Lower extremity injuries in runners. Advances in prediction

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.

Predictive Effect of Well-Known Risk Factors and Foot-Core Training in Lower Limb Running-Related Injuries in Recreational Runners: A Secondary Analysis of a Randomized Controlled Trial

BACKGROUND

Running carries the risk of several types of running-related injuries (RRIs), especially in the lower limbs. The variety of risk factors and the lack of strong evidence for several of these injury risks hinder the ability to draw assertive conclusions about them, hampering the implementation of effective preventive strategies. Because the etiology of RRIs seems to be multifactorial, the presence of RRI risk factors might influence the outcome of therapeutic strategies in different ways. Thus, further investigations on how risk and protective factors influence the incidence and prevention of RRIs should be conducted.

PURPOSE

To investigate the predictive effect of well-known risk factors and 1 protective factor-foot-core training-on the incidence of lower limb RRIs in recreational runners.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Middle- and long-distance recreational runners (N = 118) were assessed at baseline and randomly allocated to either an intervention group (n = 57) or a control group (n = 61). The intervention group underwent an 8-week (3 times/wk) foot-core training program. Participants were followed for a year after baseline assessment for the occurrence of RRIs. Logistic regression with backward elimination of variables was used to develop a model for prediction of RRI in recreational runners. Candidate predictor variables included age, sex, body mass index, years of running practice, number of races, training volume, training frequency, previous RRI, and the foot-core exercise training.

RESULTS

The final logistic regression model included 3 variables. As previously shown, the foot-core exercise program is a protective factor for RRIs (odds ratio, 0.40; 95% CI, 0.15-0.98). In addition, older age (odds ratio, 1.07; 95% CI, 1.00-1.14) and higher training volume (odds ratio, 1.02; 95% CI, 1.00-1.03) were risk factors for RRIs.

CONCLUSION

The foot-core training was identified as a protective effect against lower limb RRI, which can be negatively influenced by older age and higher weekly training volume. The predictive model showed that RRIs should be considered a multivariate entity owing to the interaction among several factors.

REGISTRATION

NCT02306148 (ClinicalTrials.gov identifier).

Plantar Injuries in Runners: Is There an Association With Weekly Running Volume?

Running is an athletic activity that is increasingly gaining popularity. Despite its benefits, there are many suspected risk factors for running-related overuse injuries. The objective of this study is to describe injuries and clinical symptoms observed on the sole of the foot in runners, giving special attention to the weekly running volume. The literature presented in this narrative review is based on a non-systematic search of the Medline, Google Scholar, and ResearchGate databases and focuses on foot injuries (the full spectrum of the foot pathology from bones to tendons and plantar fascia, nerve, and joint disorders) in runners, which represents an important topic for both professional and recreational runners. The weekly running distance appeared to be one of the strongest predictors for future overuse injuries. Marathon training and average weekly running of over 20 km are possible predictive factors in the development of plantar foot injuries. The plantar medial aspect of the foot is the anatomic area of the foot that most frequently experiences pain, with numerous pathologic conditions. As a result, diagnosis is always a challenging task. The ability to obtain an accurate medical history and carefully perform a physical examination, together with good knowledge of the foot anatomy and kinesiology, are also proven to be key players in ensuring proper diagnosis.

Recognition of Foot-Ankle Movement Patterns in Long-Distance Runners With Different Experience Levels Using Support Vector Machines

Running practice could generate musculoskeletal adaptations that modify the body mechanics and generate different biomechanical patterns for individuals with distinct levels of experience. Therefore, the aim of this study was to investigate whether foot-ankle kinetic and kinematic patterns can be used to discriminate different levels of experience in running practice of recreational runners using a machine learning approach. Seventy-eight long-distance runners (40.7 ± 7.0 years) were classified into less experienced (n = 24), moderately experienced (n = 23), or experienced (n = 31) runners using a fuzzy classification system, based on training frequency, volume, competitions and practice time. Three-dimensional kinematics of the foot-ankle and ground reaction forces (GRF) were acquired while the subjects ran on an instrumented treadmill at a self-selected speed (9.5–10.5 km/h). The foot-ankle kinematic and kinetic time series underwent a principal component analysis for data reduction, and combined with the discrete GRF variables to serve as inputs in a support vector machine (SVM), to determine if the groups could be distinguished between them in a one-vs.-all approach. The SVM models successfully classified all experience groups with significant crossvalidated accuracy rates and strong to very strong Matthew’s correlation coefficients, based on features from the input data. Overall, foot mechanics was different according to running experience level. The main distinguishing kinematic factors for the less experienced group were a greater dorsiflexion of the first metatarsophalangeal joint and a larger plantarflexion angles between the calcaneus and metatarsals, whereas the experienced runners displayed the opposite pattern for the same joints. As for the moderately experienced runners, although they were successfully classified, they did not present a visually identifiable running pattern, and seem to be an intermediate group between the less and more experienced runners. The results of this study have the potential to assist the development of training programs targeting improvement in performance and rehabilitation protocols for preventing injuries.

Training for a (half-)marathon: Training volume and longest endurance run related to performance and running injuries

OBJECTIVE

Examine the associations of training volume and longest endurance run with (half-)marathon performance and running-related injuries (RRIs) in recreational runners.

MATERIALS AND METHODS

During the preparation for and directly after the running event, 556 participants of a half marathon and 441 participants of a marathon completed three questionnaires on RRIs, average weekly training volume and the longest endurance run. With finish time, decline in pace during the running event and RRIs as dependent variables, linear and logistic regression analyses were performed to test the associations with weekly training volume and the longest endurance run.

RESULTS

In half-marathon runners, a high training volume (>32 km/wk) (β -4.19, 95% CI: -6.52;-1.85) and a long endurance run (>21 km) (β -3.87, 95% CI: -6.31;--1.44) were associated with a faster finish time, while a high training volume (β -1.81, 95% CI: -3.49;-0.12) and a long endurance run (β -1.89, 95% CI: -3.65;-0.12) were also related to less decline in pace. In marathon runners, a low training volume (<40 km/wk) was related to a slower finish time (β 6.33, 95% CI: 0.18;12.48) and a high training volume (>65 km/wk) to a faster finish time (β -14.09, 95% CI: -22.47;-5.72), while a longest endurance run of <25 km was associated with a slower finish time (β 13.44, 95% CI: 5.34;21.55). No associations between training characteristics and RRIs were identified.

CONCLUSIONS

Preparation for a (half-)marathon with a relatively high training volume and long endurance runs associates with a faster finish time, but does not seem related to an increased injury risk.

Effect of deep transverse friction massage vs stretching on football players’ performance

BACKGROUND

Flexibility, agility and muscle strength are key factors to either win or lose a game. Recently the effect of a new technique, deep transverse friction massage (DTFM) on muscle extensibility as compared to traditional stretching techniques has been examined.

AIM

To compare the effect of DTFM vs static and dynamic stretching techniques on the hamstring’s extensibility, agility, and strength amongst Lebanese and Syrian football players. Recording the incidence of non-contact hamstring muscle injury was a secondary objective.

METHODS

This study is a single-blinded prospective longitudinal randomized controlled trial. The experiment took place over a period of four weeks. Football players were randomized into three intervention groups (static stretching; dynamic stretching; DTFM). Participants of each group were followed-up carefully by assessors during their intervention sessions three times per week, for a total of 12 sessions and during the data collection. Extensibility, agility, and strength were compared between intervention groups at (baseline; acute; and chronic) phases. Straight leg raise and 1 repetition maximum tests were used to measure the dominant leg hamstring muscle extensibility and maximal strength respectively. T-drill test was used to assess the lower extremities agility.

RESULTS

Of 103 Lebanese and Syrian male football players aged between 18 and 35 were sampled from Damascus-Syria and South of Lebanon to participate in this study. Between-groups measures of acute strength (P = 0.011) and chronic extensibility (P = 0.000) solely showed a significant difference, and the static group showed to be superior as compared to the other groups. No loss to follow-up or protocol violation was recorded.

CONCLUSION

Static stretching is showing to be superior to the other techniques used, regarding gaining long-term extensibility and short-term maximal muscle strength. In addition, DTFM showed improvements but did not outweigh the effects on footballers’ performance when comparing it to static and dynamic techniques. Finally, no difference between the interventions is recorded regarding the rate of muscle injuries incidence.

Segment Coordination Variability Differs by Years of Running Experience

Running is a popular activity that results in high rates of overuse injury, with less-experienced runners becoming injured at higher rates than their more-experienced peers. Although measures of joint kinematics and kinetics and ground reaction forces have been associated with overuse running injuries, similar differences across levels of running experience have not been found. Because running is a motor skill that may develop with experience, an analysis of segment coordination and its variability could provide additional insight into why injury incidence decreases with increasing experience.

PURPOSE

The purpose of this study was to determine if less-experienced runners have different segment coordination and lower segment coordination variability compared with their more-experienced peers.

METHODS

This retrospective analysis included 20 more-experienced (≥10 yr running) and 21 less-experienced (≤2 yr running) runners. Sagittal thigh versus shank and shank versus foot segment coordination and coordination variability were calculated using a modified vector coding approach as individuals ran on a treadmill at preferred pace. Coordination and its variability were compared between groups during terminal swing and early, mid, and late stance for both segment couples.

RESULTS

Segment coordination was similar between less- and more-experienced runners. Less-experienced runners had lower segment coordination variability compared with more-experienced runners for both the thigh versus shank and shank versus foot couples. This lower variability occurred during early and mid stance.

CONCLUSIONS

Runners appeared to attain stable segment coordination patterns within 2 yr of consistent running, but had lower coordination variability compared with individuals who had been running for 10 or more years. These results suggest that assessment of movement patterns and their flexibility may help inform injury prevention or treatment strategies for less-experienced runners.

Years of running experience influences stride-to-stride fluctuations and adaptive response during step frequency perturbations in healthy distance runners

RESEARCH QUESTION

The current study investigated stride-to-stride fluctuations of step rate and contact time in response to enforced step frequency perturbations as well as adaptation and de-adaptation behavior.

METHODS

Forty distance runners ran at a self-selected speed and were asked to match five different enforced step frequencies (150, 160, 170, 180, and 190 beats per min). The influence of experience was explored, because running is a skill that presumably gets better with practice, and increased years of running experience is protective against injury. Detrended fluctuation analysis was used to determine the strength of long-range correlations in gait fluctuations at baseline, during the perturbation, and post-perturbation. Adaptive response was measured by the ability to match, rate of matching, and aftereffect of step frequency perturbations.

RESULTS

The structure of stride-to-stride fluctuations for step rate and contact time did not change during the perturbation or post-perturbation compared to baseline. However, fluctuations in step rate were affected by the level of perturbation. Runners with the most experience had a less persistent structural gait pattern for both step rate and contact time at baseline. Highly experienced runners also demonstrated the best adaptive response. They better matched the enforced step frequency, reached the enforced step frequency sooner, and returned to preferred step frequency more quickly following removal of the perturbation.

SIGNIFICANCE

These findings indicate baseline locomotor flexibility may be beneficial to achieve task demands and return to a stable state once the task is complete. Increased locomotor flexibility may also be a contributing factor for reduced injury risk in experienced runners.

Experience does not influence injury-related joint kinematics and kinetics in distance runners

PURPOSE

Increased running experience and more time spent running appears to be advantageous in reducing injury risk, although the reason behind this is unclear. It is plausible that more experience results in better running mechanics leading to less injuries. Running mechanics are often screened during clinical assessments and targeted for correction in gait retraining, particularly those thought to be global indicators of injury or those associated with elevated knee joint loading. Examining the biomechanics of runners who are less-injury prone can improve our understanding of the significance of faulty running mechanics in relation to injury. Our goal was to examine if running experience was correlated to differences in kinematics and kinetics associated with increased knee joint loading and running-related injury risk.

METHODS

One hundred runners with varying experience ran on a pressure-sensing treadmill at a self-selected speed. Trunk and lower extremity kinematics, spatiotemporal measures, and ground reaction forces were collected. Multiple linear regression was used to assess the association between experience and three-dimensional hip kinematics, sagittal plane lower-extremity mechanics, and ground reaction forces while controlling for age and speed.

RESULTS

Increased running experience was not significantly associated with running mechanics. Increased age was significantly associated with reduced peak knee flexion and increased contact time. Running speed influenced several spatiotemporal, kinematic, and kinetic variables.

CONCLUSION

Increased years of running experience does not appear to significantly influence running mechanics. However, age and running speed do influence biomechanical variables associated with injury in distance runners. Thus, there may be factors, other than running mechanics, that contribute to less risk in more experienced runners.

Body Mass and Weekly Training Distance Influence the Pain and Injuries Experienced by Runners Using Minimalist Shoes: A Randomized Controlled Trial

BACKGROUND

Minimalist shoes have been popularized as a safe alternative to conventional running shoes. However, a paucity of research is available investigating the longer-term safety of minimalist shoes.

PURPOSE

To compare running-related pain and injury between minimalist and conventional shoes in trained runners and to investigate interactions between shoe type, body mass, and weekly training distance.

STUDY DESIGN

Randomized clinical trial; Level of evidence, 2.

METHODS

Sixty-one trained, habitual rearfoot footfall runners (mean ± SD: body mass, 74.6 ± 9.3 kg; weekly training distance, 25 ± 14 km) were randomly allocated to either minimalist or conventional shoes. Runners gradually increased the time spent running in their allocated shoes over 26 weeks. Running-related pain intensity was measured weekly by use of 100-mm visual analog scales. Time to first running-related injury was also assessed.

RESULTS

Interactions were found between shoe type and weekly training distance for weekly running-related pain; greater pain was experienced with minimalist shoes ( P < .05), and clinically meaningful increases (>10 mm) were noted when the weekly training distance was more than 35 km/wk. Eleven of 30 runners sustained an injury in conventional shoes compared with 16 of 31 runners in minimalist shoes (hazard ratio, 1.64; 95% confidence interval, 0.63-4.27; P = .31). A shoe × body mass interaction was found for time to first running-related injury ( P = .01). For runners using minimalist shoes, relative to runners using conventional shoes, the risk of sustaining an injury became more likely with increasing body mass above 71.4 kg, and the risk was moderately increased (hazard ratio, 2.00; 95% confidence interval, 1.10-3.66; P = .02) for runners using minimalist shoes who had a body mass of 85.7 kg.

CONCLUSIONS

Runners should limit weekly training distance in minimalist shoes to avoid running-related pain. Heavier runners are at greater risk of injury when running in minimalist shoes. Registration: Australian New Zealand Clinical Trials Registry (ACTRN12613000642785).

How much is too much? (Part 1) International Olympic Committee consensus statement on load in sport and risk of injury

Athletes participating in elite sports are exposed to high training loads and increasingly saturated competition calendars. Emerging evidence indicates that poor load management is a major risk factor for injury. The International Olympic Committee convened an expert group to review the scientific evidence for the relationship of load (defined broadly to include rapid changes in training and competition load, competition calendar congestion, psychological load and travel) and health outcomes in sport. We summarise the results linking load to risk of injury in athletes, and provide athletes, coaches and support staff with practical guidelines to manage load in sport. This consensus statement includes guidelines for (1) prescription of training and competition load, as well as for (2) monitoring of training, competition and psychological load, athlete well-being and injury. In the process, we identified research priorities.

Cohort study of physical activity and injury among Latino farm workers

INTRODUCTION

This study characterized physical activity and its association with injury among Latino farm workers.

METHODS

An interviewer-administered questionnaire was used to collect baseline and follow-up data on 843 and 640 Latino farm workers, respectively. Participants were 18-55 years old, engaged in farm work and residing in Mendota, CA at baseline interview. The questionnaire assessed self-reported physical activity and risk of injury.

RESULTS

The 12 month prevalence of injury decreased from 9.0% at baseline to 6.9% at follow up interview. In GEE models adjusted for age, follow-up time, gender, smoking, income and years working in agriculture, poor/fair self-assessed health status (OR = 1.82, 95% CI: 1.18-2.82) and 2-3 hr per day of sitting/watching TV/using a computer (OR = 0.50, 95% CI: 0.30-0.83) were significantly associated with injury.

CONCLUSIONS

Physical activity was not associated with injury in this population. Efforts to reduce injuries should focus on known risk factors such as poor health status.

Injuries in runners; a systematic review on risk factors and sex differences

BACKGROUND

The popularity of running continues to increase, which means that the incidence of running-related injuries will probably also continue to increase. Little is known about risk factors for running injuries and whether they are sex-specific.

OBJECTIVES

The aim of this study was to review information about risk factors and sex-specific differences for running-induced injuries in adults.

SEARCH STRATEGY

The databases PubMed, EMBASE, CINAHL and Psych-INFO were searched for relevant articles.

SELECTION CRITERIA

Longitudinal cohort studies with a minimal follow-up of 1 month that investigated the association between risk factors (personal factors, running/training factors and/or health and lifestyle factors) and the occurrence of lower limb injuries in runners were included.

DATA COLLECTION AND ANALYSIS

Two reviewers' independently selected relevant articles from those identified by the systematic search and assessed the risk of bias of the included studies. The strength of the evidence was determined using a best-evidence rating system. Sex differences in risk were determined by calculating the sex ratio for risk factors (the risk factor for women divided by the risk factor for men).

MAIN RESULTS

Of 400 articles retrieved, 15 longitudinal studies were included, of which 11 were considered high-quality studies and 4 moderate-quality studies. Overall, women were at lower risk than men for sustaining running-related injuries. Strong and moderate evidence was found that a history of previous injury and of having used orthotics/inserts was associated with an increased risk of running injuries. Age, previous sports activity, running on a concrete surface, participating in a marathon, weekly running distance (30-39 miles) and wearing running shoes for 4 to 6 months were associated with a greater risk of injury in women than in men. A history of previous injuries, having a running experience of 0-2 years, restarting running, weekly running distance (20-29 miles) and having a running distance of more than 40 miles per week were associated with a greater risk of running-related injury in men than in women.

CONCLUSIONS

Previous injury and use of orthotic/inserts are risk factors for running injuries. There appeared to be differences in the risk profile of men and women, but as few studies presented results for men and women separately, the results should be interpreted with caution. Further research should attempt to minimize methodological bias by paying attention to recall bias for running injuries, follow-up time, and the participation rate of the identified target group.

Prevalence of Injury in Ultra Trail Running

Purpose. The purpose of the study was to find the rate of musculoskeletal injuries in ultra-trail runners, investigate the most sensitive anatomical areas, and discover associated predicting factors to aid in the effective prevention and rapid rehabilitation of trail running injuries. Methods. Forty ultra trail runners responded to an epidemiological questionnaire. Results. At least one running injury was reported by 90% of the sample, with a total of 135 injuries were reported (111 overuse injuries, 24 appeared during competing). Lower back pain was the most common source of injury (42.5%). Running in the mountains (p = 0.0004) and following a personalized training schedule (p = 0.0995) were found to be protective factors. Runners involved in physical labor are associated with more injuries (p = 0.058). Higher-level runners are associated with more injuries than lower-level cohorts (p = 0.067), with symptoms most commonly arising in the lower back (p = 0.091), hip joint (p = 0.083), and the plantar surface of the foot (p = 0.054). Experienced runners (> 6 years) are at greater risk of developing injuries (p = 0.001), especially in the lower back (p = 0.012), tibia (p = 0.049), and the plantar surface of the foot (p = 0 .028). Double training sessions could cause hip joint injury (p = 0.060). Conclusions. In order to avoid injury, it is recommended to train mostly on mountain trails and have a training program designed by professionals.

[Chronic knee pain in children and adolescents: review of anatomical and overload-related knee pain]

BACKGROUND

Knee pain in children and adolescents is a common reason for presentation in pediatric orthopedic consultation. The causes are manifold and require a thorough patient history, detailed physical examination and extensive diagnostics.

DIAGNOSTICS

Chronic knee pain in children and adolescents is a diagnosis by exclusion. An extensive patient history including training habits, pain localization and clinical examination provide indications vital for the diagnosis. Overuse is often the trigger. In dynamic investigations consideration should be given to muscle imbalance. Imaging techniques have a high sensitivity and specificity only in combination with the anamnesis and clinical findings.

THERAPY

With pain therapy, targeted physiotherapy, a break in active sport or training modifications, the prognosis is good for overload syndromes. An operative therapy after unsuccessful conservative therapy is necessary in only a few cases. Among the anatomy-related types of knee pain primary popliteal cysts mostly require no therapy and for plica syndrome arthroscopic resection should only be necessary if conservative treatment is unsuccessful. Operative therapy is necessary for symptomatic discoid meniscus.

Can GPS be used to detect deleterious progression in training volume among runners?

There is a need to ascertain if an association exists between excessive progression in weekly volume and development of running-related injuries (RRI). The purpose of this study was to investigate if GPS can be used to detect deleterious progression in weekly training volume among 60 novice runners included in a 10-week prospective study. All participants used GPS to quantify training volume while running. In case of injury, participants attended a clinical examination. The 13 runners who sustained injuries during follow-up had a significantly higher weekly progression in total training volume in the week before the injury origin (86% [95% confidence interval: 12.9-159.9], p = 0.026) compared with other weeks. Although not significant, participants with injuries had an increase in weekly training volume of 31.6% compared with a 22.1% increase among the healthy participants. The error of the GPS measurements in open landscape, forest, and urban area of volume was ≤6.2%. To conclude, no clinically relevant measurement errors of the GPS devices were found for training volume. Based on this, GPS has a potential to detect errors in training volume, which may be associated with development of RRI. Based on the results from the current study, increases in weekly training progression may become deleterious at a weekly increase above 30%, which is more than the 10% rule currently used as a guideline for correct progression in weekly volume by runners and coaches. Still, no clear evidence for safe progression of weekly volume exists. But it seems likely that some individuals may tolerate weekly progressions around 20-25%, at least for a short period of time.

Distance running as an ideal domain for showing a sex difference in competitiveness

Men are over-represented in the arts, sciences, and sports. This has been hypothesized to reflect an evolved male predisposition for enduring competitiveness or long-term motivation to improve one's performance and "show-off." Evidence for this hypothesis is equivocal, however, because there are viable alternative explanations for men's dominance in most cultural display domains. Here, I argue that distance running is an ideal domain for addressing this issue. Distance running is ideal because it indicates enduring competitiveness, allows objective comparisons, and is accessible, acceptable, and popular for both men and women. I review recent studies and present new data showing that substantially more men than women run relatively fast in the U.S., that this sex difference in relative performance can be attributed, at least in part, to men's greater training motivation, and that this pattern has been stable for several decades. Distance running thus provides compelling evidence for an evolved male predisposition for enduring competitiveness. I conclude with suggestions regarding how variation in achievement motivation can be informed by considering how evolved predispositions interact with environmental and social conditions.

The pathophysiology, diagnosis, and management of stress fractures in postmenopausal women

INTRODUCTION

Increasing numbers of elderly individuals are now participating in marathons. With increased participation in running, there has been an increase in the diagnosis of stress fractures in the elderly population. Postmenopausal women are particularly at risk due to osteoporosis.

DISCUSSION

There are numerous risk factors for stress fractures in the literature that need to be addressed to reduce the risk of injury and recurrence in postmenopausal women. Diagnostic tests include plain radiograph, ultrasound, therapeutic ultrasound, computed tomography scan, and isotope bone scans; however, magnetic resonance imaging remains the gold standard. Treatment is based on risk stratification, with high-risk fractures managed aggressively with either non-weightbearing or surgical intervention. Although exercise is prescribed as a well-recognized treatment modality of poor bone density, balance is essential to avoid precipitating stress fractures.

CONCLUSION

Optimal exercise programs should balance the beneficial effect of increasing bone mineral density through exercise with the detrimental effect of stress fractures. A useful algorithm is presented in this article to guide the clinician in the diagnosis and management of appropriate investigations and management of such injuries. This review article describes the pathophysiology and provides a review of the literature to determine the latest diagnostic and treatment strategies for this unique population.

Prevalência e fatores associados a lesões em corredores amadores de rua do município de Belo Horizonte, MG

INTRODUÇÃO: A prática da corrida de rua tem aumentado nos últimos anos, tanto por sua facilidade quanto pelo baixo custo envolvido. Essa prática, todavia, envolve risco de lesões musculoesqueléticas. OBJETIVO: Verificar a prevalência de lesões osteomioarticulares e analisar os fatores associados em corredores de rua amadores de Belo Horizonte, MG. MÉTODOS: Foi realizado um estudo observacional do tipo transversal. A seleção da amostra foi por conveniência. Participaram da pesquisa 100 atletas amadores com pelo menos três meses de prática de corrida com frequência mínima de duas vezes por semana. Foram coletados os dados referentes à prevalência de lesões e os fatores associados através de um questionário estruturado. RESULTADOS: A prevalência de lesões entre os atletas foi de 40%. Dentre os fatores associados à lesão destacam-se a distância média diária e a variação no volume do treinamento. CONCLUSÃO: A prevalência de lesões em corredores amadores é considerável, apesar de ter sido relatada por menos da metade dos participantes. As características do treinamento podem desencadear lesões e devem ser analisadas com cautela para que a corrida seja realizada de forma segura.

More men run relatively fast in U.S. road races, 1981-2006: a stable sex difference in non-elite runners

Recent studies indicate that more men than women run fast relative to sex- specific world records and that this sex difference has been historically stable in elite U.S. runners. These findings have been hypothesized to reflect an evolved male predisposition for enduring competitiveness in "show-off" domains. The current study tests this hypothesis in non-elite runners by analyzing 342 road races that occurred from 1981-2006, most in or near Buffalo, NY. Both absolutely and as a percentage of same-sex finishers, more men ran relatively fast in most races. During the 1980s, as female participation surged, the difference in the absolute number of relatively fast men and women decreased. However, this difference was stable for races that occurred after 1993. Since then, in any given race, about three to four times as many men as women ran relatively fast. The stable sex difference in relative performance shown here for non-elites constitutes new support for the hypothesis of an evolved male predisposition for enduring competitiveness.

Effects of motion control footwear on running: a systematic review

Excessive foot pronation is a risk factor of running injuries and motion control footwear is designed to control foot pronation. With the movement transfer between foot pronation and tibial rotation, motion control footwear may not only be confined to controlling foot pronation. In view of the controversies in the literature on effectiveness of motion control footwear, this paper reviewed the efficacy of motion control footwear functions as reported in the literature. Eligible studies were identified from seven electronic databases. Two independent authors extracted the data and assessed the methodological qualities using the Jadad Scale. A total of 14 quasi randomised controlled trials were included. Even though the included studies were rated as "low quality" according to the Jadad Scale, the data were pooled and analysed. Results revealed that motion control footwear was effective in reducing the amount of foot pronation and the peak vertical impact during landing. There is no evidence that suggests motion control footwear for controlling kinematics of the proximal segments.

Interventions for preventing lower limb soft-tissue running injuries

BACKGROUND

Overuse soft-tissue injuries occur frequently in runners. Stretching exercises, modification of training schedules, and the use of protective devices such as braces and insoles are often advocated for prevention. This is an update of a review first published in 2001.

OBJECTIVES

To assess the effects of interventions for preventing lower limb soft-tissue running injuries.

SEARCH STRATEGY

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (March 2011); The Cochrane Library 2010, Issue 4; MEDLINE (1966 to January 2011); EMBASE (1980 to January 2011); and international trial registries (17 January 2011).

SELECTION CRITERIA

Randomised or quasi-randomised trials evaluating interventions to prevent lower limb soft-tissue running injuries.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed risk of bias (relating to sequence generation, allocation concealment, blinding, incomplete outcome data) and extracted data. Data were adjusted for clustering if necessary and pooled using the fixed-effect model when appropriate.

MAIN RESULTS

We included 25 trials (30,252 participants). Participants were military recruits (19 trials), runners from the general population (three trials), soccer referees (one trial), and prisoners (two trials). The interventions tested in the included trials fell into four main preventive strategies: exercises, modification of training schedules, use of orthoses, and footwear and socks. All 25 included trials were judged as 'unclear' or 'high' risk of bias for at least one of the four domains listed above.We found no evidence that stretching reduces lower limb soft-tissue injuries (6 trials; 5130 participants; risk ratio [RR] 0.85, 95% confidence interval [95% CI] 0.65 to 1.12). As with all non-significant results, this is compatible with either a reduction or an increase in soft-tissue injuries. We found no evidence to support a training regimen of conditioning exercises to improve strength, flexibility and coordination (one trial; 1020 participants; RR 1.20, 95% CI 0.77 to 1.87).We found no evidence that a longer, more gradual increase in training reduces injuries in novice runners (one trial; 486 participants; RR 1.02, 95% CI 0.72 to 1.45). There was some evidence from a poor quality trial that additional training resulted in a significant increase in the number of naval recruits with shin splints (one trial; 1670 participants; RR 2.02, 95% CI 1.11 to 3.70). There was limited evidence that injuries were less frequent in prisoners when running duration (one trial; 69 participants; RR 0.41, 95% CI 0.21 to 0.79) or frequency (one trial; 58 participants; RR 0.19, 95% CI 0.06 to 0.66) were reduced.Patellofemoral braces appear to be effective for preventing anterior knee pain (two trials; 227 participants; RR 0.41, 95% CI 0.24 to 0.67).Custom-made biomechanical insoles may be more effective than no insoles for reducing shin splints (medial tibial stress syndrome) in military recruits (one trial; 146 participants; RR 0.24, 95% CI 0.08 to 0.69).We found no evidence in military recruits that wearing running shoes based on foot shape, rather than standard running shoes, significantly reduced rate of running injuries (2 trials; 5795 participants; Rate Ratio 1.03, 95% CI 0.93 to 1.14).

AUTHORS' CONCLUSIONS

Overall, the evidence base for the effectiveness of interventions to reduce soft-tissue injury after intensive running is very weak, with few trials at low risk of bias. More well-designed and reported RCTs are needed that test interventions in recreational and competitive runners.

Medial longitudinal arch deformation during walking and stair navigation while carrying loads

BACKGROUND

Understanding the biomechanics of the medial longitudinal arch (MLA) may provide insights into injury risk and prevention, as well as function of the arch-supporting structures. Our understanding of MLA deformation is currently limited to sit-to-stand, walking, and running.

MATERIAL AND METHODS

Three-dimensional deformation of the MLA of the right foot was characterized in 17 healthy participants during several simulated activities of daily living. MLA deformation was quantified by both changes in arch length and navicular displacement during the stance phase of three motions: walking, stair ascent, and stair descent. Three levels of load were also evaluated: no load, a front load (13.6 kg), and a backpack load (13.6 kg). Force platforms and an eight-camera motion capture system were used to collect relevant lower extremity kinetic and kinematic data.

RESULTS

Motion type had a significant (p < 0.05) effect on navicular displacement and arch length elongation with navicular displacement being greatest during stair descent, while the walking and stair descent conditions showed the greatest increase in arch length. External load did not significantly affect either of these two measures (p > 0.05).

CONCLUSION

Differences in the MLA deformation variables resulting from varied dynamic activities of daily living can be greater than those during walking and should be considered.

CLINICAL RELEVANCE

Detailing the mechanics of the MLA may aid in further understanding injuries associated with the MLA, and the results of the current study indicate that these mechanics change based on activity.

Gender-specific neuromuscular activity of the M. peroneus longus in healthy runners - A descriptive laboratory study

BACKGROUND

Gender-specific neuromuscular activity for the ankle (e.g., peroneal muscle) is currently not known. This knowledge may contribute to the understanding of overuse injury mechanisms. The purpose was therefore to analyse the neuromuscular activity of the peroneal muscle in healthy runners.

METHODS

Fifty-three male and 54 female competitive runners were tested on a treadmill at 3.33 m s(-1). Neuromuscular activity of the M. peroneus longus was measured by electromyography and analysed in the time domain (onset of activation, time of maximum of activation, total time of activation) in % of stride time in relation to touchdown (=1.0). Additionally, mean amplitudes for the gait cycle phases preactivation, weight acceptance and push-off were calculated and normalised to the mean activity of the entire gait cycle.

FINDINGS

Onset of activation (mean; female: 0.86/male: 0.90, p<0.0001) and time of maximum of activation (female: 1.13/male: 1.16, p<0.0001) occurred earlier in female compared to male and the total time of activation was longer in women (female: 0.42/male: 0.39, p=0.0036). In preactivation, women showed higher amplitudes (+21%) compared to men (female: 1.16/male: 0.92, p<0.0001). Activity during weight acceptance (female: 2.26/male: 2.41, p=0.0039) and push-off (female: 0.93/male: 1.07, p=0.0027) were higher in men.

INTERPRETATION

Activation strategies of the peroneal muscle appear to be gender-specific. Higher preactivation amplitudes in females indicate a different neuromuscular control in anticipation of touchdown ("pre-programmed activity"). These data may help interpret epidemiologically reported differences between genders in overuse injury frequency and localisation.

[Long-term success and risk for marathon runners]

The popularity of marathon running has increased during recent years, which is reflected by the dramatic increase in the number of competitions and participants. Running a marathon itself does not usually cause any severe lesions of the joints but the problems mostly occur during training prior to the marathon. Before the event runners often question whether they can successfully take part in the competition and cope with the pain that might occur during running. In addition to the rare acute trauma, which is in general caused by falls or slipping, chronic injuries are of particular relevance for long distance running.This article describes the typical patterns of injuries to long distance runners, the positive effects of running a marathon and the risk factors for injuries.

Predictors of running-related injuries in novice runners enrolled in a systematic training program: a prospective cohort study

BACKGROUND

The popularity of running is still growing. As participation increases, running-related injuries also increase. Until now, little is known about the predictors for injuries in novice runners.

HYPOTHESIS

Predictors for running-related injuries (RRIs) will differ between male and female novice runners.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Participants were 532 novice runners (226 men, 306 women) preparing for a recreational 4-mile (6.7-km) running event. After completing a baseline questionnaire and undergoing an orthopaedic examination, they were followed during the training period of 13 weeks. An RRI was defined as any self-reported running-related musculoskeletal pain of the lower extremity or back causing a restriction of running for at least 1 week.

RESULTS

Twenty-one percent of the novice runners had at least one RRI during follow-up. The multivariate adjusted Cox regression model for male participants showed that body mass index (BMI) (hazard ratio [HR], 1.15; 95% confidence interval [CI], 1.05-1.26), previous injury in the past year (HR, 2.7; 95% CI, 1.36-5.55), and previous participation in sports without axial load (HR, 2.05; 95% CI, 1.03-4.11) were associated with RRI. In female participants, only navicular drop (HR, 0.85; 95% CI, 0.75-0.97) remained a significant predictor for RRI in the multivariate Cox regression modeling. Type A behavior and range of motion (ROM) of the hip and ankle did not affect risk.

CONCLUSION

Male and female novice runners have different risk profiles. Higher BMI, previous injury, and previous sports participation without axial loading are important predictors for RRI in male participants. Further research is needed to detect more predictors for female novice runners.

Prevention of physical training-related injuries recommendations for the military and other active populations based on expedited systematic reviews

BACKGROUND

The Military Training Task Force of the Defense Safety Oversight Council chartered a Joint Services Physical Training Injury Prevention Working Group to: (1) establish the evidence base for making recommendations to prevent injuries; (2) prioritize the recommendations for prevention programs and policies; and (3) substantiate the need for further research and evaluation on interventions and programs likely to reduce physical training-related injuries.

EVIDENCE ACQUISITION

A work group was formed to identify, evaluate, and assess the level of scientific evidence for various physical training-related injury prevention strategies through an expedited systematic review process. Of 40 physical training-related injury prevention strategies identified, education, leader support, and surveillance were determined to be essential elements of a successful injury prevention program and not independent interventions. As a result of the expedited systematic reviews, one more essential element (research) was added for a total of four. Six strategies were not reviewed. The remaining 31 interventions were categorized into three levels representing the strength of recommendation: (1) recommended; (2) not recommended; and (3) insufficient evidence to recommend or not recommend.

EVIDENCE SYNTHESIS

Education, leadership support, injury surveillance, and research were determined to be critical components of any successful injury prevention program. Six interventions (i.e., prevent overtraining, agility-like training, mouthguards, semirigid ankle braces, nutrient replacement, and synthetic socks) had strong enough evidence to become working group recommendations for implementation in the military services. Two interventions (i.e., back braces and pre-exercise administration of anti-inflammatory medication) were not recommended due to evidence of ineffectiveness or harm, 23 lacked sufficient scientific evidence to support recommendations for all military services at this time, and six were not evaluated.

CONCLUSIONS

Six interventions should be implemented in all four military services immediately to reduce physical training-related injuries. Two strategies should be discouraged by all leaders at all levels. Of particular note, 23 popular physical training-related injury prevention strategies need further scientific investigation, review, and group consensus before they can be recommended to the military services or similar civilian populations. The expedited systematic process of evaluating interventions enabled the working group to build consensus around those injury prevention strategies that had enough scientific evidence to support a recommendation.

Prevalence of injuries among young adults in sport centers: relation to the type and pattern of activity

The rate of injuries resulting from physical exercise in sport centers as well as related factors has not yet been described. The aims of this study were to describe the prevalence of self-reported activity-specific injuries, to identify the relations between injury profile and different types and patterns of physical activity and to assess whether gender is a modifying variable in that connection. Four hundred and fifty-seven men and women aged 20-35 years participated in this cross-sectional study. A questionnaire was used to evaluate the types and patterns of physical activity performed in the 12 months preceding the study and sports injuries sustained during that time. One hundred and ninety of the 457 subjects reported an injury as a result of exercising (41.6%). A relationship was found between weight training and injuries of the upper extremity (UE) for men and between spinning classes and knee injuries for women. Among those who participated in weight-training exercises, more frequent and longer duration exercise was associated with UE injury, and among those who participated in spinning classes more frequent exercise was associated with knee injury. Future injury prevention programs in sport centers should pay special attention to men who participate in weight training and to women who participate in spinning classes.

Foot medial longitudinal-arch deformation during quiet standing and gait in subjects with medial tibial stress syndrome

The objective of this study was to investigate (1) if subjects with medial tibial stress syndrome demonstrate increased navicular drop and medial longitudinal-arch deformation during quiet standing and gait compared with healthy subjects, and (2) the relationship between medial longitudinal-arch deformation during quiet standing and gait. Thirty subjects aged 20 to 32 years were included (15 with medial tibial stress syndrome and 15 controls). Navicular drop and medial longitudinal-arch deformation were measured during quiet standing with neutral and loaded foot using a ruler and digital photography. Medial longitudinal-arch deformation was measured during walking gait using 3-dimensional gait analysis. Subjects with medial tibial stress syndrome demonstrated a significantly larger navicular drop (mean +/- 1 SD, 7.7 +/- 3.1 mm) and medial longitudinal-arch deformation (5.9 +/- 3.2 degrees) during quiet standing compared with controls (5.0 +/- 2.2 mm and 3.5 +/- 2.6 degrees, P < .05). Subjects with medial tibial stress syndrome also demonstrated significantly larger medial longitudinal-arch deformation (8.8 +/- 1.8 degrees) during gait compared with controls (7.1 +/- 1.7 degrees, P = .015). There was no correlation between medial longitudinal-arch deformation during quiet standing and gait in either of the 2 groups (r < 0.127, P > .653). The subjects with medial tibial stress syndrome in this study demonstrated increased navicular drop and medial longitudinal-arch deformation during quiet standing and increased medial longitudinal-arch deformation during gait compared to healthy subjects. Medial longitudinal-arch deformation during quiet standing did not correlate with medial longitudinal-arch deformation during gait in either of the 2 groups. ACFAS Level of Clinical Evidence: 5.

Stress fractures in athletes

A stress fracture is a partial or complete bone fracture that results from repeated application of stress lower than the stress required to fracture the bone in a single loading. Otherwise healthy athletes, especially runners, sustain stress injuries or fractures. Prevention or early intervention is the preferable treatment. However, it is difficult to predict injury because runners vary with regard to biomechanical predisposition, training methods, and other factors such as diet, muscle strength, and flexibility. Stress fractures account for 0.7% to 20% of all sports medicine clinic injuries. Track-and-field athletes have the highest incidence of stress fractures compared with other athletes. Stress fractures of the tibia, metatarsals, and fibula are the most frequently reported sites. The sites of stress fractures vary from sport to sport (eg, among track athletes, stress fractures of the navicular, tibia, and metatarsal are common; in distance runners, it is the tibia and fibula; in dancers, the metatarsals). In the military, the calcaneus and metatarsals were the most commonly cited injuries, especially in new recruits, owing to the sudden increase in running and marching without adequate preparation. However, newer studies from the military show the incidence and distribution of stress fractures to be similar to those found in sports clinics. Fractures of the upper extremities are relatively rare, although most studies have focused only on lower-extremity injuries. The ulna is the upper-extremity bone injured most frequently. Imaging plays a key role in the diagnosis and management of stress injuries. Plain radiography is useful when positive, but generally has low sensitivity. Radionuclide bone scanning is highly sensitive, but lacks specificity and the ability to directly visualize fracture lines. In this article, we focus on magnetic resonance imaging, which provides highly sensitive and specific evaluation for bone marrow edema, periosteal reaction as well as detection of subtle fracture lines.

Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review

The purpose of this study was to present a systematic overview of published reports on the incidence and associated potential risk factors of lower extremity running injuries in long distance runners. An electronic database search was conducted using the PubMed-Medline database. Two observers independently assessed the quality of the studies and a best evidence synthesis was used to summarise the results. The incidence of lower extremity running injuries ranged from 19.4% to 79.3%. The predominant site of these injuries was the knee. There was strong evidence that a long training distance per week in male runners and a history of previous injuries were risk factors for injuries, and that an increase in training distance per week was a protective factor for knee injuries.

Exercise distance and speed affect the risk of fracture in racehorses

In order to gain insight into those training regimens that can minimise the risk of fracture in athletic populations, we conducted a large epidemiological study in racehorses. Thoroughbred racehorses provide a suitable model for studying fracture development and exercise-related risk factors in physically active populations. They represent a homogeneous population, undertaking intensive exercise programmes that are sufficiently heterogeneous to determine those factors that influence injury risk. Daily exercise information was recorded for a cohort of 1178 thoroughbreds that were monitored for up to 2 years. A total of 148 exercise-induced fractures occurred in the study population. Results from a nested case-control study showed a strong interactive effect of exercise distances at different speeds on fracture risk. Horses that exceeded 44 km at canter (< or =14 m/s) and 6 km at gallop (>14 m/s) in a 30-day period were at particularly increased risk of fracture. These distances equate to ca. 7700 bone loading cycles at canter and 880 loading cycles at gallop. Fifty-six fractures occurred in the subset of study horses that were followed since entering training as yearlings, when skeletally immature (n = 335). Cohort analysis of this data set showed that, in previously untrained bones, accumulation of canter exercise increased the risk of fracture (P < or = 0.01), whereas accumulation of high-speed gallop exercise had a protective effect (P < 0.01). However, increasing distances at canter and gallop in short time periods (up to one month) were associated with an increasing fracture risk. All training exercise involves a balance between the risk of fracture inherent in exposure to loading and the beneficial effect that loading has by stimulating bone cells to produce a more robust architecture. Results from our study provide important epidemiological evidence of the effects of physical exercise on bone adaptation and injury risk and can be used to inform the design of safer exercise regimens in physically active populations.

Medical problems of marathon runners

Several organ systems can be affected by marathon running. Acute musculoskeletal injuries are common, but running does not result in increased rates of musculoskeletal disability. Gastrointestinal complaints are also common among runners; some of these complaints are explained by the decreased mesenteric blood flow during exercise. Although cardiac events are rare, they can be devastating. Symptomatic hyponatremia is another serious but mostly preventable problem.

Female athlete triad and stress fractures

Stress fractures are a common occurrence in athletes, and the incidence of stress fractures in female Division 1 collegiate athletes is double that of men. Hormonal influences on bone and bone morphology may influence the risk for fracture. A high level of suspicion and special imaging procedures allow for accurate diagnosis of these fractures. In stress fractures that are associated with the female athlete triad, addressing the three aspects of the triad--eating disorders, amenorrhea, and osteoporosis--are critical for successful treatment. Preparticipation screening for the presence of signs of the female athlete triad by monitoring weight, energy level, menstrual cycles, and bone mineral density may help to prevent the occurrence of stress fractures in this population.

Self-reported Injury and Physical Activity Levels: United States 2000 to 2002

PURPOSE

The aim of the study is to compare national estimates of the incidence of self-reported all-cause and activity-specific injuries in adults with differing leisure-time physical activity levels.

METHODS

Data were analyzed from the 2000 to 2002 National Health Interview Survey. Leisure-time physical activity levels were categorized as active, insufficiently active, and inactive.

RESULTS

Age-adjusted incidences of all-cause injury did not differ by leisure-time physical activity level (active, 89.3/1000; 95% confidence interval [CI], 81.8-96.8; insufficiently active, 81.6/1000; 95% CI, 73.1-90.1; and inactive, 86.3/1000; 95% CI, 78.6-93.9). Active respondents (29.4/1000; 95% CI, 25.2-33.6) had a greater incidence of injury related to sport and leisure-time activities than inactive respondents (15.2/1000; 95% CI, 12.1-18.3), whereas inactive respondents (71.1/1000; 95% CI, 63.9-78.2) had a greater incidence of injury related to nonsport and non-leisure-time activities than active respondents (59.9/1000; 95% CI, 53.6-66.2). Results were unchanged after multivariate control for confounding factors.

CONCLUSIONS

Although the incidence of sport and leisure-time injuries is associated with participation in leisure-time physical activity, no association was observed between leisure-time physical activity and overall injuries.

Incidence of chronic knee lesions in long-distance runners based on training level: Findings at MRI

PURPOSE

The purpose of this study was to evaluate the incidence of chronic knee changes in long-distance runners based on the training status, including distance, running frequency, training pace, and running experience.

METHODS

MRI of the knee was performed in 26 non-professional runners 5 days after their last training unit. Lesions of the menisci and cartilage (5-point scale), bone marrow and ligaments (3-point scale), and joint effusion were evaluated. A total score comprising all knee lesions in each runner was evaluated. The incidence of the knee changes was correlated with the training level, gender, and age of the runners.

RESULTS

Grade 1 lesions of the menisci were found in six runners with a high training level, and in only four runners with a low training level. Grade 1 cartilage lesions were found in three high-trained runners and in one low-trained runner, and grade 2 lesions were found in one high-trained runner and in two low-trained runners, respectively. Grade 1 anterior cruciate ligament lesions were seen in three runners with a high- and in two runners with a low-training level. Runners with a higher training level showed a statistically significant higher score for all chronic knee lesions than those with a lower training level (p<0.05).

CONCLUSIONS

MRI findings indicate that a higher training level in long-distance runners is a risk factor for chronic knee lesions.

Treatment of stress fractures: the fundamentals

This article is an introduction to the fundamentals of stress fracture management. Extrinsic and intrinsic factors, that may play a role in the development of stress fractures, are discussed and incorporated as possible treatment options. Different treatment modalities including ultrasound and electromagnetic fields are addressed, with an emphasis on literature support.

[Injuries and response to overload stress in running as a sport]

Running is rarely associated with acute injuries (muscle injuries, ankle sprain, ruptures of the Achilles tendon). More than 80% of the complaints are due to overuse injuries, mainly concerning knee, foot and Achilles tendon. Risk factors are high-performance sports, high training quantity, rapid increase of training intensity, previous injuries, and skeletal axis malalignment. Running is not suitable for severely overweight people and those with significant skeletal malalignment, dysplastic hips, spondylolisthesis, or cartilage damage.