In the past flat feet were a reason to be refused entry into the Armed forces. If you push your big toe back as far as possible and the arch of your foot doesn't appear, your foot is likely to over-pronate when you walk or run.You may suspect the diagnosis yourself by observing your wet footprint and noticing that the whole of the sole of your foot contacts the floor when you stand.

This may involve testing your tendons and watching you walk an X-ray or magnetic resonance imaging ( MRI) scan of part or all of your foot may also be involved. If the changes are recent a doctor will want to look for the underlying reason.Footprint analysis (a pedograph) may be used.Your doctor or podiatrist can generally make this diagnosis just by observing your feet when you stand or walk.The sensation of foot flatness or imbalance (particularly if only one foot is affected).Over-pronation frequently leads to ankle pain and Achilles tendinopathy.The altered placement of the foot on the ground can then lead to pain in the calf, knee, thigh, hip or spine.It is typically felt just inside the ankle, on the outer edge of the foot or in the arch itself.Pain may involve the whole foot or ankle, or just parts of it.This may be almost anywhere in the foot, depending on which part of the arch is dropping and which tendons are stretched or injured.

If flat feet do cause symptoms these may include: Between one in four and one in five adults have some degree of flat feet. They are likely to have otherwise normal, flexible feet with no underlying tendon or joint problems, and their walking and running will have adapted to compensate. People who have had flat feet all their lives often typically have no symptoms at all. Those who have larger feet may be more prone to developing flat feet.

Greater age - the tendency of the tendons to tire and stretch increases with age.

A long history of running (straining the posterior tibial tendon).

Rheumatoid arthritis - this may weaken the tendons or affect the joints.

Pregnancy - a combination of added weight and the effects of pregnancy hormones which tend to soften supportive ligaments.

Diabetes - this affects the nerves in the feet and can also lead to weakness of the tendons.

High blood pressure - this may be an effect on the blood supply to the tendons in the foot.

Obesity - the additional weight will place added strain on the tendons which support the arches and they are more likely to collapse.

Flat feet are more likely to develop in people with:

Flat foot vs normal