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Bone stress injuries in male distance runners: higher modified Female Athlete Triad Cumulative Risk Assessment scores predict increased rates of injury
  1. Emily Kraus1,
  2. Adam S Tenforde2,
  3. Aurelia Nattiv3,
  4. Kristin L Sainani1,
  5. Andrea Kussman1,
  6. Megan Deakins-Roche1,
  7. Sonal Singh3,
  8. Brian Young Kim4,
  9. Michelle T Barrack5,
  10. Michael Fredericson1
  1. 1 Stanford University, Stanford, California, USA
  2. 2 Spaulding Rehabilitation Hospital, Boston, Massachusetts, USA
  3. 3 University of California, Los Angeles, Los Angeles, California, USA
  4. 4 University of California, Irvine, Irvine, California, USA
  5. 5 California State University, Long Beach, Long Beach, California, USA
  1. Correspondence to Dr Michael Fredericson, Stanford University, Stanford CA 94063, USA; mfred2{at}


Objectives Bone stress injuries (BSI) are common in runners of both sexes. The purpose of this study was to determine if a modified Female Athlete Triad Cumulative Risk Assessment tool would predict BSI in male distance runners.

Methods 156 male runners at two collegiate programmes were studied using mixed retrospective and prospective design for a total of 7 years. Point values were assigned using risk assessment categories including low energy availability, low body mass index (BMI), low bone mineral density (BMD) and prior BSI. The outcome was subsequent development of BSI. Statistical models used a mixed effects Poisson regression model with p<0.05 as threshold for significance. Two regression analyses were performed: (1) baseline risk factors as the independent variable; and (2) annual change in risk factors (longitudinal data) as the independent variable.

Results 42/156 runners (27%) sustained 61 BSIs over an average 1.9 years of follow-up. In the baseline risk factor model, each 1 point increase in prior BSI score was associated with a 57% increased risk for prospective BSI (p=0.0042) and each 1 point increase in cumulative risk score was associated with a 37% increase in prospective BSI risk (p=0.0079). In the longitudinal model, each 1 point increase in cumulative risk score was associated with a 27% increase in prospective BSI risk (p=0.05). BMI (rate ratio (RR)=1.91, p=0.11) and BMD (RR=1.58, p=0.19) risk scores were not associated with BSI.

Conclusion A modified cumulative risk assessment tool may help identify male runners at elevated risk for BSI. Identifying risk factors may guide treatment and prevention strategies.

  • stress fracture
  • bone mineral density
  • running
  • energy deficiency

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  • EK and AST contributed equally.

  • Contributors All authors contributed to the edits and revisions of this manuscript with the outline and majority of manuscript shared between EK and AST. Initial retrospective and prospective study design was performed by AST, MF, AN and EK. AK, BYK and SS carried out the study implementation including consent, recruitment and data entry at one institution. EK, MDR and AST carried out the study implementation including consent, recruitment and data entry at the other institution. KLS was the statistician and contributed greatly to discussions regarding data analysis and how ideally to present the results. MTB organised all the nutrition components of study design and greatly aided in revisions to this section of the manuscript. AN and MF were the principal investigators at collaborating institutions.

  • Funding AMSSM Research Grant, PAC-12 Research Grant, Stanford Medical Scholars Research Program, Doris Factor Education Foundation.

  • Competing interests None declared.

  • Patient consent Not required.

  • Ethics approval The institutional review boards at both universities, Stanford and UCLA, approved the protocol.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement The unpublished data from this study are not being shared with any other group or institution.