Textured insoles

Region-specific textured insoles enhance static stability in young adults with chronic ankle instability
Yunqi Tang et al
J Biomech. 2025 Nov:192:112974.

 

There are two types of mechanosensory receptors embedded in the plantar dermis of the foot:

1. Meissner Corpuscules
2. Merkel’s Disks

Both are used to maintain upright posture, but they differ in how they are used:

The Neurophysiological Postural Model (Rothbart 2009)

Meissner Corpuscules are activated by velocity and movement. They utilize a method to encode the foot sensory feedback to the brainstem while walking. (FSF is a coded gradient map of the ground surface underneath your feet and is decoded by the cerebellum to make the necessary postural adjustments, e.g., leaning forward when walking up a hill).

Merkel’s Disks are activated by pressure gradients. They are utilized to codify the FSF while you are standing. This allows you to stand on uneven ground surfaces without falling.

George Sylvian DO in Australia, came up with an ingenious modification of the insoles he uses to stabilize Rothbarts Foot: he adds a robust texture, a flat, thin insole on top of the proprioceptive insoles. This enhances the effectiveness of the insoles while standing because it directly activates the Merkel’s Disks.

Again, I add the caveat: Do not use anything underneath the feet without first identifying the foot structure you are treating.

Abnormal pronation, pes planus, flexible flatfoot, metataralgia etc etc are observations (objective signs), not a diagnosis. Using insoles without a diagnosis is like prescribing an antibiotic for a fever. Just don’t do it!

Ignore this advice, when you have failures with your orthotic/insole therapy, do not be surprised.

 

Below is a photo of the texture insoles George is selling to be used on top of the Rothbarts Insoles

 

Nasa did a study on the mechanoreceptors of the foot many years ago to determine the effects of stimulation of the mechanoreceptos on postural and dynamic muscles. they found in the rat study that they did that stimulation of the Meissner and Merckel receptors decreased atrophy of the soleus by 85% and that of the Ruffini and Pacinian receptors found in the deeper dermis of the foot a decrease of about 58% in the dynamic muscles such as the gastrognemius. there have been lots of studies of textured insoles in australia by Prof Waddington and also in Asian countries such as Hong Kong, that show that a textured insole impoves muscle tone, balance and performance in athletes, the elderly, etc.

 

Hi ,
There is plenty of evidence that that textured insoles can improve balance but the study by Tang et al 2025, referenced in post #40, found no evidence of improvement in dynamic balance for the group being studied .

" This study shows that forefoot-textured insoles produce significant acute improvements in static stability in individuals with CAI, with no benefits detected for dynamic tasks."

I would be interested to here your opinion on whether the sensory receptors in the intrinsic foot muscles have a major role to play in balance and posture.

 

Texture insoles activate the Merkel’s disks. The Merkel’s are utilized during periods of standing. They are not utilized (activated) during periods of walking (e.g., dynamic balance).

This concurs with your post on the Tang et al 2025 in which you quoted:

"This study shows that forefoot-textured insoles produce significant acute improvements in static stability in individuals with CAI, with no benefits detected for dynamic tasks."

Tang found that during static stability (e.g., standing), texture insoles produce significant improvement; whereas, during dynamic tasks (e.g. walking), texture insoles offer no benefits.

His findings are consistent with my findings , which I published in Researchgate.

I realize that your interest lies in the sensory receptors in the intrinsic foot muscles.

I do not believe that these muscles have a role in maintaining balance and posture. I know other researchers feel differently. In time, who is correct will be established.

On a side note, this is exactly the kind of controversy that I experienced during 2002-2020. In 2002 I published a paper on 2 previously unrecognized foot structures (RFS and PCFD). Both foot structures are pathognomonic of "medial column supinatus." That is, based on my studies on embryological plates, I delineated exactly when and how medial column supinatus develops in the fetus.

At that time, my compeers conceded that medial column supinatus does exist prenatally, but not postnatally Hence, RFS and PCFD do not exist, basically ignoring my research.

Then, in 2021, two independent EU orthopedic research teams replicated my research published in 2002. Now it is agreed universally that medial column supinatus does exist postnatally, which is the hallmark of RFS and PCFD.

This is the second time my research has been controversial. Currently, my research on the coding of the Foot Sensory Feedback to the Cerebellum is based predominantly on the activation of Meissner and Merkels sensory receptors embedded on the plantar dermis, not on sensory receptors embedded in the intrinsic muscles of the foot.

I believe, in time, my research will be replicated and validated. Until that time, choose your own position on the role intrinsic muscles have on balance and posture.

 

"I do not believe that these muscles have a role in maintaining balance and posture."
Do we really just get to choose what best suits us ?

Figure below From Knellwolf et al 2025 .
Muscle spindle discharge signals to the brain closely following changes in centre of pressure. Knellwolf and his colleagues first published on this aspect of proprioception in 2018 and I am aware of nothing that would suggest the intrinsic foot muscles do not have a major role to play in proprioception .





Knellwolf conclusion-

5 CONCLUSION

"So, what does this mean? Are cutaneous afferents or muscle spindle afferents more important in postural control? Our observations cannot differentiate between the relative roles of muscle spindles and cutaneous afferents; clearly, both can encode various aspects of upright stance and its perturbation. However, it can be argued that much of the information provided by tactile afferents, with the potential exception of SA II afferents, appears to be incidental (e.g. making and breaking contact with the supporting surface during behavioural or reflex toe movements). It remains to be seen whether stable recordings can be obtained during walking on a treadmill, which is something we are currently embarking on"

 

I have been in contact with Thomas Knellwolf. We are discussing our different theoretical paradigms on how FSF are formed (muscle spindles vs mechanosensory receptors embedded in the dermis). And exactly how FSF regulates posture.

 

"I do not believe that these muscles have a role in maintaining balance and posture." Brian.

Characterizing the vestibular control of balance in the intrinsic foot muscles Trotman et al 2025

https://doi.org/10.1016/j.gaitpost.2024.12.026

"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."