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**Gerrard Farrell** · January 18, 2018, 08:07 AM

Re: Intrinsic foot muscles .The heart of balance ?

With regard to the above , Professor Chris Nester has just started his own blog site . In one of his articles he states -

"The foot is only ever a pure mechanical structure when it is detached from the control system. Have you ever held a fresh cadaver foot? It’s quite difficult to make the foot stand normally or simulate ground contact in a way you would recognise as “gait”. It just flops about and is quite unwieldy. It is not what you see in clinic or when you take your shoes and socks off.
The foot is therefore never a purely mechanical structure and it is always under some level of intelligent control."

Exactly . The foot is designed to be unstable especially in the rearfoot area . Unstable that is until you add in the intrinsic and extrinsic musculature and neural control . Once you add these in to the equation , the narrow heel of the human foot makes balancing the body above easier .

His blog site can be found here - talkingfeet.online/2018/01/04/why-am-i-blogging/ … via @ProfChrisNester

Actually , to be fair ,this is exactly the type of thing Professor Irene Davis has been going on about for years . Just not the short foot exercise please !

**Gerrard Farrell** · January 19, 2018, 11:03 AM

Re: Intrinsic foot muscles .The heart of balance ?

For some time it has been the view of a number of researchers that both the intrinsic foot muscles and the extrinsic foot muscles contribute to balance but by different modalities . That the extrinsic foot muscles affect balance by altering the centre of pressure under the foot is well know but the exact contribution of the intrinsics has been harder to nail down .
The previous posts in this thread outline the mechanism by which I believe the intrinsic provided fine tuning of balance and postural stability .A fine tuning system within a larger overall system if you like .

Gerry

**Gerrard Farrell** · January 19, 2018, 11:50 AM

Re: Intrinsic foot muscles .The heart of balance ?

Extract from thread on podiatry arena-

"Practical implications of the balancing effects of the intrinsic action on "talocalcaneal stack " ? With regard to acquired pes planus (flat feet ) , a medial arch support will restore the vertical component of the talocalcaneal stack allowing ,amongst other things , a better intrinsic /calcaneus balancing mechanism leading to better fine control of postural stability and stronger intrinsics . That is what seems to happen in these cases . "

**Gerrard Farrell** · January 21, 2018, 11:30 AM

Re: Intrinsic foot muscles .The heart of balance ?

A paper (1) was recently published which looked at the role of two of the intrinsic foot muscles and balance .Here is the conclusion .

"The findings of this study demonstrate that the vestibular system is able to modulate activity in the abductor hallucis and abductor digiti minimi during standing. This experiment extends the previously reported operational bandwidth of coherent frequencies in the MG (0-20 Hz) (Dakin et al. 2007; Dalton et al. 2014) to intrinsic foot muscles. Elevated cortical demand and lack of visual input increase the corrective response to a vestibular error signal at predominantly lower frequencies, indicating that there are likely different origins of the short- and medium-latency responses. The abductor hallucis and the abductor digiti minimi are likely important contributors to upright standing balance control and they are capable of dynamic vestibular responses which can be modulated by other sensory feedback as well as by cortical activity. "

(1)
vestibular modulation of the abductor hallucis and the ... - Scholars' Bank

https://scholarsbank.uoregon.edu/xmlui/bitstream/.../Final Thesis-Wallace.pdf?...1
by J Wallace - ‎2016 - ‎Related articles
explore the vestibular system. The purpose of this experiment was to determine if intrinsic foot muscles are modulated by vestibular activity and to elucidate any changes in the association between the vestibular stimulation and electromyography (EMG) responses in response to changes in head position, visual cues, and ...

Gerrard Farrell

Glasgow
scotfoot, Today at 10:26 AM

**Gerrard Farrell** · January 23, 2018, 02:52 PM

Re: Intrinsic foot muscles .The heart of balance ?

So to summarize the thead , we evolved from a gibbon like ancestor which learned to walk on feet best suited for brachiation . The divergent first ray would have given a big toe that resembles the thumb of our hand and this would have helped with mediolateral balance during upright walking .

Committing to terrestrial bipedalism would have led to the first ray coming into line with the rest of the foot and the formation of the "talocalcaneal stack " would ,amongst other things ,have allowed the muscles of the hallux and the associated neural mechanisms to continue to contribute to mediolateral balance whilst still allowing a foot with a non divergent first ray .

**Gerrard Farrell** · January 28, 2018, 06:55 AM

Re: Intrinsic foot muscles .The heart of balance ?

If you are interested in balance then this abstract is worth consideration -

Foot muscle morphology is related to center of pressure sway and control mechanisms during single-leg standing.

Zhang X1, Schütte KH2, Vanwanseele B3.
Author information

Abstract

Maintaining balance is vitally important in everyday life. Investigating the effects of individual foot muscle morphology on balance may provide insights into neuromuscular balance control mechanisms. This study aimed to examine the correlation between the morphology of foot muscles and balance performance during single-leg standing. Twenty-eight recreational runners were recruited in this study. An ultrasound device was used to measure the thickness and cross-sectional area of three intrinsic foot muscles (abductor hallucis, flexor digitorum brevis and quadratus plantae) and peroneus muscles. Participants were required to perform 30s of single-leg standing for three trials on a force plate, which was used to record the center of pressure (COP). The standard deviation of the amplitude and ellipse area of the COP were calculated. In addition, stabilogram diffusion analysis (SDA) was performed on COP data. Pearson correlation coefficients were computed to examine the correlation between foot muscle morphology and traditional COP parameters as well as with SDA parameters. Our results showed that larger abductor hallucis correlated to smaller COP sway, while larger peroneus muscles correlated to larger COP sway during single-leg standing. Larger abductor hallucis also benefited open-loop dynamic stability, as well as supported a more efficient transfer from open-loop to closed loop control mechanisms. These results suggest that the morphology of foot muscles plays an important role in balance performance, and that strengthening the intrinsic foot muscles may be an effective way to improve balance.

KEYWORDS:

Abductor hallucis; Closed-loop control; Open-loop control; Peroneus muscles; Stabilogram diffusion analysis

PMID: 28575753 DOI: 10.1016/j.gaitpost.2017.05.027

**Gerrard Farrell** · February 4, 2018, 02:19 PM

Re: Intrinsic foot muscles .The heart of balance ?

So with regard to all of the above then for the purposes of keeping the body balanced and avoiding falls we have a stepping strategy ,a hip strategy ,an ankle strategy , and , in my opinion an increasing likely "sub ankle " strategy which involves the intrinsic foot muscles and their effects on the calcaneus (inversion/eversion ) . This sub ankle strategy ,which can function independently of the extrinsic foot muscles , is likely only effective for fine mediolateral control and may be a difficult skill to master initially .

Strengthening atrophied intrinsics may help this system regain former levels of efficiency .

Any thoughts ?

Gerry

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