How Our Muscles Contract

Perfect développés. Explosive grand jetés. We all have ballet dreams and goals that we're working toward. So then we must understand muscle contraction (tension). 

With muscles, dancers have to under the Law of Approximation {ahem, clearing throat and speaking deeper}: The Law of Approximation means that muscles can only pull the ends of muscles toward each other (shortening / contraction) and not push them away. 

Now that we understand that, let's dive in! 

Evgenia Obraztsova and Alexei Timofeyev in Don Quixote.

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Dynamic [Isotonic] Muscle Contractions occur when there is a change in length of the involved muscle and observable joint. For example, when you're sitting in a chair and decide to straighten your leg, your hamstring has to change length (or shorten) in order to lift your foot off of the ground and straighten your leg. Now, there are two types of dynamic muscle contractions: 

  • Concentric "toward the center": Shortening of the muscle and visible joint movement  in the direction of the action of the primary muscle (ex: flesion, abduction). When we think of muscles contracting, we think of concentric contractions. With these type of contractions the torque (the tendency of a force to attempt to rotate an object about an axis) is greater than the resistance (the tendency to produce rotation in the opposite direction) which means you feel stronger!
  • Eccentric "away from the center": Lengthening of the muscle; the distance between the ends of the muscle gets greater. That means it gradually decreases the contraction. Using our example from above, if you're sitting in a chair and you contract the muscle to lift your leg up, you will gradually release the leg back down to the ground by lengthening the muscle until it reaches its resting length. 

Static [Isometric] Muscle Contractions involves a partial or complete contraction of the muscle where no visible joint movement occurs. This means you are holding the contraction still (or static). This means the torque and resistance are being exactly counterbalanced so no movement occurs. 

Ballerina Svetlana Zakharova. Queen of the Dryads, Don Quixote. Bolshoi Ballet. In Scene 2 Don Quixote is surrounded by beautiful Dryads and Cupid and the Queen of the Dryads presents him to Kitri, who has assumed the form of his beloved Dulcinea. Don Quixote swears eternal love and faithfulness to her. Note: Zakharova have to use isometric muscle contractions in order to maintain the desired position of her supporting leg and torso.

Fun Fact: Both Svetlana Zakharova and Evgenia Obraztsova are using what we call in dance "pulling up your knees." This means their thigh muscles are not relaxed so their kneecaps aren't loose. Tightening the quadricep will pull the patella (kneecap) upward which provides joint stability for the ballerinas. Having those muscles engaged prevents the ballerinas from relying too heavily on passive constraints - such as their ligaments - to keep them stable. 

Now, just like dancers in ballets, all of your muscles have roles for each movement you are executing. Cast list, please

Movers (Agonist): A muscle or muscles whose contraction produces the desired joint movement. If many muscles are serving as the movers, they break down into prime (primary) or assistant (secondary) movers. For example: Parallel attitude, the agonists: hip extensors including the hamstrings. 

Antagonist: Muscle or muscles with an action opposite to the action of the prime mover. They are usually on the opposite side of the joint, opposite to the agonist. The antagonist usually rest while the agonists do the work, but when something needs to be held rigid or stable, both the agonists and atangonists must work together which is called co-contraction. 

Synergist (Neutralizers): A muscle that works together with the agonists to help achieve the movement goal. 

Stabilizers (Fixators): A muscle that contracts isometrically to support a body part against forces related to muscle contraction, gravity, soft tissue constrains, momentum or recoil from the movement. For example, to achieve a strong grand battement, you need your abdominal muscles stabilized to keep the pelvis and spine in place. 

While you're dancing, you should be noticing... 

  • Which muscles are engaged? Which are resting? Which are helping support me? Which are stabilizing me? 
  • Focus on where you are sending your energy and be aware of what muscles you need to be engaging in order to achieve the movement goal. 
  • What are my agonists and antagonists? Where are they? What are they doing? 
  • Which muscle is shortening right now? Which muscle is waiting to lengthen? Visualize this happening. 
  • Understand that if there weren't some muscles engaged at all times, we'd be a heap of bones and muscles on the floor. 
  • Once you start understanding how your muscles work, your mental power will dramatically change your dancing. 

For more information on dance kinesiology: Dance Anatomy & Kinesiology by Karen Clippinger

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