In the relevé method, the dancer rises smoothly by rotating the foot downward until it reaches a fully extended, vertical orientation while the toe box remains in contact with the floor, thus "rolling up" on the foot. This may be done either gradually or rapidly, on one foot or both feet, beginning with feet flat on the floor or in demi-pointe (heels raised). In the sauté method, the dancer springs up and lands en pointe. In the process, the feet break contact with the floor and the dancer is briefly airborne. To transition to en pointe via piqué, a dancer will step out directly onto a fully extended, vertical foot. The other foot is then raised from the floor, thereby leaving the dancer en pointe. Modern ballet technique incorporates all three transition methods. Relevé and piqué transitions are typically used for adages, where strength, poise and controlled movements are highlighted. The more abrupt sauté method, which was introduced by Enrico Cecchetti, is typically used in allegros, where the relatively slow and smooth relevé and piqué transitions would be both impractical and visually inconsistent with the lively pace of movement. The sauté method is more common in Russian ballet. Training Prerequisites Although age is not necessarily a prerequisite, many ballet students do not begin to dance en pointe earlier than approximately 12–14 years of age because bones in the feet are often too soft prior to that age and in such cases, serious and permanent foot injuries could result from starting pointe work too early. While some students start pointe work at the age of ten or eleven, this should only be practiced with highly accomplished and experienced students. The long bones in feet begin to harden within the ages of 8 to 14; dancing en pointe before one's bones have hardened can lead to trauma and growth-plate fractures that create deformed feet. Exceptions may be made if a physician has determined that a dancer's feet have sufficiently ossified, and it is not uncommon for dancers to begin pointe work as early as age nine. Oftentimes dance studios require their dancers to get x-rays performed on their feet and have their physician verify whether the dancer's feet are ready for pointe work. Another key determining factor is strength in the legs, feet, ankles and core. Without strong ankles, feet and legs dancers are likely to hurt themselves once en pointe or