A bodybuilder is someone who does exercises to develop large muscles. This may be for use in sports such as wrestling or weightlifting, or just for display. Bodybuilders may be male or female. For display purposes, they will wear tight, scanty outfits, maybe just Speedos for men or a bikini for women.
Submissive men may fantasise that a female bodybuilder will be able to overpower them physically; compare macrophilia.