Practical implications
This review shows transgender women exhibited higher absolute lean mass compared with cisgender women; however, no significant differences in upper-body or lower-body strength were observed between the two groups after 1–3 years of hormone therapy. Because the lean mass and performance data were not necessarily derived from the same cohorts or study designs, direct correlations between muscle mass and functional strength cannot be inferred. Nevertheless, one may postulate that residual lean mass may not translate into clear functional strength advantages in this population. In line with this, the current results are consistent with evidence4 indicating that, although transgender women retain higher absolute lean mass, body composition-adjusted strength metrics (eg, relative strength per kg lean mass) tend to converge with cisgender women over time within the same cohort. This suggests that lean mass alone is an incomplete proxy for transgender women’s athletic performance, as neuromuscular efficiency, training history and fat distribution may play compensatory roles. In fact, when height-normalised, transgender women and cisgender women appear to show comparable appendicular lean mass/height² or lean mass/height².25 31 Importantly, a greater absolute lean mass not accompanied by increased functionality may actually impair performance, especially in weight-sensitive sports (eg, cycling and climbing), which not surprisingly have the lightest athletes.77
In fact, the absence of strength disparities between transgender women and cisgender women found in the current review was consistent and contradicts narratives framing male puberty as conferring irreversible athletic advantages despite GAHT. In a narrative review, Lundberg et al 3 argue that male developmental traits (eg, height, skeletal proportions) inherently disrupt fairness, yet the lack of measurable strength differences in the present systematic review suggests such claims may overemphasise structural factors while underestimating the impact of GAHT. For instance, transgender women’s VO₂ max, when adjusted for weight, aligns with cisgender women,4 further supporting parity in endurance capabilities. Furthermore, transgender women’s pretherapy advantages in push-ups and sit-ups disappeared after 2 years of feminising hormones among 46 individuals who started GAHT while in the US Air Force.50 These findings are corroborated by the current meta-analysis, endorsing nuanced, sport-specific policies rather than blanket bans.