U.S. Air Force fitness tests of transgender women, by time on hormones (Roberts et al. 2021, Table 4)

What this dataset measures

These are the two most-cited bodies of evidence on whether testosterone suppression removes the male athletic advantage: before-and-after clinical studies, gathered in the Harper et al. (2021) systematic review, and the only study of real fitness-test performance over time (Roberts et al. 2021). Using every adult 12-month study group in the review, rather than one study, avoids picking a favorable result.

Geography

United States, Europe

Unit of observation

Study group and measure; fitness measure and time band

Update cadence

As new before-and-after studies are published

Curator

FactHub Research Team

Curated data tables

U.S. Air Force fitness tests of transgender women, by time on hormones (Roberts et al. 2021, Table 4)

Mean push-ups and sit-ups in one minute and 1.5-mile run time of 46 transgender women in the U.S. Air Force before hormones and at 0-1, 1-2 and 2-2.5 years of treatment, with the difference from the average Air Force woman under 30 (2004-2014) and 95% confidence intervals, exactly as printed.

Unit of observation: One fitness measure in one time band

air-force-fitness-trans-women.csv text/csv · 1,007 bytes

All 12 rows 10 columns Download the file

All 12 rows

measure	timeOnHormones	binOrder	transWomenMean see unit	transWomenCiLow see unit	transWomenCiHigh see unit	diffVsAverageWoman see unit	diffCiLow see unit	diffCiHigh see unit	unit
pushups	Before hormones	0	47.3	44.6	50.0	14.8	12.1	17.4	repetitions in 1 minute
pushups	Under 1 year	1	44.6	41.8	47.4	12.1	9.3	14.8	repetitions in 1 minute
pushups	1 to 2 years	2	43.2	39.3	47.1	10.7	6.8	14.5	repetitions in 1 minute
pushups	2 to 2.5 years	3	34.6	26.1	43.1	2.1	-6.4	10.5	repetitions in 1 minute
situps	Before hormones	0	53.5	51.3	55.7	7.9	5.7	10.0	repetitions in 1 minute
situps	Under 1 year	1	54.1	51.9	56.3	8.5	6.3	10.7	repetitions in 1 minute
situps	1 to 2 years	2	51.8	48.6	55.0	6.2	3.0	9.3	repetitions in 1 minute
situps	2 to 2.5 years	3	44.8	37.1	52.4	-0.9	-8.4	6.7	repetitions in 1 minute
run	Before hormones	0	708	681	734	-147	-173	-121	seconds for 1.5 miles
run	Under 1 year	1	758	731	786	-97	-124	-70	seconds for 1.5 miles
run	1 to 2 years	2	791	753	829	-64	-101	-26	seconds for 1.5 miles
run	2 to 2.5 years	3	765	685	846	-90	-169	-10	seconds for 1.5 miles

10 field definitions

Field	Type	Meaning	Units	Value type
measure	string	pushups, situps or run.	—	observed
timeOnHormones	string	Time band as printed: Before hormones, Under 1 year, 1 to 2 years, 2 to 2.5 years.	—	observed
binOrder	integer	Order of the time band, 0 = before hormones.	—	derived
transWomenMean	number	Mean score of transgender women in the band.	see unit	observed
transWomenCiLow	number	Lower end of the 95% confidence interval for the mean.	see unit	observed
transWomenCiHigh	number	Upper end of the 95% confidence interval for the mean.	see unit	observed
diffVsAverageWoman	number	Mean difference from the average Air Force woman under 30; for the run, negative means faster.	see unit	observed
diffCiLow	number	Lower end of the 95% confidence interval for the difference.	see unit	observed
diffCiHigh	number	Upper end of the 95% confidence interval for the difference.	see unit	observed
unit	string	repetitions in 1 minute, or seconds for 1.5 miles.	—	observed

Supporting files

Source snapshots, manifests, quality reports, documentation, and other materials used to produce or review this release.

• analyses.json Derived table · application/json · 16.7 KB (17,090 bytes)

  Every saved-analysis result in this dataset, as computed by build.js.

• build.js Transformation manifest · text/javascript · 4.2 KB (4,317 bytes)

  Node.js script that computes every saved analysis from the two curated tables.

Sources

1. Harper J, O'Donnell E, Sorouri Khorashad B, McDermott H, Witcomb GL (British Journal of Sports Medicine) Systematic review, Tables 2-5: per-study changes in lean body mass, muscle cross-sectional area, strength and hemoglobin or hematocrit, with each study's testosterone before and after treatment, in transgender women on hormones. Free copy

   Retrieved November 5, 2026. CC BY 4.0. Open access under CC BY 4.0; FactHub republishes the extracted numbers with attribution.

   Reliability: Peer-reviewed study. Peer-reviewed systematic review of 24 studies of non-athletic transgender women, from Loughborough University and partners; no specific funding and no competing interests declared.

2. Roberts TA, Smalley J, Ahrendt D (British Journal of Sports Medicine) Table 4: U.S. Air Force fitness-test push-ups, sit-ups and 1.5-mile run times of 46 transgender women before and during hormone treatment, compared with the average Air Force woman and man under 30.

   Retrieved November 5, 2026. Copyright BMJ; numbers reported as facts. FactHub republishes the table's means, differences and confidence intervals as facts, with attribution; the article text is not redistributed.

   Reliability: Peer-reviewed study. Peer-reviewed study of U.S. Air Force medical and fitness records, 2004-2018, by military and academic pediatricians; no specific grant. Fitness tests measure endurance, not maximal strength, and the comparison is to an Air Force average, not matched controls.

3. Scharff M, Wiepjes CM, Klaver M, Schreiner T, T'Sjoen G, den Heijer M (Endocrine Connections) Cross-check of the largest 12-month study group: 249 transgender women in the European ENIGI cohort, grip strength 41.8 kg before and 40.0 kg after 1 year; median testosterone 17.9-18.5 nmol/L before and 0.4-0.8 nmol/L during treatment by clinic (Table 1). Free copy

   Retrieved November 5, 2026. CC BY 4.0. Open access; numbers republished with attribution.

   Reliability: Peer-reviewed study. Multicenter prospective clinical cohort in Amsterdam, Ghent and Oslo; authors declare no conflict of interest.

4. Wiik A, Lundberg TR, et al. (Journal of Clinical Endocrinology & Metabolism) Cross-check of the Wiik study group: thigh muscle volume fell 5% and quadriceps cross-sectional area 4% in 11 transgender women after 12 months, while strength was maintained.

   Retrieved November 5, 2026. Copyright Endocrine Society; numbers reported as facts. Numbers republished as facts with attribution.

   Reliability: Peer-reviewed study. Prospective study of 11 untrained transgender women at Karolinska Institutet, Stockholm; funded by Stockholm County Council and two foundations; no conflicts declared.

License: FactHub's selection, cleaning and combined tables are licensed under CC BY 4.0. Source data keeps the terms listed above (terms).

Limitations and reproducibility

Reproducible from public sources: Both curated tables are transcribed from published tables (Harper et al. 2021, Tables 2-5; Roberts et al. 2021, Table 4). build.js computes every saved analysis from them. The largest 12-month group (Scharff 2019) and the Wiik 2020 group were cross-checked against the original papers.

• Nearly all participants were adults, and none were competitive athletes. No before-and-after study has measured athletic performance in transgender girls.
• The 12-month medians count each study group once, regardless of size, and pool different muscles and strength tests.
• The Air Force comparison is to an average woman, not to matched women with the same training.
• Changes after 12 months are not charted; the review found too few studies to say whether losses continue.