Dancers are renowned for their flexibility, and to many non-dancers, the main aspect that defines 'a dancer' is whether they can do the splits or not! It is without question that dancers have an increased range of movement in comparison to the average person, and often dancers coincidentally have a natural flexibility aside from that as a result of their training.
Your students naturally spend a lot of time in the studios or dance environments, and their whole craft is based on the physical attributes of their bodies. Much time must be spent maintaining and enhancing their skills, keeping them in top condition for what is required. Dancers must ensure they take time at the beginning of the class to warm the body up sufficiently with cardiovascular activity, and they must also take time afterwards to cool down properly. This is done through lowering the heart rate properly and stretching out their muscles, as this is much safer when they are warm.