Strength training for plantar fasciitis and the intrinsic foot musculature

Members do not see these Ads. Sign Up.

Strength training for plantar fasciitis and the intrinsic foot musculature: A systematic review
Dean Huffer et al
Physical Therapy in Sport; Article in Press

 

....yet I see so many alleged 'evidence based' clinicians citing a whole lot of references to justify this approach..... go figure.

I not saying it doesn't work (and I do use load programs clinically), I just saying the evidence that many think is there, is just not really there.

 

The Effect of Isometric Exercise on Pain in Individuals with Plantar Fasciopathy: a randomised crossover trial.
Riel H, Vicenzino B, Jensen MB, Olesen JL, Holden S, Rathleff MS
Scand J Med Sci Sports. 2018 Sep 11

 

Muscle Function and Muscle Size Differences in People With and Without Plantar Heel Pain: A Systematic Review
Journal of Orthopaedic & Sports Physical Therapy, 2019 Volume:0 Issue:0 Pages:1–35 DOI:

 

The Evalaution Of The Foot Core System In Individuals With Plantar Heel Pain
HoganKK PrinceJA HochMC
Physical Therapy in Sport 29 November 2019

 

Intrinsic Foot Muscle Cross-Sectional Area on MRI in People With and Without Plantar Heel Pain: A Cross-Sectional Observational Study
John W. A. Osborne, Ana M. Azevedo, Hylton B. Menz, Glen A. Whittaker, Matthew Cotchett, Tom Entwisle, David A. Connell, Shannon E. Munteanu, Karl B. Landorf
Source

 

Plantar Fasciitis or Flexor Digitorum Brevis Myositis. Is It Time to Reconsider the True Causes of Heel Pain?

Author to whom correspondence should be addressed.
J. Am. Podiatr. Med. Assoc. 2023, 113(3), 17090; https://doi.org/10.7547/17-090
Published: 1 May 2023
Browse Figures Versions Notes
Abstract

Background: As common as plantar fasciitis is, there’s a lack of evidence regarding the true pathophysiologic process causing plantar fasciitis and plantar heel pain in general. This may partially explain the high variability and outcomes with current treatment of recalcitrant plantar fasciitis. Although Lemont reported myxoid degeneration of plantar fascia with histologic analysis of patients with fasciitis, muscle biopsy results were not reported. So far it appears we have not focused on the muscular component that may be present with plantar heel pain in general and in patients we diagnose with plantar fasciitis in particular. Methods: In this article we performed a retrospective analysis of biopsy results from five patients with the diagnosis of recalcitrant plantar fasciitis to determine whether this diagnosis was correct or whether other component pathologies contribute to the chronicity of symptoms or to the failure of treatment. Results: Three of the five pathology reports included specific mention of inflammation, degeneration and atrophy of the intrinsic musculature consistent with myositis. Two of these showed lymphocytic infiltration in the muscle consistent with inflammation, with no signs of inflammation in the fascia. One showed inflammation of the fascia without signs of inflammation of the muscle. Conclusions: This small study introduces the idea that intrinsic myositis may contribute to, or be responsible for some cases of plantar heel pain and plantar fasciitis. This may be important in changing the way we deal with plantar heel pain in the future.

 

People have been asking whether strengthening the intrinsic foot muscles ,or toe flexor muscles generally, can help offload the plantar fascia during gait and reduce pain from plantar fasciitis. The idea of a load sharing system has been proposed. However, the toe flexor muscles can only help share load if they are active.
We have evidence that features of modern shoes make our feet a lot weaker, indicating they cause reduced demands on the toe flexor musculature. If the muscles which might share load with the PF are less active during gait they will be less effective at taking load away from the PF .
If a muscle or group of muscles is to unload the PF then they must be strong and active. If shoe features prevent activation then maximum strength is less relevant, IMO .
So perhaps if we want to take load off of the PF we need to strengthen and cause the muscles to activate which might mean a subject changing the characteristcis of their footwear.

 

Recently, research showed that when a group of individuals walked around in more minimal shoes for 6 months their toe flexors got 57% stronger. IMO, more minimal shoes may place greater demands on the toe flexor muscles causing them to be more active during gait producing greater tension in the muscles and so perhaps contributing more to offloading of the PF (It may be understood that more minimal shoes may lead to more direct loading of the PF ).

Whether and by how much a toe flexor muscle reduces stress in the PF depends on how much tension is in that muscle when the fascia is under load.

In my opinion it is likely that a number of shoe features affect the tension in toe flexor muscles and overall strength is only one of them. You can have a comparatively large, strong, abductor hallucis muscle, but it will not help support the arch and take stress away from the plantar fascia if the muscle inactive.

I suspect that the features that probably dial down activation and therefore tension in the toe flexor muscles ( including the intrinsic foot muscles) are toe springs and shoes with a stiff sole in the region of the MTPJs.

In a research situation ,when a person in everyday shoes walks, the activation/tension in the toe flexor muscles might be represented by a figure x. Strengthen the toe flexor muscles and the figure will probably still be x or a least I don't see why it would change in the medium term.

 

Below is a figure from D'Aout et al 2009 .

The image on the right ( BI>W ) shows a comparison between habitually barefoot individuals and their Western shod counterparts of peak plantar pressures during gait . The barefoot population creates higher pressures under the toes indicating greater tension in the toe flexor muscles and hence potentially greater arch support . IMO, the toe flexor muscles can only share load with the PF when active and the evidence suggests that some aspects of modern western shoes makes even strong toe flexor muscles less active.