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Irish dancers ‘get pilot G-force’
02. 05. 2010 | 292 reads
From The Sunday Times - March 14, 2010 - Jan Battles
Warning: Irish dancing can seriously damage your health. Engineers at Coventry University have discovered that Irish dancers’ ankles have to bear 14 times their bodyweight while executing certain steps and have compared the force with that experienced by fighter pilots.
The load is far greater than a person would experience while running. The researchers said one well-known Irish dancing step, known as the rock move, should be monitored because of its potential to cause injury.
Performers from Riverdance, as well as world champions, were monitored while dancing in a laboratory which measures the impact of various activities on the body. The study team, whose work is in the Journal of Dance Medicine & Science, had to check their readings because they did not believe how large the forces were. The measurements for Irish dancers were the highest recorded.
In the rock move, legs are crossed at the ankle and the dancer rocks from side to side on the balls of their feet. Most of the force is taken by ankle joints as the weight is transferred rapidly back and forth. The force was found to be 14 times bodyweight, while that on the Achilles tendon was 42.5 stone. The soles of some of the dancers’ feet bore 4.5 times their bodyweight.
“That’s 4.5G — fighter pilot stuff. If you were subjected to 4.5G long term, you would be at great risk of blacking out,” said James Shippen, a lecturer at Coventry University’s School of Art and Design.
“Obviously, Irish dancers are doing it in short bursts, but at that instant they are pulling fighter pilot loads on their feet.
“We take engineering principles and apply them to Irish dancers. The loads are enormous. It’s very punishing on the body. Classical ballet dancers’ loads are incredibly light, about one quarter the level.”
Sinead Whelan, director of Celtic Feet Irish Dance and Theatre Company in Coventry, took part in the study. “A lot of our dancers get injured but because a dancer’s career is so short we don’t, if we’re honest, take as much time out as the physios recommend,” she said.
Irish dancers suffer injuries similar to those of footballers, according to Whelan. In particular, they get knee injuries such as floating cartilage.
“James had to recalculate the force that went through our dancers’ legs about five times before he believed the data he was getting. He said they’re not dancers, they’re paratroopers,” Whelan said.
Julian Erskine, senior executive producer of Riverdance, said the studies were an eye-opener. “When Riverdance started, nobody knew what Irish dancing did to the body because it wasn’t done on a sustained basis. We realised early on that it shouldn’t be taken lightly and we’ve always had a physio and two massage people with every company.”
Riverdance has a physical therapist on-call 24 hours a day for performers, who can tap out 46,000 beats per show and perform eight shows a week.
One dancer, Melissa Convery, ruptured her Achilles tendon and blacked out on stage. “You usually dance through the pain,” she told the San Jose Mercury News in December. “But I sprang and it popped. I had to learn to walk again.”
Ophelia Shadow wrote:
Well, I think it's pretty clear that Irish dancers aren't physicists... and neither is James Shippen. There's a fundamentally untrue statement in this article, which is that a force of 4.5G is the acceleration of Earth's gravity RAISED to the 4.5th power (in physics that is just the notation)..... which is NOT the same thing AT ALL as 4.5 times someone's body weight. The normal force exerted on someone's body who is motionless is (uniformly) their mass times the force of gravity, ONE (1) G, which I think is where the misconception must have stemmed from. There is NO WAY the force on the dancer's feet is as great as the force a fighter pilot experiences, no way in hell, it's a physical impossibility. Mr. Shippen obviously misunderstood Newton's equations, and so his statements have made for a very exaggerated article. I'm only saying that there is no reason for as much alarm as this article may cause. As a recently retired championship dancer AND physics major, I know a little about both.
April 28, 2010 4:12 AM BST on community.timesonline.co.uk
Jim Snyder wrote:
It just goes to show how punishing the Irish Step Dancing can be, compared to the relatively moderate Ceili and Set Dances that usually don't find their way on stage, but are more of a traditional folk type of dance. Personally, I think that some very strong G-forces can be experienced in such movements like the "ceili swing", but the forces are centrifugal, almost entirely. Keep on dancing!
April 26, 2010 6:44 AM BST