Subo Flex
A semiflexible hybrid for daily extended comfort — a supportive Subortholene frame with EVA filler, built congruent to the foot for low-impact activity and long days on the feet.
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Built for daily comfort and long days on the feet.
The Subo-Flex is designed for low-impact activities such as walking, and for patients who spend long periods of time on their feet. Its semiflexible Subortholene frame supports while molding to the contours of the foot over time, and an EVA frame filler adds stability and shock absorption — a hybrid of functional correction and cushioned support.
The perfect hybrid. Semiflexible support that molds to the patient's foot over time, with EVA filler calibrated per weight for stability and cushioning — built congruent to the patient's own foot model, not an average.
Work & walking shoes with removable insoles
Fits most work and walking footwear once the factory sock liner is removed — including Strobel or board-lasted shoes with generous midfoot width.
Low-impact, long-duration wear
Designed for walking and standing occupations where patients spend long periods of time on their feet.
Semiflexible support that molds over time
The Subortholene frame provides support while gradually conforming to the contours of the patient's foot.
Functional correction, congruent to the foot.
Built from a positive model of the patient's foot and modifiable at the clinician's discretion — scanned and ordered through FootID Pro.
Shape is everything.
What separates Root from generic insoles is the precise morphological shape captured from the patient's foot — held in the exact clinical position the clinician chose. No averaging. No guesswork.
The Subo Flex is built from a positive model of the patient's foot and can be modified at the practitioner's discretion. This means every device fits the patient it was made for — not an approximation.
Modern Root
Width adjusted considering both borders. Default for all Root models.
Traditional Root
Justified to the lateral border. Used for specific clinical indications at practitioner discretion.
Modern Root shape process
- Forefoot balanced to rearfoot — forefoot-to-rearfoot relationship is optimised as the first step in shape modification.
- Fat pad expanded ~3mm — ensures the device fills the calcaneal contour precisely for the patient's heel.
- Arch lowered ~3mm — creates optimal heel-to-arch-to-met-head geometry. Not applied to foam impressions.
- Width tuned to both borders — medial and lateral widths considered together, giving a foundation that matches the patient's actual foot width.
*Subtalar joint neutral is found by palpating the talus head against the navicular. The neutral position can present many joint-on-joint and bone-on-bone relationships and varies from person to person. An everted or inverted calcaneus may be a neutral position for an individual person. Biomechanical evaluation required.
How you hold the foot is what we build.
Root is not just the orthotic — it's the clinician's positioning, captured and preserved in the device. After scanning, FootID Pro asks the questions no other lab asks.
After every scan, we need to know:
- Was the subtalar joint held in neutral?
- Was the midtarsal joint maximally pronated — loading the 5th metatarsal head?
- Was the midtarsal joint maximally supinated — loading the 1st metatarsal head?
- Was the forefoot brought perpendicular to the rearfoot?
- Was a forefoot-to-rearfoot balance bisection achieved at 90° relative to the calcaneal bisection?
The positioning of those 19 joints in the foot is what gives us the shape.
CAD/CAM fabrication
- Scan or cast captured — clinician captures foot morphology via FootID Pro, holding the subtalar joint in the chosen clinical position.
- Shape modification applied — forefoot balanced to rearfoot, fat pad expanded, arch adjusted using Root's design process.
- Technical staff review — every device reviewed against Traditional Root, Modern Root, Blake Inverted, or Accommodative principles.
- Fabricated to the shape — the polypropylene frame and EVA post are fabricated to match the submitted shape precisely.
See how the scan becomes an order.
Watch Kevin capture a foot, confirm the clinical position, and send a Root order — start to finish.
Variation converted to anatomy-match accuracy by impression & fabrication method
How closely each method preserves the patient’s intended foot shape. Scale: 0–100%, where 100% = optimal congruence.
Plaster bandage is wrapped around the foot in the clinician’s prescribed corrected position, setting into a precise negative of the foot’s contour.
The foot is pressed into a crushable foam box, leaving a negative impression of the plantar surface.
An existing positive model from the patient’s previous orthotics is reused — KevinRoot accepts models from any lab, with frame-contour variance as low as 1%.
A digital scanner such as FootID Pro captures the foot surface as a 3D model.
A fiberglass casting sock is applied over the foot and cures to capture its contour.
Pedobarography captures the patient’s plantar pressure distribution (static or dynamic) at 1:1 scale — used with arch height and shoe size to select a redimold positive model, not to capture true 3D contour.
A direct-molding system using prefabricated, size- and arch-based positive models (33 in total) rather than an individual foot impression.
Heated material is vacuum-pressed over a plaster positive model, drawing it intimately into every contour.
The frame is 3D printed by selective laser sintering (SLS) directly from the CAD-designed digital frame.
A positive model is CNC-milled (CAD/CAM) from an STS, 3D scan, plaster, or foam impression, then the frame is vacuum formed over it.
A CNC machine subtractively mills the frame from a block of polypropylene or EVA per the digital design.
*Redimold has no physical or digital foot impression — patient-foot-to-cast congruent accuracy is unavailable. Variation from positive model to frame is low.
How your patient's foot shape becomes a precision frame.
The journey from clinical capture to finished Subo Flex frame is where Root's expertise lives. Every step preserves the shape and position the clinician chose for that patient.
- Foot impression captured — the clinician captures the foot using their preferred method. How the foot is held directly determines the congruency of the finished device.
- Positive model created — the impression becomes a physical plaster model or a digital CAD/CAM model. Digital models are stored indefinitely for future pairs.
- Root technicians modify the shape — every modification reviewed against the prescription. Rearfoot post, heel cup depth, and cover selection confirmed per patient.
- Subo Flex frame fabricated — the semiflexible Subortholene shell is vacuum formed over the positive model. EVA frame filler, Spenco top cover, Myolite extension, and suede bottom cover are applied, forefoot balanced to rearfoot.
FitFoot360 Foot Model
- Root digital model stored indefinitely → recalled for future pairs
- Root technicians modify the digital shape in real-time: arch, heel, width, postings
- Vacuum formed over CAD/CAM positive model, direct milled or 3D printed Root Frame — replicable, consistent, precise
Real-time control over shape, function, and fit.
FitFoot360 gives Root's technicians complete digital control over every dimension of the orthotic frame — in real time. What once required physical carving and guesswork is now precise, repeatable, and stored permanently for every patient.
Digital positive model
Stored indefinitely. Future pairs, replacements, or modifications can be fabricated from the exact same shape without a new impression.
Real-time shape modification
Root technicians control arch, heel, width, and postings directly in the software.
Every parameter visible
Heel cup depth, frame reinforcement, ray cut-outs, flanges, and more are set per patient, not per template.
Plaster and foam digitisation
Physical models can be digitised for permanent storage. Note: digitising may not perfectly replicate the intimate contours achieved when vacuum forming directly over plaster.
Built to their spec. Built for their foot.
Every parameter of the Subo Flex is set to the individual patient — frame rigidity, rearfoot posting, heel cup depth, and covers are all chosen for that patient's anatomy, weight, and activity demands. Forefoot is balanced to rearfoot and the device is custom congruent to the foot model.
Semiflexible Subortholene shell calibrated to patient weight — supportive yet moldable, conforming to the contours of the foot over time.
Soft EVA frame filler calibrated per patient weight fills the midfoot so the device sits flat and level — adding stability, rigidity, and shock absorption.
Extrinsic EVA rearfoot post congruent to the patient's foot — substantial rearfoot control without a generic wedge that shifts load unpredictably.
Pressed directly from the patient's calcaneus, the heel cup fits their heel precisely — controlling their specific degree of inversion and eversion.
Spenco top cover adds cushioning and moisture control underfoot for all-day comfort on the feet.
Full-length Myolite extension carries a smooth, cushioned surface from heel to toe for a consistent underfoot feel.
Suede bottom cover protects the Subortholene shell and seats cleanly on the shoe's footbed across shoe environments.
The full picture.
Everything you need to prescribe the Subo Flex.
- Midfoot arthritis
- Midfoot joint dysfunction
- Lower extremity pathology
- Poor posture
Recommended for
- Athletic shoes with removable insoles
- Mild biomechanical control
- Strobel or board-lasted shoes with generous midfoot width
The Subo-Flex is a semiflexible hybrid device for daily extended comfort — primarily supportive, with a Subortholene frame that molds to the contours of the patient's foot over time. Designed to fit most work and walking shoes with removable insoles.
EVA frame filler calibrated per weight adds stability, rigidity, and shock absorption, while a rigid to very rigid (60–75 Shore A) EVA extrinsic rearfoot post delivers substantial rearfoot control. Built from a positive model of the patient's foot and modifiable at the clinician's discretion.
- L3000 (UCB)
- L3010 (longitudinal/metatarsal support)
- L3020 (arch support)
- L5000 (filler)
Based on configuration. For reference only. Final coding and billing are the provider's responsibility.
Delivery Time
- Standard: 2 weeks
- Expedited: Available on request
Semiflexible support with substantial rearfoot control.
The Subo-Flex pairs a semiflexible Subortholene frame with a rigid to very rigid (60–75 Shore A) EVA extrinsic rearfoot post — delivering substantial rearfoot control and stability while the frame molds to the foot over time. The deep 12mm heel cup controls inversion and eversion of the calcaneus, stabilizing the foot at the subtalar joint through the gait cycle.
EVA frame filler calibrated per patient weight sits flat and level in the midfoot — adding stability, rigidity, and shock absorption — while a Spenco top cover and Myolite extension keep the device comfortable through long days on the feet.
The right frame
for long days.
Subo Flex sits on the Performance frame profile — a semiflexible platform built
for comfort through low-impact activity and extended time on the feet.
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