A dorsally placed point of leverage greatly improves toe flexor activation.

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Researchers investigating the muscles of the foot have struggled to both measure toe flexor strength and come up with exercises for increasing it.

The largest strength increases I have seen are 70% gains in just 7 weeks in athletically active young men, Goldmann et al . The strengthen system Goldmann used involved an isometric hold using a base, a toe plate to incline the toes, and an inelastic band across the top of the foot against which the toe flexor muscles could lever .
The point of leverage is crucial for full toe flexor activation.

Note in the included figure how the inelastic band over the top of foot is preventing the ball of the foot from being lifted from the base. This provides a point of leverage and greatly increases possible maximum activation in muscles like the abductor hallucis.

The potential of toe flexor muscles to enhance performance

Jan-Peter Goldmann 1, Maximilian Sanno, Steffen Willwacher, Kai Heinrich, Gert-Peter Brüggemann
Affiliations Expand

• DOI: 10.1080/02640414.2012.736627

Abstract

........TFM(toe flexor muscles) responded highly to increased loading within a few weeks. The increased force potential made a contribution to an athlete's performance enhancement.

 

So is there any actual evidence that an inelastic, dorsally placed point of leverage improves foot muscle activation during toe flexion exercises, research with actual numbers ? Yes, there is, and the difference in muscle activation levels between standing and pressing your toes down as hard as you can and using an inelastic, rigid, point of leverage in a simple device, is huge.

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)

 

So a point of leverage, or put another way, placing an inelastic band across the top of the foot at the MTPJs, improves activation of the toe flexors (esp the intrinsic foot muscles) . But is this point of view shared by anyone else?

Dr Roman Tourillon has been very active in the field of toe flexor force in recent years and has published widely on the subject during his PhD .

On the subject of measuring maximum toe flexor force, here is some of what he and his colleagues have to say. Clearly he has identified that merely press the toes down onto a measuring system, without securing the MTPJs and stopping them lifting, will not fully activate the intrinsic and extrinsic foot muscles.
Roma ,Tourillon et al 2024- DOI:10.1016/j.foot.2024.102095 ;

"Some authors tried to measure a similar construct by proposing several types of tests. Mickle et al. [11] used a pressure platform, asking the participants to push from a standing position with the toes off the ground. The main advantage was the simplicity, but since the MTP joints were not constrained, the force estimated from the pressure was not equivalent to the force that generates the joint plantarflexion moment. "

• Here( below) is the set up Tourillon and Roma used . Note that the MTPJs are" constrained" by multiplebands of inelastic material against which the toe flexor muscles can lever . This allows maximum activation and force production.
• 

 

Tourillon then, realised that to fully activate the intrinsic foot muscles and get a true reading of their functional capacity, a dorsal pivot ( orange and black bands) is required against which the toe flexors can work ( all of the plantar intrinsic foot muscles plantarflex the toes).He further realised that to fully activate the intrinsics you need to place the toes in a dorsiflexed position.

Although it was recognised that the set up shown in the post above was the best way, by a considerable margin, of activating the intrinsics, it is an isometric exercise and so Tourillon went in the direction of more functional exercises when it came to strengthening the foot.

So there is a bit of a trade off here. Using the set up in post #3 gives the best activation/stimulation of the intrinsics but it's not as functional as, for example, the sled push.

But can we make adapt Tourillons measuring system, with its vital inelastic dorsal pivot point ( MTPJ anchor) to a more functional form, allowing it to be used as a strengthening system which can activate the toe flexors to a higher level than functional exercises like the sled push ( For many, sled pushes are impractical) . Yes, we can, and we need look no further then the first image in this thread ( Goldmann). The plate on which the toes rest is pressed down and the inelastic band across the top of the foot holds the MTPJs down or "constrains" them. Take away the dorsal pivot and the exercise will be far less effective.

I would say that research needs to be done about intrinsic foot muscle activation/stimulus levels for toe plantarflexion with a dorsal pivot( point of leverage) vs standing and pressing down without a dorsal pivot ,but this has already been done within very clear results. See post #2 above Dustin Bruening et al 2019 . DOI:10.1186/s12891-019-2981-6 pos