Treating plantar fasciitis with foot strengthening

I have done no research specifically regarding modern shoes, hence I have no comment to offer.

 

You are unaware of the effects of footwear on proprioception and foot mechanics?

 

Of course the other major contributor to the obvious weakening effect that modern footwear has on toe flexor strength might be stiff soles . If you bend a modern running shoe in the region of the MTPJ it will spring back into position with considerable force . The toes need not develop force if the shoe is doing it for them.

If you stuck a couple of these stiffer shoes together you could probably use the result to power a reasonable crossbow!

 

That was not the question, you asked, which was: what aspect of the modern shoe do you think causes disuse atrophy of the toe flexor muscles? And I replied inferring that I have done no specific research regarding this issue.

However, regarding the effect footwear has on proprioceptive insoles, the quick answer is, shoes can only distort the proprioceptive signal generated by the insole. If you desire a more detailed explanation (which is beyond the purview of this thread), start a new thread and entitle it something like Shoes Impact on Proprioceptive Insoles.

Also, the impact footwear has on foot mechanics is profound. And IMO, most shoes have a negative impact on foot biomechanics. The reason is that shoe manufacturers market their shoes to sell, not necessarily to be biomechanically sound (I got this directly from a researcher at Nike). This is another thread you could start, entitle it something like The Impact Shoes have on Foot Biomechanics.

 

Agreed .

I seem to remember a person coming onto the site who had attempted to do a PhD on foot mechanics. I don't think he got the PhD but his theory was base around the 1st ray leading the kinetic chain.( It may even have been the hallux itself )

 

Interesting. That is exactly what happens in Gravity Drive Pronation - The medial column of the foot leads the kinetic chain, foot to jaw.

 

Actually, I believe his idea was that the medial column leads the chain in non pathological states.

I have read that the FHL "stabilizes the first metatarsal head and keeps distal pad of the great toe in contact with ground in toe-off and when on tip-toe." Since modern shoes greatly reduce toe flexor strength, and this would include FDL and FHL , it is easy to see how foot strengthening exercises would help those with flat feet and related medial column problems.

The FDL is a powerful muscle ,more powerful than the tibialis posterior muscle for example, and weakness will no doubt impact on many aspects of foot function.

Since almost all modern shoe wearers have weakened toe flexors and you cannot say your orthotic will result in muscle strengthening, would it not be prudent to include muscle strengthening in your treatment protocol?

 

Barefoot walking is beneficial for individuals with persistent plantar heel pain: A single-blind randomized controlled trial

Author links open overlay panelMiriam Reinstein a b, Asaf Weisman b, Youssef Masharawi b
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https://doi.org/10.1016/j.rehab.2023.101786Get rights and content
Abstract

Background

A lack of data exist about the effectiveness of active treatments for persistent plantar heel pain (PPHP).
Objectives

To compare short-term functional and clinical effects of a 4-week barefoot or shod treadmill walking program for people with PPHP.
Methods

A single-blinded clinical trial randomized 52 participants with PPHP into either a barefoot walking group (BWG), or a shod walking group (SWG). All participants received therapeutic ultrasound. Outcomes were measured at baseline (t0), following 4 weeks of treatment (t1), and at 1-month follow-up (t2). The SF-36 functional questionnaire score was the main outcome. Secondary outcomes were self-reported and clinically-assessed pain provocation levels, pressure pain thresholds and pain tolerance. Treadmill walking time and speed were measured at t0 and t1; people also recorded the time spent walking each day in a diary.
Results

The BWG exhibited significant improvements in all SF-36 items (except “emotional well-being”) (P < 0.05), whereas the SWG exhibited improvements only in “pain” and “health change” items (P = 0.0001; effect size 0.13–0.94). Greater improvements were observed in the BWG than the SWG for “physical function” (P = 0.019) and “role limitations due to physical health” items (P = 0.035). Both groups demonstrated significant improvements in pain, with greater improvements in the BWG (P = 0.0001; effect size 0.89). Only the BWG showed significant improvements in pain pressure thresholds (P < 0.05; effect size 0.70) and pain tolerance (P < 0.001; effect size 0.67). Both groups significantly increased their speed and time spent walking on the treadmill (BWG Δ=19.7 min and Δ=1.7 km/h; SWG Δ=16.7 min and Δ=1.1 km/h) and time outdoors (SWG ∆=38.2 min/week; BWG mean ∆=48.5 min/week) (P < 0.001). All clinical tests of pain were significantly less positive in the BWG at all time points (P < 0.05).
Conclusions

Both walking programs benefited people with PPHP by alleviating pain and improving function and quality of life. Greater improvements were observed in the BWG than the SWG overall.

 

So why would barefoot walking give significant improvements in persistent plantar heel pain (PPHP)? Over 4 weeks I think it unlikely that the plantar intrinsic muscles will increase much in strength but they will certainly start to become more active during gait. More active because of the mechanics of walking.

We think of ourselves as moving in a straight line, in the direction we are pointed in, but in actual fact we progress via a series of rotations, left swinging past right, right swinging past left.

At various points through gait we will find ourselves with only the ball of one foot, and the toes of that foot, in contact with the ground. The toes help prevent outward rotation of the foot around the ball of the foot as we swing one side past the other.( see linked to video if you are interested)

As the toes resist rotation around the ball of the foot, they are splayed apart and this is where the adductor hallucis comes to the aid of the biomechanical party. This is also where a lot of the stimulation of this muscle comes from and what keeps it strong.

Weakness in this muscle will contribute to hallux valgus formation /worsening. This view is of course contrary to the idea that hallux valgus can be worsened by an hallucis adductor /abductor imbalance, which is a well entrenched biomechanical fallacy.

Likely then, the intrinsic foot muscles derive their strength from resisting rotations/spreading load, but who needs intrinsic foot muscle strength if shoes do the anti-rotation job for us?

The answer is we all do if we want to avoid walking/running like chimpanzees, since the intrinsics are vital to arch recoil and tibial angle . See seminal work of Welte et al 2023

So anti rotation work/load spreading during heel off keeps the intrinsics strong and this strength is utilized during arch recoil, which is critical for whole body mechanics.

Deck shoes ?

https://www.youtube.com/shorts/SorZTV7CZ9Q

 

Re calf raises on an inclined plane, I tried a simple little experiment, and promptly injured myself. Seriously, don't try this, I have been in pain for about a week. Briefly, I tried to do calf raises with my toe flexors on "full beam" as it were.

I strengthen my feet every other day and my toe flexors are probably stronger than most peoples. I could not see how calf raises on an incline could effectively target the plantar intrinsics since these are toe flexors and the toes must dorsiflex to allow the calf raise exercise.

Anyway, I was at the gym and got myself an inclined plane . After a bit of a warm up I tried a tried a single leg heel raise starting with my toes pressing down as hard as I could. I got pretty close to a "modified" calf raise, levering up around the tips of my toes rather than the ball of my foot , then ping and ouch, as a muscle, probably the abductor hallucis, tore . Predictable, and I would repeat, please don't try this at home.

If I fully activate my intrinsic foot muscles I can't do calf raises. Not without risk of significant injury. I have noticed that some authorities seem to be advocating heel raises with focused, volitional, toe flexor activation . IMO, this is not a good idea .


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