At the recent World Championships an artistic swimmer passed out and had to be rescued by her coach. It was evidently the second time this has happened to her. This seems to be inherently dangerous and exactly the sort of thing that FINA has acted upon before. In the 40s and early 50s, I believe, breaststrokers had discovered that it was faster to swim underwater than on the surface. Some competitors passed out in meets and in practice and FINA changed the breaststroke rule so there's only one stroke is allowed underwater at the start and each turn. Then when it was found that backstroke was faster underwater than on the surface it recognized that that was dangerous and changed the maximum distance underwater to 15M off each start and turn, which was then expanded to include butterfly and freestyle. This seems exactly the same sort of dangerous issue.
