Looking at records for 100 mile and other ultra marathon distances the men’s record is significantly faster than 10%. The 100 mile for men is 11:14:56 while the women’s is 12:41:11. I certainly don’t see the 4% the article claims.
In the source:
In 50-mile races, race times were 11.74 ± 1.95 h for men and 12.31 ± 1.69 h for women. In 100-mile races, race times were 26.6 ± 3.49 h for men and 27.47 ± 3.6 h for women. The sex differences decreased with older age and were smaller in 100-mile (4.41%) than in 50-mile races (9.13%)
My point was longer distances are not the cause of a narrower sex difference, the records show that. They only found that trend in older racers where men will have lower testosterone levels.
The disparity is also lower for longer races, it’s right there in the article and papers