Mod 42. For the record, the answer to your question is yes. Perhaps I wasn’t clear. Let’s forget for a moment how the woman is dressed during excercise, the act of excercising in and of itself it in many cases not tzniusdkik. The question should really be, are the laws of tznius somehow different in front of non jewish men with excercise being just one example.
Regarding males at a female production, I remember seeing in the igros moshe that under extenuating circumstances (in the case of the shayla it would have caused a tremendous machlokes in the area) men would be allowed to attend as long as the girls were less than 11 years old, if older he held it was assur. Bli neder later today will provide the source in igros moshe.