Here is a great read we discovered! Check out what The Journal of Dance Medicine and Science had to say about importance of flexibility in dance.
Dance and Flexibility
Dance, and in particular ballet, is portrayed by beautiful body shapes and lines, much of which are due to flexibility. In all its beauty, ballet is an art form based on standardized movements, stylized steps and time-honored techniques that have been passed down by dancers for more than 300 years.
The ability to achieve seemingly impossible positions is essential and an integral part of the art form. A dancer's facility is their main tool to be able to achieve these positions and communicate through their movements. Therefore, excellent levels of flexibility, or range of motion (ROM), are imperative for maximizing the versatility of movement. Typical extreme joint positions include hip flexion, extension and outward rotation, spinal extension, and ankle plantar flexion.
Joint flexibility is essential for dancers to be able to perform the correct positions, execute the steps with ease, and supply the choreographic demands.
Learn more about stretching techniques for dancers from the International Association for Dance Medicine and Science http://www.iadms.org/displaycommon.cfm?an=1&subarticlenbr=353.