gluteusmusclesThe muscles in your body allow you to move. In this lab we will do two quick experiments to explore how your muscles work.


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Here’s what you need


  • 1 partner
  • 1 clock with second hand

Here’s what you do


  1. Hold your arm out straight. Ask your partner to push down on it while you try to raise it up against the pressure they are applying. Both of you should apply steady pressure in opposite directions for 30 seconds.
  2. After half a minute, your partner should let go. Try to relax your arm. What happens?  Your arm should try to lift itself up!
  3. The muscles in your fingers were made to grip, but they don’t have a lot of stamina. To test this, close your hand into a tight fist for one second. Then open and relax it for a second. Continue doing this, counting each time you are able to pen and close your hand. How many times can you open and close before your hand gets tired and you must stop?

What’s going on?


In the first experiment, your arm’s muscles and nerves got used to the pressure being applied by your friend and adjusted to the force. Once your friend stopped applying the pressure your muscles could not adapt immediately. This resulted in your arm lifting up into the air, seemingly of its own accord.


In the second part, your hand was doing a job that it wasn’t really designed to do. You just wore it out!


What do you think are some of your strongest muscles?  Would you be surprised to learn that the jaw muscles rank near the top? It’s true: humans can exert the same force when biting down as a shark. This is a force equal to about 200 pounds per square inch!


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Comments

4 Responses to “Tricking your Muscles”

  1. suzanne_262003 says:

    Wowwee! I really liked the first experiment even though it was tiresome. And I can’t believe our jaw muscles are as strong as a shark’s jaw muscle. I am just bblloooownn away!!!

  2. Irenio and Deena Mateo says:

    nearly whacked my head!

  3. Crystal Burling says:

    this is pretty cool… it felt like my muscle had late reaction when the presurre was stopped.

  4. Angelyn Tag says:

    I’ve seen this experiment before!