The DOI matches its Crossref record; 35 of the 35 references it cites were found in a registry or an index.
Muscle Strength, Size, and Composition Following 12 Months of Gender-affirming Treatment in Transgender Individuals
Abstract
Context: As many sports are divided in male/female categories, governing bodies have formed regulations on the eligibility for transgender individuals to compete in these categories. Yet, the magnitude of change in muscle mass and strength with gender-affirming treatment remains insufficiently explored. Objective: This study explored the effects of gender-affirming treatment on muscle function, size, and composition during 12 months of therapy. Design, settings, participants: In this single-center observational cohort study, untrained transgender women (TW, n = 11) and transgender men (TM, n = 12), approved to start gender-affirming medical interventions, underwent assessments at baseline, 4 weeks after gonadal suppression of endogenous hormones but before hormone replacement, and 4 and 12 months after treatment initiation. Main outcome measures: Knee extensor and flexor strength were assessed at all examination time points, and muscle size and radiological density (using magnetic resonance imaging and computed tomography) at baseline and 12 months after treatment initiation. Results: Thigh muscle volume increased (15%) in TM, which was paralleled by increased quadriceps cross-sectional area (CSA) (15%) and radiological density (6%). In TW, the corresponding parameters decreased by –5% (muscle volume) and –4% (CSA), while density remained unaltered. The TM increased strength over the assessment period, while the TW generally maintained their strength levels. Conclusions: One year of gender-affirming treatment resulted in robust increases in muscle mass and strength in TM, but modest changes in TW. These findings add new knowledge on the magnitude of changes in muscle function, size, and composition with cross-hormone therapy, which could be relevant when evaluating the transgender eligibility rules for athletic competitions.
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In the citing paper
“Data showing lower baseline isometric torque and muscle volume [51] in transwomen compared to cisgender males”
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 [51]
In the citing paper
“This finding agrees with previous studies that have shown that baseline muscular strength in transwomen is not significantly diminished after 1 year [51, 53] but is after 2 years of HRT [53].”
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 [51]
In the citing paper
“However, studies in non-athletic transwomen undergoing GAHT also report changes in lean body mass (LBM),15 muscle cross-sectional area (CSA),16 muscular strength17 and haemoglobin (Hgb)18 and/or haematocrit (HCT).19”
In the citing paper
“A decrease in CSA of 1.5%–11.7% was reported over periods ranging from 12 to 36 months.”
In the citing paper
“Five longitudinal studies16 17 37 40 41 investigated the muscular strength of transwomen.”
In the citing paper
“Eight of these studies,16 19 36–38 43 48 49 including the large (n=239) ENIGI study,19 found that hormone therapy led to a significant (4.6%–14.0%) decrease in Hgb/HCT (p<0.01)”
In the citing paper
“After 3–4 months on GAHT, the HCT19 or Hgb16 levels of transwomen matched those of cisgender women”
In the citing paper
“while in six16 19 36 37 43 48 of the eight other studies mean testosterone after GAHT was less than 2.0 nmol/L.”
In the citing paper
“The fifth longitudinal study to assess strength measured upper leg strength using knee flexion and extension and found no significant difference after 12 months.16”
In the citing paper
“hormone-naive transwomen and cisgender men have similar testosterone levels.16 17 19 42”
In the citing paper
“Nine studies16 19 36–38 43 47–49 reported the levels of Hgb or HCT in transwomen before and after GAHT, from a minimum of three to a maximum of 36 months post hormone therapy.”
In the citing paper
“Hemoglobin levels appear to decrease by 11–14% with cross-hormone therapy in transgender women [62, 71]”
From Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage (2021) · cites this paper as [71]
In the citing paper
“Thigh volume (both anterior and posterior thigh) and quadriceps cross-sectional area decreased − 4 and − 5%, respectively, after the 12-month period”
From Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage (2021) · cites this paper as [71]
In the citing 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.”
From Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage (2021) · cites this paper as [71]
Citations
Cites
The effects of supraphysiologic doses of testosterone on muscle size and strength in normal men
Bhasin, S., Storer, T. W., Berman, N., Callegari, C., Clevenger, B., Phillips, J., Bunnell, T. J., Tricker, R., Shirazi, A., & Casaburi, R. (1996) · New England Journal of Medicine · doi:10.1056/nejm199607043350101 · Cited by 1,659
The importance of muscular strength: Training considerations
Suchomel, T. J., Nimphius, S., Bellon, C. R., & Stone, M. H. (2018) · Sports Medicine · doi:10.1007/s40279-018-0862-z · Cited by 940
Advanced Body Composition Assessment: From Body Mass Index to Body Composition Profiling
Borga, M., West, J., Bell, J. D., Harvey, N. C., Romu, T., Heymsfield, S. B., & Leinhard, O. D. (2018) · Journal of Investigative Medicine · doi:10.1136/jim-2018-000722 · Cited by 626
Circulating Testosterone as the Hormonal Basis of Sex Differences in Athletic Performance
Handelsman, D. J., Hirschberg, A. L., & Bermon, S. (2018) · Endocrine Reviews · doi:10.1210/er.2018-00020 · Cited by 594
Berg, H. E., Tedner, B., & Tesch, P. A. (1993) · Acta Physiologica Scandinavica · doi:10.1111/j.1748-1716.1993.tb09573.x · Cited by 366
Jones, B. A., Arcelus, J., Bouman, W. P., & Haycraft, E. (2016) · Sports Medicine · doi:10.1007/s40279-016-0621-y · Cited by 318
Composition of Skeletal Muscle Evaluated with Computed Tomography
Goodpaster, B. H., Thaete, F. L., & Kelley, D. E. (2000) · Annals of the New York Academy of Sciences · doi:10.1111/j.1749-6632.2000.tb06416.x · Cited by 257
Hormone Therapy and Skeletal Muscle Strength: A Meta-Analysis
Greising, S. M., Baltgalvis, K. A., Lowe, D. A., & Warren, G. L. (2009) · The Journals of Gerontology Series A · doi:10.1093/gerona/glp082 · Cited by 252
Elbers, J. M. H., Asscheman, H., Seidell, J. C., & Gooren, L. J. G. (1999) · American Journal of Physiology-Endocrinology and Metabolism · doi:10.1152/ajpendo.1999.276.2.e317 · Cited by 236
Karlsson, A., Rosander, J., Romu, T., Tallberg, J., Grönqvist, A., Borga, M., & Leinhard, O. D. (2014) · Journal of Magnetic Resonance Imaging · doi:10.1002/jmri.24726 · Cited by 215
Cited by
Sorted by citations
HUNTER, 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
Hilton, E. N., & Lundberg, T. R. (2021) · Sports Medicine · doi:10.1007/s40279-020-01389-3 · Cited by 236
Self-citationHarper, J., O'Donnell, E., Sorouri Khorashad, B., McDermott, H., & Witcomb, G. L. (2021) · British Journal of Sports Medicine · doi:10.1136/bjsports-2020-103106 · Cited by 206
Gender‐affirming hormone therapy: An updated literature review with an eye on the future
D'hoore, L., & T'Sjoen, G. (2022) · Journal of Internal Medicine · doi:10.1111/joim.13441 · Cited by 109
Roberts, T. A., Smalley, J., & Ahrendt, D. (2021) · British Journal of Sports Medicine · doi:10.1136/bjsports-2020-102329 · Cited by 92
Metadata
- Authors
- Wiik, A., Lundberg, T. R., Rullman, E., Andersson, D. P., Holmberg, M., Mandić, M., Brismar, T. B., Dahlqvist Leinhard, O., Chanpen, S., Flanagan, J. N., Arver, S., & Gustafsson, T.
- Affiliations
- Karolinska University Hospital (SE)
- AMRA Medical AB, Linköping, Sweden
- Corresponding author
- Lundberg, Tommy R
- ORCID
- Venue
- The Journal of Clinical Endocrinology & Metabolism
- Publisher
- The Endocrine Society
- Published
- 2019-12-03
- Volume
- 105
- Issue
- 3
- Pages
- e805-e813
- ISSN
- 0021-972X (ISSN-L)
- 1945-7197
- OpenAlex
- W2992734117
- Cited by
- 116
- References
- 35
- Citations by year
- 2026: 10 · 2025: 20 · 2024: 16 · 2023: 25 · 2022: 24 · 2021: 12 · 2020: 9
- FWCI
- 9.13
- Type
- journal article
- Language
- en
- Open access
- closed
- Licence
- academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model (vor)
- Locations
- The Journal of Clinical Endocrinology & Metabolism (publishedVersion)
- PubMed (publishedVersion)
- Funders
- Stockholm County Council (20160337, K0138-2015)
- Topics
- Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Hormonal and reproductive studies
- Social Sciences › Psychology › Social Psychology › LGBTQ Health, Identity, and Policy
- Health Sciences › Medicine › Orthopedics and Sports Medicine › Sports Performance and Training
- Keywords
- gender-affirming hormone therapy, transgender women, transgender men, muscle strength, muscle size, muscle composition, thigh muscle volume, quadriceps cross-sectional area, muscle density, gonadal suppression, sports eligibility, transgender athletes
- MeSH terms
- Adult, Female, Humans, Male, Transsexualism, Cohort Studies, Treatment Outcome, Muscle, Skeletal, Hormone Replacement Therapy, Muscle Strength, Sex Reassignment Procedures, Gender-Affirming Procedures
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