Are shorts that one uses for exercise considered begged ish, and therefore a women couldn’t use shorts for excercise, or do we say that since in general society both men and women wear shorts, there is no problem? Does begged ish go by in general what frum people generally wear or does it go by what the general society wears?
Some poskim would permit women to wear shorts for the purpose of exercise, provided the shorts are not “men’s shorts” but women’s or “unisex” shorts. One may rely on these opinions. Of course, this is only true for purposes of exercise where no issue of tzenius is involved.
Sources: Some poskim have written that pants (trousers) are considered begged ish per se–defined as men’s clothing even if tailor-made for women–and it is therefore forbidden for women to wear any form of pants (Shevet Halevi, vol. 6, no. 14; Tzitz Eliezer, vol. 11, no. 62). Even according to this opinion, it would be permitted for women to wear pajama trousers, because the trousers are not designed to be seen by others (based on Avnei Tzedek 72, who permitted the wearing of woolly pants under a skirt for keeping warm in the winter; Avnei Yashfei vol. 5, no. 110). According to this opinion, it would be prohibited for a woman to wear ordinary (not pajamas) shorts.
However, a number of poskimwrite that becausewomen of today wear pants, and many pants are actually made exclusively for women, the prohibition of wearing a man’s clothing does not apply. However, they prohibit the wearing of pants because of tzenius considerations (Yaskil Avdi, Yoreh De’ah 72; Yabia Omer, vol. 6, Yoreh De’ah 14; see Avnei Tzedek no. 72; Minchas Yitzchak vol. 2, no. 108; this is also the opinion of Rav Elyashiv and Rav Scheinberg, as quoted in Avnei Yashfei, loc. cit.). According to these opinions, it would be permitted to wear (women’s) pants, where issues of tzenius do not apply. The general custom is to be lenient on this matter.