@Zergling_man al explained previously this diose not apply to humanoid swimming as we use arms for propulsion not the overall geometry of our bodys , when humanoids swim it is basically the same as being dragged by set of propellers that have controllable angles of thrust this is something our fishy friends are simply incapable of

@Zergling_man however that being said i did just check out Olympic women's swimming outfits and they do all seem to deliberally flatten and redistribute the breast tissue across the chest evenly so it proberbly has an impact when performance is prioritised over comfort and aesthetics