Arch support insoles — what two million customers found
Arch pain is real.
You're not imagining it.
But it starts somewhere else.
Two million people came to Protalus with different problems — arch pain, knee pain, back pain, fatigue. They got the same answer. Not because they had the same condition. Because they walked on the same floor.
Shop M-100 Landing GearPut them in your shoes. Take a step. Your body will tell you.
95 out of 100 say yes. The other 5 get every cent back.
Or keep reading — the arch is where you feel it, not where it starts.
The arch has almost zero mechanical leverage over your foot's axis.
This isn't an opinion about arch support. It's lever arm geometry — and it's why arch support has never solved the underlying problem for most people.
The subtalar joint — the hinge below your ankle that controls how your entire foot rotates — operates on a specific axis. That axis runs at 42° from horizontal and 16° from the midline of your body. Every structure in your foot, knee, hip, and lower back follows from how that axis is loaded at each step.
Mechanical advantage is determined by distance from the axis of rotation. The further from the axis, the more leverage. The closer, the less. The arch of the foot sits almost directly on the subtalar joint axis. It has nearly zero lever arm. An arch support can push on the arch as hard as it wants — the axis doesn't notice.
The heel, by contrast, sits at a meaningful distance from the subtalar joint axis. A geometry that acts at the heel has real mechanical leverage. That is not a design preference — it's the physics of the structure.
The subtalar joint axis passes almost directly through the arch. Pushing up here has almost no mechanical effect on the axis that controls your gait. Arch support works on the wrong point.
The subtalar joint axis passes well away from the heel contact point. Geometry that acts here has genuine mechanical control over how the axis rotates — which is what changes how your entire body moves above it.
It is an axis problem.
Arch support insoles work at the arch because the arch is where people feel discomfort. That's an understandable design decision. But the discomfort at the arch is a downstream consequence — it's what happens when the subtalar joint axis is never correctly loaded, and the plantar fascia compensates thousands of times a day. Supporting the arch addresses the consequence without touching the cause.
The cause is upstream. It starts at heel strike, before any arch contact occurs. And it starts at the heel — which is where Landing Gear acts.
The arch support category was built on a model that was never proven.
This isn't a new finding. The biomechanics community has been accumulating evidence against the foundational paradigm for decades. In 2023 it became impossible to ignore.
The entire arch support and orthotic industry was built on what biomechanists call the mobile adaptor–rigid lever model. The model describes the foot as a flexible shock absorber at heel strike that becomes a rigid lever at push-off — and prescribes arch support as the mechanism for controlling that transition.
The problem: this model was never experimentally validated. It was a theoretical framework that made intuitive sense and became the design basis for every arch support product on the market — from $15 pharmacy insoles to $400 custom orthotics.
A comprehensive peer-reviewed analysis of the biomechanics literature concluded that the mobile adaptor–rigid lever model is "not supported by available evidence" and called for the scientific community to formally abandon it as the theoretical basis for footwear and orthotic design.
This is not a fringe position. Biological Reviews is published by the Cambridge Philosophical Society — one of the oldest and most respected scientific societies in the world. The review analysed decades of accumulated evidence and found the paradigm contradicted by modern research at every key point.
doi.org/10.1111/brv.12981 ↗What does this mean practically? Every arch support insole — including the best-selling OTC brands and custom orthotics — was designed around a model that has since been shown to be wrong. The arch support itself isn't harmful. But it is solving for the wrong variable, using the wrong mechanism, at the wrong location.
The subtalar joint axis — 42° of obliquity, 16° of medial deviation — was documented in peer-reviewed anatomy literature in 1941 (Manter, The Anatomical Record). It is the actual governing mechanism of human gait. No arch support addresses it. Every arch support ignores it.
If you've tried arch support insoles — including custom orthotics — and they helped but didn't solve the problem, this is the most likely explanation. They were acting on the right system (your foot) at the wrong location (the arch) with the wrong mechanism (shape, not geometry).
If you're here for arch pain, there's a reasonable chance you also have knee pain that comes and goes — or a lower back that stiffens after a few hours on your feet. That's not a coincidence. It's the same kinematic chain. The arch is where you feel it first. The knee and lower back are where it ends up after years of the same misloaded step, thousands of times a day.
"Two million customers. Different problems — feet, back, knees, fatigue. One thing in common: the flat ground we all live on."
Shop M-100 — $64.95 Read their stories →When the axis was used as the design specification, the results were measurable.
BioMechanica LLC, an independent Portland biomechanics laboratory, conducted a controlled 3D motion capture study comparing arch-based insoles against geometry-based Landing Gear. n=31. All differences p << 0.005.
The study measured tibia–heel deviation — how far each subject's gait deviated from the correct subtalar joint axis range during walking. The comparison included standard EVA foam, the market-leading OTC arch support (Superfeet), and both Protalus Landing Gear models. Every subject was measured under all four conditions using 20 NaturalPoint Optitrack cameras at 100fps.
Mean deviation from correct subtalar axis — n=31 subjects
Lower = closer to correct axis range. BioMechanica LLC, 2019. All differences p << 0.005.
| Product | Mean deviation | Visual | vs. standard |
|---|---|---|---|
| Standard EVA foam | 9.2° | Baseline | |
| Superfeet — arch support | 6.8° | −26% | |
| Protalus T-100 Landing Gear | 5.0° | −46% | |
| Protalus M-100 Landing Gear | 3.2° | −65% |
People walking within correct axis range — n=31
How many real people crossed into the mechanical range where the foot can sequence correctly.
"No other OTC insole has demonstrated statistically significant tibia–heel and tibia–arch pronation reduction through 3D motion capture. The geometry-based approach produced results the shape-based approach — including the best-selling arch support — could not."
— Dr. Martyn R. Shorten, Ph.D., Former Director, Nike Sport Research Laboratory · BioMechanica LLC, 2019Arch support is a shape.
Landing Gear is geometry.
These are not the same discipline. Shape describes how something looks at rest. Geometry describes how forces and motion move through space.
Molds, scans, or contours are taken from a static foot. The shape captured at rest is built into the product. But gait is not a static event — it's a sequence of rotations governed by a moving axis.
The geometry was developed by testing against the foot through the full gait cycle — not molded from a static position. The two heel projections create the asymmetric surface the subtalar joint axis requires at each phase of every step.
Arch support engages when the arch contacts it — which is midstance, after heel strike has already determined the starting position of the gait cycle. The decisive moment is already past.
Landing Gear acts the moment the heel contacts the surface — before the foot loads, before the arch engages, before the kinematic chain above begins its sequence. The starting position is set correctly from step one.
Every arch support is symmetric — the same on both sides. The subtalar joint axis deviates 16° toward the body's midline. A symmetric surface cannot guide an asymmetric rotation. The geometry mismatch is structural.
The medial heel projection is higher than the lateral. This mirrors the 16° deviation of the subtalar joint axis — creating the asymmetric contact surface the heel bone needs to initiate correct rotation at landing.
The geometry the arch can't provide
Stop supporting the arch.
Start loading the axis.
9 in 10 people walk within correct mechanical range with M-100 Landing Gear — regardless of starting point. Independent 3D motion capture. 31 subjects. The science is a measurement, not a claim.
Shop M-100 — For arch support Flat feet? Start with T-100 →Put them in your shoes. Take a step. Your body will tell you.
95 out of 100 say yes. The other 5 get every cent back.
Still not convinced?
Not sure if this is right for your situation?
Talk to someone who knows. Protalus Care is available Mon–Fri 6am–5pm PT.