Swimming races are held in pools measured in metres, with lanes separated by floating lane ropes.

The longer version

Competition pools are built to a stated length in metres and certified by measuring the touch pads rather than the walls, because a pool can be a fraction out and still be usable. Floating lane ropes are strung with discs that swivel, which is deliberate: they break up waves instead of reflecting them back.

Without them, the wake from one swimmer would cross into neighbouring lanes and slow everyone unevenly, which is why the middle lanes are preferred in the biggest races. Short-course pools of half the standard length produce faster times, because every turn gives a push off a solid wall. Water temperature, depth and gutter design are regulated too, since they change drag and turbulence.

Where this entry sits

Facts here look at the rules, equipment and odd histories behind familiar sports and games, from balls and rackets to cards, boards and playing fields. Expect small details about scoring quirks, stadium design and the long story of the Olympic Games. The full list sits on the Sports and Games page, where every entry is listed in order.