Olympic rules OK - A-Z of sporting regulations

H - Horseplay will not be tolerated - decorating a horse's mane with "extravagant items" such as ribbons or flowers is "strictly forbidden" in the incomparably genteel dressage event.

I - Impromptu displays of gymnastics are best avoided - in the pole vault a contestant will be disqualified if "he employs any form of somersaulting whilst running up".

J - Jumping on the podium in your wetsuit is frowned upon - canoe slalom rules state: "To maintain the solemnity and dignity of the presentation ceremony the competitors receiving medals must wear proper clothing (training suits or national uniforms)".

K - Kitchenware, train sets, playing cards and bookmarks with Olympic branding may only be sold by their respective licensed companies - which have paid a premium to associate their ostensibly un-Olympian goods with the Games.

L - Lashing out at competitors on Facebook is not allowed - the International Olympic Committee says that athletes "must not report on competition or comment on the activities of other participants" online.

M - Moustaches are not the preserve of respectable brawlers - in boxing, "beards and moustaches are not allowed". Piercings and any "body accessories" are out too.

N - Noisy synchronised swimmers will be punished - poolside music levels must be monitored to "ensure that no person is exposed to average sound levels exceeding 90 decibels or momentary peak sound levels exceeding 100 decibels".

O - Officiating umpires at the rowing events caught in a downpour may only wear blue raincoats. They must also wear a dark blue blazer, light blue shirt, an International Rowing Federation tie, grey trousers and have the option of donning a dark blue hat. In "very hot" weather, they're allowed to remove the blazer and tie.

P - Pink, blue or shiny balls are an affront to the International Table Tennis Federation - "the ball shall be made of celluloid or similar plastics material and shall be white or orange, and matt".

Q - Quaffing ginseng tea could cost you a podium position. A brew made with the plant can contain the stimulant ephedrine, a banned substance, as 100m runner Linford Christie discovered to his cost at the Games in South Korea in 1988.

R - Remove those tracksuit bottoms - only a skin-tight leotard will cut it on the trampolines: "any other 'dress' which is not skin-tight is not allowed".

S - Skimpy bikinis are a must for any officially accredited beach volleyball game, says the rule book. The top should be "closely fitted to be body" and the briefs must have "a side width no greater than 7cm".

T - Transgender athletes may only compete if they have undergone sex reassignment surgery before puberty.

U - Umbrellas won't spoil your view of the 100m - large ones have been banned from the Games for safety reasons, along with other "blunt instruments" such as bats, flagpoles, sticks and tripods.

V - Vuvuzelas will not be allowed to ruin the Games - horns, whistles, drums, rattles, musical instruments and "any other devices that in the opinion of Locog may disturb a session (including mobile telephones)" are strictly forbidden.

W - Wrestlers cannot compete unless they have a cloth handkerchief tucked under their singlet. The "blood rag" - surely the most macho accessory of any athlete - is there to mop up after injuries.

X - X-rated tweets will not be tolerated - athletes must not to post "vulgar or obscene words or images" to Twitter. Promoting brands, products or services has been outlawed too.

Y - You could be fined up to £20,000 if you're caught trying to sell that elusive 100m final ticket. Resale is only permitted through an official online ticket exchange, due to open next year.

Z - Zippers are for tracksuits, not Speedos - swimsuits must be "in good moral taste" and must conform to a bewildering array of regulations governing porosity, weight, thickness, coatings, compression (zips not permitted), surface roughness and overall hydrodynamic resistance.