Prognosis and prognostic factors of running-related injuries in novice runners: A prospective cohort study.

OBJECTIVES: To investigate the prognosis and possible prognostic factors of running-related injuries (RRIs) in novice runners. DESIGN: Prospective cohort study. METHODS: Participants of Start to Run, a 6-weeks course for novice runners in The Netherlands, were asked to participate in this study. Before the start of the course a baseline questionnaire, on demographics, physical activity and perceived health, was sent to runners willing to participate. The 26- or 52-weeks follow-up questionnaires assessed information on RRIs and their duration. Only participants that sustained a RRI during follow-up were included in the analyses. An injury duration of 10weeks or shorter was regarded as a relatively good prognosis, while an injury duration of more than 10weeks was defined as a poor prognosis. To determine the associations between baseline characteristics and injury prognosis and between injury location and injury prognosis, multivariable logistic regression analyses were performed. RESULTS: 347 participants (48.8%) sustained an RRI during follow-up. The RRIs had an overall median duration of eight weeks (range: 1-52weeks). Participants with a previous RRI were more likely to have a poor prognosis (OR 2.31; 95%CI 1.12-4.79), while a calf injury showed a trend towards an association with a relatively good prognosis (OR 0.49; 95%CI 0.22-1.11). CONCLUSIONS: The duration of RRIs in novice runners is relatively long, with only calf injuries being associated with a good prognosis. This emphasizes the need of injury prevention measures in novice runners and adequate support during and after an RRI, especially in runners with a previous injury.

Reasons and predictors of discontinuation of running after a running program for novice runners.

OBJECTIVES: To determine the proportion of participants of a running program for novice runners that discontinued running and investigate the main reasons to discontinue and characteristics associated with discontinuation. DESIGN: Prospective cohort study. METHODS: The study included 774 participants of Start to Run, a 6-week running program for novice runners. Before the start of the program, participants filled-in a baseline questionnaire to collect information on demographics, physical activity and perceived health. The 26-weeks follow-up questionnaire was used to obtain information on the continuation of running (yes/no) and main reasons for discontinuation. To determine predictors for discontinuation of running, multivariable logistic regression was performed. RESULTS: Within 26 weeks after the start of the 6-week running program, 29.5% of the novice runners (n=225) had stopped running. The main reason for discontinuation was a running-related injury (n=108, 48%). Being female (OR 1.74; 95% CI 1.13-2.68), being unsure about the continuation of running after the program (OR 2.06; 95% CI 1.31-3.24) and (almost) no alcohol use (OR 1.62; 95%CI 1.11-2.37) were associated with a higher chance of discontinuation of running. Previous running experience less than one year previously (OR 0.46; 95% CI 0.26-0.83) and a higher score on the RAND-36 subscale physical functioning (OR 0.98; 95% CI 0.96-0.99) were associated with a lower chance of discontinuation. CONCLUSIONS: In this group of novice runners, almost one-third stopped running within six months. A running-related injury was the main reason to stop running. Women with a low perceived physical functioning and without running experience were prone to discontinue running.

Validity of injury self-reports by novice runners: comparison with reports by sports medicine physicians.

This study examined the criterion validity of self-reported running-related injuries (RRI) by novice runners. Fifty-eight participants (41 females; age 46 ± 11 yrs) of the "Start-to-Run" program provided self-reports on their RRIs using an online questionnaire. Subsequently, they attended injury consultations with sports medicine physicians who provided physician-reports (blinded for the self-reports) as a reference standard. Self-reports and physician-reports included information on injury location (i.e., hip/groin, upper leg, knee, lower leg, and ankle/foot) and injury type (i.e., muscle-tendon unit, joint, ligament, or bone). Sensitivity, specificity, and positive predictive values were 100% for all five injury locations. For injury type, sensitivity was low (66% for muscle-tendon unit, 50% for ligament, and 40% for bone) and lowest for joint injuries (17%). In conclusion, the validity of self-reported RRIs by novice runners is good for injury locations but not for injury types. In particular for joint injuries, the validity of novice runners' self-reports is low. Abbreviations: RRI: Running Related Injury; SMC: Sports Medicine Centre; MTU: Muscle Tendon Unit; PPV: Positive Predictive Value.

Biomechanics of running with rocker shoes.

OBJECTIVES: Load reduction is an important consideration in conservative management of tendon overuse injuries such as Achilles tendinopathy. Previous research has shown that the use of rocker shoes can reduce the positive ankle power and plantar flexion moment which might help in unloading the Achilles tendon. Despite this promising implication of rocker shoes, the effects on hip and knee biomechanics remain unclear. Moreover, the effect of wearing rocker shoes on different running strike types is unexplored. The aim of this study was to investigate biomechanics of the ankle, knee and hip joints and the role of strike type on these outcomes. DESIGN: Randomized cross-over study. METHODS: In this study, 16 female endurance runners underwent three-dimensional gait analysis wearing rocker shoes and standard shoes. We examined work, moments, and angles of the ankle, knee and hip during the stance phase of running. RESULTS: In comparison with standard shoes, running with rocker shoes significantly (p<0.001) reduced the positive (16%), and negative (32%) work at the ankle joint. Plantar flexion moment peak and impulse were also reduced by 11% and 12%, respectively. Reduction in these variables was almost two times larger for midfoot strikers than for rearfoot strikers. At the knee joint running with rocker shoes significantly increased the positive work (14%), extension moment peak (6%), and extension moment impulse (12%). CONCLUSIONS: These findings indicate that although running with rocker shoes might lower mechanical load on the Achilles tendon, it could increase the risk of overuse injuries of the knee joint.

Short-Term Absenteeism and Health Care Utilization Due to Lower Extremity Injuries Among Novice Runners: A Prospective Cohort Study.

OBJECTIVE: To describe absenteeism and health care utilization (HCU) within 6 weeks after occurrence of running-related injuries (RRIs) among novice runners and to explore differences relating to injury and personal characteristics. DESIGN: Prospective cohort study. SETTING: Primary care. PARTICIPANTS: One thousand six hundred ninety-six novice runners (18-65 years) participating in a 6-week running program ("Start-to-Run"). MAIN OUTCOME MEASURES: Injury characteristics were assessed by weekly training logs and personal characteristics by a baseline questionnaire. Data on absenteeism and HCU were collected using questionnaires at 2 and 6 weeks after the RRI occurred. RESULTS: A total of 185 novice runners (11%) reported an RRI during the 6-week program. Of these injured novice runners, 78% reported absence from sports, whereas only 4% reported absence from work. Fifty-one percent of the injured novice runners visited a health care professional, mostly physical therapists (PTs) rather than physicians. Absenteeism was more common among women than men and was also more common with acute RRIs than gradual-onset RRIs. As regards HCU, both the variety of professionals visited and the number of PT visits were higher among runners with muscle-tendon injuries in the ankle/foot region than among those with other RRIs. CONCLUSIONS: Among novice runners sustaining an RRI during a 6-week running program, over three quarters reported short-term absence from sports, whereas absence from work was very limited, and over half used professional health care. Both absence and HCU are associated with injury characteristics. CLINICAL RELEVANCE: In future running promotion programs (eg in Start-to-Run programs), specific attention should be paid to acute injuries and to muscle-tendon injuries in the ankle/foot region.

The NLstart2run study: Economic burden of running-related injuries in novice runners participating in a novice running program.

OBJECTIVES: To investigate the economic burden of running-related injuries (RRI) occurred during the 6-week 'Start-to-Run' program of the Dutch Athletics Federation in 2013. DESIGN: Prospective cohort study. METHODS: This was a monetary cost analysis using the data prospectively gathered alongside the RRI registration in the NLstart2run study. RRI data were collected weekly. Cost diaries were applied two and six weeks after the RRI registration to collect data regarding healthcare utilisation (direct costs) and absenteeism from paid and unpaid work (indirect costs). RRI was defined as running-related pain that hampered running ability for three consecutive training sessions. RESULTS: From the 1696 participants included in the analysis, 185 reported a total of 272 RRIs. A total of 26.1% of the cost data (71 RRIs reported by 50 participants) were missing. Therefore, a multiple imputation procedure was performed. The economic burden (direct plus indirect costs) of RRIs was estimated at €83.22 (95% CI €50.42-€116.02) per RRI, and €13.35 (95% CI €7.07-€19.63) per participant. The direct cost per RRI was €56.93 (95% CI €42.05-€71.81) and the indirect cost per RRI was €26.29 (95% CI €0.00-€54.79). The indirect cost was higher for sudden onset RRIs than for gradual onset RRIs, with a mean difference of €33.92 (95% CI €17.96-€49.87). CONCLUSIONS: Direct costs of RRIs were 2-fold higher than the indirect costs, and sudden onset RRIs presented higher costs than gradual onset RRIs. The results of this study are important to provide information to public health agencies and policymakers about the economic burden of RRIs in novice runners.

The NLstart2run study: Training-related factors associated with running-related injuries in novice runners.

OBJECTIVES: The incidence of running-related injuries is high. Some risk factors for injury were identified in novice runners, however, not much is known about the effect of training factors on injury risk. Therefore, the purpose of this study was to examine the associations between training factors and running-related injuries in novice runners, taking the time varying nature of these training-related factors into account. DESIGN: Prospective cohort study. METHODS: 1696 participants completed weekly diaries on running exposure and injuries during a 6-week running program for novice runners. Total running volume (min), frequency and mean intensity (Rate of Perceived Exertion) were calculated for the seven days prior to each training session. The association of these time-varying variables with injury was determined in an extended Cox regression analysis. RESULTS: The results of the multivariable analysis showed that running with a higher intensity in the previous week was associated with a higher injury risk. Running frequency was not significantly associated with injury, however a trend towards running three times per week being more hazardous than two times could be observed. Finally, lower running volume was associated with a higher risk of sustaining an injury. CONCLUSIONS: These results suggest that running more than 60min at a lower intensity is least injurious. This finding is contrary to our expectations and is presumably the result of other factors. Therefore, the findings should not be used plainly as a guideline for novices. More research is needed to establish the person-specific training patterns that are associated with injury.

The impact of injury definition on injury surveillance in novice runners.

OBJECTIVES: Despite several consensus statements, different injury definitions are used in the literature. This study aimed to identify the impact of different injury definitions on the nature and incidence of complaints captured during a short-term running program for novice runners. DESIGN: Prospective cohort study. METHODS: 1696 participants completed weekly diaries on running exposure and musculoskeletal complaints during a 6-week running program. These data were used to compare six different injury definitions (presence of running-related pain, training-reduction, time-loss of one day or one week). Injuries were registered under these different definitions. Consequently incidence and the nature of complaints were compared between definitions. RESULTS: The different injury definitions resulted in incidences that varied between 7.5% and 58.0%, or 18.7 and 239.6 injuries per 1000h of running. The median duration of injury complaints was 4-7 days for injuries registered under a 'day definition', while complaints registered under a 'week definition' lasted 20-22 days. For running-related pain injuries the median of the maximum amount of pain was 3.0. In training-reduction and time-loss injuries these median values were scored between 5.0 and 7.0. No significant differences in anatomical locations between injuries that were registered under a 'day definition' or a 'week definition' were found. Injuries registered under a time-loss definition were located relatively more often at the knee, while complaints at the pelvis/sacrum/buttock were captured more often under a running-related pain definition. CONCLUSIONS: Injury definitions largely impact injury incidence. Location of injury is also affected by choice of injury definition. This stressed the need for standardized injury registration methods.

What are the Differences in Injury Proportions Between Different Populations of Runners? A Systematic Review and Meta-Analysis.

BACKGROUND: Many runners suffer from injuries. No information on high-risk populations is available so far though. OBJECTIVES: The aims of this study were to systematically review injury proportions in different populations of runners and to compare injury locations between these populations. DATA SOURCES: An electronic search with no date restrictions was conducted up to February 2014 in the PubMed, Embase, SPORTDiscus and Web of Science databases. The search was limited to original articles written in English. The reference lists of the included articles were checked for potentially relevant studies. STUDY ELIGIBILITY CRITERIA: Studies were eligible when the proportion of running injuries was reported and the participants belonged to one or more homogeneous populations of runners that were clearly described. Study selection was conducted by two independent reviewers, and disagreements were resolved in a consensus meeting. STUDY APPRAISAL AND SYNTHESIS METHODS: Details of the study design, population of runners, sample size, injury definition, method of injury assessment, number of injuries and injury locations were extracted from the articles. The risk of bias was assessed with a scale consisting of eight items, which was specifically developed for studies focusing on musculoskeletal complaints. RESULTS: A total of 86 articles were included in this review. Where possible, injury proportions were pooled for each identified population of runners, using a random-effects model. Injury proportions were affected by injury definitions and durations of follow-up. Large differences between populations existed. The number of medical-attention injuries during an event was small for most populations of runners, except for ultra-marathon runners, in which the pooled estimate was 65.6%. Time-loss injury proportions between different populations of runners ranged from 3.2% in cross-country runners to 84.9% in novice runners. Overall, the proportions were highest among short-distance track runners and ultra-marathon runners. LIMITATIONS: The results were pooled by stratification of studies according to the population, injury definition and follow-up/recall period; however, heterogeneity was high. CONCLUSIONS: Large differences in injury proportions between different populations of runners existed. Injury proportions were affected by the duration of follow-up. A U-shaped pattern between the running distance and the time-loss injury proportion seemed to exist. Future prospective studies of injury surveillance are highly recommended to take running exposure and censoring into account.

Rocker shoe, minimalist shoe, and standard running shoe: a comparison of running economy.

OBJECTIVES: Running with rocker shoes is believed to prevent lower limb injuries. However, it is not clear how running in these shoes affects the energy expenditure. The purpose of this study was, therefore, to assess the effects of rocker shoes on running economy in comparison with standard and minimalist running shoes. DESIGN: Cross-over design. METHODS: Eighteen endurance female runners (age=23.6 ± 3 years), who were inexperienced in running with rocker shoes and with minimalist/barefoot running, participated in this study. Oxygen consumption, carbon dioxide production, heart rate and rate of perceived exertion were measured while participants completed a 6-min sub-maximal treadmill running test for each footwear condition. The data of the last 2 min of each shoe condition were averaged for analysis. A linear mixed model was used to compare differences among three footwear conditions. RESULTS: Oxygen consumption during running with rocker shoes was on average 4.5% higher than with the standard shoes (p<0.001) and 5.6% higher than with the minimalist shoe (p<0.001). No significant differences were found in heart rate and rate of perceived exertion across three shoe conditions. CONCLUSIONS: Female runners, who are not experienced in running with the rocker shoes and minimalist shoes, show more energy expenditure during running with the rocker shoes compared with the standard and minimalist shoes. As the studied shoes were of different masses, part of the effect of increased energy expenditure with the rocker shoe is likely to be due to its larger mass as compared with standard running shoes and minimalist shoes.

Effect of rocker shoes on plantar pressure pattern in healthy female runners.

Rocker profile shoes (rocker shoes) are one of the treatment options of metatarsalgia and forefoot stress fractures. The efficacy of rocker shoes in unloading the forefoot pressure has been shown in walking. In running, however, the effect of rocker shoes on forefoot pressure is unknown. Eighteen healthy female runners participated in this study. In-shoe plantar pressures were recorded during running with the standard running shoes and rocker shoes. Shoe comfort was assessed after each shoe measurement. Peak pressure (PP), maximum mean pressure (MMP) and force-time integral (FTI) were determined for seven foot areas. The effects of shoes on the different outcome variables were statistically analyzed using a linear mixed model. Running with the rocker shoes caused a significant reduction (p<0.001) in all pressure parameters in the central and lateral forefoot. FTI and MMP were also reduced by 11% and 12% in the medial forefoot while running with rocker shoes. Running with rocker shoes resulted in a significant increase in all pressure parameters at the heel region (p<0.001). Running with rocker shoes received a significant (p<0.01) lower comfort rate than running with standard running shoes. Rocker shoes might be beneficial for runners who are recovering from metatarsalgia or stress fractures of the forefoot region, as it reduces plantar pressure in the forefoot region.

The NLstart2run study: health effects of a running promotion program in novice runners, design of a prospective cohort study.

BACKGROUND: Running is associated with desirable lifestyle changes. Therefore several initiatives have been undertaken to promote running. Exact data on the health effects as a result of participating in a short-term running promotion program, however, is scarce. One important reason for dropout from a running program is a running-related injury (RRI). The incidence of RRIs is high, especially in novice runners. Several studies examined potential risk factors for RRIs, however, due to the often underpowered studies it is not possible to reveal the complex mechanism leading to an RRI yet.The primary objectives are to determine short- and long-term health effects of a nationwide "Start to Run" program and to identify determinants for RRIs in novice runners. Secondary objectives include examining reasons and determinants for dropout, medical consumption and economical consequences of RRIs as a result of a running promotion program. METHODS/DESIGN: The NLstart2run study is a multi-center prospective cohort study with a follow-up at 6, 12, 24 and 52 weeks. All participants that sign up for the Start to Run program in 2013, which is offered by the Dutch Athletics Federation, will be asked to participate in the study.During the running program a digital running log will be completed by the participants every week to administer exposure and running related pain. After the running program the log will be completed every second week. An RRI is defined as any musculoskeletal ailment of the lower extremity or back that the participant attributed to running and hampers running ability for at least one week. DISCUSSION: The NLstart2run study will provide insight into the short- and long-term health effects as a result of a short-term running promotion program. Reasons and determinants for dropout from a running promotion program will be examined as well. The study will result in several leads for future RRI prevention and as a result minimize dropout due to injury. This information may increase the effectiveness of future running promotion programs and will thereby contribute positively to public health. TRIAL REGISTRATION: The Netherlands National Trial Register NTR3676. The NTR is part of the WHO Primary Registries.

Differences in kinetic variables between injured and noninjured novice runners: a prospective cohort study.

OBJECTIVES: This prospective study examined differences in kinetic variables between injured and noninjured novice female and male runners and their potential contribution to RRIs. DESIGN: A prospective cohort study. METHODS: At baseline vertical ground reaction forces 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). Primary outcome measure was a running related injury (RRI). Participants were novice female and male recreational runners and were followed during a 9-week running program with three running sessions a week. RESULTS: One hundred thirty three female and seventy seven male runners participated in this study. Mean age was 37.2years and the BMI was 23.9kgm(-2). During the nine week running program 16.2% of the participants sustained an injury and no difference in incidence between female and male runners was seen. In injured male runners loading rate was significantly higher compared to noninjured male runners at both running speeds and contact time in the injured male group was significantly shorter at 9kmh(-1). In the group of female injured and noninjured runners no differences on kinetic or spatio-temporal variables were observed. Female runners had significantly higher loading rates compared to male runners but this did not have an effect on the incidence of RRIs. CONCLUSIONS: This study showed that male injured runners had higher loading rates and shorter contact times than noninjured male runners. In female runners, however, no differences in kinetic or spatio-temporal variables were observed between injured and noninjured novice runners.

Comparison of vertical ground reaction forces during overground and treadmill running. A validation study.

BACKGROUND: One major drawback in measuring ground-reaction forces during running is that it is time consuming to get representative ground-reaction force (GRF) values with a traditional force platform. An instrumented force measuring treadmill can overcome the shortcomings inherent to overground testing. The purpose of the current study was to determine the validity of an instrumented force measuring treadmill for measuring vertical ground-reaction force parameters during running. METHODS: Vertical ground-reaction forces of experienced runners (12 male, 12 female) were obtained during overground and treadmill running at slow, preferred and fast self-selected running speeds. For each runner, 7 mean vertical ground-reaction force parameters of the right leg were calculated based on five successful overground steps and 30 seconds of treadmill running data. Intraclass correlations (ICC3,1) and ratio limits of agreement (RLOA) were used for further analysis. RESULTS: Qualitatively, the overground and treadmill ground-reaction force curves for heelstrike runners and non-heelstrike runners were very similar. Quantitatively, the time-related parameters and active peak showed excellent agreement (ICCs between 0.76 and 0.95, RLOA between 5.7% and 15.5%). Impact peak showed modest agreement (ICCs between 0.71 and 0.76, RLOA between 19.9% and 28.8%). The maximal and average loading-rate showed modest to excellent ICCs (between 0.70 and 0.89), but RLOA were higher (between 34.3% and 45.4%). CONCLUSIONS: The results of this study demonstrated that the treadmill is a moderate to highly valid tool for the assessment of vertical ground-reaction forces during running for runners who showed a consistent landing strategy during overground and treadmill running. The high stride-to-stride variance during both overground and treadmill running demonstrates the importance of measuring sufficient steps for representative ground-reaction force values. Therefore, an instrumented treadmill seems to be suitable for measuring representative vertical ground-reaction forces during running.