Testosterone suppression for transgender women has little effect on reducing muscle strength even after a year of treatment, according to new findings. Researchers say the findings could have important implications for transgender athletes in female sport.

Most sports governing bodies, including the International Olympic Committee, now have policies saying transwomen must take testosterone blockers for at least a year before they can compete at elite level.

But findings by the Karolinska Institute in Sweden, to be published this year, have shown the effect of the hormone treatment in relation to reducing leg muscle strength, is almost neglible for men who transition to become women.

That could be significant in sporting terms because it indicates the physical advantages of biological males are maintained even after transitioning