Some part of the swimmer must break the surface of the water throughout the race, except it shall be permissible for the swimmer to be completely submerged during the turn and for a distance of not more than 15 meters after the start and each turn. By that point the head must have broken the surface
I fail to see the point of this rule, it seems completely arbitrary to me.
While arbitrary rules are usual in heavily regulated sports, this strikes me as quite odd in a "freestyle" environment...
Why does freestyle swimming restrict underwater swimming?