What's the fastest way to strengthen the intrinsic muscles of the plantar foot?

[Gerrard Farrell]

What's the most effective, proven, way to strengthen the intrinsic muscles of the plantar foot? The answer is actually pretty easy ,use an inelastic leverage point (or point against which to lever) across the dorsal surface of the foot and plantar flex the toes against resistance in an isometric hold type exercise. Basically, the same type of set up as was used Goldmann et al 2012. Goldmann achieved 70% toe flexor gains in just 7 weeks demonstrating that-

"TFM responded highly to increased loading within a few weeks. The increased force potential made a contribution to an athlete’s performance enhancement."

One of the most important elements of the Goldmann set up, and a feature whose importance seems to have been lost on many, is the inelastic band of material across the top of the foot against which the toe flexors can work to generate force. What I have taken to calling the "dorsal leverage point".

Why bother with such wee muscles? Well, apart from anything else, recent research has shown that via muscle spindle discharge, they send very accurate information about centre of pressure fluctuations to the brain, making them perhaps more important to balance than the cutaneous receptors in the sole of the foot.

Further recent research has demonstrated a direct link between the vestibular apparatus and the intrinsics . The paper concludes " Our findings demonstrate that whole-body vestibular-evoked balance responses were adjusted in response to altered mediolateral stability and head posture, in part, via modification of intrinsic foot muscle activity."

So the wee muscles in the foot ,subject to atrophy as we age and in conditions like diabetes, likely play a huge role in keeping us upright .

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[Gerrard Farrell]

So an inelastic "dorsal leverage point " (inelastic, non stretch, band across the top of the foot against which the intrinsic foot muscles can work to generate torque around the MTPJs ) allows the intrinsics to be more active and apply more force likely giving a much more effective isometric exercise than, for example, not using a leverage point/inelastic band . There is evidence for this.

Below is a post I placed on podiatry arena a few days ago and it can be clearly seen that an inelastic leverage point ups intrinsic activation by almost double as opposed to standing and pressing the toes down as hard as you can .

"The paper is Dustin Bruening et al 2019 . DOI:10.1186/s12891-019-2981-6

A couple of images from the paper make the point.

In the figure immediately below look at photographs B and C . In B the subject stands and presses the toes down as hard as possible and a reading is taken of muscle activation levels in the foot . In photograph C a doming type action is used and straight toes lever against an inelastic leather band placed across the top of the foot.

Muscle activation levels for exercises B and C can be seen in the bottom figure . Activation in all the muscles measured is far higher in the exercise that uses a point of leverage. With regard to activation of the abductor hallucis, activation in exercise C is almost double that of the toe press exercises, B .
B, and exercise like it, likely don't make much of a difference to toe flexor strength but C ,with an inelastic point of leverage against which the toes can work, does. This is why the Goldmann set up works so well, promoting huge strength gains even in diabetic, neuropathy affected, feet ( 55% gains in 7 weeks)

Integrated exercise are also advised by experts but they will not deliver even nearly the same level of stimulus to the intrinsics.





GL/TP toe press exercise ( exercise B ) AH abductor hallucis activity (exercise C, Doming)