Wednesday, July 17, 2019

What are flat feet, what are the main causes and how can we help them? By Mike Blackwell July 2019

What are flat feet?

We often see patients with flat feet of varying degrees at Fix Physio. In its most extreme case, the medial arch of the foot drops completely and the entire sole of foot touches the floor when standing. The other important thing to mention is that flat arches can contribute to a myriad of injuries and conditions but also may be present and have no detrimental effects and just be an anatomical anomaly.



Image credit: Zeidan et al (2019)



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Why do flat feet happen?

There are numerous causes of flat feet as you can see below:

  1. Structural– Structural changes- the way our bones are made ie foot anatomy, knocked knees, women with larger Q   angle


2. Muscular imbalances– weakness or tightness

a. Weak Tibialis Posterior – Tibialis Posterior is a muscle that extends from the back of the tibia & fibula and down into the inside aspect of the foot attaching into the navicular & medial cuneiform.

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Its primary roles are Inversion of foot (turning the foot in towards the other foot), Plantarflexion of the foot & ankle (pointing the foot down) and most importantly for this blog post is that it helps support the medial arch of the foot.

b. Weak foot intrinsic muscles– the “intrinsic” muscles of the foot are where both the attachments are inside the foot as opposed to “extrinsic” muscles where one attachment is higher up in the leg and one is in the foot. Examples of intrinsic muscles of the foot are:

– Flexor Digitorum Brevis
– Abductor Halucis
– Abductor Digiti Minimi

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Intrinsic muscles control supination and pronation of foot, fine tune balance & stability and provide a stiff lever to facilitate propulsion when walking .

c. Tight Achilles – If the achilles and calf are tight then this can reduce the ability to dorsiflex the ankle which is required in normal walking to bring shin over the foot. If ankle dorsiflexion is reduced then the foot will likely pronate (roll in) more to achieve this stage of walking pattern.

3. Foot & ankle joint stiffness-

As per tight achilles above, if the foot & ankle joints are stiff then dorsiflexion of the ankle is sometimes difficult and therefore the foot pronates to compensate for this lack of mobility during walking.

4. Prolonged poor footwear

Footwear is another factor that assists arch support. If you have flat feet that are contributing to an injury, then we recommend that you avoid unsupportive footwear such as thongs, sandals or flat shoes with no arch support. We would also recommend shoes with a more firm sole- one of the most common things we see at Fix Physio is people with flat feet wearing soft cushioned fashion shoes such as Nike Frees which provide minimal support to their medial arch. A supportive shoe is recommended for people with flat feet- one example is Asics GT 2000 running shoe.

5. Hypermobility of foot

One cause of ligament laxity in the foot is during & post pregnancy due to the change in particular hormone levels. It is important to wear good supportive footwear during pregnancy to support the arch of the foot.


How long will it take to fix?

This is a more difficult question to answer than usual as it is unlikely that you will ever truly “fix” flat feet. The “treatments” below of flat feet are more appropriately termed “management” strategies which assist the maintenance of the medial arch. The reason we are trying to maintain our foot arches is because if the foot alignment is good, the forces can act directly through the foot, knee and hip and therefore injuries are less likely- joints & tendons prefer straight lines & forces acting directly through aligned joints

Potential injury problems for somebody who has flat feet:

A. Bunions

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B. Plantarfasciitis/ plantarfasciopathy
C. Tib post tendinopathy
D. Achilles tendinopathy
E. Med gastroc calf strains
F. Med knee pain
G. PFJ pain
H. More susceptible to ACL – in extreme cases (women > men)
I. ITB pain
J. Gluteal tendinopathy

What do I do to fix it?

Strengthen weak muscles:

A. Tibialis posterior strengthening:


B. Foot intrinsic muscle strengthening:

2. Stretch tight muscles

Gastrocnemius stretch                                  Soleus stretch

3. Mobility work

Your physio can do specific joint mobilisation techniques and also you can do specific ankle mobility exercises:

4. Wear good shoes with arch supports

As well as wearing good supportive shoes, taping the foot can help in the short term to support the medial arch:

Furthermore, in more severe cases of flat feet that are contributing to injuries then orthotics can be helpful. Off the shelf orthotics can work for some people and the benefits of them over customised orthotics are the price as they are considerably cheaper. However, customised orthotics are far more specific in their prescription and are sometimes needed.

If you have any further questions on flat feet or any other injury then please email us at , call us on http://Tel:0292310420 or come and see us at Fix Physio Sydney in Sydney CBD


Photo/ image references:

  2. Zeidan, H et al (2019), Comparison of the change in the structure of the transverse arch of the normal & hallux valgus feet under different loading positions. Applied System Innovation
  5. Physitrack