Short foot exercise . Which muscles are involved ?

[Gerrard Farrell]

The short foot exercise has recently gained a lot of traction with physiotherapists and podiatrists for improving foot function , particularity among flat footed patients .

The exercise , as prescribed by Janda , involves pulling the metatarsal heads towards the heel to produce a raised arch . During this maneuver ,the toes are kept relaxed and the present belief is that this exercise targets the intrinsic muscles of the foot making them stronger and improving many measures of foot function .

My belief is that the muscles being targeted by Janda's version of the short foot exercise can't be the plantar intrinsics if the toes are not being plantarflexed and that instead it is the tibialis posterior ,tibialis anterior and the peroneal muscles that are being exercised . In closed chain these muscles are known to both dorsilflex the more proximal part of foot and plantarflex the distal aspect .

Am I correct ?

Gerry

[Gerrard Farrell]

Re: Short foot exercise . Which muscles are involved ?

This extract ,from a thread on podiatry arena , illustrates the apparently confused thinking that surrounds the short foot exercise . The confusion is not limited to this paper , it is pretty much universal .



EXTRACT

• A paper was recently published which looked at the effects of foot exercises on the function of flat feet (below 1 ) .
  
  The researchers used the short foot exercise to strengthen the foot and the paper grip test to measure toe flexor strength .
  Here is how they described the paper grip test .
  
  ". Although techniques to assess foot muscle strength [4,22] are evolving, this study used force during an established clinical test, the PGT [4,9]. The paper grip test asks participants to hold a piece of paper placed between the big toe and the floor while the examiner attempts to pull the paper out. Participants were seated in a chair with their backs touching the back of the chair, arms crossed over their chest, feet resting on the floor, and were required to keep their feet on the floor during the test. Participants sat with the pad of their big toe on an embedded force plate (AMTI, Watertown, MA). The sensitivity of the force plate was adjusted so that the range was 0 to 350N. "
  
  So the researchers used an electronic version of the paper grip test to measure " first metatarsophalangeal joint (MTP) flexion strength."
  
  Question . If pressing the toes down and noting the force with which this can be done is an established clinical test for the plantar toe flexors , then how can you exercise these muscles using the short foot exercise without pressing the toes into the floor ?
  
  As I understand it , Janda seems to have advocated a version of the short foot exercise in which the toes are relaxed , but also claims this strengthens the plantar intrinsics .That makes no sense .
  
  Paper 1
  
  Can Foot Exercises and Barefoot Weight Bearing Improve Foot ...
  
  
  

  https://crimsonpublishers.com/oproj/fulltext/OPROJ.000567.php

  
  3 Jul 2018 - The home exercise program included: short foot (foot doming), toe spreading, ... The paper grip test asks participants to hold a piece of paper placed between the big toe and the floor while the examiner attempts to pull the paper out. ... their backs touching the back of the chair, arms crossed over their chest, ...
  
  Gerrard Farrell
  
  Glasgow
  scotfoot, May 27, 2019
  #33

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[Gerrard Farrell]

Re: Short foot exercise . Which muscles are involved ?

Is there direct evidence that the tibialis anterior and peroneals are central to the short foot exercise ? Yes ,please see the link below to a recent study ( H Yoon et al 2017) .

The researchers took care to make sure that subjects activated the abductor hallucis in the exercise , so although the toes remained straight they would have have exerted pressure on the ground .

Maximum voluntary isometric contraction for the tibialis anterior and peroneus longus was recorded for each subject . Subsequent results showed an EMG in the peroneus longus of 46.34±22.76 % of MVIC for flat footed individuals with the ankle plantarflexed , and of 51.45±14.54 with the ankle dorsiflexed . See table 2 in the paper .

That level of activation is enough to produce a progressive strengthening response in the peroneus longus . In my opinion the tibialis posterior is likely activated to the same sort of level as the peroneus longus in the short foot exercise .

Provided the toes are kept straight and pressed into the ground during the exercise then the short foot exercise ticks a lot of boxes .


Link to paper
Comparison of the Foot Muscle EMG and Medial ... - ScienceCentral

https://www.e-sciencecentral.org/articles/SC000026926

by H Yoon - 2017 - Related articlesThe short foot exercise (SFE) is effective in increasing the height of the MLA for people with flat feet. Most of the research related to the SFE has simply evaluated the efficiency of the exercise using enhanced ABH electromyography (EMG) activation.

[Gerrard Farrell]

On the subject of the short foot exercise and of the progressive resistance training of the muscles of the foot in general ,the topic is becoming more important as time passes .

A paper was published a few years ago which looked at the effects of this type of exercise as a treatment for Charcot-Marie -Tooth disease . The study , led by Professor Joshua Burns concluded as follows ;


"Interpretation
6 months of targeted progressive resistance exercise attenuated long-term progression of dorsiflexion weakness without detrimental effect on muscle morphology or other signs of overwork weakness in paediatric patients with Charcot-Marie-Tooth disease."

Here is a link to an article on the subject ;


First effective treatment of children with Charcot-Marie-Tooth ...

www.sydney.edu.au › news › 2017/07/17 › first-effecti...
17 Jul 2017 - Led by Professor Joshua Burns from University of Sydney and The Children's Hospital at Westmead, the study found that progressive resistance exercise could help to significantly reduce the muscle weakness experienced by patients with the genetic disease.

--------

Forward to the present day and Professor Burns is moving to improve methods of strengthening the intrinsic muscles of the foot . He is basing his method around the short foot exercise but has correctly identified that,during exercise , the toes should remain straight but flex around the MTFJs causing pressure to be applied to the ground through the tips of the toes and the ball of the foot to leave the ground ( see link to photographs from the paper and to the paper itself ) . He and his team are calling their system the "Archercise biofeedback device ".

https://images.app.goo.gl/dTEDiE1swjaX3c6P7

Feasibility of the Archercise biofeedback device to strengthen ...

jfootankleres.biomedcentral.com › articles
13 Jul 2020 - Toe flexor and foot arch exercises focused on intrinsic foot muscle strength and ... We investigated the feasibility of using a novel medical device, known as ... J. McKay, Claire E. Hiller, Elizabeth J. Nightingale & Joshua Burns.
by PJ Latey - 2020

[Edmund Cramp]

It sounds like a simple fine-wire EMG activity test would answer a lot of the questions about which muscles are active, when they are active, and how active they are if the subject is sitting in a gait lab with their foot on a force plate. This should generate some interesting information and would be very easy to do..

[Gerrard Farrell]

Hi Edmund ,

Here is a quote from a recent paper which looked at intrinsic foot muscle strength in the feet of diabetics . Taken together with the work of Prof Burns (above ) it's easy to see that finding a way of providing effective progressive resistance exercise for the intrinsics is a very serious business esp in some conditions which cause neuromusculature degeneration .

Quote

"One potential clinical implication is that while patient education and adequate control of blood glucose level are certainly important, our results indicate that a strength training program for the intrinsic muscles of the foot [26, 27] may help to improve specific muscle strength and prevent muscle atrophy. This can minimize the risk of development of deformity that could lead to amputation." Kimura et al 2020

I agree that fine wire EMG studies would be a good way of finding out just exactly what muscles are involved in the short foot exercise although a study ( Bruening et al 2020 ) was published after I started this thread which used surface electrodes and goes some way towards illustrating muscle activity during a number of foot exercises .

The 3 exercises investigated by Bruening and colleagues are represented in the photographs below and all are interesting .

Photograph A shows toe curling activities and the rig devised was about as good as you can get for activating the abductor hallucis ,one of the principle intrinsic foot muscles . What the researchers found was that even when curling with maximum effort the EMG recorded in the abd hallucis was less than 35 % EMG max indicating that the abd is only an assisting muscle in the toe curl with the flexor hallucis muscle ,an extrinsic , being the principle muscle involved .

In other words toe curl exercises , including towel curls , will strengthen long toe flexors but not ,quatratus plantae aside , any of the intrinsics . Toe curl exercises , even with a following wind and a youthful physiology ,are not an effective exercise for targeting the crucial intrinsics notwithstanding the fact that such exercises have been used for generations for this purpose .

[Thomas M. Greiner]

There are no foot muscles, intrinsic or extrinsic, that cross only the tarsometatarsal joints. Tibialis anterior, tibialis posterior and fibularis longus all share an insertion site joint between the first cuneiform and the base of the first metatarsal. That means that for some individuals these muscle cross the tarsometatarsal joint for the first digit ray. Similarly, fibularis brevis inserts onto the tuberosity of the fifth metatarsal, and so will influence the tarsometatarsal joint of the fifith digital ray. However, these muscles also cross many other joints, and are poorly situated to flex (plantarflex) the tarsometarsal joints that they influence.

That's it. All the other muscles that cross the tarsometatarsal joints insert onto one or more of the digital phalanges (flexor digitorum longus, flexor digitorum brevis, flexor hallucis longus, abductor hallucis, extensor hallucis, extensor digitorum brevis, extensor digitorum longus). So, you cannot just flex (plantarflex) the tarsometatarsal joints because there are no muscles available for this action. At least not in standard human anatomy.

[Gerrard Farrell]

Hi Thomas
It is generally recognized that in closed chain the tibialis posterior helps support and maintain the medial arch of the foot .
Contraction of this muscle plantar flexes the forefoot relative to the rearfoot .
If you were standing on one foot and the tib post were suddenly to fail completely, the navicular would lower and the 1st met would dorsiflex relative to rearfoot .

Out of interest and from an anatomists point of view ,would you recommend toe curling exercises as a way of strengthening abductor hallucis ?

The EMG recorded in measuring set up C ,above in previous post, was about 3x that recorded for set up A .

Were you aware that the short foot exercise of Janda was supposed by many leading academics to be about approximating the met heads with the heel of the foot but without flexing the toes at all ?So activation of the toe flexors with no toe flexion which sounds a bit unlikely to me . But it passed peer review.

I should declare here that I have invented and patented a device and method of strenghening the foot .