Hi Rabbi, Shavua tov! I wanted to ask a question which I have thought about time to time, but now has become more relevant; is it permissible to join a marathon in which men and women will participate? Thanks!
ב"ה Shalom This question was asked 7 years ago in the Hebrew counterpart of this website, to which Rav Ya'akov Ariel Shlit"a answered, that it would be permitted people were modestly dressed, however that is not the case. (שו"ת אגרות משה חלק א סי' מ, שו"ת אגרות משה אבן העזר חלק א סימן נו : See also ) All the best