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Welcome to my blog!This is my blog about my science fair project, Pointe Shoe Physics. I am testing the amount of force per square centimeter on a ballet dancer's feet while dancing in pointe shoes. I am also studying how this changes in three different positions. Be sure to check out my report, background information, videos and other cool stuff! My final report and other files can be accessed through the "Documents" link on the right. Enjoy!

Introduction


One of the well-known characteristics of a ballerina is her ability to stand on the tips of her toes in shiny, satin shoes. Pointe shoes are special ballet shoes that support the foot and allow a dancer to stand on the tips of her toes. Because all of the dancer’s weight is distributed over a very small platform at the tip of the shoe, a lot of force is put on the dancer’s feet.
          Marie Taglioni is credited as being the first to wear pointe shoes. In 1832, she performed the ballet La Sylphide entirely en pointe. However, her shoes were very different from today’s pointe shoes. She stood on the tips of her toes in shoes that were nothing more than tightly fitting ballet slippers with darning on the edges.
          Since then, there have been many changes in the way pointe shoes are made. Modern pointe shoes have many parts that allow them to support the ballerina. The “box” is the hard area around the dancer's toes. It supports the sides of the foot. The box is made of canvas, linen, and glue. The stiffness may vary in different shoes. The “platform” is the part of the shoe that the dancer stands on. It provides a flat surface to balance on. The “vamp” is the front of the box. The depth of the vamp varies in different types of shoes. The “shank” is what supports the dancer's arch. It is made of hard leather, plastic, cardboard, or burlap. Shanks come in many different strengths. Different strengths are used depending on the strength of the dancer's foot.
          Every pointe shoe is made by hand. Because of this, pointe shoes range in price from $50-$100.
          When a dancer buys a new pair of pointe shoes, they are usually not ready to wear out of the box. Most dancers sew ribbons (to support the ankle) and/or elastics (to hold the shoe on) to their pointe shoes.
          When they are new, the shoes are very hard. There are many methods to “breaking in” pointe shoes, including slamming them in a door and bending the shoe with your hands. Other dancers prefer to break in their shoes by wearing them and bending them with their feet. It is important that the shoes are broken in because broken in shoes form to the dancer’s arch. This helps to support the dancer. However, once they are broken in, the shoes quickly deteriorate. When they are too soft to properly support the dancer, the shoes are referred to as “dead”.
          Even with rigid shoes to support their feet, a ballerina still requires tremendous muscle strength in the feet, legs, and core in order to dance en pointe. She must be able to pull herself up from standing flat to full pointe, where she is completely on her toes. Between these two stages is a position known as “demi-pointe”. In demi-pointe, the dancer is standing on the ball of  their foot. In regular ballet shoes, dancers do not rise to full pointe. They can only go to demi-pointe.
Though beautiful, pointe work is very painful. Many injuries result from the force  being put on the feet and toes. These injuries can be minor, such as blisters, or major, such as a broken ankle. Other injuries caused by pointe shoes are bunions, ingrown toenails, tendonitis (commonly in the Achilles tendon) , os trigonum syndrome (associated with flexing the foot), osteoarthritis,  and stress fractures. Although nonspecific to pointe shoes, knee and hip injuries may result from forcing turnout and repeated bending of the knees (known as pliĆ©).
          Despite all of the pain involved in pointe work, ballerinas wear minimal padding. Dancers have many different strategies for padding their pointe shoes. They may use thin gel pads, lamb’s wool, toe tape, paper towels, or other materials. However, some dancers wear no padding at all. It is important that a ballerina does not use  too much padding. This inhibits their ability to “feel the floor.”
          In order to be able to dance in pointe shoes, the dancer must meet many requirements. They must have been training for several years in ballet slippers in order to gain the strength and level of technique needed. They must also be old enough to go en pointe. It is not safe for a very young girl to dance in pointe shoes because certain bones must have fused in order to prevent serious injury. Most ballet instructors start girls in pointe shoes between the ages of ten and fourteen.
          Even if they are old enough and have the desirable strength, pointe shoes still are very dangerous. Dancers are putting the weight of their entire body on a very small platform.  This means that a lot of force is being put on their feet and toes.
          This force can be measured in Newtons (N). Newtons are the metric unit of force. Because weight is the pull of gravity on an object, weight can also be measured in Newtons. For example, a textbook weighing two pounds would be exerting 8.8964432565 Newtons of force. By converting weight to force, it is possible to calculate how much force is being put on a dancer’s feet while they are wearing pointe shoes. This can be calculated by dividing the Newtons of a test subject divided by the area of their feet:
N/cm²

          This formula can be expanded to include many different positions of the foot. This can be achieved by changing the area of the foot (cm²) to the area of the foot in a different position.
          In this study, this formula will be used to calculate the amount of force put on the feet in pointe shoes and how this changes in different positions.