The DOI matches its Crossref record; 123 of the 123 references it cites were found in a registry or an index; 29 of the 100 sources its claims cite were checked for support.
Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage
Open accessAbstract
Males enjoy physical performance advantages over females within competitive sport. The sex-based segregation into male and female sporting categories does not account for transgender persons who experience incongruence between their biological sex and their experienced gender identity. Accordingly, the International Olympic Committee (IOC) determined criteria by which a transgender woman may be eligible to compete in the female category, requiring total serum testosterone levels to be suppressed below 10 nmol/L for at least 12 months prior to and during competition. Whether this regulation removes the male performance advantage has not been scrutinized. Here, we review how differences in biological characteristics between biological males and females affect sporting performance and assess whether evidence exists to support the assumption that testosterone suppression in transgender women removes the male performance advantage and thus delivers fair and safe competition. We report that the performance gap between males and females becomes significant at puberty and often amounts to 10–50% depending on sport. The performance gap is more pronounced in sporting activities relying on muscle mass and explosive strength, particularly in the upper body. Longitudinal studies examining the effects of testosterone suppression on muscle mass and strength in transgender women consistently show very modest changes, where the loss of lean body mass, muscle area and strength typically amounts to approximately 5% after 12 months of treatment. Thus, the muscular advantage enjoyed by transgender women is only minimally reduced when testosterone is suppressed. Sports organizations should consider this evidence when reassessing current policies regarding participation of transgender women in the female category of sport.
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Written from the paper’s full text.
TL;DR
This review argues that current testosterone-suppression criteria for transgender women in female sport do not remove the male performance advantage established at puberty. It reports male–female performance gaps of 10–50% and only modest (~5%) average loss of lean mass or muscle size after 12 months of testosterone suppression, with skeletal and strength advantages largely retained.
Key findings
- The male–female performance gap becomes significant at puberty and often amounts to 10–50% depending on sport; it is larger in activities relying on muscle mass and explosive strength, especially upper-body actions (e.g., Olympic weightlifting 31–37%, tennis serve 20%, baseball pitch and field hockey drag flick >50%).
- Across 12 longitudinal studies, testosterone suppression to female-typical levels produced only modest changes: approximately −5% lean body mass or muscle size after 12 months, with no study reporting muscle loss exceeding −12% after 3 years; baseline male–female muscle mass differences are about 40%.
- Strength advantages persist: after 12 months, transgender women remained about 50% stronger than reference females in one study; grip strength fell 4–9% but retained a 17–23% advantage; height, skeletal parameters, and bone mineral density were maintained.
- Endurance effects are less clear: hemoglobin decreases by 11–14% with an estimated 2–5% performance penalty, but effects on VO2max, cardiac parameters, lactate threshold, and exercise economy remain unknown.
Methods
- Narrative/systematic review of biological sex differences in sporting performance and a literature search on anthropometric and muscle characteristics of transgender women (search terms in Supplementary Table S1).
- Performance gaps were compiled from publicly available sports federation databases and competition records; the main synthesis focused on 12 longitudinal studies of testosterone suppression and lean body mass, muscle size, or strength (Table 4), plus cross-sectional and related training/androgen-deprivation evidence.
- No new primary data were collected; the paper synthesizes existing studies and discusses implications for transgender inclusion policies.
Limitations
- The authors state that findings come from healthy adults with regular or low physical activity levels, not highly trained athletes, so further research is required in athletic transgender populations.
- The authors state that no controlled longitudinal study has explored endurance performance, and effects on VO2max, left ventricular size, stroke volume, blood volume, cardiac output, lactate threshold, and exercise economy remain unknown; no research evaluates agility, jumping, sprint, competition strength, or discipline-specific performance.
- Evident from the text: the review relies on heterogeneous studies, some with small samples, and cross-sectional data without baseline measurements; the running analysis by Harper used self-reported, uncontrolled race times, and there is no consensus on an acceptable residual advantage.
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Claims the paper makes
31 Own interpretation · 27 No full text of the sources · 25 No basis given · 12 Partly supported · 7 Own result · 4 Supported · 3 Supported so far · 3 Sources not found · 2 Not checked yet · accuracy not yet measured
Every source the paper cites for this claim was checked and supports it.
In the paper
“Thus, the biological effects of elevated pubertal testosterone are primarily responsible for driving the divergence of athletic performances between males and females [4].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > The Biological Basis for Sporting Performance Advantages in Males
What the sources say
- Supportedcites [4] Handelsman DJ, Hirschberg AL, Bermon S. Circulating testosterone as the hormonal basis of sex differences in athletic performance. Endocr Rev. 2018;39(5):803–29. source
The 'Sex, Fairness, and Segregation in Sport' section says male testosterone rises sharply after puberty and provides a major physical advantage in sport. The 'Muscle' section likewise describes athletic performances diverging from puberty onward as male testosterone levels increase. No page numbers are supplied in the passages. (LLM, conf=0.94)
plaindirect- Asserted: passes — The authors put it forward as true.
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- Supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“Many of these physiological factors differ significantly between biological males and females as a result of genetic differences and androgen-directed development of secondary sex characteristics [3, 4].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Introduction
What the sources say
- Partly supportedcites [3] Haizlip KM, Harrison BC, Leinwand LA. Sex-based differences in skeletal muscle kinetics and fiber-type composition. Physiology. 2015;30(1):30–9. sourceExperimental — accuracy not yet measured
The Abstract reports sex differences in skeletal-muscle physiology and gene expression, and the Conclusions implicate testosterone in muscle growth and fiber size (page numbers unavailable). The paper does not establish that broad physiological differences result from genetic differences or androgen-directed development of secondary sex characteristics; its discussion is focused on skeletal muscle. (LLM, conf=0.86)
- Partly supportedcites [4] Handelsman DJ, Hirschberg AL, Bermon S. Circulating testosterone as the hormonal basis of sex differences in athletic performance. Endocr Rev. 2018;39(5):803–29. sourceExperimental — accuracy not yet measured
The sections on muscle and bone link several male–female physiological differences to androgen action, and the section on other androgen-sensitive effects says many aspects of physiology differ by sex. But that section says the androgen dependence of other differences remains uncertain, while the section on genetic effects of the Y chromosome does not support a general genetic explanation for them. Our copy provides no page numbers for these passages. (LLM, conf=0.86)
plaindirect- Asserted: passes — The authors put it forward as true.
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- Partly supported
The sources with a verdict support this claim; the rest weren’t checked yet, have no full text we could read, or their verdicts aren’t rated yet.
In the paper
“Segregating sports by biological sex does not account for transgender persons who experience incongruence between their biological sex and their experienced gender identity, and whose legal sex may be different to that recorded at birth [6, 7].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Introduction
What the sources say
- Not checked — no full text of the sourcecites [6] Genel M. Transgender athletes: how can they be accommodated? Curr Sports Med Rep. 2017;16(1):12–3. source
- Supportedcites [7] Coggon J, Hammond N, Holm S. Transsexuals in sport—fairness and freedom, regulation and law. Sport Ethics Philos. 2008;2(1):4–17. source
The Definitions section describes gender dysphoria as a gender identity different from anatomical sex. The Gender Recognition Act 2004 section says a person can be legally recognised in a sex different from the one into which they were born while retaining their original biological characteristics. Together with the paper’s discussion of transsexual participation in sex-segregated sport, these passages support the paraphrase. Page numbers were not available in our copy. (LLM, conf=0.93)
plain- Asserted: passes — The authors put it forward as true.
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The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“Despite this modest reduction in strength, transgender women retained a 17% grip strength advantage over transgender men measured at baseline.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
What the sources say
- Partly supportedcites [70] Scharff M, Wiepjes CM, Klaver M, et al. Change in grip strength in trans people and its association with lean body mass and bone density. Endocr Connect. 2019;8:1020–8. sourceExperimental — accuracy not yet measured
Table 1 (Results > Characteristics; page unavailable) reports grip strength of 40.0 kg for transgender women after treatment and 33.1 kg for transgender men at baseline, supporting the comparison despite the women's modest decline. The gap is 17% of the women's 40.0 kg value, but approximately 21% of the men's baseline value; the stated 17% advantage over baseline transgender men therefore depends on an unstated denominator. (LLM, conf=0.86)
plaincorrelationaln = 249- Asserted: passes — The authors put it forward as true.
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- Partly supported
The sources with a verdict support this claim; the rest weren’t checked yet, have no full text we could read, or their verdicts aren’t rated yet.
In the paper
“Including Gooren and Bunck [62], 12 longitudinal studies [53, 63–73] have examined the effects of testosterone suppression on lean body mass or muscle size in transgender women.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
What the sources say
- Not checked — no full text of the sourcecites [62] Gooren LJG, Bunck MCM. Transsexuals and competitive sports. Eur J Endocrinol. 2004;151(4):425–9. source
- Not checked — no full text of the sourcecites [53] Van Caenegem E, Wierckx K, Taes Y, et al. Preservation of volumetric bone density and geometry in trans women during cross-sex hormonal therapy: a prospective observational study. Osteoporos Int. 2015a;26(1):35–47. source
- Not checked — no full text of the sourcecites [63] Haraldsen IR, Haug E, Falch J, et al. Cross-sex pattern of bone mineral density in early onset gender identity disorder. Horm Behav. 2007;52(3):334–43. source
- Not checked — no full text of the sourcecites [64] Mueller A, Zollver H, Kronawitter D, et al. Body composition and bone mineral density in male-to-female transsexuals during cross-sex hormone therapy using gonadotrophin-releasing hormone agonist. Exp Clin Endocrinol Diabetes. 2011;119(2):95–100. source
- Supportedcites [65] Wierckx K, Van Caenegem E, Schreiner T, et al. Cross-sex hormone therapy in trans persons is safe and effective at short-time follow-up: results from the European network for the investigation of gender incongruence. J Sex Med. 2014;11(8):1999–2011. source
The Abstract describes a one-year prospective study that included 53 trans women treated with cyproterone acetate and estradiol. The Trans Women section reports a decrease in total body lean mass during treatment, so this paper qualifies as one of the longitudinal studies cited. The count of 12 is the citing authors’ tally across multiple references, not a finding attributed to this paper alone. (LLM, conf=0.91)
- Not checked — no full text of the sourcecites [66] Gava G, Cerpolini S, Martelli V, et al. Cyproterone acetate vs leuprolide acetate in combination with transdermal oestradiol in transwomen: a comparison of safety and effectiveness. Clin Endocrinol (Oxf). 2016;85(2):239–46. source
- Supportedcites [67] Auer MK, Ebert T, Pietzner M, et al. Effects of sex hormone treatment on the metabolic syndrome in transgender individuals: focus on metabolic cytokines. J Clin Endocrinol Metab. 2018;103(2):790–802. source
The Patients section describes a study with one-year follow-up in transwomen. The Sex hormones section reports decreased testosterone, and Markers of the MS reports that lean mass was measured and remained unchanged. This supports citing the paper as one of the longitudinal studies in the group; it does not itself establish the total of 12. (LLM, conf=0.90)
- Supportedcites [68] Klaver M, De Blok CJM, Wiepjes CM, et al. Changes in regional body fat, lean body mass and body shape in trans persons using cross-sex hormonal therapy: results from a multicenter prospective study. Eur J Endocrinol. 2018;178(2):163–71. source
The Introduction says transwomen received estradiol with an anti-androgen. The Results report lean body mass in 179 transwomen after approximately one year of follow-up, confirming that this paper is one of the longitudinal studies identified by the citation. (LLM, conf=0.91)
- Not checked — no full text of the sourcecites [69] Fighera TM, da Silva E, Lindenau JDR, Spritzer PM. Impact of cross-sex hormone therapy on bone mineral density and body composition in transwomen. Clin Endocrinol (Oxf). 2018;88(6):856–62. source
- Supportedcites [70] Scharff M, Wiepjes CM, Klaver M, et al. Change in grip strength in trans people and its association with lean body mass and bone density. Endocr Connect. 2019;8:1020–8. source
This citation identifies one of the longitudinal studies, rather than supporting the total of 12 on its own. The Study design and study population section describes anti-androgen treatment in transwomen, the DXA methods describe measurement of lean body mass, and the Results (Characteristics) report lean-body-mass analyses for 171 transwomen. Page numbers are unavailable in our copy. (LLM, conf=0.90)
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“The performance gap is more pronounced in sporting activities relying on muscle mass and explosive strength, particularly in the upper body.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Abstract
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In the paper
“In Olympic weightlifting, where weight categories differ between males and females, the performance gap is between 31 and 37% across the range of competitive body weights between 1998 and 2020 (Fig. 1).”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Olympic Weightlifting
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In the paper
“Between 1998 and 2018, a 69 kg category was common to both males and females, with the male record holder (69 kg, 1.68 m) lifting a combined weight 30.1% heavier than the female record holder (69 kg, 1.64 m).”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Olympic Weightlifting
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In the paper
“Performance differences larger than 20% are generally present when considering sports and activities that involve extensive upper body contributions.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > An Overview of Elite Adult Athletes
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“For example, in the top/open weight category of Olympic weightlifting, in the absence of weight (and associated height) limits, maximum male lifting strength exceeds female lifting strength by nearly 40%.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Olympic Weightlifting
plaincorrelational- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“No controlled longitudinal study has explored the effects of testosterone suppression on endurance-based performance.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Endurance Performance and Cardiovascular Parameters
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“and that the 69-kg male record is 3.2% higher than the record held in the female open category by a 108-kg female (359 kg vs 348 kg).”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Olympic Weightlifting
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“Further analysis of Olympic weightlifting data shows that the 55-kg male record holder is 6.5% stronger than the 69-kg female record holder (294 kg vs 276 kg)”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Olympic Weightlifting
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“For example, approximately 10,000 males have personal best times that are faster than the current Olympic 100 m female champion (World Athletics, personal communication, July 2019).”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Perspectives on Elite Athlete Performance Differences
What the sources say
- Not matchedcites World Athletics, personal communication, July 2019
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
hedged- Asserted: passes — The authors put it forward as true.
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In the paper
“The collective evidence from these studies suggests that 12 months, which is the most commonly examined intervention period, of testosterone suppression to female-typical reference levels results in a modest (approximately − 5%) loss of lean body mass or muscle size (Table 4).”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
hedgeddirect- Asserted: passes — The authors put it forward as true.
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In the paper
“The male performance advantages described above in athletic cohorts are similar in magnitude in untrained people.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Performance Differences in Non-elite Individuals
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“However, importantly, male vs. female weightlifting performance gaps increase with increasing bodyweight.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Olympic Weightlifting
plaindirect- Asserted: passes — The authors put it forward as true.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The current male record holder (55 kg, 1.52 m) lifts 29.5% heavier than the female record holder (55 kg, 1.52 m).”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Olympic Weightlifting
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“This is further manifested in powerlifting, where the male record (total of squat, bench press and deadlift) is 65% higher than the female record in the open weight category of the World Open Classic Records.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Olympic Weightlifting
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“No study has reported muscle loss exceeding the − 12% found by Gooren and Bunck after 3 years of therapy.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“This is further apparent upon examination of selected junior male records, which surpass adult elite female performances by the age of 14–15 years (Table 3), demonstrating superior male athletic performance over elite females within a few years of the onset of puberty.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Perspectives on Elite Athlete Performance Differences
boostedcorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“The research conducted so far has studied untrained transgender women.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Conclusions
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“The reductions observed in muscle mass, size, and strength are very small compared to the baseline differences between males and females in these variables”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Conclusions
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“From the longitudinal muscle mass/strength studies summarised here, however, it is apparent that most therapeutic interventions result in almost complete suppression of testosterone levels, certainly well below 5 nmol/L (Table 4).”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > Testosterone-Based Criteria for Inclusion of Transgender Women in Female Sports
hedgeddirect- Asserted: passes — The authors put it forward as true.
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In the paper
“when in fact not even suppression down to around 1 nmol/L removes the anthropometric and muscle mass/strength advantage in any significant way.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > Testosterone-Based Criteria for Inclusion of Transgender Women in Female Sports
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“However, based on the studies reviewed here, evidence is lacking that this would diminish the male advantage to a tolerable degree.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > Testosterone-Based Criteria for Inclusion of Transgender Women in Female Sports
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“although 12 months of treatment is not sufficient to remove the male advantage”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > Testosterone-Based Criteria for Inclusion of Transgender Women in Female Sports
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“Males enjoy physical performance advantages over females within competitive sport.”
- Also stated in: § Introduction · boosted
“This confers large sporting performance advantages on biological males over females [5].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Abstract
What the sources say
- Not checked — no full text of the sourcecites [5] Sandbakk Ø, Solli GS, Holmberg HC. Sex differences in world-record performance: the influence of sport discipline and competition duration. Int J Sports Physiol Perform. 2018;13(1):2–8. source
boosteddirect- Asserted: passes — The authors put it forward as true.
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- Also stated in: § Introduction · boosted
A claim is checked only against the cited paper’s full text, never its abstract, and none is available for its sources.
In the paper
“The increasing performance gap between males and females as upper body strength becomes more critical for performance is likely explained to a large extent by the observation that males have disproportionately greater strength in their upper compared to lower body, while females show the inverse [44, 45].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > An Overview of Elite Adult Athletes
What the sources say
- Not checked — no full text of the sourcecites [44] Lassek WD, Gaulin SJC. Costs and benefits of fat-free muscle mass in men: relationship to mating success, dietary requirements, and native immunity. Evol Hum Behav. 2009;20(5):322–8. source
- Not checked — no full text of the sourcecites [45] Stoll T, Huber E, Seifert B, et al. Maximal isometric muscle strength: normative values and gender-specific relation to age. Clin Rheumatol. 2000;19(2):105–11. source
hedgedconditional- Asserted: passes — The authors put it forward as true.
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In the paper
“Accordingly, the International Olympic Committee (IOC) determined criteria by which a transgender woman may be eligible to compete in the female category, requiring total serum testosterone levels to be suppressed below 10 nmol/L for at least 12 months prior to and during competition.”
- Also stated in: § Introduction · plain
“These include a solemn declaration that her gender identity is female and the maintenance of total serum testosterone levels below 10 nmol/L for at least 12 months prior to competing and during competition [14].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Abstract
What the sources say
- Not matchedcites [14] Harper J, Hirschberg AL, Jose M, et al. IOC consensus meeting on sex reassignment and hyperandrogenism. 2015. https://stillmed.olympic.org/Documents/Commissions_PDFfiles/Medical_commission/2015-11_ioc_consensus_meeting_on_sex_reassignment_and_hyperandrogenism-en.pdf. Accessed 28 Nov 2020
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
plain- Asserted: passes — The authors put it forward as true.
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- Also stated in: § Introduction · plain
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Thus, the muscular advantage enjoyed by transgender women is only minimally reduced when testosterone is suppressed.”
- Also stated in: § Key Points · plain
“Here, we report that current evidence shows the biological advantage, most notably in terms of muscle mass and strength, conferred by male puberty and thus enjoyed by most transgender women is only minimally reduced when testosterone is suppressed as per current sporting guidelines for transgender athletes.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Abstract
plaindirect- Asserted: passes — The authors put it forward as true.
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- The authors state this as an assumption: The IOC's rationale for the 10 nmol/L testosterone threshold is that it reduces the male performance advantages to an acceptable degree, thus permitting fair and safe competition.
- Also stated in: § Key Points · plain
In the paper
“In Olympic javelin throwers, this is manifested in differences in the peak linear velocities of the shoulder, wrist, elbow and hand, all of which are 13–21% higher for male athletes compared with females [43].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > An Overview of Elite Adult Athletes
What the sources say
- Not checked — no full text of the sourcecites [43] Antti M, Komi PV, Korjus T, et al. Body segment contributions to javelin throwing during final thrust phases. J Appl Biomech. 1994;10:166–77. source
plaincorrelational- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“When comparing athletes who compete directly against one another, such as elite or comparable levels of school-aged athletes, the physiological advantages conferred by biological sex appear, on assessment of performance data, insurmountable.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Introduction
hedgeddirect- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This cross-sectional comparison suggests that prolonged testosterone suppression, well beyond the time period mandated by sports federations substantially reduces muscle mass and strength in transgender women.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
hedgeddirectn = 23- Asserted: passes — The authors put it forward as true.
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A claim is checked only against the cited paper’s full text, never its abstract, and none is available for its sources.
In the paper
“Male bone geometry and density may also provide protection against some sport-related injuries”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Anthropometrics
What the sources say
- Not checked — no full text of the sourcecites [59] Sigward SM, Powers CM. The influence of gender on knee kinematics, kinetics and muscle activation patterns during side-step cutting. Clin Biomech. 2006;21(1):41–8. source
- Not checked — no full text of the sourcecites [60] Francis P, Whatman C, Sheerin K, et al. The proportion of lower limb running injuries by gender, anatomical location and specific pathology: a systematic review. J Sport Sci Med. 2019;18(1):21–31.
hedgedconditional- Asserted: passes — The authors put it forward as true.
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In the paper
“Indeed, already at 17 years of age, the average male throws a ball further than 99% of 17-year-old females [51], despite no single variable (arm length, muscle mass etc.) reaching this numerical advantage.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Performance Differences in Non-elite Individuals
What the sources say
- Not checked — no full text of the sourcecites [51] Thomas JR, Thomas KT. Development of gender differences in physical activity. Quest. 1988;40(3):219–29. source
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“van Caenegem et al. [53] reported that hand-grip strength was reduced from baseline measurements by − 7% and − 9% after 12 and 24 months, respectively, of cross-hormone treatment in transgender women.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
What the sources say
- Not checked — no full text of the sourcecites [53] Van Caenegem E, Wierckx K, Taes Y, et al. Preservation of volumetric bone density and geometry in trans women during cross-sex hormonal therapy: a prospective observational study. Osteoporos Int. 2015a;26(1):35–47. source
plaindirect- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This reinforces the finding in athletic cohorts that sex differences in muscle size and strength are more pronounced in the upper body.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Performance Differences in Non-elite Individuals
plaincorrelationaln = 342- Asserted: passes — The authors put it forward as true.
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In the paper
“Thigh volume (both anterior and posterior thigh) and quadriceps cross-sectional area decreased − 4 and − 5%, respectively, after the 12-month period”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
What the sources say
- Not checked — no full text of the sourcecites [71] Wiik A, Lundberg TR, Rullman E, et al. Muscle strength, size, and composition following 12 months of gender-affirming treatment in transgender individuals. J Clin Endocrinol Metab. 2020;105(3):247. source
plaindirectn = 11- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Given the maintenance of BMD and the lack of a plausible biological mechanism by which testosterone suppression might affect skeletal measurements such as bone length and hip width, we conclude that height and skeletal parameters remain unaltered in transgender women”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Anthropometrics
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Rests on an assumption: Bone mineral density is maintained in transgender women undergoing testosterone suppression.
- Rests on an assumption: No plausible biological mechanism exists by which testosterone suppression might affect skeletal measurements such as bone length and hip width.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“We, therefore, conclude that the muscle mass advantage males possess over females, and the performance implications thereof, are not removed by the currently studied durations (4 months, 1, 2 and 3 years) of testosterone suppression in transgender women.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
plain- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This highlights that sex differences in parameters such as mass, strength and speed may combine to produce even larger sex differences in sport-specific actions, which often are a product of how various physical capacities combine.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Performance Differences in Non-elite Individuals
hedgedconditional- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“These comparisons demonstrate that males are approximately 30% stronger than females of equivalent stature and mass.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Olympic Weightlifting
boostedcorrelational- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“our analysis strongly suggests that the reduction in testosterone levels required by many sports federation transgender policies is insufficient to remove or reduce the male advantage, in terms of muscle mass and strength, by any meaningful degree.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
boosted- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“and that sporting advantage conferred by skeletal size and bone density would be retained despite testosterone reductions compliant with the IOC’s current guidelines.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Anthropometrics
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Rests on an assumption: Bone mineral density is maintained in transgender women undergoing testosterone suppression.
- Rests on an assumption: No plausible biological mechanism exists by which testosterone suppression might affect skeletal measurements such as bone length and hip width.
In the paper
“Even when expressed relative to fat-free weight, VO2max is 12–15% higher in males than in females [48].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Performance Differences in Non-elite Individuals
What the sources say
- Not checked — no full text of the sourcecites [48] Sparling PB. A meta-analysis of studies comparing maximal oxygen uptake in men and women. Res Q Exerc Sport. 1980;51(3):542–52. source
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
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A claim is checked only against the cited paper’s full text, never its abstract, and none is available for its sources.
In the paper
“Hemoglobin levels appear to decrease by 11–14% with cross-hormone therapy in transgender women [62, 71]”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Endurance Performance and Cardiovascular Parameters
What the sources say
- Not checked — no full text of the sourcecites [62] Gooren LJG, Bunck MCM. Transsexuals and competitive sports. Eur J Endocrinol. 2004;151(4):425–9. source
- Not checked — no full text of the sourcecites [71] Wiik A, Lundberg TR, Rullman E, et al. Muscle strength, size, and composition following 12 months of gender-affirming treatment in transgender individuals. J Clin Endocrinol Metab. 2020;105(3):247. source
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“Comparison with data in a separately-published, parallel cohort of transgender men [76] demonstrated a retained hand-grip strength advantage after 2 years of 23% over female baseline measurements”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
What the sources say
- Not checked — no full text of the sourcecites [76] Van Caenegem E, Wierckx K, Taes Y, et al. Body composition, bone turnover, and bone mass in trans men during testosterone treatment: 1-year follow-up data from a prospective case-controlled study (ENIGI). Eur J Endocrinol. 2015b;172(2):163–71. source
boostedcorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“Records of lower-limb muscle strength reveal a consistent 50% difference in peak torque between males and females across the lifespan [31].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Performance Differences in Non-elite Individuals
What the sources say
- Not checked — no full text of the sourcecites [31] Neder JA, Nery LE, Shinzato GT, et al. Reference values for concentric knee isokinetic strength and power in nonathletic men and women from 20 to 80 years old. J Orthop Sports Phys Ther. 1999;29:116–26. source
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Collectively, this implies a retained physical advantage even after 8 years of testosterone suppression.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
hedgeddirectn = 23- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“These longitudinal data comprise a clear pattern of very modest to negligible changes in muscle mass and strength in transgender women suppressing testosterone for at least 12 months.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
boosted- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This indicates that a plateau or a new steady state is reached within the first or second year of treatment”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > Testosterone-Based Criteria for Inclusion of Transgender Women in Female Sports
hedgeddirect- Asserted: passes — The authors put it forward as true.
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In the paper
“resistance exercise every third day during 90-days bed rest was sufficient to completely offset the 20% reduction in knee extensor muscle size noted in the resting control subjects [92].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > Perspectives on Athletic Status of Transgender Women
What the sources say
- Not checked — no full text of the sourcecites [92] Alkner BA, Tesch PA. Knee extensor and plantar flexor muscle size and function following 90 days of bed rest with or without resistance exercise. Eur J Appl Physiol. 2004;93:294–305. source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Whilst available evidence is strong and convincing that strength, skeletal- and muscle-mass derived advantages will largely remain after cross-hormone therapy in transgender women”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > Perspectives on Athletic Status of Transgender Women
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: unclear — It is unclear why the paper says it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The data presented here demonstrate that superior anthropometric, muscle mass and strength parameters achieved by males at puberty, and underpinning a considerable portion of the male performance advantage over females, are not removed by the current regimen of testosterone suppression permitting participation of transgender women in female sports categories.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion
boosted- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“and thus, there are major performance and safety implications in sports where these attributes are competitively significant.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Conclusions
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“the importance of the nervous system, e.g. muscle agonist activation (recruitment and firing frequency) and antagonist co-activation, for muscle strength must be acknowledged [104].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > The Focus on Muscle Mass and Strength
What the sources say
- Not checked — no full text of the sourcecites [104] Balshaw TG, Massey GJ, Maden-Wilkinson TM, et al. Neural adaptations after 4 years vs. 12 weeks of resistance training vs. untrained. Scand J Med Sci Sports. 2018;29(3):348–59. source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Thus, while this research is important to understand the isolated effects of testosterone suppression, it is still uncertain how transgender women athletes, perhaps undergoing advanced training regimens to counteract the muscle loss during the therapy, would respond.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Conclusions
hedged- Asserted: passes — The authors put it forward as true.
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- Based: passes — The paper gives a reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“These data significantly undermine the delivery of fairness and safety presumed by the criteria set out in transgender inclusion policies”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Conclusions
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Considering transgender women athletes who train during testosterone suppression, it is plausible to conclude that any losses will be similar to or even smaller in magnitude than documented in the longitudinal studies described in this review.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > Perspectives on Athletic Status of Transgender Women
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
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- Based: passes — The paper gives a reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“we argue that it is implausible that athletic transgender women would achieve final muscle mass and strength metrics that are on par with reference females at comparable athletic level.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > Perspectives on Athletic Status of Transgender Women
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Rather, it appears that the male performance advantage remains substantial.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- It may state two separate claims as one. 46
- Probably not a substantial claim. 11
Every source the paper cites for this claim was checked and supports it.
In the paper
“Testosterone in males induces changes in muscle mass, strength, anthropometric variables and hemoglobin levels [4], as part of the range of sexually dimorphic characteristics observed in humans.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > The Biological Basis for Sporting Performance Advantages in Males
What the sources say
- Supportedcites [4] Handelsman DJ, Hirschberg AL, Bermon S. Circulating testosterone as the hormonal basis of sex differences in athletic performance. Endocr Rev. 2018;39(5):803–29. source
The Muscle section reports testosterone-related increases in muscle mass and strength in men. The Hemoglobin section reports a dose-dependent increase in hemoglobin in young and older men, while the Bone section links male pubertal testosterone exposure to differences in height and bone size—anthropometric characteristics. The indexed passages provide no page numbers. (LLM, conf=0.91)
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
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It may state two separate claims as one.
- Supported
The sources with a verdict support this claim; the rest weren’t checked yet, have no full text we could read, or their verdicts aren’t rated yet.
In the paper
“During puberty, testes-derived testosterone levels increase 20-fold in males, but remain low in females, resulting in circulating testosterone concentrations at least 15 times higher in males than in females of any age [4, 25].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > The Biological Basis for Sporting Performance Advantages in Males
What the sources say
- Supportedcites [4] Handelsman DJ, Hirschberg AL, Bermon S. Circulating testosterone as the hormonal basis of sex differences in athletic performance. Endocr Rev. 2018;39(5):803–29. source
The ‘Sex, Fairness, and Segregation in Sport’ section states that after puberty men produce 20 times more testosterone than women, resulting in circulating concentrations 15-fold higher than in women of any age. The ‘Sex Difference in Circulating Testosterone Levels’ section adds that testosterone in girls rises during puberty but remains below 2 nmol/L. (LLM, conf=0.94)
- Not checked — no full text of the sourcecites [25] Bae YJ, Zeidler R, Baber R, et al. Reference intervals of nine steroid hormones over the life-span analyzed by LC-MS/MS: Effect of age, gender, puberty, and oral contraceptives. J Steroid Biochem Mol Biol. 2019;193:105409. source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“superior cardiovascular and respiratory function, with larger blood and heart volumes, higher hemoglobin concentration, greater cross-sectional area of the trachea and lower oxygen cost of respiration [3, 4, 39, 40].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > The Biological Basis for Sporting Performance Advantages in Males
What the sources say
- Could not verifycites [3] Haizlip KM, Harrison BC, Leinwand LA. Sex-based differences in skeletal muscle kinetics and fiber-type composition. Physiology. 2015;30(1):30–9. sourceExperimental — accuracy not yet measured
The Abstract mentions sex-based differences in cardiovascular health and disease, but does not describe males as having superior cardiovascular or respiratory function. Searches for blood and heart volume, hemoglobin, tracheal area, and the oxygen cost of respiration found no passage in our copy addressing those comparisons. (LLM, conf=0.76)
- Partly supportedcites [4] Handelsman DJ, Hirschberg AL, Bermon S. Circulating testosterone as the hormonal basis of sex differences in athletic performance. Endocr Rev. 2018;39(5):803–29. sourceExperimental — accuracy not yet measured
The Hemoglobin section (page not provided) says men have, on average, 12% higher circulating hemoglobin than women and estimates greater maximal oxygen transfer. The Other androgen-sensitive sex dichotomous effects section notes sex differences in exercise-induced cardiac and lung function, but does not establish the claimed larger blood and heart volumes, greater tracheal cross-sectional area, or lower oxygen cost of respiration. (LLM, conf=0.88)
- Not checked — no full text of the sourcecites [39] Dominelli PB, Molgat-Seon Y, Sheel AW. Sex differences in the pulmonary system influence the integrative response to exercise. Exerc Sport Sci Rev. 2019;47(3):142–50. source
- Not checked — no full text of the sourcecites [40] Wingate S. Cardiovascular anatomy and physiology in the female. Crit Care Nurs Clin N Am. 1997;9(4):447–52. source
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Could not verify
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“reduced fat mass, and different distribution of body fat and lean muscle mass, which increases power to weight ratios and upper to lower limb strength in sports where this may be a crucial determinant of success”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > The Biological Basis for Sporting Performance Advantages in Males
What the sources say
- Partly supportedcites [28] Lee DH, Keum N, Hu FB, et al. Development and validation of anthropometric prediction equations for lean body mass, fat mass and percent fat in adults using the National Health and Nutrition Examination Survey (NHANES) 1999–2006. Br J Nutr. 2017;118(10):858–66. sourceExperimental — accuracy not yet measured
The Results (page unavailable) report that men had lower fat mass and higher lean body mass than women; the Discussion (page unavailable) describes a possible sex difference in where fat accumulates. The paper does not establish differences in limb-specific muscle distribution or show that these body-composition differences increase power-to-weight ratios, upper-to-lower limb strength, or sporting success. (LLM, conf=0.88)
- Not checked — no full text of the sourcecites [29] Janssen I, Heymsfield SB, Wang ZM, Ross R. Skeletal muscle mass and distribution in 468 men and women aged 18–88 yr. J Appl Physiol. 2000;89:81–8. source
- Partly supportedcites [30] Bohannon RW, Wang YC, Yen SC, Grogan KA. Handgrip strength: a comparison of values obtained from the NHANES and NIH Toolbox studies. Am J Occup Ther. 2019;73(2):1–9. sourceExperimental — accuracy not yet measured
The Results (page unavailable) report higher handgrip strength in males than females. The paper does not address fat mass, the distribution of body fat or lean muscle, power-to-weight ratios, or relative upper- and lower-limb strength; those parts of the claim are unsupported. (LLM, conf=0.84)
- Not checked — no full text of the sourcecites [31] Neder JA, Nery LE, Shinzato GT, et al. Reference values for concentric knee isokinetic strength and power in nonathletic men and women from 20 to 80 years old. J Orthop Sports Phys Ther. 1999;29:116–26. source
- Not checked — no full text of the sourcecites [32] Jantz LM, Jantz RL. Secular change in long bone length and proportion in the United States, 1800–1970. Am J Phys Anthropol. 1999;110(1):57–67. source
- Not checked — no full text of the sourcecites [33] Brinckmann P, Hoefert H, Jongen HT. Sex differences in the skeletal geometry of the human pelvis and hip joint. J Biomech. 1981;14(6):427–30. source
- Not checked — no full text of the sourcecites [34] Lepley AS, Joseph MF, Daigle NR, et al. Sex differences in mechanical properties of the Achilles tendon: longitudinal response to repetitive loading exercise. J Strength Cond Res. 2018;32(11):3070–9. source
- Not checked — no full text of the sourcecites [35] Pate RR, Kriska A. Physiological basis of the sex difference in cardiorespiratory endurance. Sports Med. 1984;1(2):87–9. source
- Not checked — no full text of the sourcecites [36] Astrand PO, Cuddy TE, Saltin B, Stenberg J. Cardiac output during submaximal and maximal work. J Appl Physiol. 1964;19:268–74. source
- Not checked — no full text of the sourcecites [37] Best SA, Okada Y, Galbreath MM, et al. Age and sex differences in muscle sympathetic nerve activity in relation to haemodynamics, blood volume and left ventricular size. Exp Physiol. 2014;99(6):839–48. source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Partly supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“longer and larger skeletal structure, which creates advantages in sports where levers influence force application, where longer limb/digit length is favorable, and where height, mass and proportions are directly responsible for performance capacity”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > The Biological Basis for Sporting Performance Advantages in Males
What the sources say
- Partly supportedcites [28] Lee DH, Keum N, Hu FB, et al. Development and validation of anthropometric prediction equations for lean body mass, fat mass and percent fat in adults using the National Health and Nutrition Examination Survey (NHANES) 1999–2006. Br J Nutr. 2017;118(10):858–66. sourceExperimental — accuracy not yet measured
Split into 2 atoms — 0 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 1 unverifiable. Expand the claim to see per-atom verdicts.
- Not checked — no full text of the sourcecites [29] Janssen I, Heymsfield SB, Wang ZM, Ross R. Skeletal muscle mass and distribution in 468 men and women aged 18–88 yr. J Appl Physiol. 2000;89:81–8. source
- Could not verifycites [30] Bohannon RW, Wang YC, Yen SC, Grogan KA. Handgrip strength: a comparison of values obtained from the NHANES and NIH Toolbox studies. Am J Occup Ther. 2019;73(2):1–9. sourceExperimental — accuracy not yet measured
Split into 2 atoms — 0 confirmed, 0 partially supported, 0 disputed, 0 misattributed, 2 unverifiable. Expand the claim to see per-atom verdicts.
- Not checked — no full text of the sourcecites [31] Neder JA, Nery LE, Shinzato GT, et al. Reference values for concentric knee isokinetic strength and power in nonathletic men and women from 20 to 80 years old. J Orthop Sports Phys Ther. 1999;29:116–26. source
- Not checked — no full text of the sourcecites [32] Jantz LM, Jantz RL. Secular change in long bone length and proportion in the United States, 1800–1970. Am J Phys Anthropol. 1999;110(1):57–67. source
- Not checked — no full text of the sourcecites [33] Brinckmann P, Hoefert H, Jongen HT. Sex differences in the skeletal geometry of the human pelvis and hip joint. J Biomech. 1981;14(6):427–30. source
- Not checked — no full text of the sourcecites [34] Lepley AS, Joseph MF, Daigle NR, et al. Sex differences in mechanical properties of the Achilles tendon: longitudinal response to repetitive loading exercise. J Strength Cond Res. 2018;32(11):3070–9. source
- Not checked — no full text of the sourcecites [35] Pate RR, Kriska A. Physiological basis of the sex difference in cardiorespiratory endurance. Sports Med. 1984;1(2):87–9. source
- Not checked — no full text of the sourcecites [36] Astrand PO, Cuddy TE, Saltin B, Stenberg J. Cardiac output during submaximal and maximal work. J Appl Physiol. 1964;19:268–74. source
- Not checked — no full text of the sourcecites [37] Best SA, Okada Y, Galbreath MM, et al. Age and sex differences in muscle sympathetic nerve activity in relation to haemodynamics, blood volume and left ventricular size. Exp Physiol. 2014;99(6):839–48. source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Partly supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“Males have: larger and denser muscle mass, and stiffer connective tissue, with associated capacity to exert greater muscular force more rapidly and efficiently”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > The Biological Basis for Sporting Performance Advantages in Males
What the sources say
- Partly supportedcites [28] Lee DH, Keum N, Hu FB, et al. Development and validation of anthropometric prediction equations for lean body mass, fat mass and percent fat in adults using the National Health and Nutrition Examination Survey (NHANES) 1999–2006. Br J Nutr. 2017;118(10):858–66. sourceExperimental — accuracy not yet measured
The Results (page not available in our copy) report that men had, on average, 18 kg more lean body mass than women. Lean body mass is not a direct measure of muscle size or density, and the paper does not establish the claimed differences in connective-tissue stiffness or the speed and efficiency of force production. (LLM, conf=0.87)
- Not checked — no full text of the sourcecites [29] Janssen I, Heymsfield SB, Wang ZM, Ross R. Skeletal muscle mass and distribution in 468 men and women aged 18–88 yr. J Appl Physiol. 2000;89:81–8. source
- Partly supportedcites [30] Bohannon RW, Wang YC, Yen SC, Grogan KA. Handgrip strength: a comparison of values obtained from the NHANES and NIH Toolbox studies. Am J Occup Ther. 2019;73(2):1–9. sourceExperimental — accuracy not yet measured
The Results report higher handgrip strength values for males than females, supporting the claim of greater measured grip force. The paper does not address muscle size or density, connective-tissue stiffness, or whether males exert force more rapidly or efficiently; it does not establish those as explanations for the grip-strength difference. The indexed copy provides no page numbers for these passages. (LLM, conf=0.90)
- Not checked — no full text of the sourcecites [31] Neder JA, Nery LE, Shinzato GT, et al. Reference values for concentric knee isokinetic strength and power in nonathletic men and women from 20 to 80 years old. J Orthop Sports Phys Ther. 1999;29:116–26. source
- Not checked — no full text of the sourcecites [32] Jantz LM, Jantz RL. Secular change in long bone length and proportion in the United States, 1800–1970. Am J Phys Anthropol. 1999;110(1):57–67. source
- Not checked — no full text of the sourcecites [33] Brinckmann P, Hoefert H, Jongen HT. Sex differences in the skeletal geometry of the human pelvis and hip joint. J Biomech. 1981;14(6):427–30. source
- Not checked — no full text of the sourcecites [34] Lepley AS, Joseph MF, Daigle NR, et al. Sex differences in mechanical properties of the Achilles tendon: longitudinal response to repetitive loading exercise. J Strength Cond Res. 2018;32(11):3070–9. source
- Not checked — no full text of the sourcecites [35] Pate RR, Kriska A. Physiological basis of the sex difference in cardiorespiratory endurance. Sports Med. 1984;1(2):87–9. source
- Not checked — no full text of the sourcecites [36] Astrand PO, Cuddy TE, Saltin B, Stenberg J. Cardiac output during submaximal and maximal work. J Appl Physiol. 1964;19:268–74. source
- Not checked — no full text of the sourcecites [37] Best SA, Okada Y, Galbreath MM, et al. Age and sex differences in muscle sympathetic nerve activity in relation to haemodynamics, blood volume and left ventricular size. Exp Physiol. 2014;99(6):839–48. source
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Partly supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“handgrip strength in transgender women was in approximately the 25th percentile for males but was over the 90th percentile for females, both before and after hormone treatment.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
What the sources say
- Partly supportedcites [70] Scharff M, Wiepjes CM, Klaver M, et al. Change in grip strength in trans people and its association with lean body mass and bone density. Endocr Connect. 2019;8:1020–8. sourceExperimental — accuracy not yet measured
The Discussion reports that, after 12 months of hormone treatment, transwomen’s median grip strength was at the 95th percentile for age-matched females. But it assigns the 25th percentile for age-matched males to transmen, not transwomen, and does not give both percentile comparisons for transwomen before treatment. The Results report that transwomen’s grip strength decreased during treatment, but do not establish the claimed pretreatment percentiles. (LLM, conf=0.90)
plainn = 249- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Partly supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“examination of 249 transgender women revealed a decrease of − 4% in grip strength after 12 months of cross-hormone treatment, with no variation between different testosterone level, age or BMI tertiles”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
What the sources say
- Partly supportedcites [70] Scharff M, Wiepjes CM, Klaver M, et al. Change in grip strength in trans people and its association with lean body mass and bone density. Endocr Connect. 2019;8:1020–8. sourceExperimental — accuracy not yet measured
The study population section reports 249 transwomen, and the Results > Grip strength section reports a 1.8 kg decrease after 12 months with no difference across age or BMI groups. Table 1 gives a baseline grip strength of 41.8 kg, making the decrease approximately 4%. However, the Results explicitly say testosterone-concentration analyses could not be performed in transwomen, so the claimed absence of variation across testosterone tertiles is unsupported; age and BMI were analyzed as groups, not tertiles. Page numbers are unavailable in our copy. (LLM, conf=0.90)
plaindirectn = 249- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Partly supported
Every source the paper cites for this claim was checked and supports it.
In the paper
“Circulating hemoglobin levels are androgen-dependent [82] and typically reported as 12% higher in males compared with females [4].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Endurance Performance and Cardiovascular Parameters
What the sources say
- Supportedcites [82] Coviello AD, Kaplan B, Lakshman KM, et al. Effects of graded doses of testosterone on erythropoiesis in healthy young and older men. J Clin Endocrinol Metab. 2008;93(3):914–9. source
Citation [82] supports only the statement that hemoglobin levels are androgen-dependent; the 12% male–female comparison has a separate citation [4]. In the Hormones section, hemoglobin changed in a testosterone dose-dependent fashion and its change correlated with testosterone concentrations. (LLM, conf=0.93)
- Supportedcites [4] Handelsman DJ, Hirschberg AL, Bermon S. Circulating testosterone as the hormonal basis of sex differences in athletic performance. Endocr Rev. 2018;39(5):803–29. source
Citation [4] is attached to the claim that circulating hemoglobin is about 12% higher in males than females. The Hemoglobin section states that it is higher in men by 12% on average (page not specified). (LLM, conf=0.95)
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“studies have found very consistent changes in lean body mass (using dual-energy X-ray absorptiometry) after 12 months of treatment, where the change has always been between − 3 and − 5% on average, with slightly greater reductions in the arm compared with the leg region [68].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
What the sources say
- Partly supportedcites [68] Klaver M, De Blok CJM, Wiepjes CM, et al. Changes in regional body fat, lean body mass and body shape in trans persons using cross-sex hormonal therapy: results from a multicenter prospective study. Eur J Endocrinol. 2018;178(2):163–71. sourceExperimental — accuracy not yet measured
The Results report a 3% decrease in total lean body mass after one year in transwomen, and the regional-results section reports a larger decrease in the arm (6%). But the arm result falls outside the claimed −3% to −5% range, and lean body mass increased by 10% in transmen. The paper therefore does not support the unqualified claim that changes were always within that range. (LLM, conf=0.88)
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Partly supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“The more novel measure of radiological attenuation of the quadriceps muscle, a valid proxy of contractile density [74, 75], showed no significant change in transgender women after 12 months of treatment, whereas the parallel group of transgender men demonstrated a + 6% increase in contractile density with testosterone supplementation.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
What the sources say
- Partly supportedcites [74] Aubrey J, Esfandiari N, Baracos VE, et al. Measurement of skeletal muscle radiation attenuation and basis of its biological variation. Acta Physiol (Oxf). 2014;210(3):489–97. sourceExperimental — accuracy not yet measured
Split into 2 atoms — 0 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 1 unverifiable. Expand the claim to see per-atom verdicts.
- Supportedcites [75] Rasch A, Byström AH, Dalen N, Berg HE. Reduced muscle radiological density, cross-sectional area, and strength of major hip and knee muscles in 22 patients with hip osteoarthritis. Acta Orthop. 2007;78(4):505–10. source
Split into 2 atoms — 2 confirmed, 0 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.
plainn = 11- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Partly supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“The final average lean body mass of the transgender women was 51.2 kg, which puts them in the 90th percentile for women [79].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
What the sources say
- Partly supportedcites [79] Imboden MT, Swartz AM, Finch HW, et al. Reference standards for lean mass measures using GE dual energy x-ray absorptiometry in Caucasian adults. PLoS ONE. 2017;12(4):e0176161. sourceExperimental — accuracy not yet measured
Table 2 (Results) places 51.2 kg approximately at the 90th percentile for women aged 20–29 (51.1 kg), but its percentiles vary by age; it does not establish a single 90th-percentile value for all women. The paper provides reference values, not the reported final average for transgender women. (LLM, conf=0.86)
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Partly supported
Every source the paper cites for this claim was checked and supports it.
In the paper
“We acknowledge that changes in muscle mass are not always correlated in magnitude to changes in strength measurements because muscle mass (or total mass) is not the only contributor to strength [103].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > The Focus on Muscle Mass and Strength
What the sources say
- Supportedcites [103] Balshaw TG, Massey GJ, Maden-Wilkinson TM, et al. Changes in agonist neural drive, hypertrophy and pre-training strength all contribute to the individual strength gains after resistance training. Eur J Appl Physiol. 2017;117:631–40. source
The Discussion (page not supplied) reports a moderate correlation between changes in quadriceps volume and strength (r = 0.461), so changes in muscle size do not fully account for the magnitude of strength gains. It also identifies agonist neural drive and pre-training strength as additional contributors. (LLM, conf=0.93)
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“factors such as fiber types, biomechanical levers, pennation angle, fascicle length and tendon/extracellular matrix composition may all influence the ability to develop muscular force [105].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > The Focus on Muscle Mass and Strength
What the sources say
- Partly supportedcites [105] Maden-Wilkinson TM, Balshaw TG, Massey GJ, Folland JP. What makes long-term resistance-trained individuals so strong? A comparison of skeletal muscle morphology, architecture, and joint mechanics. J Appl Physiol. 2020;128:1000–11. sourceExperimental — accuracy not yet measured
The Introduction links pennation angle to force-generating capacity and identifies fiber-type composition as a possible contributor to contractile specific tension. The Methods use fascicle length in a measure of muscular force production, and the Discussion says joint leverage may contribute to maximal torque. The paper does not address how tendon or extracellular-matrix composition influences force development. (LLM, conf=0.88)
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
- Partly supported
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“We report that the performance gap between males and females becomes significant at puberty and often amounts to 10–50% depending on sport.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Abstract
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: unclear — It is unclear why the paper says it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The performance gap increases to an average of 16% in track cycling, with higher variation across events (from 9% in the 4000 m team pursuit to 24% in the flying 500 m time trial).”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > An Overview of Elite Adult Athletes
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: unclear — It is unclear why the paper says it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The smallest performance gaps were seen in rowing, swimming and running (11–13%), with low variation across individual events within each of those categories.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > An Overview of Elite Adult Athletes
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The average performance gap is 18% in jumping events (long jump, high jump and triple jump).”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > An Overview of Elite Adult Athletes
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The gap between fastest recorded tennis serve is 20%, while the gaps between fastest recorded baseball pitches and field hockey drag flicks exceed 50%.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > An Overview of Elite Adult Athletes
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“On the contrary, it appears that the net loss of lean mass and grip strength is not substantially decreased at year 2 or 3 of cross-hormone treatment (Table 4), nor evident in cohorts after an average 8 years after transition.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > Testosterone-Based Criteria for Inclusion of Transgender Women in Female Sports
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“there is no research evaluating the effects of transgender hormone treatment on factors such as agility, jumping or sprint performance, competition strength performance (e.g. bench press), or discipline-specific performance.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > The Focus on Muscle Mass and Strength
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Rather, the data show that strength, lean body mass, muscle size and bone density are only trivially affected.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Conclusions
boosted- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A claim is checked only against the cited paper’s full text, never its abstract, and none is available for its sources.
In the paper
“Yet, since the 1990s, the difference in performance records between males and females has been relatively stable, suggesting that biological differences created by androgenization explain most of the male advantage, and are insurmountable [5, 26, 27].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > The Biological Basis for Sporting Performance Advantages in Males
What the sources say
- Not checked — no full text of the sourcecites [5] Sandbakk Ø, Solli GS, Holmberg HC. Sex differences in world-record performance: the influence of sport discipline and competition duration. Int J Sports Physiol Perform. 2018;13(1):2–8. source
- Not checked — no full text of the sourcecites [26] Thibault V, Guillaume M, Berthelot G, et al. Women and men in sport performance: the gender gap has not evolved since 1983. J Sport Sci Med. 2010;9(2):214–23.
- Not checked — no full text of the sourcecites [27] Millard-Stafford M, Swanson AE, Wittbrodt MT. Nature versus nurture: have performance gaps between men and women reached an asymptote? Int J Sports Physiol Perform. 2018;13(4):530–5. source
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Further, in sports where contact, collision or combat are important for gameplay, widely different physiological attributes may create safety and athlete welfare concerns, necessitating not only segregation of sport into male and female categories, but also, for example, into weight and age classes.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Introduction
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Males also have longer arms than females, which allows greater torque production from the arm lever when, for example, throwing a ball, punching or pushing.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > An Overview of Elite Adult Athletes
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.
In the paper
“the performance gap is known to be substantial, and throwing represents the widest sex difference in motor performance from an early age [42].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > An Overview of Elite Adult Athletes
What the sources say
- Not checked — no full text of the sourcecites [42] Thomas JR, French KE. Gender differences across age in motor performance a meta-analysis. Psychol Bull. 1985;98(2):260–82. source
boostedcorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“vertical jump performance is on average 33% greater in elite men than women, with differences ranging from 27.8% for endurance sports to in excess of 40% for precision and combat sports [41].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > An Overview of Elite Adult Athletes
What the sources say
- Not checked — no full text of the sourcecites [41] Haugen T, Breitschädel F, Wiig H, Seiler S. Countermovement jump height in national team athletes of various sports: a framework for practitioners and scientists. Int J Sports Physiol Perform. 2020 (accessed 4 May 2020 from Researchgate) source
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“It shows that, even after adjustment for mass, biological males are significantly stronger (30%) than females, and that females who are 60% heavier than males do not overcome these strength deficits.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Olympic Weightlifting
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Strength differences range between 30 and 100%, depending upon the cohort studied and the task used to assess strength.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper may give no reason why it holds.
None of the sources cited for this claim have been checked yet.
In the paper
“males have a lower incidence of knee injuries, often attributed to low quadriceps (Q) angle conferred by a narrow pelvic girdle [59, 60].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Anthropometrics
What the sources say
- Not checked — no full text of the sourcecites [59] Sigward SM, Powers CM. The influence of gender on knee kinematics, kinetics and muscle activation patterns during side-step cutting. Clin Biomech. 2006;21(1):41–8. source
- Not matchedcites [60] Francis P, Whatman C, Sheerin K, et al. The proportion of lower limb running injuries by gender, anatomical location and specific pathology: a systematic review. J Sport Sci Med. 2019;18(1):21–31.
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
plainconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“The males had 57% greater muscle size, 109% greater isometric strength, and 89% greater 1RM strength than age-matched females.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Performance Differences in Non-elite Individuals
What the sources say
- Not checked — no full text of the sourcecites [49] Hubal MJ, Gordish-Dressman H, Thompson PD, et al. Muscle size and strength gain after unilateral resistance training. Med Sci Sport Exerc. 2005;37(6):964–72.
plaincorrelationaln = 342- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“The power produced during a punch was 162% greater in males than in females, and the least powerful man produced more power than the most powerful woman.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Performance Differences in Non-elite Individuals
What the sources say
- Not checked — no full text of the sourcecites [50] Morris JS, Link J, Martin JC, Carrier DR. Sexual dimorphism in human arm power and force: implications for sexual selection on fighting ability. J Exp Biol. 2020;223(Pt 2):jeb212365. source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“These data overwhelmingly confirm that testosterone-driven puberty, as the driving force of development of male secondary sex characteristics, underpins sporting advantages that are so large no female could reasonably hope to succeed without sex segregation in most sporting competitions.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Perspectives on Elite Athlete Performance Differences
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Similarly, punch power is 162% greater in men than women even though no single parameter that produces punching actions achieves this magnitude of difference [50].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Performance Differences in Non-elite Individuals
What the sources say
- Not checked — no full text of the sourcecites [50] Morris JS, Link J, Martin JC, Carrier DR. Sexual dimorphism in human arm power and force: implications for sexual selection on fighting ability. J Exp Biol. 2020;223(Pt 2):jeb212365. source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Similarly, the final grip strength was 41 kg, 25% higher than the female reference value [80].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
What the sources say
- Not checked — no full text of the sourcecites [80] Bohannon RW, Peolsson A, Massy-Westropp N, et al. Reference values for adult grip strength measured with a Jamar dynamometer: a descriptive meta-analysis. Physiotherapy. 2006;92(1):11–5. source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In running events, for example, where the male–female gap is approximately 11%, it follows that many thousands of males are faster than the very best females.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Sports Performance Differences Between Males and Females > Perspectives on Elite Athlete Performance Differences
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Sex differences in endurance performance are generally smaller than for events relying more on muscle mass and explosive strength.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Endurance Performance and Cardiovascular Parameters
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper may give no reason why it holds.
In the paper
“The results showed that transgender women had 17% less lean mass and 25% lower peak quadriceps muscle strength than the control males [78].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
What the sources say
- Not checked — no full text of the sourcecites [78] Lapauw B, Taes Y, Simoens S, et al. Body composition, volumetric and areal bone parameters in male-to-female transsexual persons. Bone. 2008;43(6):1016–21. source
plaincorrelationaln = 23- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“The age-graded scores for these eight runners were the same in both categories, suggesting that cross-hormone treatment reduced running performance by approximately the size of the typical male advantage.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Endurance Performance and Cardiovascular Parameters
What the sources say
- Not checked — no full text of the sourcecites [81] Harper J. Race times for transgender athletes. J Sport Cult Identities. 2015;6(1):1–9. source
hedgeddirectn = 8- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“They reported that muscle strength after 12 months of testosterone suppression was comparable to baseline strength. As a result, transgender women remained about 50% stronger than both the group of transgender men at baseline and a reference group of females.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
What the sources say
- Not checked — no full text of the sourcecites [71] Wiik A, Lundberg TR, Rullman E, et al. Muscle strength, size, and composition following 12 months of gender-affirming treatment in transgender individuals. J Clin Endocrinol Metab. 2020;105(3):247. source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“this study demonstrates that training during a period of testosterone suppression not only counteracts muscle loss, but can actually increase muscle mass and strength.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > Perspectives on Athletic Status of Transgender Women
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“which may create safety considerations and may alter the importance of retained performance advantages.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Conclusions
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Rests on an assumption: Different sports differ vastly in terms of physiological determinants of success.
In the paper
“in select exercises used during the training program, 10RM leg press and bench press increased + 32% and + 17%, respectively.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > Perspectives on Athletic Status of Transgender Women
What the sources say
- Not checked — no full text of the sourcecites [93] Kvorning T, Andersen M, Brixen K, Madsen K. Suppression of endogenous testosterone production attenuates the response to strength training: a randomized, placebo-controlled, and blinded intervention study. Am J Physiol Metab. 2006;291:E1325-32. source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“a phenomenon also noted in transgender men, where the increase in muscle mass seems to stabilise between the first and the second year of testosterone treatment [111].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > Testosterone-Based Criteria for Inclusion of Transgender Women in Female Sports
What the sources say
- Not matchedcites [111] Elbers JMH, Asscheman H, Seidell JC, et al. Long-term testosterone administration increases visceral fat in female to male transsexuals. J Clin Endocrinol Metab. 1997;82(7):2044–7.
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
- Not matched
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“and the balance between inclusion, safety and fairness therefore differs between sports.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Conclusions
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
- Rests on an assumption: Performance in most sports may be influenced by factors outside muscle mass and strength.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“If the advantage persists to a large degree, as evidence suggests, then a stated objective of targeting a certain testosterone level to be eligible will not achieve its objective”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Conclusions
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“it is acknowledged that the findings presented here are from healthy adults with regular or even low physical activity levels [91], and not highly trained athletes.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > Perspectives on Athletic Status of Transgender Women
What the sources say
- Not checked — no full text of the sourcecites [91] Muchicko MM, Lepp A, Barkley JE. Peer victimization, social support and leisure-time physical activity in transgender and cisgender individuals. Leis Loisir. 2014;3–4:295–308. source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Oxygen-carrying capacity in transgender women is most likely reduced with testosterone suppression, with a concomitant performance penalty estimated at 2–5% for the female athletic population [83].”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Endurance Performance and Cardiovascular Parameters
What the sources say
- Not checked — no full text of the sourcecites [83] Bermon S. Androgens and athletic performance of elite female athletes. Curr Opin Endocrinol Diabetes Obes. 2017;24(3):246–51. source
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Thus, while a reduction in hemoglobin is strongly predicted to impact aerobic capacity and reduce endurance performance in transgender women, it is unlikely to completely close the baseline gap in aerobic capacity between males and females.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Endurance Performance and Cardiovascular Parameters
boostedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Thus, in well-controlled studies in biological males who train while undergoing testosterone reduction, training is protective of, and may even enhance, muscle mass and strength attributes.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > Perspectives on Athletic Status of Transgender Women
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: unclear — It is unclear why the paper says it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Other factors that may impact sports performance, known to be affected by testosterone and some of them measurably different between males and females, include visuospatial abilities, aggressiveness, coordination and flexibility.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > The Focus on Muscle Mass and Strength
hedgedcorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.
In the paper
“Despite testosterone suppression to female levels of 2 nmol/L, there was a significant + 4% increase in leg lean mass and a + 2% increase in total lean body mass, and a measurable though insignificant increase in isometric knee extension strength.”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Discussion > Perspectives on Athletic Status of Transgender Women
What the sources say
- Not checked — no full text of the sourcecites [93] Kvorning T, Andersen M, Brixen K, Madsen K. Suppression of endogenous testosterone production attenuates the response to strength training: a randomized, placebo-controlled, and blinded intervention study. Am J Physiol Metab. 2006;291:E1325-32. source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The authors state this as an assumption.
The IOC's rationale for the 10 nmol/L testosterone threshold is that it reduces the male performance advantages to an acceptable degree, thus permitting fair and safe competition.
“Given the IOC’s stated position that the “overriding sporting objective is and remains the guarantee of fair competition” [14], it is reasonable to assume that the rationale for this requirement is that it reduces the male performance advantages described previously to an acceptable degree, thus permitting fair and safe competition.”
The paper relies on this without support.
Bone mineral density is maintained in transgender women undergoing testosterone suppression.
“Given the maintenance of BMD”
The paper relies on this without support.
No plausible biological mechanism exists by which testosterone suppression might affect skeletal measurements such as bone length and hip width.
“the lack of a plausible biological mechanism by which testosterone suppression might affect skeletal measurements such as bone length and hip width”
The paper relies on this without support.
The male performance advantage established by testosterone at puberty translates in elite athletes to a 10–50% performance advantage.
“the male performance advantage, established by testosterone at puberty and translating in elite athletes to a 10–50% performance advantage”
The paper relies on this without support.
The biological factors underpinning athletic performance are unequivocally established.
“it is still important to recognize that the biological factors underpinning athletic performance are unequivocally established.”
The paper relies on this without support.
Different sports differ vastly in terms of physiological determinants of success.
“it is clear that different sports differ vastly in terms of physiological determinants of success”
The paper relies on this without support.
Performance in most sports may be influenced by factors outside muscle mass and strength.
“It is also important to recognize that performance in most sports may be influenced by factors outside muscle mass and strength”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
The source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“the main criticism of this review is the purely biological argument from an elite male versus elite female position, implying that transwomen athletes are the same as elite male athletes”
From Integrating Transwomen and Female Athletes with Differences of Sex Development (DSD) into Elite Competition: The FIMS 2021 Consensus Statement (2021) · cites this paper as [43]
Experimental — accuracy not yet measuredThe cited source says what the claim attributes to it.
In the citing paper
“The authors concluded that anthropometric and muscle mass advantages are sustained in transwomen after 12 months of gender-affirming treatment based on studies showing the physiological changes caused by HRT in transwomen and chemical castration in men.”
From Integrating Transwomen and Female Athletes with Differences of Sex Development (DSD) into Elite Competition: The FIMS 2021 Consensus Statement (2021) · cites this paper as [43]
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
Each contradiction between two passages listed here was confirmed by an independent check.
Rated minor: it would not touch a result — a value no result rests on, a p-value that stays on the same side of the significance level, or a conflict that is clerical, resolved elsewhere in the paper, or outside its own findings.
In the paper
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
“Thigh volume (both anterior and posterior thigh) and quadriceps cross-sectional area decreased − 4 and − 5%, respectively, after the 12-month period”
§ Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage > Is the Male Performance Advantage Lost when Testosterone is Suppressed in Transgender Women? > Muscle and Strength Metrics
“Thigh volume1 yr − 5%Quad area1 yr − 4%”
Citations
Cites
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Cited by
Sorted by citations
Nuzzo, J. L. (2022) · The Journal of Strength and Conditioning Research · doi:10.1519/jsc.0000000000004329 · Cited by 360
“First, a general update on sex differences in muscle strength would be timely given ongoing discussions about (a) biological male subjects competing in the female category of sport (44,191,218,226,227,385) and (b) sex-specific physical fitness standards within the military (124), law enforcement (281), and firefightin…”
BackgroundHUNTER, S. K., S. ANGADI, S., BHARGAVA, A., HARPER, J., HIRSCHBERG, A. L., D. LEVINE, B., L. MOREAU, K., J. NOKOFF, N., STACHENFELD, N. S., & BERMON, S. (2023) · Medicine & Science in Sports & Exercise · doi:10.1249/mss.0000000000003300 · Cited by 241
Sex differences in skeletal muscle fiber types: A meta‐analysis
Nuzzo, J. L. (2023) · Clinical Anatomy · doi:10.1002/ca.24091 · Cited by 260
Sex differences in human performance
Hunter, S. K., & Senefeld, J. W. (2024) · The Journal of Physiology · doi:10.1113/jp284198 · Cited by 172
“…anatomical structure develop, such that, on average, males are taller; have longer limbs; have larger lungs and greater cross-sectional areas of conducting airways; possess more muscle mass, and have larger hearts than females (Dominelli et al., 2019; Hilton & Lundberg, 2021; Hunter et al., 2023).”
Sex and gender in respiratory physiology
LoMauro, A., & Aliverti, A. (2021) · European Respiratory Review · doi:10.1183/16000617.0038-2021 · Cited by 102
Metadata
- Authors
- Hilton, E. N., & Lundberg, T. R.
- Affiliations
- University of Manchester (GB)
- Karolinska University Hospital (SE)
- Corresponding author
- Lundberg, Tommy R.
- Venue
- Sports Medicine
- Published
- 2020-12-08
- Volume
- 51
- Issue
- 2
- Pages
- 199-214
- ISSN
- 0112-1642 (ISSN-L)
- 1179-2035
- PMC
- PMC7846503
- OpenAlex
- W3112696807
- Cited by
- 236
- References
- 112
- Citations by year
- 2026: 63 · 2025: 35 · 2024: 41 · 2023: 40 · 2022: 34 · 2021: 20 · 2020: 3
- FWCI
- 4.70
- Type
- journal article
- Language
- en
- Update notices
- correction (2021-04-29)
- Open access
- hybrid
- doi.org
- Locations
- Sports Medicine (publishedVersion, cc-by)
- Preprints.org (submittedVersion, cc-by)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- Research Explorer (The University of Manchester) (submittedVersion, other-oa)
- Funders
- Karolinska Institute
- Topics
- Social Sciences › Gender Studies › Sports, Gender, and Society
- Social Sciences › Psychology › Social Psychology › LGBTQ Health, Identity, and Policy
- Health Sciences › Medicine › Orthopedics and Sports Medicine › Sports Performance and Training
- Keywords
- transgender women, testosterone suppression, serum testosterone levels, muscle mass, muscle strength, lean body mass, puberty, gender identity
- MeSH terms
- Emotions, Female, Gender Identity, Humans, Male, Sports, Testosterone, Transgender Persons
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