This photo shows a pole vaulter as she launches up into the air, nearly inverted with the pole bent in an arc. The physics concept shown here is a snapshot of conversion of energy, specifically the stage of elastic potential energy. Before she reaches this stage, the vaulter runs down the runway, which is a minimum of 40 meters long. As she runs, her velocity will increase, which as a result increases her kinetic energy. This energy is then converted to elastic potential, as seen in the image. When the pole begins to extend and revert back to its original shape, elastic potential energy is converted to gravitational potential energy, thus allowing the vaulter to clear the crossbar. However, at the top of her arc, she must still obtain some kinetic energy to vault beyond the bar. Throughout history, the material used to construct the pole itself has developed and improved, thus increasing the spring constant, k, in elastic potential energy. In the early 20th century, poles were made out of stiff materials, such as bamboo or aluminum. As pole vaulting became more competitive, carbon fiber and fiberglass (which can be seen in the image) were used to increase the elasticity of the pole, resulting in a larger spring constant to increase the elastic potential energy, consequently allowing the sport of pole vaulting to reach new heights.