Men are more likely to try something new because a friend told them to than because an ad told them to. That makes referrals the highest-leverage growth channel a studio has, if there's a reason to talk about the class in the first place.
Give people something worth sharing: a before/after strength benchmark, a milestone board, a group chat for the regulars. Broformer studios that build an actual community, not just a class roster, see referral rates that paid marketing can't match.