Rio Olympics 2016: The most bizarre Olympic rules

If there's one thing we know about this horse, it's that it is definitely less than four months pregnant. Photo / AP

American gymnast Laurie Hernandez performed exceptionally on the beam in Rio on Tuesday on the way to winning a silver medal.

But after completing her routine she - and the American team - felt the judges had incorrectly scored its difficulty. They believed it deserved an extra 0.1 rating points and decided to challenge.

So they pulled out their wallets. It seems archaic - and in a way against what the Olympics are supposed to represent - but in gymnastics you have to pay cash, up to $300, to launch an inquiry into scoring.

It's designed to ward off frivolous disputes but it's not the best look for the sport.

Teams are handed back their money if their challenges are upheld. But if they're not - like Hernandez - the dollars reportedly go to charity.

It's just one of the weird rules you'll see at the Olympics.

Wrestlers are some of the fiercest competitors at the Games but you won't see one without a handkerchief tucked somewhere in their uniform.

That's because all competitors are required to carry a "blood rag" to wipe up any claret or other body fluids that spill on to the mat during a match.

It makes perfect sense when you think about it, which is less than you can say about the pedantic technicality which requires cyclists' socks to be a certain height (less than half the length of their knee to their ankle).

But it's not only humans being ruled with an iron fist. Any horse entered in the equestrian competition has to be nine years old - and cannot be past four months pregnant.

Three and a half months knocked up? You're good to go. But once you've entered the second trimester (horse pregnancies last around 11-12 months) your Olympic dream is over.

There's plenty of over-saturation when it comes to rules involving water sports.

Swimmers are allowed to wear two caps - but no more - and despite being half-human half-fish, they must not compete without a lifeguard present.

Water polo players have their toe nails checked to avoid nasty scrapes under the water and synchronised swimmers can be penalised if the tape their musical accompaniment is on doesn't play.

We saw one of athletics' stranger rules in force on day 10 when Jamaica's Veronica Campbell-Brown competed in the 200m. The three-time gold medallist wasn't penalised for finishing her run in her opponent's lane because you only earn the wrath of officials if a) you veer into the inside lane therefore shortening your trip home, or b) you impede an opponent.

Oh, and apparently taking performance-enhancing drugs is outlawed too. Not that you can tell sometimes.