The Claim

In transgender women endurance runners, average race times increase by approximately 14.6% after 31 months of gender-affirming hormone therapy (GAHT), with greater performance decrements in middle- and long-distance events (14.6–17.4%) compared to sprint events (11.2%), indicating that event duration modulates the magnitude of performance change following hormonal intervention.

Source: Longitudinal Performance Changes in Transgender Women Athletes Pre and Post Gender Affirming Hormone Therapy

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
44score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Quantitative
1 study reviewed
In plain English

Trans women runners get slower over time after starting hormone therapy, especially in longer races — their race times go up by about 14-17%, while sprints are less affected.

See the scientific wording

In transgender women endurance runners, race times increase by approximately 14.6% on average after 31 months of gender-affirming hormone therapy (GAHT), with greater performance decrements observed in middle- and long-distance events (14.6–17.4%) compared to sprint events (11.2%), suggesting that event duration influences the magnitude of performance change following hormonal intervention.

What the research says

1 study
  1. Study: Longitudinal Performance Changes in Transgender Women Athletes Pre and Post Gender Affirming Hormone Therapy

    The study looked at how running times changed for transgender women after hormone therapy and found they got slower by about 14.6% after 31 months, especially in longer races, just like the claim says.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

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