"The arch of the foot actually helps posture and puts the weight of your movement on the balls and heels of your foot. This weight distribution puts the stress on the parts of your foot that are meant to support it.

With flat feet, although the weight that comes with your every step is still distributed throughout the whole foot, the stress on your hip joint is different and can lead to different symptoms after repeated “unusual” wear and tear.

Over pronation is a common problem while walking or running, where the foot tends to roll inwards upon every step and can put a lot of unnecessary stress on your knees and back. If you’ve faced problems with your knees or hips hurting after running, it may be because you over pronate your gait (the way you walk/run). In cases like this, choosing the best shoes for over pronation correction can drastically help. You may also benefit from using an orthotic that is specially fitted and made to your feet by a podiatrist.

What to Look for When Selecting the Best Shoes for Your Flat Feet

When you first set out on your journey to select the perfect pair of shoes for your flat feet, there are three tests you can do while purchasing to make sure you’re getting the correct support you need.

1. If the shoe bends where the toes are, it’s supportive enough, but if it bends toward the middle, it is not going to have the support you need. Your middles need support, not this bendy sole. Try another pair.
2. How well are you able to twist and torque it? Pick a shoe that is difficult to move. These are the shoes that will give you the most support for your arches.
3. Is the heel stiff? Proper heel support – often found in the best shoes for flat feet – just puts the whole package together. You won’t want to roll an ankle right after you get your arch support would you?

It all comes down to the basic premise – a stiffer shoe will be more supportive for your feet and will help prevent over pronation. There is no single best shoe that relieves everybody’s aching flat feet. You will have to shop around, and that’s easier if you know what to look for.

Support

People with flat feet need more support in their shoes than others. Gently bend and twist the shoe, just like we suggested above. It should be bendy in the toes, but not in the middle, where your arch is.

Stiff Outer Sole

Stiff outer soles are a must in good shoes for flat feet. They reinforce the built-in shoe support and resist your foot’s tendency to roll inward. Strong outer soles in everyday footwear are also rugged enough to withstand many hours of daily wear and tear.

Stability

Many people with flat feet find relief with stability shoes. These have extra material in the midsole to buttress your arch as well as to prevent over-pronation. There is also plenty of cushioning to provide a snug but easy fit. Finally, the heel counter at the back of the shoe will resist pressure when you push on it, just like it will gently resist movement of your foot when it tries to slip back into pronation."

Reference and picture: http://www.feetgenius.com/buyers-guide/best-shoes-for-flat-feet/