Study analysis · British Journal of Sports Medicine · 2018
A checklist designed for female athletes may predict bone injuries in male runners—and prior injury was the strongest warning sign.
In 156 male college runners, about 1 in 4 got a bone stress injury over ~2 years, and those with higher risk scores—especially a past bone injury—had higher relative risk of another injury.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
In simple terms
This study followed a group of male runners over time to see if certain risk scores were linked to getting bone injuries. It can show that higher scores go together with more injuries, but it can't prove that the scores cause the injuries. Something else might be involved.
What’s the bottom line?
Researchers studied 156 male college distance runners for about 2 years to see if a risk assessment tool (originally for female athletes) could predict bone stress injuries. They found that higher risk scores were linked to more injuries, especially if the runner had a prior bone injury.
How strong is this study?
The study is decent because it followed runners for several years and used statistical models, but it wasn't a randomized experiment and only included 156 male college runners. That means the results are suggestive but not definitive, and may not apply to all runners.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
26 / 100
- Randomizationnot randomized
- Blindingblinding unclear
- Control groupno control group
- Sample size (n=156)+10.8/20
- Follow-up+10/10
100 / 100
54 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervalsno confidence intervals
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 543 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
This design cannot establish causation — the findings describe an association, not a cause. Observational cohort design without randomization or a control group cannot establish cause-effect relationships. Findings are associations that may be influenced by unmeasured confounding, selection effects, and measurement error.
No Conflicts
No conflicts of interest identified
No conflicts of interest declared; funding from non-industry research and education grants.
Funders
Authors declare no competing interests. Funding comes from professional society, conference, institutional, and education foundation sources; no industry funding or funder involvement in study conduct is reported.
Key takeaways
- 01
42 out of 156 runners (27%) got at least one bone stress injury over ~1.9 years.
- 02
Each 1-point increase in the cumulative risk score was linked to a 37% higher relative risk of injury in one analysis and a 27% higher relative risk in another.
- 03
A prior bone injury increased relative risk by 57% per point.
- 04
BMI and bone density scores did not show a significant link.
- 05
The overall risk was about 27% (about 1 in 4 runners) over ~2 years.
- 06
For the risk scores, we know the relative increase (e.g., 37% higher relative risk per point), but the study did not report how many extra injuries that means per 100 runners, so the absolute risk increase per point is unknown.
Surprising findings
- Low BMI and low BMD risk scores were not significantly associated with bone stress injuries in male runners.The Female Athlete Triad framework traditionally highlights low BMI and low BMD as key risk factors, so their null findings in men are counterintuitive.
- A tool originally designed for female athletes predicted BSI risk in male distance runners.Sex-specific tools are often assumed to need separate validation, but this modified version showed a signal in men.
- Prior BSI was the strongest predictor, with a 57% higher relative risk per point.It suggests that past injury history may matter more than current body composition or bone density for predicting future injury.
- The overall injury burden was high: 27% of runners sustained at least one BSI, with 61 total injuries.Many people think of bone stress injuries as relatively rare, but in this collegiate male runner cohort they were common.
Practical takeaways
If you are a male collegiate distance runner with a prior bone stress injury, treat yourself as higher risk and prioritize gradual return-to-run, strength work, and injury prevention.
This is observational; prior injury is a marker of risk, not necessarily a direct cause. The absolute risk increase per prior BSI point was not reported.
medium confidencePay attention to energy availability and fueling—especially during high-mileage training—since low energy availability is part of the risk score linked to BSI.
The study did not test whether improving fueling prevents injuries. The causal claim that underfueling increases injury risk is not proven by this design.
low-medium confidenceCoaches and athletes can use a modified cumulative risk checklist to start conversations about BSI risk, but should not rely on BMI or BMD alone.
BMI and BMD risk scores were not significantly associated with BSI in this study, and the tool was adapted from a female-specific assessment. Small sample and no confidence intervals limit certainty.
low-medium confidenceWhen reading injury studies, ask for absolute risk: how many extra injuries per 100 runners? Relative risks alone can overstate practical impact.
This study reports relative risks but not absolute risk per point, so we cannot calculate the exact number needed to harm or benefit.
high confidenceWhy this study matters
1 in 4 male college runners got a bone stress injury
Among 156 male collegiate distance runners followed for an average of 1.9 years, 42 runners (27%) sustained at least one bone stress injury (BSI), with 61 total injuries. That is a substantial absolute risk: about 1 in 4 runners over roughly two years.
Bone stress injuries are often framed as a female athlete problem, but this study shows they are common in male distance runners too.
A female-specific risk tool predicted injuries in men
A modified Female Athlete Triad Cumulative Risk Assessment—covering low energy availability, low BMI, low bone mineral density (BMD), and prior BSI—was applied to male runners. Each 1-point increase in cumulative risk score was associated with a 37% higher relative risk of prospective BSI in a baseline model (p=0.0079) and a 27% higher relative risk in a longitudinal model (p=0.05). The absolute risk increase per point was not reported.
It suggests the underlying risk factors may be shared across sexes, even if the original tool was built for female athletes.
Prior injury is the strongest warning sign
Each 1-point increase in prior BSI score was associated with a 57% higher relative risk of a subsequent BSI (p=0.0042). That was the strongest and most statistically robust predictor in the study.
Once a runner has had a bone stress injury, they may be much more likely to get another—making return-to-run and prevention critical.
BMI and bone density didn’t significantly predict BSI
In this cohort, low BMI risk score had a rate ratio of 1.91 (p=0.11) and low BMD risk score had a rate ratio of 1.58 (p=0.19)—neither was statistically significant. That contrasts with the classic Female Athlete Triad emphasis on low BMI and low BMD.
It challenges the assumption that low body weight or low bone density are the main drivers of bone injuries in male runners.
Relative risks sound scary, but absolute risk per point is missing
The study reports relative risks like 37% and 57% higher risk per point, but it did not report how many extra injuries that means per 100 runners. The overall absolute risk was 27% (42/156) over ~1.9 years, but the absolute increase per risk-score point is unknown.
Without absolute risk, it’s hard to know how meaningful a 1-point change is for an individual runner.
Want the whole report?
Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Researchers studied 156 male college distance runners for about 2 years to see if a risk assessment tool (originally for female athletes) could predict bone stress injuries. They found that higher risk scores were linked to more injuries, especially if the runner had a prior bone injury.
Research results
42 out of 156 runners (27%) got at least one bone stress injury over ~1.9 years. Each 1-point increase in the cumulative risk score was linked to a 37% higher relative risk of injury in one analysis and a 27% higher relative risk in another. A prior bone injury increased relative risk by 57% per point. BMI and bone density scores did not show a significant link.
What this means - more context
The overall risk was about 27% (about 1 in 4 runners) over ~2 years. For the risk scores, we know the relative increase (e.g., 37% higher relative risk per point), but the study did not report how many extra injuries that means per 100 runners, so the absolute risk increase per point is unknown.
To determine if a modified Female Athlete Triad Cumulative Risk Assessment tool predicts bone stress injuries (BSI) in male distance runners.
In 156 male collegiate distance runners followed for an average of 1.9 years, 27% (42 runners) sustained at least one BSI. Each 1-point increase in cumulative risk score was associated with a 37% higher relative risk of BSI in a baseline model (p=0.0079) and a 27% higher relative risk in a longitudinal model (p=0.05). Prior BSI score was associated with a 57% higher relative risk per point (p=0.0042). BMI and BMD risk scores were not significantly associated with BSI. The absolute risk increase per point was not reported.
Methods Used
Mixed retrospective and prospective cohort study of 156 male runners at two collegiate programs over 7 years. Risk assessment categories included low energy availability, low BMI, low BMD, and prior BSI. Mixed effects Poisson regression was used, with baseline and longitudinal models.
Main Finding
Higher modified Female Athlete Triad Cumulative Risk Assessment scores predict increased rates of BSI in male distance runners. Each 1-point increase in cumulative risk score was associated with a 37% higher relative risk in the baseline model and 27% higher relative risk in the longitudinal model. Prior BSI score was associated with a 57% higher relative risk per point. The absolute risk increase per point was not reported; overall, 27% of runners sustained a BSI over ~1.9 years.
Confidence Level
Moderate. Cohort design with clear outcomes, but small sample size, no confidence intervals reported, and mixed retrospective/prospective data collection may limit precision.
Study Flags
Red Flags
- •Small sample size (156 runners)
- •No confidence intervals reported
- •Mixed retrospective and prospective design
- •Risk assessment tool originally designed for female athletes
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Surprising Findings
Low BMI and low BMD risk scores were not significantly associated with bone stress injuries in male runners.
The Female Athlete Triad framework traditionally highlights low BMI and low BMD as key risk factors, so their null findings in men are counterintuitive.
Practical Takeaways
If you are a male collegiate distance runner with a prior bone stress injury, treat yourself as higher risk and prioritize gradual return-to-run, strength work, and injury prevention.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 543 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Human Cohort Study
Subject
Moderate probability
on the GRADE evidence scale
This study followed a group of male runners over time to see if certain risk scores were linked to getting bone injuries. It can show that higher scores go together with more injuries, but it can't prove that the scores cause the injuries. Something else might be involved.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Prospective follow-up with a 7-year mixed retrospective/prospective design.
- Objective outcome of bone stress injuries assessed.
- Mixed effects Poisson regression appropriate for repeated events.
Weaknesses
- Observational design cannot control for unmeasured confounding.
- Small sample size and only two collegiate programmes.
- Blinding unknown/not applicable.
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Researchers studied 156 male college distance runners for about 2 years to see if a risk assessment tool (originally for female athletes) could predict bone stress injuries. They found that higher risk scores were linked to more injuries, especially if the runner had a prior bone injury.
Research results
42 out of 156 runners (27%) got at least one bone stress injury over ~1.9 years. Each 1-point increase in the cumulative risk score was linked to a 37% higher relative risk of injury in one analysis and a 27% higher relative risk in another. A prior bone injury increased relative risk by 57% per point. BMI and bone density scores did not show a significant link.
What this means - more context
The overall risk was about 27% (about 1 in 4 runners) over ~2 years. For the risk scores, we know the relative increase (e.g., 37% higher relative risk per point), but the study did not report how many extra injuries that means per 100 runners, so the absolute risk increase per point is unknown.
To determine if a modified Female Athlete Triad Cumulative Risk Assessment tool predicts bone stress injuries (BSI) in male distance runners.
In 156 male collegiate distance runners followed for an average of 1.9 years, 27% (42 runners) sustained at least one BSI. Each 1-point increase in cumulative risk score was associated with a 37% higher relative risk of BSI in a baseline model (p=0.0079) and a 27% higher relative risk in a longitudinal model (p=0.05). Prior BSI score was associated with a 57% higher relative risk per point (p=0.0042). BMI and BMD risk scores were not significantly associated with BSI. The absolute risk increase per point was not reported.
Methods Used
Mixed retrospective and prospective cohort study of 156 male runners at two collegiate programs over 7 years. Risk assessment categories included low energy availability, low BMI, low BMD, and prior BSI. Mixed effects Poisson regression was used, with baseline and longitudinal models.
Main Finding
Higher modified Female Athlete Triad Cumulative Risk Assessment scores predict increased rates of BSI in male distance runners. Each 1-point increase in cumulative risk score was associated with a 37% higher relative risk in the baseline model and 27% higher relative risk in the longitudinal model. Prior BSI score was associated with a 57% higher relative risk per point. The absolute risk increase per point was not reported; overall, 27% of runners sustained a BSI over ~1.9 years.
Confidence Level
Moderate. Cohort design with clear outcomes, but small sample size, no confidence intervals reported, and mixed retrospective/prospective data collection may limit precision.
Study Flags
Red Flags
- •Small sample size (156 runners)
- •No confidence intervals reported
- •Mixed retrospective and prospective design
- •Risk assessment tool originally designed for female athletes
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Surprising Findings
Low BMI and low BMD risk scores were not significantly associated with bone stress injuries in male runners.
The Female Athlete Triad framework traditionally highlights low BMI and low BMD as key risk factors, so their null findings in men are counterintuitive.
Practical Takeaways
If you are a male collegiate distance runner with a prior bone stress injury, treat yourself as higher risk and prioritize gradual return-to-run, strength work, and injury prevention.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 543 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Human Cohort Study
Subject
Moderate probability
on the GRADE evidence scale
This study followed a group of male runners over time to see if certain risk scores were linked to getting bone injuries. It can show that higher scores go together with more injuries, but it can't prove that the scores cause the injuries. Something else might be involved.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Prospective follow-up with a 7-year mixed retrospective/prospective design.
- Objective outcome of bone stress injuries assessed.
- Mixed effects Poisson regression appropriate for repeated events.
Weaknesses
- Observational design cannot control for unmeasured confounding.
- Small sample size and only two collegiate programmes.
- Blinding unknown/not applicable.
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
The study is decent because it followed runners for several years and used statistical models, but it wasn't a randomized experiment and only included 156 male college runners. That means the results are suggestive but not definitive, and may not apply to all runners.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
26 / 100
- Randomizationnot randomized
- Blindingblinding unclear
- Control groupno control group
- Sample size (n=156)+10.8/20
- Follow-up+10/10
100 / 100
54 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervalsno confidence intervals
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 543 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
This design cannot establish causation — the findings describe an association, not a cause. Observational cohort design without randomization or a control group cannot establish cause-effect relationships. Findings are associations that may be influenced by unmeasured confounding, selection effects, and measurement error.
No Conflicts
No conflicts of interest identified
No conflicts of interest declared; funding from non-industry research and education grants.
Funders
Authors declare no competing interests. Funding comes from professional society, conference, institutional, and education foundation sources; no industry funding or funder involvement in study conduct is reported.
Standing
The people behind it
The researchers who wrote the study this analysis is built on.
Authored by
10 researchersIf this is your work, this is how we attribute it on Fit Body Science. Emily Kraus is listed as the lead author.