The technology inside your shoe

Stability without
stiffness.

Stability shoes make the sole hard so your foot can't roll — and lock it up in the process. FIRMO separates the two: sideways the sole holds, rolling forward it stays free.

How it worksExperience it in the VENTU RUN

FIG. 01 — EXPLODED VIEW · 360°

Patented
FIRMOFLEX®
Force transfer
FIRMOBRIDGE®
Proven
In a production shoe
Available
VENTU RUN
FIG. 02The problem

Why hard shoes make tired feet.

A sole has to do two things at once: keep you stable sideways and let your foot bend freely at push-off. Conventional stability shoes solve this with a stiff plate — it holds, but it blocks exactly the movement your foot needs with every step.

Conventional — stiff plate

Conventional — stiff plate
Sideways
holds
Rolling forward
blocks your foot's bend

FIRMO — flexible struts

FIRMO — flexible struts
Sideways
holds
Rolling forward
bends freely with you
FIG. 03FIRMOFLEX®

firmoflex· patented

Stable across. Free along.

  1. 1

    Struts like small beams

    Struts span the width of the sole and give sideways support — your foot doesn't tip away.

  2. 2

    Gaps for the movement

    Between the struts there is room. As you roll forward, the gaps open and the sole bends freely.

  3. 3

    Shaped after your foot

    The fan follows the natural bend line of your toe joints — the sole flexes exactly where your foot wants to.

FIRMOFLEX strut array: five fanned struts as separate parts, isometric view
X-ray view of the sole from below: the FIRMOFLEX struts sit embedded across the forefoot

Feel the difference.

Sagittal — free

The forefoot hinges in the direction of travel. The gaps between the struts open — nothing resists the bend.

Frontal — held
FOAM

Conventional0° — tilts away

FIRMOFLEX®0° — holds

Same foam · Same weight· Different stiffness per axis

FIG. 04FIRMOBRIDGE®
Underside of the outsole: the force path runs from heel across the FIRMOBRIDGE element into the forefoot without breaking
X-ray view of the sole from below: the FIRMOBRIDGE element spans the midfoot

firmobridge· registered

So no energy gets lost along the way.

  1. 4

    A bridge in the midfoot

    The FIRMOBRIDGE element connects heel and forefoot, so your energy arrives at push-off instead of seeping into the foam.

  2. 5

    Guided roll-through

    The transition from landing to push-off is guided instead of spongy.

FIG. 05Inside the sole

What's inside the sole.

Four layers working as one system — press the button and take it apart.

Exploded view of the four-layer sole assembly
  1. 01

    FIRMOFLEX®

    The strut array in the forefoot.

  2. 02

    Cushioning foam

    Light, comfortable EVA.

  3. 03

    FIRMOBRIDGE®

    The bridge in the midfoot.

  4. 04

    Outsole

    Grippy, abrasion-resistant rubber.

FIG. 06In the shoe

Experience it in the VENTU RUN.

The VENTU RUN is the first shoe with the complete FIRMO system — developed, tested and produced in series. No concept, a shoe you can lace up.

System
FIRMOFLEX® + FIRMOBRIDGE®
Status
In production
Category
Running & everyday
VENTU RUN production shoe, outsole view with visible FIRMOBRIDGE element