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. (C) 2018 Published by Elsevier Ltd on behalf of Sports Medicine Australia.

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 10 weeks or shorter was regarded as a relatively good prognosis, while an injury duration of more than 10 weeks 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: 1-52 weeks). 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. (C) 2018 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

This study examined the criterion validity of self-reported running-related injuries (RRI) by novice runners. Fifty-eight participants (41 females; age 4611yrs) 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

Background In sedentary subjects use of medication is expected to be high which may cause problems when taking up exercise as several types of medication have been linked to musculoskeletal disorders. Objective To study the relation between medication use and the incidence of running-related injuries in novice runners. Design Prospective cohort study with propensity score matching analysis. Setting A nationwide start to run program for novice runners (N=7,660). Patients (or Participants) Novice runners (N=1,696) aged between 18–65 years taking part in a start to run program. Interventions (or Assessment of Risk Factors) Self-reported medication use was assessed with a questionnaire at baseline. Medication was categorized according to (1) condition and (2) chemical properties. Subjects who used medication were matched to controls using propensity score matching. Main Outcome Measurements Incidence rate differences were calculated between subjects that used medication and matched controls for each medication category. Results Women who took contraceptives had lower incidence densities of running-related injuries compared to matched controls both when medication was categorized according to condition (all contraceptives: incidence rate difference=−21.2 injuries/1000 h, 95% CI −41.9−−0.5) and according to chemical properties (hormonal contraceptives: incidence rate difference=−35.7 injuries/1000 h, 95% CI −61.3−−10.1). For other medication types no relation with injuries was established. Conclusions The study gives an overview of the influence of medication use on injuries in novice runners. Only for contraceptive use a relation with injuries was found. The use of contraceptives seems to have a preventive effect on the occurrence of injuries. An explanation for this finding may be the direct hormonal effect of contraceptives, for example on neuromuscular control and joint laxity, or an indirect effect through personal characteristics related to contraceptive use, such as health behaviour or risk-taking behaviour.

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. (C) 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

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.

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 1000 h 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. (C) 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

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.

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 (sic)83.22 (95% CI(sic)50.42-(sic)116.02) per RRI, and (sic)13.35 (95% CI(sic)7.07-(sic)19.63) per participant. The direct cost per RRI was (sic)56.93 (95% CI (sic)42.05-(sic)71.81) and the indirect cost per RRI was (sic)26.29(95% CI (sic)0.00-(sic)54.79). The indirect cost was higher for sudden onset RRIs than for gradual onset RRIs, with a mean difference of (sic)33.92 (95% CI (sic)17.96-(sic)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. (C) 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Hardlopen is wereldwijd een populaire sport welke vaak wordt beoefend voor de positieve gezondheidseffecten. Er is echter een keerzijde. Hardlopers worden vaak geplaagd door blessures. Een probleem waar veelal beginners tegenaan lopen. Dit proefschrift beschrijft de NLstart2run studie, een onderzoek waarin een groep van 1.700 beginnende hardlopers gedurende een 6-weekse “Start to Run” cursus is gevolgd. Doel van dit onderzoek was de kennis betreffende incidentie en risicofactoren voor hardloopblessures te vergroten. Dit zal uiteindelijk moeten bijdragen aan de introductie van blessurepreventieve maatregelen. Tijdens de loopcursus liep 10,9% van de deelnemers een blessure op wat gelijk was aan een incidentie van 27,5 blessures per 1.000 uur hardlopen. De meeste blessures ontstonden rond de knie (38,4%) en kuit (20,0%). Hardlopers zonder hardloopervaring, met vroegere beweeg klachten, een hogere leeftijd en hogere BMI hadden een verhoogd risico op het ontstaan van een blessure. Daarnaast bleek trainingsfrequentie geen significante relatie met blessure ontstaan te hebben en trainen op hogere intensiteit in de voorafgaande week het blessurerisico te verhogen. Meer dan 60 minuten hardlopen in de voorgaande week bleek het blessurerisico te verlagen. Dit is verrassend, omdat dit betekent dat minder hardlopen het blessurerisico verhoogd. Waarschijnlijk liggen andere factoren hieraan ten grondslag. In toekomstige studies moeten we ons daarom realiseren dat de relatie tussen training en blessure verandert door persoonsfactoren. Dit inzicht moet gebruikt gaan worden om persoonspecifieke trainingsprogramma’s aan te kunnen bieden met als doel het blessurerisico te verlagen. Vanuit dit oogpunt kan een digitale coaching app veel mogelijkheden voor zowel onderzoek als implementatie.

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.

Objectives: Minimalist running shoes have been proposed as an alternative to barefoot running. However, several studies have reported cases of forefoot stress fractures after switching from standard to minimalist shoes. Therefore, the aim of the current study was to investigate the differences in plantar pressure in the forefoot region between running with a minimalist shoe and running with a standard shoe in healthy female runners during overground running.Design: Randomized crossover design.Methods: In-shoe plantar pressure measurements were recorded from eighteen healthy female runners. Peak pressure, maximum mean pressure, pressure time integral and instant of peak pressure were assessed for seven foot areas. Force time integral, stride time, stance time, swing time, shoe comfort and landing type were assessed for both shoe types. A linear mixed model was used to analyze the data.Results: Peak pressure and maximum mean pressure were higher in the medial forefoot (respectively 13.5% and 7.46%), central forefoot (respectively 37.5% and 29.2%) and lateral forefoot (respectively 37.9% and 20.4%) for the minimalist shoe condition. Stance time was reduced with 3.81%. No relevant differences in shoe comfort or landing strategy were found.Conclusions: Running with a minimalist shoe increased plantar pressure without a change in landing pattern. This increased pressure in the forefoot region might play a role in the occurrence of metatarsal stress fractures in runners who switched to minimalist shoes and warrants a cautious approach to transitioning to minimalist shoe use. (C) 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

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. (C) 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Background Running is a sport practiced by many individuals. The positive health effects as a result of running are well known. On the other side, between 17 and 79% of the runners sustain an injury each year. Several studies examined potential risk factors for injuries, however, due to the often underpowered studies it is not possible to reveal the complex mechanism leading to a running related injury yet. Objective To examine the incidence of running related injuries and its determinants in novice runners. Design Prospective cohort study. Participants Novice runners participating in a “Start to Run” course were eligible for inclusion. 1075 novice runners were included in the study and were followed during the six week running program. Risk factor assessment Before the start of the running course, all runners completed a baseline questionnaire concerning personal characteristics and sports and injury history. During the running program training information was monitored with a digital weekly running log. This running log was used to obtain running exposure and register running related injuries. Main outcome measures A running related injury. Results During the running course 181 running related injuries were registered in 120 participants, which represents an incidence of 11.2%. The data on predisposing variables on injury development was not analyzed yet, but will be available at the conference April 2014. Conclusion During a six-week running course for novice runners, 11.2% of the participants will sustain at least one running related injury.

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.

Running is a popular form of physical activity, despite of the high incidence of running‐related injuries (RRIs). Because of methodological issues, the etiology of RRIs remains unclear. Therefore, the purposes of the study were to assess the incidence of RRIs and to identify risk factors for RRIs in a large group of novice runners. In total, 1696 runners of a 6‐week supervised “Start to Run” program were included in the NLstart2run study. All participants were aged between 18 and 65, completed a baseline questionnaire that covered potential risk factors, and completed at least one running diary. RRIs were registered during the program with a weekly running log. An RRI was defined as a musculo‐skeletal complaint of the lower extremity or back attributed to running and hampering running ability for three consecutive training sessions. During the running program, 10.9% of the runners sustained an RRI. The multivariable Cox regression analysis showed that a higher age, higher BMI, previous musculo‐skeletal complaints not attributed to sports and no previous running experience were related to RRI. These findings indicate that many novice runners participating in a short‐term running program suffer from RRIs. Therefore, the identified risk factors should be considered for screening and prevention purposes.

Purpose: The 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.Methods: At 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 9 km h(-1) and male runners ran at 9 and 10 km h(-1). Participants were novice female and male recreational runners and were followed during a 9-week running program.Results: Two 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 9 km h(-1). In injured runners the SA of the impact peak was significantly lower compared to noninjured runners.Conclusions: Natural 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. (c) 2013 Elsevier B.V. All rights reserved.

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.

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 (ICC(3,1)) 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.

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.