Intrinsic Foot Muscles in Kids

The Intrinsic muscles of the Foot are those muscles which originate & attach within the foot itself. Extrinsic muscles are those that act between the foot and the leg. In the last few years intrinsic muscle function and strength has become an exciting topic for practitioners. New Articles are being published, where the researchers have been able to test the power, strength, size and the role of these tiny muscles on load through technology available in the digital age. As more studies are published, practitioners are discovering evidence to support atrophied (weakened) intrinsic muscles against a range of Adult foot pathologies. In Paediatric Podiatry, this research helps us identify what we can do better in our little ones, to reduce their risk of these pain pathologies in adulthood….. And this is really exciting stuff!

Layers of Intrinsic Muscles of the Foot

When I went through Uni some 20 odd years ago, the intrinsic muscles were thought to have very little effect of foot function and position. The extrinsic’s were always considered the only power players in mechanics ….. but back then we also used to draw lines on people legs and heels saying they need to line up to be straight. This just isn’t the case anymore! As Practitioners adapt to what the research tells us, we start to understand the correlations more between some pathologies of the foot and the role these intrinsic muscles can have at protecting you and your children from pain.

In my years working as a Podiatrist I’ve seen the strong correlation of child foot pain with extrinsic muscle/tendon function. It is generally around the rearfoot loading of tissues acting between the foot and ankle, that work to facilitate movement, that get overused and sore. The mechanics of those muscles/tissues and how they act around the foot and ankle can also have an effect at the knee in various pain syndromes.

Which poses the question- “Why don’t we see intrinsic muscle weakness commonly linked to creating/aiding Children’s foot pain as we do in Adult foot pain?”

There are so many possible answers to this question. It could be based around the mechanics of the foot and ankle through a developing foot. It could also be caused through external factors, like the sports we play, our weight, lifestyle, shoe type or just plain old endurance and muscle memory that ultimately put those intrinsic muscles to the test..… Clinically, I have seen evidence that all of these play a role in some part. What we can take from this research, is that intrinsic muscles strength does play a role in overall foot health. So developing the strength of these muscles in our children is only going to be beneficial for them now and into their adult years. Here are 2 great exercises you can do with your children to work on their intrinsic muscles strength.

Now lets take a look at Orthotics. Depending on whether an orthotic is a functional orthotic, or full contact…….. plus where the correction is placed on the foot can ultimately change the effect it has on intrinsic muscle strength. In children we don’t want to over-correct the plantar arches. As we discussed, most pathologies in children lie around the extrinsic muscles function through the foot and ankle. This is why when creating kidzoles I worked around the rearfoot of the orthotic to make gentler pitch points for extrinsic muscle function, but made sure not to over correct plantar arches. I want those feet to work work work…. and continue to build intrinsic muscle strength through load. Over-correcting those plantar arches can mean we weaken our intrinsics with too much support. Nowadays all Podiatrists should be giving you an orthotic with strengthening programs attached. I encourage my young patients to include these basic intrinsic strengthening alongside the 60:40 orthotics:barefoot approach to load.