Dancing in pointe shoes is a very precise technique – if you want to avoid common dance injuries such as sprained ankles and knee sprains. A young dancer, or an adult ballet beginner, may take two or three years of classes, and be constantly sickling in, or curving the ankle inwards towards the center of the body, or “fishing”, or curving the ankle outwards away from the center of the body. On a working, or presenting leg, where there is no weight on the foot, it really does not matter. But on a supporting leg, the leg that bears the body weight, it certainly does matter – especially if you want to dance in pointe shoes.
Keeping the ankle aligned, meaning neither sickling or curving in, nor curved out, is the ideal situation. But dancers with less arch curve may want to sickle out, or “fish” the ankle curve, on a working, or lifted leg, to show a lovely curve of the foot that a very flexible ankle joint would show. This will not result in a ballet injury, to the foot or the knee.
However, allowing the ankle to sickle in, or out, on a supporting leg, will eventually affect the condition of the foot’s arch muscles, as well as the ligaments supporting the knee joints.
So a properly instructed dance student may choose to “fish” or sickle out a working leg foot, in an extension devant, or an arabesque, to create the ballet aesthetic that ballet teachers, choreographers, and artistic directors look for. This is okay in a presenting leg ballet position.
Most audience members that go to ballet are not looking for this kind of detail, please believe me. PLEASE.
On a supporting foot, whether in toe shoes or on demi-pointe, the ankle must be aligned, that is, in a position a straight line down from the knee joint, in order to protect the tendons and ligaments that keep the structure of the upper leg, knee joint, and lower leg, safely intact.