Well, if you care about realism so much, why don't you remove dragons (who cannot fly by any means due to physical laws), magic (which breaks mentioned laws), demons and angels and all the stuff?
8 level human fighter can have 22 strength with no magic items, (18 base +2 racical bonus +2 ability gains) and this str allows him to overcome the real world heavy lifting records. And female record is way lower, though character girl can lift enormous weight equally. This game is not about ordinary or common men and women.