Complex sentence: The two records from 2009,101 m and 90 m, were repealed by the federation eight months after they had been set, due to the introduction of a new rule, which was then applied retroactively.
Split into simpler sentences: The two records from 2009,101 m and 90 m, were repealed by the federation 8 months after they had been set. The reason for that was the introduction of a new rule, which was then applied retroactively.