Balance is vitally important for any dancer, your center of gravity shifts frequently putting your core muscles and particularly ankle muscles on constant alert. As children grow they often become unstable and this can affect just about everything that they do in dance.
A great way to test a dancer's balance is to have them face a barre just holding on very lightly and rise up to half or three quarter point and then hold their balance for 30 seconds. As they hold the balance they should try to let go of the barre so that they can truly test their stability. Now repeat the same exercise but with the eyes closed. A large majority of dancers will find that they have difficulty staying on balance once their eyes are closed, even on 2 feet and of course that feeling of instability only intensifies when the eyes are closed! With more experienced and stronger dancers you can try the same exercise in the center. The key is to not have any of the students fall on the floor. It is extremely important when trying this test that the dancers understand that they must hold their bodies in a well supported way using the core and leg muscles so that they have good posture.
Here are some exercises that I have found helpful for my students to improve the strength in their feet and ankles:
1) Picking up pencils : Stand with both feet flat on the floor, you can hold on to a chair or a barre - Pick up a pencil with one foot 20 times then repeat on the other foot.
2) Picking up marbles : Sitting on the floor with the legs straight out in front of you, pick up a marble and put it back down on the floor 20 times, then repeat with the other leg.
These 2 exercises are working the plantar flexors.
Theraband Exercises :
1) Sitting on the floor with both legs straight in front of you, place the resistance band around both feet keeping them tight together. Make sure that the theraband covers the little toes. Pushing through the ball of the foot, point the toes then return to the ball of the foot and then flex the feet. Repeat 20 times. You can increase the resistance with the theraband as needed. Make sure that the dancer sits very straight and keeps the legs totally straight.
2) Sitting on the floor with one leg bent at the knee, with the foot touching the other knee and the other leg straight in front of you. Place the theraband around the foot, again making sure that the little toes are covered and hold it on the opposite hip. Slowly open the foot and then bring it back to the straight position. The most important and also difficult thing about this exercise is to keep the working leg absolutely still, (Not always easy to do) if your dancers have trouble with this you can help by holding on to the leg to make sure that it does not move. Do this exercise 10 times. Repeat with the other leg.
3) This exercise is the reverse to the previous one. The position is the same but instead of turning the foot outwards it will go inwards. Again, making sure that the working leg does not move and that the resistance band is held on the opposite hip.
It is important that after these exercises are completed that the calf muscles are stretched as you want the muscles to be long and lean.
Stand facing the barre, keeping the hips and feet parallel, take one foot back with a straight knee and the heel firmly pushed into the floor. Bend the front knee and push the weight over the foot. Hold the stretch for 30 seconds and then repeat on the other side.
Balance will improve with better foot and ankle strength - but the core and upper body also need strengthening in order to have correct posture on top of the legs and feet.