Prevalence and factors associated with bone stress injury in middle school runners

A systematic review, meta-analysis, and meta-regression of the prevalence of self-reported disordered eating and associated factors among athletes worldwide

BACKGROUND

The purpose of this meta-analysis was to provide a pooled prevalence estimate of self-reported disordered eating (SRDE) in athletes based on the available literature, and to identify risk factors for their occurrence.

METHODS

Across ten academic databases, an electronic search was conducted from inception to 7th January 2024. The proportion of athletes scoring at or above predetermined cutoffs on validated self-reporting screening measures was used to identify disordered eating (DE). Subgroup analysis per country, per culture, and per research measure were also conducted. Age, body mass index (BMI), and sex were considered as associated/correlated factors.

RESULTS

The mean prevalence of SRDE among 70,957 athletes in 177 studies (132 publications) was 19.23% (17.04%; 21.62%), I2 = 97.4%, τ2 = 0.8990, Cochran's Q p value = 0. Australia had the highest percentage of SRDE athletes with a mean of 57.1% (36.0%-75.8%), while Iceland had the lowest, with a mean of 4.9% (1.2%-17.7%). The SRDE prevalence in Eastern countries was higher than in Western countries with 29.1% versus 18.5%. Anaerobic sports had almost double the prevalence of SRDE 37.9% (27.0%-50.2%) compared to aerobic sports 19.6% (15.2%-25%). Gymnastics sports had the highest SRDE prevalence rate, with 41.5% (30.4%-53.6%) while outdoor sports showed the lowest at 15.4% (11.6%-20.2%). Among various tools used to assess SRDE, the three-factor eating questionnaire yielded the highest SRDE rate 73.0% (60.1%-82.8%). Meta-regression analyses showed that female sex, older age, and higher BMI (all p < 0.01) are associated with higher prevalence rates of SRDE.

CONCLUSION

The outcome of this review suggests that factors specific to the sport affect eating behaviors throughout an athlete's life. As a result, one in five athletes run the risk of developing an eating disorder. Culture-specific and sport-specific diagnostic tools need to be developed and increased attention paid to nutritional deficiencies in athletes.

Clinical assessment, treatment, and referral trends for adolescent runners seeking care at an injured runners' clinic

PURPOSE

Over a 10-year time frame, this study aimed to evaluate diagnosis, treatment, and referral trends for adolescent runners seeking care for running-related injuries (RRIs) at a clinic that specializes in running medicine.

METHODS

This study was a retrospective chart review of 392 adolescent runners (2,326 encounters) who sought care for RRIs between the years 2011 and 2021. Descriptive statistics were used to summarize clinical assessments, referrals, assistive devices, and medications prescribed or administered overall and by injury type. Chi-square analyses were used to compare proportions of services rendered across the 10-year time frame.

RESULTS

Patients most frequently received manual evaluations or special tests during clinic visits. Most visits resulted in at least one referral (91%), primarily for physical therapy or gait-training. Assistive devices and medications/supplements were offered at only 18% of patient visits. The majority of assessments (X2 = 69.7, p = 0.002), treatments (X2: 23.6-43.8, p: <  0.001-0.003), and referrals (X2 = 132, p <  0.001) were for shin injuries. Larger proportions of nutrition assessments (X2 = 40.7, p <  0.001), interventions (X2 = 26.8, p = 0.003), and referrals (X2 = 27.5, p = 0.002) were performed in or after the year 2015.

CONCLUSION

Clinic visits for shin injuries required the most clinical resources per episode of care. There were observed shifts in clinical assessment and treatment approaches to include more expanded nutritional and physiologic considerations.

Triggers for eating disorder onset in youth with anorexia nervosa across the weight spectrum

To aid in more targeted eating disorder (ED) prevention efforts, we sought to identify sociodemographic and weight-related risk factors for identified triggers for the onset of anorexia nervosa (AN) in youth. We conducted a retrospective chart review of youth admitted for medical treatment of AN between January 2015 and February 2020. From multidisciplinary admission notes, we extracted patient-reported reasons for diet/exercise changes. We used qualitative thematic analysis to identify ED triggers, then categorized each trigger as binary variables (presence/absence) for logistic regression analysis of risks associated with each trigger. Of 150 patients, mean (SD) age was 14.1(2.3) years. A total of 129 (86%) were female and 120 (80%) were Non-Hispanic White. Triggers included environmental stressors (reported by 30%), external pressures of the thin/fit ideal (29%), internalized thin/fit ideal (29%), weight-related teasing (19%), and receiving health education (14%). Younger age was associated with higher odds of weight-related teasing (p = .04) and health education (p = .03). Males had greater odds of internalized thin/fit ideal than females (p = .04). Those with premorbid body mass indices ≥85th percentile for age and sex had greater odds of reporting positive reinforcement (p = .03) and weight-related teasing (p = .04) than those with weights <85th percentile. We use these findings to detail potential targets for advancing ED prevention efforts.

Outpatient Runners Clinic Visit Trends and Injury Characteristics Among 392 Child and Adolescent Patients: A 10-year Chart Review

OBJECTIVE

To evaluate clinic visits and running-related injury (RRI) characteristics among child and adolescent runners seeking care at an outpatient clinic over a 10-year time frame.

DESIGN

Retrospective chart review.

SETTING

Outpatient hospital-affiliated Injured Runners Clinic.

PATIENTS

Children and adolescent runners (6-17 years) with RRIs.

INDEPENDENT VARIABLES

We examined electronic medical records (EMRs) among child and adolescent patients in the hospital database from 2011 to 2021 to obtain RRI characteristics and key demographic factors.

MAIN OUTCOME MEASURES

We assessed volume and frequency of patient visits to the clinic by RRI characteristics. Chi square analyses were used to compare the proportion of clinic visits over time and injury trends by body region and diagnosis.

RESULTS

There were 392 patients (sex: 277 F; mean age: 16.1 ± 1.3 years) and an average of 5 clinic visits per diagnosis (5 ± 4 visits; min: 1 visit, max: 31 visits). Number of visits generally increased over time up to 2016 but declined most drastically during the years of the pandemic (2020-2021; χ 2 = 644, P < 0 .001). Of the 654 new injury diagnoses, 77.68% were attributed to repetitive stress. Bone stress injuries to the tibia were the most common RRI (χ 2 = 1940, P < 0 .001; N = 132; 20.2% of all injuries) and constituted most of the clinic visits (χ 2 = 9271, P < 0 .001; N = 591; 25.4% of all visits).

CONCLUSION

We identified that adolescents with overuse injuries, particularly bone stress injuries to the tibia, constituted most of the visits to the outpatient healthcare setting. Clinicians should emphasize injury prevention efforts in clinical practice to reduce RRI burden.

Higher Triad Risk Scores Are Associated With Increased Risk for Trabecular-Rich Bone Stress Injuries in Female Runners

OBJECTIVE

Bone stress injuries (BSIs) in trabecular-rich bone are associated with greater biological risk factors compared with cortical-rich bone. We hypothesized that female runners with high Female Athlete Triad (Triad)-related risk would be at greater risk for trabecular-rich BSIs than runners with low Triad-related risk.

DESIGN

Prospective cohort study.

SETTING

Two NCAA institutions.

PARTICIPANTS

Female runners were followed prospectively for up to 5 years.

INTERVENTION

The intervention consisted of team nutrition presentations focused on optimizing energy availability plus individualized nutrition sessions. Triad Cumulative Risk Assessment (CRA) categories were assigned yearly based on low-energy availability, menstrual status, age of menarche, low body mass index, low bone mineral density, and prior BSI.

MAIN OUTCOME MEASURES

The outcome was the annual incidence of trabecular- and cortical-rich BSI. Generalized Estimating Equations (GEE, to account for the correlated nature of the observations) with a Poisson distribution and log link were used for statistical modeling.

RESULTS

Cortical-rich BSI rates were higher than trabecular-rich BSI rates (0.32 vs 0.13 events per person-year). Female runners with high Triad-related risk had a significantly higher incidence rate ratio of trabecular-rich BSI (RR: 4.40, P = 0.025) and cortical-rich BSI (RR: 2.87, P = 0.025) than women with low Triad-related risk. Each 1-point increase in Triad CRA score was associated with a significant 26% increased risk of trabecular-rich BSI ( P = 0.0007) and a nonsignificant 14% increased risk of cortical-rich BSI ( P = 0.054).

CONCLUSIONS

Increased Triad CRA scores were strongly associated with increased risk for trabecular-rich BSI. Incorporating Triad CRA scores in clinical care could guide BSI prevention.

A hierarchical clustering approach for examining the relationship between pelvis-proximal femur geometry and bone stress injury in runners

Bone stress injury (BSI) risk in runners is multifactorial and not well understood. Unsupervised machine learning approaches can potentially elucidate risk factors for BSI by identifying groups of similar runners within a population which differ in BSI incidence. Here, a hierarchical clustering approach is used to identify groups of collegiate cross country runners based on 2-dimensional frontal plane pelvis and proximal femur geometry, which was extracted from dual-energy X-ray absorptiometry scans and dimensionally reduced by principal component analysis. Seven distinct groups were identified using the cluster tree, with the initial split being highly related to female-male differences. Visual inspection revealed clear differences between groups in pelvis and proximal femur geometry, and groups were found to differ in lower body BSI incidence during the subsequent academic year (Rand index = 0.53; adjusted Rand index = 0.07). Linear models showed between-cluster differences in visually identified geometric measures. Geometric measures were aggregated into a pelvis shape factor based on trends with BSI incidence, and the resulting shape factor was significantly different between clusters (p < 0.001). Lower shape factor values, corresponding with lower pelvis height and ischial span, and greater iliac span and trochanteric span, appeared to be related to increased BSI incidence. This trend was dominated by the effect observed across clusters of male runners, indicating that geometric effects may be more relevant to BSI risk in males, or that other factors masked the relationship in females. More broadly, this work outlines a methodological approach for distilling complex geometric differences into simple metrics that relate to injury risk.

Mapping the complexities of Relative Energy Deficiency in Sport (REDs): development of a physiological model by a subgroup of the International Olympic Committee (IOC) Consensus on REDs

The 2023 International Olympic Committee (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs) notes that exposure to low energy availability (LEA) exists on a continuum between adaptable and problematic LEA, with a range of potential effects on both health and performance. However, there is variability in the outcomes of LEA exposure between and among individuals as well as the specific manifestations of REDs. We outline a framework for a 'systems biology' examination of the effect of LEA on individual body systems, with the eventual goal of creating an integrated map of body system interactions. We provide a template that systematically identifies characteristics of LEA exposure (eg, magnitude, duration, origin) and a variety of moderating factors (eg, medical history, diet and training characteristics) that could exacerbate or attenuate the type and severity of impairments to health and performance faced by an individual athlete. The REDs Physiological Model may assist the diagnosis of underlying causes of problems associated with LEA, with a personalised and nuanced treatment plan promoting compliance and treatment efficacy. It could also be used in the strategic prevention of REDs by drawing attention to scenarios of LEA in which impairments of health and performance are most likely, based on knowledge of the characteristics of the LEA exposure or moderating factors that may increase the risk of harmful outcomes. We challenge researchers and practitioners to create a unifying and dynamic physiological model for each body system that can be continuously updated and mapped as knowledge is gained.

Current risks factors and emerging biomarkers for bone stress injuries in military personnel

INTRODUCTION

Bone stress injuries (BSIs) have plagued the military for over 150 years; they afflict around 5 to 10% of military recruits, more so in women, and continue to place a medical and financial burden on defence. While the tibia generally adapts to the rigours of basic military training, the putative mechanisms for bone maladaptation are still unclear.

METHODS

This paper provides a review of the published literature on current risk factors and emerging biomarkers for BSIs in military personnel; the potential for biochemical markers of bone metabolism to monitor the response to military training; and, the association of novel biochemical 'exerkines' with bone health.

RESULTS

The primary risk factor for BSI in military (and athletic) populations is too much training, too soon. Appropriate physical preparation before training will likely be most protective, but routine biomarkers will not yet identify those at risk. Nutritional interventions will support a bone anabolic response to training, but exposure to stress, sleep loss, and medication is likely harmful to bone. Monitoring physiology using wearables-ovulation, sleep and stress-offer potential to inform prevention strategies.

CONCLUSIONS

The risk factors for BSIs are well described, but their aetiology is very complex particularly in the multi-stressor military environment. Our understanding of the skeletal responses to military training is improving as technology advances, and potential biomarkers are constantly emerging, but sophisticated and integrated approaches to prevention of BSI are warranted.

A Comparison of Factors Associated with Running-Related Injuries between Adult and Adolescent Runners

Background

There are multiple personal and environmental factors that influence the risk of developing running-related injuries (RRIs). However, it is unclear how these key clinical factors differ between adult and adolescent runners.

Purpose

The purpose of this study was to compare anthropometric, training, and self-reported outcomes among adult and adolescent runners with and without lower extremity musculoskeletal RRIs.

Study Design

Cross-sectional study.

Methods

Questionnaire responses and clinical assessment data were extracted from 38 adult runners (F: 25, M: 13; median age: 23 [range 18-36]) and 91 adolescent runners (F: 56, M: 35; median age: 15 [range 14-16]) who underwent a physical injury prevention evaluation at a hospital-affiliated sports injury prevention center between 2013 and 2021. Participants were sub-grouped into those with (adults: 25; adolescents: 38) and those without (adults: 13; adolescents: 53) a history of self-reported RRIs based on questionnaire responses. Multivariate analyses of covariance (MANCOVA) covarying for gender were conducted to compare outcomes across groups.

Results

Adult runners had lower Functional Movement Screen™ (FMS™) scores (mean differences [MD]: -1.4, p=0.01), were more likely to report intentional weight-loss to improve athletic performance (% difference: 33.0%; p:<.001), and more frequently included resistance training into their training routines (% difference: 21.0%, p=0.01) compared to adolescents. Those with a history of RRIs were more likely to report intentional weight-loss compared to uninjured runners (% difference: 21.3; p=0.02) and had shorter single leg bridge durations than those without RRIs (RRI: 57.9±30, uninjured: 72.0±44, p=0.01).

Conclusion

The findings indicate that addressing aspects of biomechanics identified by the FMS™ and behaviors of weight loss as an effort to improve performance may represent targets for the prevention of RRIs for adult and adolescent runners, given the association with history of RRIs.

Level of Evidence

3.

Biomechanical running gait assessments across prevalent adolescent musculoskeletal injuries

BACKGROUND

While there is substantial information available regarding expected biomechanical adaptations associated with adult running-related injuries, less is known about adolescent gait profiles that may influence injury development.

RESEARCH QUESTIONS

Which biomechanical profiles are associated with prevalent musculoskeletal lower extremity injuries among adolescent runners, and how do these profiles compare across injury types and body regions?

METHODS

We conducted a cross-sectional study of 149 injured adolescents (110 F; 39 M) seen at a hospital-affiliated injured runner's clinic between the years 2016-2021. Biomechanical data were obtained from 2-dimensional video analyses and an instrumented treadmill system. Multivariate analyses of variance covarying for gender and body mass index were used to compare continuous biomechanical measures, and Chi-square analyses were used to compare categorical biomechanical variables across injury types and body regions. Spearman's rho correlation analyses were conducted to assess the relationship of significant outcomes.

RESULTS

Patients with bony injuries had significantly higher maximum vertical ground reaction forces (bony: 1.87 body weight [BW] vs. soft tissue: 1.79BW, p = 0.05), and a higher proportion of runners with contralateral pelvic drop at midstance (χ² =5.3, p = 0.02). Maximum vertical ground reaction forces and pelvic drop were significantly yet weakly correlated (ρ = 0.20, p = 0.01). Foot strike patterns differed across injured body regions, with a higher proportion of hip and knee injury patients presenting with forefoot strike patterns (χ² =22.0, p = 0.01).

SIGNIFICANCE

These biomechanical factors may represent risk factors for injuries sustained by young runners. Clinicians may consider assessing these gait adaptations when treating injured adolescent patients.

Low energy availability surrogates associated with lower bone mineral density and bone stress injury site

BACKGROUND

Exercise is an osteogenic stimulus that should increase bone mineral density (BMD) and protect against injury. However, some female athletes have lower BMD and increased bone stress injury (BSI) risk. Impaired bone health seen in athletes may be explained by low energy availability as described by concepts of Relative Energy Deficiency in Sport (RED-S) and Female Athlete Triad (Triad).

OBJECTIVE

To elucidate the relationship between RED-S/Triad risk factors and BSI to high-risk (femoral neck, sacrum) and low-risk (other) bones.

DESIGN

Cross-sectional survey and retrospective chart review.

SETTING

Tertiary care academic center.

PATIENTS

Female athletes aged 15-30 years participating in ≥4 h/week of exercise presenting to sports medicine/orthopedics clinic who had a self-reported BSI and available dual-energy x-ray absorptiometry (DXA) measurement of BMD.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASUREMENTS

Location of BSI.

RESULTS

In 127 athletes, high-risk BSI was associated with surrogates of low energy availability (p = .032) and having a DXA Z-score < -1 (p = .035) but not a current/past history of menstrual dysfunction (p = .348). Accumulating RED-S/Triad risk factors increase the odds of incurring a high-risk BSI (p = .048).

CONCLUSIONS

Adolescent/young female athletes who sustain BSI at high-risk sites (femoral neck, sacrum) may have underlying risk factors (eg, low energy availability, poor overall bone health) that should prompt further workup and referral to optimize health in these athletes.

A Life History Perspective on Athletes with Low Energy Availability

The energy costs of athletic training can be substantial, and deficits arising from costs unmet by adequate energy intake, leading to a state of low energy availability, may adversely impact athlete health and performance. Life history theory is a branch of evolutionary theory that recognizes that the way the body uses energy-and responds to low energy availability-is an evolved trait. Energy is a finite resource that must be distributed throughout the body to simultaneously fuel all biological processes. When energy availability is low, insufficient energy may be available to equally support all processes. As energy used for one function cannot be used for others, energetic "trade-offs" will arise. Biological processes offering the greatest immediate survival value will be protected, even if this results in energy being diverted away from others, potentially leading to their downregulation. Athletes with low energy availability provide a useful model for anthropologists investigating the biological trade-offs that occur when energy is scarce, while the broader conceptual framework provided by life history theory may be useful to sport and exercise researchers who investigate the influence of low energy availability on athlete health and performance. The goals of this review are: (1) to describe the core tenets of life history theory; (2) consider trade-offs that might occur in athletes with low energy availability in the context of four broad biological areas: reproduction, somatic maintenance, growth, and immunity; and (3) use this evolutionary perspective to consider potential directions for future research.

Adolescent Running Biomechanics - Implications for Injury Prevention and Rehabilitation

Global participation in running continues to increase, especially amongst adolescents. Consequently, the number of running-related injuries (RRI) in adolescents is rising. Emerging evidence now suggests that overuse type injuries involving growing bone (e.g., bone stress injuries) and soft tissues (e.g., tendinopathies) predominate in adolescents that participate in running-related sports. Associations between running biomechanics and overuse injuries have been widely studied in adults, however, relatively little research has comparatively targeted running biomechanics in adolescents. Moreover, available literature on injury prevention and rehabilitation for adolescent runners is limited, and there is a tendency to generalize adult literature to adolescent populations despite pertinent considerations regarding growth-related changes unique to these athletes. This perspective article provides commentary and expert opinion surrounding the state of knowledge and future directions for research in adolescent running biomechanics, injury prevention and supplemental training.