ReviewSports medicine (Auckland, N.Z.)2021
Do Sex Differences in Physiology Confer a Female Advantage in Ultra-Endurance Sport?
Review in Sports medicine (Auckland, N.Z.), 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 58 papers, 4 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
58 citing papers in PubMed, 4 syntheses or guidelines pooled it, 101 citations in OpenAlex.
- Nutritional Strategies for Optimizing Health, Sports Performance, and Recovery for Female Athletes and Other Physically Active Women: A Systematic Review.Nutrition reviews · 2025Pooled it
- Is There Evidence for the Development of Sex-Specific Guidelines for Ultramarathon Coaches and Athletes? A Systematic Review.Sports medicine - open · 2023Pooled it
- Running economy and lower extremity stiffness in endurance runners: A systematic review and meta-analysis.Frontiers in physiology · 2022Pooled it
- Analysis of sex-based differences in energy substrate utilization during moderate-intensity aerobic exercise.European journal of applied physiology · 2022Pooled it
- Effect of oral contraceptive consumption timing on substrate metabolism, cognition, and exercise performance in females: a randomised controlled trial.European journal of applied physiology · 2025Trial
- Sex Differences in Supplement Intake in Recreational Endurance Runners-Results from the NURMI Study (Step 2).Nutrients · 2021Trial
- Risk of Menstrual Dysfunction, Low Energy Availability, Eating Disorders and Injury in the First All-Female UK Military Team Rowing 3000 Miles Across the Atlantic.Sports (Basel, Switzerland) · 2026Article
- Project FURTHER: A Physiological, Biomechanical, and Psychosocial Profile of an All-Female 6-Day Ultramarathon Race.Sports medicine - open · 2026Article
- Highly Trained Female Runners Show Greater Durability and Physiological Resilience Than Performance-Matched Male Counterparts.Scandinavian journal of medicine & science in sports · 2026Article
- Pacing of the first and only female finisher in the world's longest triathlon: The 2024 Triple Deca ultra triathlon.Journal of exercise science and fitness · 2026Article
- Ageing, Sex Differences, and REDs Risk in Endurance Runners: An Integrated Cross-Sectional Study Protocol.Sports (Basel, Switzerland) · 2026Article
- ATLAS study: Design, athletic performance, and sex-specific regression models for muscle strength in the Greek population.Sports medicine and health science · 2026Article
- Sex- and nationality-based participation and performance trends in the Swissman Xtreme Triathlon (2019-2025).PloS one · 2026Article
- Model-based estimates of sex differences in peak power and fatigue index in track cyclists using directed acyclic graphs, inverse probability of treatment weighting, and Bayesian modeling.Frontiers in physiology · 2026Article
- Sexual dimorphism in the serum metabolome following acute exhaustive exercise.Biology of sex differences · 2025Article
- Sex-specific differences in performance and pacing in the world's longest triathlon in history.Scientific reports · 2025Article
- Sex-differences in Mountain Ultra-trail Performance: Look at the Scenery.Sports medicine - open · 2025Article
- Race course characteristics are the most important predictors in 48 h ultramarathon running.Scientific reports · 2025Article
- Analysis of the 50-mile ultramarathon distance using a predictive XGBoost model.Scientific reports · 2025Article
- Muscle transcriptome profiles in elite male ultra-endurance athletes acclimated to a high-carbohydrate versus low-carbohydrate diet.Scientific reports · 2025Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
6 authors at 6 institutions in 4 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Ultra-endurance has been defined as any exercise bout that exceeds 6 h. A number of exceptional, record-breaking performances by female athletes in ultra-endurance sport have roused speculation that they might be predisposed to success in such events. Indeed, while the male-to-female performance gap in traditional endurance sport (e.g., marathon) remains at ~ 10%, the disparity in ultra-endurance competition has been reported as low as 4% despite the markedly lower number of female participants. Moreover, females generally outperform males in extreme-distance swimming. The issue is complex, however, with many sports-specific considerations and caveats. This review summarizes the sex-based differences in physiological functions and draws attention to those which likely determine success in extreme exercise endeavors. The aim is to provide a balanced discussion of the female versus male predisposition to ultra-endurance sport. Herein, we discuss sex-based differences in muscle morphology and fatigability, respiratory-neuromechanical function, substrate utilization, oxygen utilization, gastrointestinal structure and function, and hormonal control. The literature indicates that while females exhibit numerous phenotypes that would be expected to confer an advantage in ultra-endurance competition (e.g., greater fatigue resistance, greater substrate efficiency, and lower energetic demands), they also exhibit several characteristics that unequivocally impinge on performance (e.g., lower O
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.