Saturday Science: Ballet Balance
There are lots of different ways to dance, and some of them hardly need any special training at all (I’m looking at you, Cupid Shuffle). There are lots of styles, though, that require strict training and years of practice to master. There’s swing dancing, different kinds of ballroom dancing, and breakdancing, and you need to work at them to get good. What may be one of the hardest to master, though is ballet. Ballerinas (and ballerinos, which are male ballet dancers, and if you just learned that today that makes two of us) have to be in peak physical condition, which high levels of strength, stamina, and agility. One of the most recognizable moves in ballet is called a pirouette, which is when a dancer spins on one foot. A pirouette can go for a while, which leads to an important question: how does a ballet dancer spin and spin and spin and then keep dancing? Don’t they get dizzy?
Today’s experiment casts you as an amateur ballet dancer trying out a ballet technique called “spotting,” something they do to help avoid being getting dizzy and puking right in the middle of Swan Lake.
- A large space around you
- Something to stare at (it can really be anything, as long as it doesn’t move)
- Step 1 is to create a control trial. This may get messy (hopefully not literally). Stand in the middle of your large space and spin around in a circle for 15-20 seconds. How do you feel afterward? Not great, probably.
- Take a breather. Get over your dizziness. Sit down, take some deep breaths, and locate your “something to stare at.” Stare at it. Picking a point to focus on will help your body kick the dizziness a bit more quickly.
- Now it’s time to practice some ballet. Stand up again, and face the thing you’re staring at. What you want to do is to turn your body in a pirouette, but keep your eyes on your thing until the last possible second. So even though your body is turning, your head doesn’t turn until it absolutely has to. When it does, turn it all the way around, so you’re staring at your thing again immediately, with the rest of your body following. Watch the ballerino’s head in this video. It should help you out.
- Picking that spot and focusing on it as you spin, instead of just spinning your head with the rest of your body, is what’s called “spotting.” Practice this slowly a few times until you start to get the hang of it.
- Once you think you’re pretty okay at spotting, repeat Step 1: spin for 15-20 seconds, but this time keep your focus on your thing and spot the whole time. How do you feel at the end of this spinning session? If you did it right, you should feel a little better than the first time.
The part of your body that helps you keep your balance is, weirdly, the same part that causes you to get dizzy, or carsick, or seasick. It’s called your vestibular system. It’s located inside your inner ears. You may not know it, but your sense of balance (fancy science word: equilibrioception) is just as much a sense as the classical five: touch, taste, hearing, sight, and smell. It’s just not quite as easy to notice. Most of the time, if it’s doing its job right, you don’t think of your sense of balance at all.
The vestibular apparatus in each ear is filled with a fluid. When you move or spin, that fluid lags behind the rest of you just a little bit, kind of like how if you move a glass across a table really fast the water will seem to climb up the back side. That slight lag is felt by sensors in each vestibular apparatus, and that information is sent to your brain to tell you what’s what. That’s how you can know you’re moving even if you’re in total pitch darkness. Your vestibular system senses it and tells your brain.
When you spin a bunch, the same thing happens, but it goes a little crazy. Here’s a secondary experiment: find a clear jar with a lid. Fill it about halfway up with water and then put the lid on tight. Spin the jar around as fast as you can. What happens to the water? The way that water keeps spinning for a while after the jar has stopped moving is exactly what happens inside your vestibular system when you spin. Your body stops moving, but that vestibular fluid just keeps going, telling your now-motionless body that you’re still spinning. Your eyes know you’re not spinning. Your skin knows it because it isn’t feeling air rush by it anymore. You have sensory confusion, and your brain interprets that as a really nasty dizzy feeling.
When a ballerina spots, the fluid isn’t turning quite as violently. It spins quickly and then settles, spins quickly and settles. Spotting keeps it from building up a ton of energy and just going and going after the pirouette stops. It’s actually not the whole picture, though. Scientists have studies ballet dancers to help figure out exactly how they keep from hurling during The Nutcracker and it turns out practice is important, too. Spotting is important, but just as important is that they have been pirouetting so much during their training that they can ignore whatever dizzy signals their vestibular system is still sending them. They’ve gotten so good at spinning that they just don’t get as dizzy as a normal person does.
Who says there’s no science involved in dance?