The Science of Spinning
Dizziness can be a described as the result of a confusion between what the eyes see and the brain is told. If we spin round and round then stop suddenly it can feel as if the room is still moving even though we can see quite clearly that everything is standing still and that our feet are planted firmly on the floor. In classical dancing spinning can form the centre piece of many famous ballets and being able to avoid or control dizziness is essential.
Dizziness alters our ability to balance.
Balance is governed primarily by information received through our eyes and by three fluid filled chambers, called semi-circular canals, in the inner ear. When we turn our head from side to side this fluid stays relatively static compared with the movement of the head. Fine hairs projecting into the fluid and connected to special nerve cells which pick up the movement of the fluid and send a message to the brain. The difference between the movement of the fluid and the movement of the head is processed by the brain to calculate the speed and direction of the movement.
However when the body spins round continually the fluid in the inner ear picks up momentum and spins as well. Once this momentum is built up, it is slow to stop. The fluid in the balance organs keeps spinning even after the head is static. So the brain believes the body is still spinning even though the eyes are telling it the opposite. This contradiction between inner ear balance organs and vision (you can see you have stopped but it feels as if you haven't) causes dizziness. The brain gets two different messages and is trying to work out which one is telling the truth.
In most people dizziness calms down quite soon but for people with diseases in the inner ear, such as Meniere's Disease, a simple turn of the head can cause extreme dizziness that leads to nausea and vomiting and the only respite is when they lie down.
A dancer stops him or herself from getting dizzy by "spotting": focussing on one point for as long as possible before turning the head round in the spin to catch up with the body and focus on the same spot. The head is therefore being kept as still as possible for as long a time as possible while the body is continually moving. This enables the fluid in the inner ear to remain relatively still and not build any momentum thus avoid the confusing signals when the body stops.
There are other qualities a dancer needs to enable them to turn. Marianela Nuñez and Jonathan Cope are principal dancers with The Royal Ballet. In order to do the multiple pirouettes needed in Don Quixote the dancer must have strength as well as balance, but in duets the partner can also help as Jonathan Cope explains: "If the girl can turn on her own, it's very easy to partner her. But if she can't turn on her own then the secret is to get her straight and on her leg, and then the boy can turn her. But Marianela can turn very well on her own so pretty much I'm not actually doing anything. I'm starting the turn and she's just spinning in my hands.
With a girl that can't turn very well I'd have to push the turn round. And obviously the trouble with doing that is that you can actually sometimes send a pirouette off, so it's pushing to keep it straight, exactly like spinning a top really. But obviously a great turn is when it's completely on balance and it just keeps going, and going, and going, and going. But everybody's different and I think with some girls it's more like I have to keep rotating her "