Overpronation is the inward roll of the foot while standing, walking, running or dancing. Allowing the foot to roll inwards causes noticeable internal rotation of the lower leg and knee and can influence the body's posture. This can result in extra strain on the lower body and can cause foot pain of the arches, heels and ankles, knee pain, leg pain, and lower back pain. A ballet student only needs to understand this, and can correct a flat foot by developing the sole of the foot muscles.
Studying ballet without correcting pronation can lead to knee pain, shin splints, arch pain, and overall tension in the lower leg.
Flat feet may be flexible and may show a curve when pointed, but on the floor, they still need to be supported properly. Rolling ankles, with the lower leg internally rotating inwards, and the thighs turning out, can eventually lead to a twisting of the knee joint with irritation, inflammation, and pain.
Excess wear on the inner sides of the street shoes, is an obvious sign of overpronation.
If you can get a parent or a fellow dance student to take a picture of your flat feet standing in parallel, (from the back) you'll see if you are rolling in from the heel, with your arches mushed on the floor.
See if your heels lean inwards and if your kneecaps turn inwards while standing. This would be in a relaxed position, not holding your thighs in any particular way. You'll see that if you then turn out, your feet may adjust somewhat, with the heels pulling up straighter, and the arches maybe lifting a little. This will definitely help avoid a knee injury.
However, holding your turnout is not enough to correct this. Also, just lifting the arches up by rolling outward is not a good correction.
Locating and strengthening the tiny foot muscles is your best bet to not compensate for flat feet in the wrong ways and then send the feet's workload up into the calf and shin muscles.
If you already have ankle, lower leg or knee pain, see a chiropractor, physiotherapist or a podiatrist. You may need orthotics (supportive shoe inserts) and even a heel counter (an insert in the heel of your shoe that stabilizes your heel position) in your street shoes. This heel counter should fit well to prevent extra movement and twisting ankles.
Morton’s foot (big toe shorter than second) can cause a slight roll inward when the foot moves upward to rise or take off for a jump. Even though weight goes off the foot in many of these movements, just try counting how often in a class that happens - and imagine the uneven pressure on the feet muscles and bones.
Having the weight spread evenly from the center of the heel, big toe joint and little toe joint, is your foundation. It gives the level base, just like the platform a house is built on, for your skeleton to stack up above.
Understanding flat feet, overpronation, and the possibility of foot/calf/shin/knee sprain, will help you prevent dance injuries.
Learn how to develop your foot muscles.