0.06 m; mass 72.6 ± 9.2 kg). Overground 15-m runs were completed in flat, canvas plimsolls both with and without textured insoles at self-selected velocity on an indoor track in an order that was balanced among participants. Average vertical loading rate and peak vertical force (Fpeak) were captured by force platforms. Video footage was digitised for sagittal plane hip, knee and ankle angles at foot strike and mid stance. Velocity, stride rate and length and contact and flight time were determined. Subjectively rated plantar sensation was recorded by visual scale. 95% confidence intervals estimated mean differences. Smallest worthwhile change in loading rate was defined as standardised reduction of 0.54 from a previous comparison of injured versus non-injured runners. Loading rate decreased (−25 to −9.3 BW s−1; 60% likely beneficial reduction) and plantar sensation was increased (46–58 mm) with the insole. Fpeak (−0.1 to 0.14 BW) and velocity (−0.02 to 0.06 m s−1) were similar. Stride length, flight and contact time were lower (−0.13 to −0.01 m; −0.02 to−0.01 s; −0.016 to −0.006 s) and stride rate was higher (0.01–0.07 steps s−1) with insoles. Textured insoles elicited an acute, meaningful decrease in vertical loading rate in short distance, overground running and were associated with subjectively increased plantar sensation. Reduced vertical loading rate could be explained by altered stride characteristics.

RECREATIONAL RUNNER' STRATEGIES TO COPE WITH INJURY AND ILLNESS DURING MARATHON RACE PREPARATIONS: CROSS-SECTIONAL STUDY IN SWEDEN

BackgroundRunning is one of the most popular forms of physical exercise worldwide. It is therefore discomforting that pain and overuse injuries are common among recreational runners. The coping concept is...

Mechanical Risk Factors for Stress Fracture in Elite Runners

Objectives:Bone stress injuries (BSI) are responsible for significant missed competition and training in distance runners. A recent review of our institution’s injury database revealed that one-fifth of NCAA-level runners sustained one or more BSI over a three-year period. While much is known about certain risk factors for stress injury such as the Female Athlete Triad, little is known about biomechanical risk factors including dynamic loading of the foot during running differs between athletes with history of BSI and those without. The aims of this study were: 1) characterize the dynamic loading patterns of elite distance runners during athletic movement, 2) determine the difference in dynamic loading magnitude and location in runners who have history of a BSI compared to non-injured runners and 3) establish a database to be used for follow-up evaluation. We hypothesized that athletes with a history of BSI in the lower extremity apply greater dynamic loads during athletic movements compared to uninjured athletes.Methods:We recruited 40 healthy varsity distance runners (16 females, 24 males) from our institution to participate in the study. Dynamic foot loading data was collected on all athletes using a validated wireless insole pressure measurement system during a series of athletic movements (e.g., walking, running and lateral cutting). Data was collected for contact area, maximum force, peak pressure, maximum mean pressure and force-time integral at each of eleven foot regions during each athletic movement. All force and pressure data were normalized to body weight. Injury history and other potential risk factors of interest were collected by self-report questionnaire and chart review. All BSI occurred as a result of participation of running, diagnosed by a physician and confirmed with advanced imaging. Mean values were calculated for each variable and foot region in each athlete and paired t-tests were performed for injury history comparisons.Results:A total of 23 runners with a history of 1 or more lower extremity BSI (11 females, 12 males), and 17 athletes with no history of BSI (5 females, 12 males) participated. Runners with a history of BSI trended toward greater peak pressures during running activities (p = .13) compared to uninjured controls, and displayed significantly greater peak pressures in the forefoot during cutting movements (p < .05). Further, those with history of BSI in the foot and ankle displayed greater force-time integral in the forefoot during running (p = .06). In the medial forefoot, athletes with history of BSI displayed significantly greater maximum mean pressures during jump takeoff (p < .05), running (p = .05) and cutting (p < .05). We did not observe a difference in foot strike patterns or FAAM Sport scores between injured and uninjured runners. Menstrual irregularities were seen in a majority of female athletes and were not associated with BSI.Conclusion:Our findings suggest that elite runners with a history of BSI exert greater pressures and force-time integral in the forefoot and medial midfoot during running and cutting compared to uninjured athletes. The greater loads in the forefoot and medial midfoot may play a role in the incidence and recurrence of BSI in running athletes. Further study of our athlete cohort will allow elucidation of specific high pressure points in the foot that may place athletes at risk for specific BSI, and allow us to investigate the utility of preventive measures.

Stride Frequency And Injury Rates In Recreational Runners Training For A Half-marathon

Injuries are common among runners training for distance events with annual incidence rates ranging from 19.4 to 79.3%. Recently, lower stride frequencies (SF) have been hypothesized as a potential factor contributing to these high injury rates. It has been suggested that SF ≤162 steps per minutes (spm) may increase the likelihood of injury, whereas, SF ≥169 spm may be protective. PURPOSE: To compare SF in injured and non-injured runners before and after training for a half-marathon. METHODS: Twenty-eight recreational runners (males: n=9, 47.8±7.8yrs; females: n=19, 46.6±7.7yrs) training for a half-marathon volunteered to participate. Prior to beginning training (PRE), a 30-second 3-dimensional gait analysis was performed at a self-selected pace. The pace was used again for analysis at the conclusion of training (POST). Throughout training, participants submitted an online daily questionnaire regarding training and injury. Paired t-tests compared participants PRE to POST and a chi-square analysis examined the difference in injury rates between groups. RESULTS: Overall, SF significantly increased, 165.3 ± 8.3 spm PRE to 173.2 ± 11.6 spm POST (p=<0.01). 15 of the 28 runners sustained an injury and their SF significantly increased, 162.1 ± 6.6 spm PRE to 171.6 ± 10.5 spm POST, p=<0.01. During PRE analysis, 12 runners had SF ≤162 spm (Low SF) and 9 had SF ≥169 spm (High SF). Difference in injury rates between SF groups was found to be significantly different (8/12, Low SF vs. 2/9, High SF; p=0.04). Of the Low SF group, 8 reported an injury and of the High SF group, only 2 reported an injury. Compared to PRE, the Low SF group significantly improved their cadence, 157.8 ± 3.0 spm PRE to 166.3 ± 8.8 spm POST (p=0.02). As well, 8 of the 12 Low SF runners improved their rates above 162 spm; 7 were runners reporting an injury (87.5%), and only 1 was a non-injured runner (25%). CONCLUSIONS: Prior to beginning training, 42.9% of participants had SF below 163 spm, and this group had injury rates of 66.7%. Comparatively, 32.1% of participants had SF above 168 spm, and their injury rates were 22.2%. This suggests SF ≥169 spm may have been protective. Future research is needed to examine if altering SF for those with cadences ≤162 spm prior to training would decrease injury rates for runners training for half-marathons.

Does Non-Running Physical Activity Contribute to the Risk of Developing a Running Related Overuse Injury?

Running related overuse injury (RROI) affects a significant proportion of runners annually. To date, only running mileage has been considered when quantifying the amount of loading that may elicit tissue micro-damage and injury, while the loading that occurs from activities of daily living and non-running physical activity has been ignored. By ignoring non-running physical activity (PA), we may be severely underestimating the amount of loading that leads to RROI. PURPOSE: To determine the role of daily non-running PA on the risk of RROI development among recreational and competitive runners. METHODS: As part of a larger prospective running injury pilot study, 50 recreational and competitive male and female runners will be enrolled and complete questionnaires regarding running history, injury history, and all forms of non-running daily PA. Participants will receive a FitBit Charge activity monitor to track PA for 24 hrs/day over 12 months. To date, questionnaires and a typical running gait analysis had been completed by 21 participants (9 male, 12 female; 27.5±6.3 years; BMI = 22.6±2.0 kg/m^2). RESULTS: Participants had mean±SD running experience of 8.6±5.6 years and run 24.1±15.2 mi/wk. Among n = 21 participants, RROI occurred within the past year in n = 4, within the past two years in n = 11, and in their lifetime in n = 16. Current mi/wk was 54% greater in those that had sustained a RROI in their lifetime compared with those that had not (No RROI = 15.3±4.5 mi/wk; Yes RROI 26.9±16.4 mi/wk, P=0.02). Total PA was not different between those who had and had not sustained a RROI in their lifetime or in the past 1-2 years (P>0.05). Non-running PA was greater in those that did not sustain a RROI in each time period, but the differences were not significant with this initial sample size (No RROI vs Yes RROI: lifetime 11.8±8.3 vs 7.1±7.2 hrs/wk, P>0.05; 1 yr: 8.7±8.2 vs 6.1±3.9 hrs/wk, P>0.05; 2 yr: 9.2±8.6 vs 7.3±6.8 hrs/wk, P>0.05). CONCLUSIONS: Results from the first 21 participants enrolled in this study support previous reports that running mi/wk may increase RROI risk. Given that total PA was the same between injured and non-injured runners in this sample, more hrs/wk spent in non-running PA vs running PA may reduce RROI risk. Continuous monitoring of PA collected in this 12 month study will provide evidence to support or reject this hypothesis.

Comparison Of Biomechanics And Metabolic Cost Among Elliptical Exercises And Running In Runners

Standard elliptical devices are a popular cross-training modality as they have similar metabolic cost as running with minimal lower extremity impact. A modified elliptical device produces lateral movement of the lower extremities and yields knee and hip joint motion that may have positive clinical implications for injured runners. PURPOSE: Compare acute differences in joint kinematics and metabolic cost between treadmill running (TR), standard elliptical (SE), and lateral elliptical (LE) in runners. METHODS: 16 non-injured runners (8 men) completed ten minutes of randomized exercise on TR, SE and LE on separate days. 3D knee and hip joint kinematics for the right limb were collected using a motion capture system (Qualisys). Oxygen consumption (VO2; ml/kg/min) was collected using a metabolic system (Parvo Medics). Motion data were analyzed using Visual3D (C-Motion). One-way repeated measures ANOVA to assess exercise type main effects (p<0.05) and cohen’s d effect sizes (ES) to assess mean differences were used. RESULTS: The knee ROM were different in LE (69.2±9.4°; extension) compared to SE (32.4±6.5°; ES=4.70; extension) and TR (-17.9±3.2°; ES=12.81; flexion) and, different between SE and TR (ES=10.14). The transverse plane hip ROM were different in LE (-8.9±8.1°; ES=2.94; external rotation) and TR (-3.3±4.9°; ES=3.07; external rotation) compared to SE (8.0±2.2°; internal rotation) and different between LE and SE (ES=0.86). Frontal plane hip ROM were different in LE (-16.4±5.5°; ES=5.32; abduction) and SE (2.7±1.9°; ES=1.27; adduction) compared to TR (5.3±2.3°; adduction) and, different between LE and SE (ES=4.79). Contralateral pelvic drop ROM were greater in LE (-5.3±4.8°; ES=0.83) and TR (-5.7±1.9°; ES=1.71) compared to SE (-2.3±2.2°). Finally, VO2 were greater in both TR (36.9±4.4; ES=2.65) and LE (36.8±8.3; ES=1.70) compared to SE (26.1±4.0). CONCLUSIONS: The LE yields joint motions that could have strengthening effects to help prevent knee and hip joint running injuries. However, greater pelvis drop in LE may have injurious consequences. The greater VO2 during LE suggests that LE may be more comparable to TR for metabolic activity than SE. The greater VO2 in LE may be due to greater frontal plane muscle control. Studies on chronic elliptical training effects are warranted in healthy and injured runners.

Effectiveness of Preseason Functional Movement Screen in Predicting Injuries in Collegiate Female Cross Country Runners

Functional Movement Screen (FMS) testing includes seven movement sets scored 0 through 3, with a maximum FMS score of 21. A preseason FMS score of 14 or below and preseason FMS asymmetries between contralateral limbs have been associated with increased likelihood of sports-related injury during the competitive season in footballand other sports. PURPOSE: To determine whether preseason FMS testing is reliable for predicting injury in female collegiate cross country runners during their season. METHODS: Fifty-seven female collegiate cross country runners from three division I and III universities were enrolled and tested before the fall 2013 competitive season. Runners provided informed consent and reported history of previous injuries. Participants with existing running-related injury at recruitment were excluded. Each participant was tested independently by two experienced testers, and the mean of the two scores was used. During the 12-week season, participants completed a weekly survey on running-related injuries, defined as injury requiring missing at least one practice or competition. RESULTS: Four consented athletes dropped off their team before the competitive season. Athletes had been running 5.8±2.0 yrs, did speed training 2.2±0.7 times per week, and had longest weekly run of 9.9±2.5 miles. FMS score for all athletes (n=53) was 13.2±1.7 (mean±SD), and 36 runners (68%) scored 14 or below. Of the 53 athletes, 47 (89%) completed an average of 65% of the weekly surveys and 12 (23%) completed all 12 weekly surveys. Six athletes (13%) completed no surveys. Of the 47 runners with surveys, 22 (47%) reported one or more running injuries and 25 (53%) reported no injury. Running injuries were responsible for 142 missed practices and 17 missed competitions. There was no significant difference among FMS scores of noninjured runners (13.0±1.5 [n=25]), those with one injury (13.7±1.4 [n=6]), or more than one injury (13.3±2.0 [n=16]; p=0.66). No difference was found in number of asymmetries between runners with no seasonal injuries (1.3±0.85 [n=25]) and those with at least one injury (1.07±0.76 [n=22]; p=0.38). CONCLUSION: Preseason FMS scores and asymmetry measures in female collegiate cross country runners did not predict who will sustain a running-related injury during the competitive season

Differences in joint-position sense and vibratory threshold in runners with and without a history of overuse injury.

A relationship between altered postural control and injury has been reported in sports. Sensorimotor function serves a fundamental role in postural control and is not often studied in runners. Persons who sustain running injury may have altered sensorimotor function contributing to risk of injury or reinjury. To determine if differences in knee and ankle proprioception or plantar sensation exist between injured and noninjured runners. Retrospective case-control study. University campus. Twenty runners with a history of lower-extremity overuse injury and 20 noninjured runners were examined. Injured runners were subcategorized into 2 groups based on site of injury: foot/ankle and knee/hip. Active absolute joint-repositioning error of the ankle at 20° inversion and 10° eversion and the knee at 15° and 40° flexion was assessed using an isokinetic dynamometer. Vibratory threshold at the calcaneus, arch, and great toe was determined for each subject using a handheld electric sensory threshold instrument. Runners in the injured-foot/ankle group had increased absolute error during ankle-eversion repositioning (6.55° ± 3.58°) compared with those in the noninjured (4.04° ± 1.78°, P = .01) and the hip/knee (3.63° ± 2.2°, P = .01) groups. Runners in the injured group, as a whole, had greater sensitivity in the arch of the plantar surface (2.94 ± 0.52 V) than noninjured runners (2.38 ± 0.53 V, P = .02). Differences in ankle-eversion proprioception between runners with a history of ankle and foot injuries and noninjured runners were observed. Runners with a history of injury also displayed an increased vibratory threshold in the arch region compared with noninjured runners. Poor ankle-joint-position sense and increased plantar sensitivity suggest altered sensorimotor function after injury. These factors may influence underlying postural control and contribute to altered loading responses commonly observed in injured runners.

Differences in kinetic asymmetry between injured and noninjured novice runners: A prospective cohort study

PurposeThe purpose of this prospective study was to describe natural levels of asymmetry in running, compare levels of asymmetry between injured and noninjured novice runners and compare kinetic variables between the injured and noninjured lower limb within the novice runners with an injury. MethodsAt baseline vertical ground reaction forces and symmetry angles (SA) were assessed with an instrumented treadmill equipped with three force measuring transducers. Female participants ran at 8 and 9kmh−1 and male runners ran at 9 and 10kmh−1. Participants were novice female and male recreational runners and were followed during a 9-week running program. ResultsTwo hundred and ten novice runners enrolled this study, 133 (63.3%) female and 77 (36.7%) male runners. Thirty-four runners reported an RRI. At baseline SA values varied widely for all spatio-temporal and kinetic variables. The inter-individual differences in SA were also high. No significant differences in SA were found between female and male runners running at 9kmh−1. In injured runners the SA of the impact peak was significantly lower compared to noninjured runners. ConclusionsNatural levels of asymmetry in running were high. The SA of impact peak in injured runners was lower compared to noninjured runners and no differences were seen between the injured and noninjured lower limbs.