Ankle ligaments, Spiderman and seatbelts. An introduction to the hypermobile foot.

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Ankle ligaments, Spiderman and seatbelts. An introduction to the hypermobile foot.

Ankle ligaments spiderman seatbelts hypermobile foot 1

Ankle ligaments, Spiderman and seatbelts. An introduction to the hypermobile foot.

An interesting article came to my attention recently and after reading it has already been a great discussion topic with multiple team members at Pride Podiatry and our extended health care family of physiotherapists and doctors. The article in question uses complex computer modelling to investigate joint loading in those with hypermobility.

Biomechanics of first ray hypermobility: An investigation on joint force during walking use finite element analysis.

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And, people are tuning out now. But wait, this is actually interesting, trust me.

Spiderman!

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“With hypermobility there must also come great responsibility.”

Stan Lee of Marvel fame coined the phrase “WITH GREAT POWER THERE MUST ALSO COME–GREAT RESPONSIBILITY!” way back in 1962 in the first Spiderman comic. Who knew he could have been referring to the flexible, or hypermobile foot. Unlike Spider Man, the hypermobile foot has a difficult task of getting around efficiently, as without the assistance of tall building and spidey-webs, the hypermobile foot does all it’s hard work on the ground. To understand this more, we need to get back to the basics.

When walking, the 26 bones and 33 joints in the foot perform a complex dance of movements to allow our bodies to absorb the impact of hitting the ground, stabilise and balance, then spring forwards towards our goals. During this dance, the joints of the feet are moving, with many of the movements instigated by the ground reaction force (the equal and opposite reaction of our foot hitting the ground). These movements are then controlled or facilitated by our muscles and tendons, which can increase, decrease or stop our joints moving all together. If there is not enough strength in these active soft tissues (muscles and tendons) then the movements continue to occur unopposed. As you could imagine, moving a joint further than where we have the strength to control the movement can put us at big risk of injury. But luckily, just like our cars, we have a seat belt in case of emergencies.

Ligaments are seatbelts. Seatbelts are ligaments.

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All the joints in the feet are surrounded by a capsule of sinew which keeps joint stuff in, and non-joint stuff out. Some parts of these capsules are extra thick, and cross over the joints in their at-risk areas. These thick bits are called ligaments. The role of the ligament is much like a seatbelt, when you’re driving along day to day you put your seatbelt on and hope that your safe driving sees that you never actually need it to hold you in your seat. Our ligaments are similar in that they do not contract like active muscles and tendons (or fascia), but if our joints start moving outside of their comfort zone then these seatbelts/ligaments should hopefully hold them in place.

In a hypermobile foot, every step sees movement being facilitated with ease, and if there is enough strength of the stabilising musculature then the seatbelts will never be called upon. Unfortunately, this is not always the case, and there are incredibly strong people out there who due to their hypermobile feet are unable to completely keep these movements under control.

So what happens when strength is not responsible for the hypermobility?

One step, nothing. Two steps, still nothing. Three steps, all good. The seatbelts (ligaments) are doing their jobs. Let’s keep this going, 10,000 steps, three days, two weeks, a couple of months? The ligaments will be pulled into action over and over again, leading to wearing down, damage to the ligament and joints themselves. Depending on the joints and the direction of the force this can lead to many different deformities. Often the big toe joint is involved, with osteoarthritic changes (bunions), the lesser toes might suffer a rupture of their stabilising ligaments and “pop up” into hammertoes. Sometimes the joints in the middle of the foot get moved more and bony spurring can present at the top of the arch which can put pressure on shoes and become quite painful.

What can I do?

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If you have a hypermobile, or very flexible foot then ensuring adequate strength in your stabilising muscles is absolutely paramount. An example of a basic strengthening program is here:

Also, the footwear we wear can either increase or decrease the load on our ‘at risk’ areas and ensuring your shoes are right for your feet, and your desired activity is also key. Some of us are unable to build strength due to time constraints, workload or other medical conditions. In this case strapping, padding or orthoses can be used to influence the timing and direction of the ground reaction forces acting across hypermobile joints.

If you have hypermobile feet or would like to know more on how to fix please call and book an assessment today. We would love to see you at Pride Podiatry soon.

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