There's no trick to the shaded squares - just emphasizing the theme!
Hope you enjoyed learning about these amazing women who had a major impact on the sport of running! This was part of the March 2022 midi contest (broad theme was "women").
nice puzzle and apt title - i really appreciate you adding the extra hints in the NE corner because that RICOH5AMaker of large printers that is an anagram of "choir"[-----]/RAYE5DComic Martha nicknamed "The Big Mouth" (rhymes with "weigh")[----] crossing is tough