A question of leverage
Most people have arches on their feet. An arch is the gap between the inner side of the foot and the ground when you're standing.
Not all feet are made equal
Flat feet is when the foot doesn't have a normal arch. If the whole foot touches the ground and there's no gap at all when you're standing, then you have flat feet. Flat feet can affect one or both feet. It's quite normal for babies and toddlers to have flat feet - that's because the foot arch hasn't developed yet. Most of us develop arches between the ages of three to 10 years old but arches never form in some people. Flat feet may also run in a family - if your parents or brothers and sisters have flat feet, you might have them, too. Sometimes, flat feet develop later on in life. Years of wear and tear can take their toll, especially if your feet have pounded repeatedly on hard surfaces such as concrete and tarmac. The foot arches eventually weaken and can 'fall'.
Why do we need arches?
Arches help you walk properly by spreading your body weight evenly across your legs and feet. They act as levers for movement, helping to push off from the ground, as well as providing flexibility to cope with walking on different surfaces.
People with flat feet can't walk or run normally. They need to change the way they walk because they don't have an arch to act as a lever.
So, to compensate for this, flat feet have to roll inwards so that the whole foot is on the ground before they can push off from the ground to walk. This action is responsible for causing pain in some people with flat feet.
What are the symptoms of flat feet?
If you have flat feet, you may have pain or swelling on the inside of your ankle, and also calf and knee pain. You may find that your shoes wear out more quickly. In many people, flat feet don't cause any problems at all; it might be that your legs have positioned themselves in such a way as to cope without having any arches.
Is there any treatment available?
Different treatments may be recommended by a podiatrist (foot and ankle doctor), depending on how severe the symptoms are. For children and teens, an arch support and/or a wedge may be recommended. Arch supports are moulded to the shape of your feet, while wedges can take some of the weight off your feet. Others might need special insoles, soles or foot braces to support their legs and feet. These usually need to be custom-made.
Children's bones are soft and can easily develop abnormally. Ligaments, which are sheets of connective tissue that join bones together, are flexible and also still developing. Using support means that bones and ligaments in the foot can be held in the correct position to allow them to develop normally.
If you have swelling or pain, you might just need to rest your feet and legs until they're better. Cycling or swimming is more suitable than running or football.