Biology in Dance

1. Biology in Dance

2. How Our Bodies Move • Movement is the result of our muscular and skeletal systems working together. Our bones give us a solid frame to which the muscles are attached. The skeleton protects our organs. Joints between bones allow us to move and bend. Ligaments join bone to bone and tendons join muscle to bone. The muscles connect the bones, pulling them into place. Muscles are controlled by our nervous system. Your muscles can be strengthened by exercise!

3. Skeletal System • 3 major functions: • Support-gives body form and support • Protection-provides internal organs protection • Movement-plays a passive role in movement, but their shape, length and place where the muscles can attach dictate how the body moves

4. Do you know how many bones are in the body?

5. Joints • Joints are where two bones meet. • Movement occurs at the joints. • 3 categories of joints: • Immovable-between skull bones, pelvis • Slightly moveable-joints b/w vertebrae • Freely moveable

6. Types of Joints Hinge Joint (examples are the elbow and knee) Movement up and down from one bone fitting into the rounded part of the other bone We use this joint in plies to allow our legs to bend. It is also the joint used in petit battement. Ball & Socket ( examples are shoulder and hip) The rotation of the ball and socket joint of the hip is what gives us our turnout. Bones slide over one another since they are almost flat

7. Types of Joints Gliding Examples are joints in the foot and wrist Circular movement from the rounded head of one bone fitting into the socket of another Pivot (examples are top two vertebrae inside the neck) Movement from side to side created by one bone fitting into the ring shape of another When we turn our heads, we are using a pivot joint. This is important for presentation but also has a particular function in pirouettes or turns, where spotting helps us maintain our balance. Rocking motion with limited rotation Saddle (example is the base of the thumb)

8. Muscles • 650 muscles in body • Exercise builds stronger, larger, and firmer muscles giving us strength • Muscular system contains muscles, tendons (connects muscle to bones), and ligaments (connects bones to bones). • Muscles activity work to produce movement. They shorten and lengthen while pulling on the bones to create motion.

9. How Muscles Work Muscles work by contracting (becoming shorter and wider) and relaxing (becoming longer and narrower) when stimulated by a message from the brain. As the muscle changes length, it pulls on the tendon which in turn pulls the bone causing movement. Muscles have to work in pairs, because they can only pull. They cannot push, so instead they have to have a partner to pull in the opposite direction. These pairs (antagonistic pairs) are made up of a bending muscles (the flexor) and a straightening muscle (the extensor). These muscles work together at every joint positioning the bones as required.

10. What happens when we point our feet? From above, in this picture we can again see the bones, but we are looking mainly at the muscle structure and associated tendons. You can see how the muscles are attached to bones to allow movement. When you point your foot, your brain sends messages to the muscles. First the ankle joint straightens. The ankle is actually quite complex, since the tibia, fibula, and talus all join here. It is the Achilles tendon at the back of the ankle that is responsible for this flexing motion of the foot, since it connects the calf muscle and the heel of the foot. The Achilles is the strongest and largest tendon – it can take strains equivalent to six times our own body weight when we run and jump. As you point, the muscles on the underside of the foot contract, becoming shorter, and those on the top relax and lengthen, causing the foot to curl in the familiar way. Often you may say to point through the metatarsals. If you point your foot with little effort, you often only send messages to the muscles connected to your ankle, the bones in your upper foot and your toes, so your foot curves a bit but not fully! If we work hard, we can use the whole foot, and point right through the metatarsal bones to create curvature through the entire foot. This is a perfect point!

11. Questions to Ponder: • 1. What are 3 major functions of the skeletal system? • Name four examples of joints we have in our bodies. • What connects bones to bones? • What connects muscles to bones? • What helps create the perfect point? • Why is it important to understand the skeletal and muscular system in dance?