Every time your race receives a comment it goes back to the top of the front page and on all of the category lists it is on. Categories are the links at the bottom of each event. You add these on the add event page.
All pages have moderated comments. Irrelevant comments are discarded.
Just follow the add comments link at the bottom of the page or use the comment form at the bottom of the page. See the illustration below with the black arrow.