The floating arm trick boils down to an involuntary contraction in the aftermath of a prolonged, voluntary one

Sep 25, 2014 07:05 GMT  ·  By

There is no use for a PhD if you don't use your brains to study the downright bizarre stunts the human body sometimes likes to pull, neuroscientists Arko Gosh, John Rothwell and Patrick Haggard seem to think.

Hence their decision to take some time and study the so-called floating arm trick, otherwise known as the Kohnstamm phenomenon. Their focus was not on muscle behavior, but on brain activity.

More precisely, these neuroscientists wanted to find out exactly how the brain behaves whenever people do this trick. Their findings are detailed in a paper in the journal Proceedings of the Royal Society B: Biological Sciences.

The floating arm trick explained

For those who didn't even hear of the floating arm trick before stumbling upon this article, here is what this weird experiment is all about: a person stands in a doorway and pushes against the frame with the back of both their hands.

In order for the trick to work, one must push against the frame with all their strength, and maintain this position for about a minute. Roaring and whining as a means to cope with whatever pain might result are perfectly acceptable, just keep pushing.

After this minute of tormenting one's muscles is over, all that is left is to step away from the doorway. If all went well, the arms should begin to rise on their own, as if they had about a dozen helium balloons attached to them.

Mind you, this trick can also be performed with just one hand. Thus, one can always choose to push against a wall with the back of just one hand, and then have some fun watching this limb suddenly grow a mind of its own while the other is resting and pointing towards the floor.

The science behind this trick

By now, you've probably figured out that the floating arm trick boils down to an involuntary muscle contraction that occurs in the aftermath of a prolonged voluntary one. What Arko Gosh, John Rothwell and Patrick Haggard did was study brain activity during such performances.

As detailed in their paper in the journal Proceedings of the Royal Society B: Biological Sciences, the scientists had 39 male and female volunteers do the trick, and used electrodes to keep tabs on their brain activity the entire time they were carrying out their designated task.

The researchers were interested in learning what happens inside the human brain when a person consciously tries to block the involuntary contraction that landed the Kohnstamm phenomenon its rather funny nickname, Medical Express informs.

They found that, contrary to what was said before, the brain does not send two signals (one voluntary and one involuntary), of which the stronger manages to override the weaker. On the contrary, the brain is very much capable of shutting down the Kohnstamm response even before it begins to manifest.

Interestingly enough, the volunteers who consciously kept their arms from lifting all reported experiencing a feeling of resisting pressure. Otherwise put, they felt that keeping their arms close to their bodies instead of allowing them to float free was not quite right.

The scientists behind this research project expect that their findings will help specialists reach a better understanding of medical conditions such as Parkinson's, maybe even pave the way towards better treatment options for people diagnosed with motor issues.

This is how you must position your body if you want to do the floating arm trick
This is how you must position your body if you want to do the floating arm trick

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Scientists study the human brain during the floating arm trick
This is how you must position your body if you want to do the floating arm trick
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