Contortion (sometimes contortionism) is an unusual form of physical display which involves the dramatic bending and flexing of the human body. Contortion is often part of acrobatics and circus acts. In general, “contortionists” have unusual natural flexibility, which is then enhanced through acrobatic training, or they put themselves through intense, vigorous and painful training to gain this flexibility.
In some countries like Mongolia and China, many people (mainly girls) learn contortion and it is considered a nationally respected art form that holds cultural importance. For hundreds of years contortionists have entertained crowds all over Mongolia. Contortionists usually start practicing from a very early age.
Some sports, rhythmic gymnastics for example, demand extreme flexibility but not the hand balancing skills or performance skills of a contortionist (source: Wikipedia)