Last year, the Washington Post reported that participating in trendy tough-guy mud runs often comes with a painful case of abdominal cramps and diarrhea brought on by literally eating shit—fecal bacteria mixed in with the mud. More than a thousand people are suffering those ill effects after a popular French event last week. (Not so tough now, are you?)

Regional health authorities confirm that cases of norovirus, a fun bug that comes with fever, vomiting, and diarrhea, reached the four digits after Mud Day in Nice June 20. An environmental review is underway, but animal fecal bacteria are a common transmission vector for norovirus, so there’s a strong suspicion that le mud was full of le merde.

More than 8,400 “Mud Guys” and “Mud Girls” entered the event, organizers confirmed. Hundreds of them complained on the event’s Facebook page, according to The Local, with one running noting “the distinct smell of horse manure” on the course.

Remember, tough guys: When you sign up for a mud run, you sign up for the mud runs.

[Photo (from a different event in Austria) via AP Images]