July 19th, 2011
07:51 AM ET

Scientist: Tae Bo workout sent skyscraper shaking

Seventeen people performing a vigorous Tae Bo workout caused tremors that forced the evacuation of a South Korean skyscraper earlier this month, the building's owners say.

Prime Group, owner of the 39-story TechnoMart commercial-residential high-rise in Seoul, said 17 middle-aged people were working out to the pop song "The Power" by Snap on July 5 when their movements set the upper floors of the tower shaking for 10 minutes, according to a report from the Korea JoongAng Daily.

Scientists recreated the event in the 12th floor gym, according to a report in the Korea Times.

“We observed the vibrometer while performing the same kind of aerobic exercise that was performed at the time of the shaking which occurred on July 5. We noticed that the shaking was felt in the upper floors while the exercise was being performed while no other place showed signs of tremor,” Chung Lan, a professor of architectural engineering at Dankook University, told the Korea Times.

“It just happens to be that the vibration cycle caused by Tae Bo collided with the vertical vibration cycle unique to the building,” Chung told the Korea Times. The action amplified the building's vibration and caused the shaking, he said.

Chung was one of six professors from the Architectural Institute of Korea who inspected the building and recreated the Tae Bo exercise.

Tae Bo is a mixture of boxing and tae kwon do.

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Filed under: South Korea • World
soundoff (322 Responses)
  1. karlj324

    , if the vibrations are amplified by a tae boe workout imagine what an earth would do?

    July 19, 2011 at 11:21 am | Report abuse |
    • Engineer

      It has to do with the activity of the class and the natural resonance of the building. The actions of the class were at the same natural frequency as the resonance frequency of the building. For example, think of the classic case where a person sings and a wine glass breaks. The singing voice matches the resonance frequency of the glass causing the frequency to double and the glass breaking. The glass breaks because it can not handle the deflection caused by the increase in frequency.

      July 19, 2011 at 11:35 am | Report abuse |
    • wow

      That and the 17 overweight people jumping up and down.

      July 19, 2011 at 11:45 am | Report abuse |
    • Rell

      Like the "Engineer" said...it's "simple" quantum physics.

      July 19, 2011 at 11:47 am | Report abuse |
    • Engineer2

      Where's Carl Sagan when you need him...a few people who know something about natural frequency, and billions and billions of primates who don't.

      July 19, 2011 at 12:06 pm | Report abuse |
    • BS

      It doesn't "double the frequency". It magnifies the waves, i.e. increases the amplitude. Same frequency/wavelength.

      July 19, 2011 at 1:10 pm | Report abuse |
  2. George

    Tae Bo, or cheap, shoddy construction. You decide.

    July 19, 2011 at 11:21 am | Report abuse |
    • Stubby

      It is called resonance frequency people. Time to pick up a physics book for the first time in your lives.

      July 19, 2011 at 11:29 am | Report abuse |
    • Bubba

      Heck, why can't it be both?

      July 19, 2011 at 11:30 am | Report abuse |
    • brett

      Sorry Stubby. We've been to busy getting laid. You should try it sometime.

      July 19, 2011 at 11:47 am | Report abuse |
    • Pandakannon

      Last I remember there are more nerds getting laid than meatheads these days. GO NERDS! ENGINEERS AND SCIENTISTS RULE!

      July 19, 2011 at 11:51 am | Report abuse |
    • Bob

      LOL Brett!

      July 19, 2011 at 11:52 am | Report abuse |
    • Wow what an idiot

      @Brett, So let me get this straight. The requirement for getting pu**y is to be a moron and to be uneducated. LMAO. That is the worst attempt at an insult I've ever heard. You basically just said, "yea, I can get girls, but I'm an idiot". LOL? See subject line.

      July 19, 2011 at 12:12 pm | Report abuse |
    • Rob

      Oh Brett, that was bad. Why don't you just come right out and tell everyone you're a virgin.

      July 19, 2011 at 1:46 pm | Report abuse |
  3. Bettefw

    Shades of the Tacoma Narrows Bridge collapse http://www.archive.org/details/SF121 (scroll down to last comment, although I believe there are other opinions as to the cause). I love how everyone is so calm, even those walking off the bridge.

    July 19, 2011 at 11:23 am | Report abuse |
  4. ConcernedNetizen

    Not sure im liking this answer... And what a coincidence it happened to involve not structural defect nor permanent condition.. So I guess the property value wont be decreasing with this news, eh?

    July 19, 2011 at 11:23 am | Report abuse |
    • mike

      Naw, my two-ton upstairs neighbor at my ( flexible 1970's wood ) condo worked out on his stationary bike one day, and set up just that kind of vibration pattern. I've got a small vertical crack in my wall now. I gave him so much hell, he actually moved to another apartment. I wonder how they'll work it with these people?

      July 19, 2011 at 11:35 am | Report abuse |
  5. MarciaMarcia

    Billy Blanks is tearin the roof off!

    July 19, 2011 at 11:24 am | Report abuse |
    • Canadian Genius

      I can't remember, is Billy Blanks the guy that got stabbed a whole bunch of times in the trunk in Goodfellas, or is he the guy that shot Al Pacino in Carlito's Way?

      July 19, 2011 at 12:37 pm | Report abuse |
    • Billy Batts

      Go home and get your f–king shinebox.

      July 19, 2011 at 2:08 pm | Report abuse |
  6. Person

    Harmonic oscillation..

    July 19, 2011 at 11:31 am | Report abuse |
  7. Alan

    I bet a Richard Simmons workout would be worse...

    July 19, 2011 at 11:32 am | Report abuse |
    • bobo2000

      If it had been Simmons then there would only be a dusty pile of rubble.

      July 19, 2011 at 1:09 pm | Report abuse |
  8. DBM

    That Billy Blanks is such a badass.

    July 19, 2011 at 11:40 am | Report abuse |
  9. Samuel R. Preston, III

    Simple fix, they just need to dampen the structural components of the building so the sympathetic frequency for this type of event is moved outside the normally expected (low) frequency range of the people busting moves.

    July 19, 2011 at 11:43 am | Report abuse |
  10. Jack Tors

    "The Power" might be the best workout song ever. Word.

    July 19, 2011 at 11:44 am | Report abuse |
  11. Jeremy

    Good reason to have a gym on the ground floor or basement. I remember around 1999 or 2000 during a tornado warning when I was in high school. We were moved to storm shelters through out the building. The shelter my class was put in had the school's weight room right above our heads on the next floor up. I thought to myself during the whole experience "this can't be a safe storm shelter."

    July 19, 2011 at 11:44 am | Report abuse |
  12. Denise

    It seems that they do, indeed, have the power.

    July 19, 2011 at 11:45 am | Report abuse |
  13. Ohmagawdyes Ohmagawd

    It's gettin'

    It's gettin'

    It's gettin' kinda hectic...

    July 19, 2011 at 11:49 am | Report abuse |
  14. RUFFNUTT

    they need to get some shake weights......

    July 19, 2011 at 11:52 am | Report abuse |
  15. NoodleHat

    Sometimes I make vibrations after eating a burrito that shake buildings 5 miles away!

    July 19, 2011 at 11:55 am | Report abuse |
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