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Soft Insoles Feel Comfortable - But Are They Supporting Your Foot Properly?

21 October 2026

By Mark Reyneker, BTech (Podiatry), MSc (Palaeontology), Registered Podiatrist, Foot & Gait Specialist | Founder & Clinical Director, Family Podiatry Centre

Published: 21 October 2026 | Last reviewed: 21 October 2026

Soft insoles can cushion the foot and redistribute pressure. However, when treatment requires a change in foot movement or mechanical support, the orthotic must have sufficient stiffness to resist deformation under load. Research shows that increasing orthotic stiffness can produce greater changes in certain foot movements, although design, posting and the individual prescription also matter. The softest device is not necessarily the most effective—and the hardest device is not automatically the best.

Why an insole can feel good but still provide insufficient support

When you first step onto a soft insole, the cushioning can feel immediately reassuring. For someone with sensitive feet, that relief can be valuable. However, the sensation beneath your foot does not tell us everything about how the device performs while you walk, run or exercise.

An orthotic prescribed to influence foot mechanics has a specific job. It may need to support a region of the foot, redistribute loading or influence movement during a particular part of the step. To achieve that, its shape and resistance to deformation must suit the demands placed on it. An insole can feel comfortable when you first put it on yet provide insufficient mechanical support during activity. That distinction matters when choosing between a soft foam insole and a rigid or semi-rigid orthotic.

Cushioning and mechanical support serve different purposes

Cushioning allows a material to compress beneath the foot. Depending on its construction, this can spread contact over a larger area and reduce pressure at particular locations. Mechanical support depends on how the complete device responds to loading. An orthotic needs to generate forces in the appropriate places to influence the foot.

These functions can coexist. A device can have a supportive shell beneath a cushioning cover, and some firm foam orthotics can provide meaningful support. The question is therefore: Does this orthotic maintain enough of its prescribed shape under load to produce the intended effect?

What does research say about orthotic stiffness?

A study by Desmyttere and colleagues investigated foot orthoses with different levels of stiffness in 15 healthy participants. Increasing stiffness produced greater changes in certain foot movements, including a further reduction in rearfoot eversion—the outward tilting movement of the heel associated with part of pronation. Adding rearfoot postings also influenced movement.

The study demonstrates that orthotic stiffness can affect how the foot moves. It does not prove that maximum stiffness is best: stiffer devices also increased pressure in some regions, and the researchers did not establish long-term pain relief or injury prevention. (pubmed.ncbi.nlm.nih.gov)

For clinical practice, the implication is that stiffness should be part of the prescription. It should be selected to achieve a particular objective rather than chosen simply because a material feels pleasant beneath the foot.

Why resistance to deformation matters

An orthotic’s unloaded shape is only part of its design. What happens when the person stands and moves on it is equally important.

In a laboratory study, Tavera Pelaez and colleagues measured the force required to lower the arch of different orthotic constructions. Thicker shells increased stiffness. Adding medially wedged forefoot and rearfoot posts had an even larger effect: the posted designs were approximately 3.4 times stiffer than those without the additions.

These were mechanical tests of printed nylon orthoses, rather than a clinical comparison of polypropylene and EVA. Nevertheless, they demonstrate an important principle: shell construction and supporting components substantially affect how well an orthotic resists deformation. (pubmed.ncbi.nlm.nih.gov)

If the aim is to maintain a particular support contour during loading, excessive deformation may compromise that objective. This is a mechanical interpretation of the findings, rather than proof that every softer device will fail.

A harder material alone does not make a better orthotic

Stiffness works together with shape.

In a study involving people with flexible flatfeet, Desmyttere and colleagues found that adding an anti-pronator component was more effective than increasing orthotic stiffness alone for influencing excessive pronation.

This supports a more precise approach to prescribing: the device needs both an appropriate design and sufficient stiffness for its intended purpose. A hard shell with unsuitable contours or posting is not automatically an effective treatment. (sciencedirect.com)

Why we may recommend rigid or semi-rigid plastic orthotics

In my practice at Family Podiatry Centre, the choice of material follows the clinical assessment and the mechanical change we are trying to achieve. 

Drawing on my podiatry practice since 2001 and experience in footwear design and manufacture, I consider how the orthotic behaves together with the foot and shoe. When sustained mechanical support is required, I may recommend a rigid or semi-rigid plastic shell, such as polypropylene. The intention is to provide a structure that retains the prescribed support under the patient’s loading conditions, with flexibility adjusted to the individual.

My clinical concerns with some softer devices include:
  • Loss of shape: compression can reduce the height or contour of the prescribed support.
  • Footwear fit: some foam constructions occupy more space than is practical inside the patient’s suitable shoes.
  • Insufficient resistance during activity: a device may deform more than intended when walking, running or exercising.

These are observations about particular devices and patients. They should not be interpreted as evidence that every EVA orthotic has these limitations.

Are all EVA orthotics soft?

No. EVA—ethylene-vinyl acetate—is available in different formulations, densities and hardnesses. A soft cushioning layer and a firm structural EVA orthotic can behave very differently. Thickness, contour, construction and support from the footwear also influence the final result.

Paton and colleagues tested orthotic materials for properties including stiffness, durability and compression set—the deformation remaining after compression. They identified particular high-density EVA materials as suitable for motion control. Their findings reinforce why the label “EVA” alone cannot tell us whether a device is appropriate. The properties of the specific material and the finished orthotic need to be considered. (pubmed.ncbi.nlm.nih.gov)

What happens if an orthotic compresses over time?

Some deformation during use is expected and may be part of the design. The concern is whether the device changes enough to compromise its prescribed function. In our clinical reviews, we sometimes find softer devices that have flattened or lost important contours after use. How quickly this happens varies with the material, construction, patient and activity.

It would be inaccurate to give all EVA orthotics the same lifespan. Instead, the device should be reviewed for whether it still provides the support it was prescribed to deliver. An orthotic can remain comfortable even after its shape has changed. Feeling comfortable is therefore one part of the review, alongside its condition and the patient’s symptoms and activity tolerance.

Can a pressure scan tell us which material is needed?

Plantar pressure measurements help us understand where loading occurs beneath the foot. They do not, on their own, determine the required orthotic material. For example, a reading of 300 kPa describes local pressure. It does not establish how much the orthotic’s arch bends, whether a foam has compressed excessively or whether a plastic shell has the appropriate stiffness.

Those questions require consideration of the device’s construction and its behaviour during use. Pressure findings are most useful when interpreted alongside the clinical examination, movement assessment, footwear and response to treatment.

Should an effective orthotic feel uncomfortable?

No. Greater stiffness should have a clinical purpose, and persistent discomfort deserves reassessment.

A supportive shell can be combined with cushioning where appropriate. Equally, a softer device may be suitable when pressure accommodation and comfort are the main treatment objectives. The aim is to find a device that the patient can tolerate and use, while achieving the intended mechanical and clinical result.

For patients whose symptoms return after changing orthotics, we assess whether the replacement provides comparable support, whether footwear or activity has changed, and whether another factor is contributing.

How do we judge whether an orthotic is working?

Initial comfort matters, but it is only one measure. 

We also consider symptoms over time, walking and exercise tolerance, relevant movement or pressure findings, footwear compatibility and whether the orthotic maintains its prescribed shape. A visible change in movement is useful when it relates to the patient’s problem. It is not, by itself, proof of successful treatment. Similarly, these studies do not establish that an orthotic permanently corrects foot structure after it is removed.

When a foot requires mechanical support, the orthotic must have enough structural resistance to deliver it. Choosing the right stiffness, shape and footwear combination is part of the prescription. If your insoles feel comfortable but your symptoms persist—or they have flattened and no longer seem supportive—a clinical review can help establish whether they are still appropriate for your feet and activities.

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Disclaimer: The word "treatment" in this article refers to the care and management of a patient’s health to prevent, cure, or improve a condition. Treatment results vary and do not necessarily indicate a cure. This article is for informational and educational purposes only and does not constitute medical advice.

About the Author

Mark B. Reyneker, BTech (Podiatry), MSc (Palaeontology) is a podiatrist and Founder & Clinical Director of Family Podiatry Centre, with more than 25 years of clinical experience across South Africa, Malaysia and Singapore. His clinical interests include foot and lower-limb pain, gait and biomechanics, sports-related foot conditions, orthotic therapy and footwear.

Alongside his clinical practice, Mark conducts research into human gait and foot biomechanics. His MSc research at the University of the Witwatersrand investigated human propulsion and the structural properties of the metatarsals. He is also the inventor of A Foot Orthotic, an orthotic technology developed through an international patent family.

References

  1. Desmyttere, G., Leteneur, S., Hajizadeh, M., Bleau, J. and Begon, M. (2020) ‘Effect of 3D printed foot orthoses stiffness and design on foot kinematics and plantar pressures in healthy people’, Gait & Posture, 81, pp. 247–253.
    Available article:  https://doi.org/10.1016/j.gaitpost.2020.07.146.

  2. Desmyttere, G., Hajizadeh, M., Bleau, J., Leteneur, S. and Begon, M. (2021) ‘Anti-pronator components are essential to effectively alter lower-limb kinematics and kinetics in individuals with flexible flatfeet’, Clinical Biomechanics, 86, 105390.
    Available article: https://doi.org/10.1016/j.clinbiomech.2021.105390.

  3. Paton, J., Jones, R.B., Stenhouse, E. and Bruce, G. (2007) ‘The physical characteristics of materials used in the manufacture of orthoses for patients with diabetes’, Foot & Ankle International, 28(10), pp. 1057–1063.
    Available article:  https://doi.org/10.3113/FAI.2007.1057.

  4. Tavera Pelaez, A.S., Farahpour, N., Griffiths, I.B. and Moisan, G. (2023) ‘Thick shells and medially wedged posts increase foot orthoses medial longitudinal arch stiffness: an experimental study’, Journal of Foot and Ankle Research, 16, 11.
    Available article: https://doi.org/10.1186/s13047-023-00609-z.

Frequently Asked Questions

Soft insoles can redistribute pressure and may influence foot mechanics, depending on their shape, firmness and construction. However, a device that deforms excessively under load may provide insufficient support for the intended treatment. Cushioning alone does not establish that an insole is improving foot function.

They may be more suitable when treatment requires greater resistance to deformation. Research shows that increasing orthotic stiffness can produce greater changes in certain foot movements. However, the appropriate stiffness depends on the patient, and the orthotic’s shape and posting also influence its effect (Desmyttere et al., 2020; 2021).

Soft materials compress beneath the foot, which can create a pleasant cushioning sensation. That initial comfort is valuable, but it does not tell us whether the device provides sufficient support during prolonged walking or exercise. Both comfort and function should be assessed.

No. EVA is available in different densities and hardnesses. Some EVA materials are primarily used for cushioning, while firmer formulations can provide structural support. The material’s name alone does not establish how the finished orthotic will perform (Paton et al., 2007).

There is no single lifespan that applies to every EVA orthotic. Durability depends on the material, construction, activity and loading. Flattening, loss of support contours or returning symptoms are reasons to have the devices reviewed rather than relying on a fixed replacement schedule.

Yes. A rigid or semi-rigid shell can be combined with a cushioning cover. This allows the supporting structure and the surface beneath the foot to serve different purposes. The combination should suit the patient’s condition, skin sensitivity and footwear.

No. Persistent pain, rubbing, numbness or worsening symptoms should prompt a review. The aim is to provide the prescribed support with acceptable comfort. Greater stiffness is useful only when it serves the treatment objective and the device fits appropriately.

A pressure scan helps identify where loading occurs beneath the foot, but it cannot determine the required material by itself. Even a high local pressure reading does not directly measure how much an orthotic bends or compresses. Material selection also requires clinical assessment, movement analysis and consideration of footwear.

Rigid orthotics can influence loading and movement while they are worn. This does not mean they permanently change foot structure or that their mechanical effects remain after removal. Treatment success is assessed through symptoms, activity tolerance and relevant clinical findings.

Look beyond how they feel during the first few minutes. Useful signs include improved walking or exercise tolerance, reduced symptoms and maintenance of the prescribed support over time. Your podiatrist can assess whether changes in movement or pressure relate to your treatment goals and check whether the devices still fit your footwear properly.

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