Description
Formthotics Sport Run Single – Lightweight Running Insole for Runners
The Formthotics Sport Run Single is a lightweight, single-density running insole designed for runners who want structured arch support without adding unnecessary bulk to their shoes.
Its slim profile makes it particularly suitable for low-volume running shoes, race shoes, trail shoes and other footwear where a thicker insole may take up too much internal space — including carbon-plated race shoes, minimalist trainers and tight-fitting road shoes.
Made from thermoformable Formax™ foam in New Zealand, the Run Single can be used straight from the pack or heat-moulded by a podiatrist for a more personalised fit. The closed-cell foam resists moisture and is treated with Ultra-Fresh antimicrobial protection to manage odour over long training blocks.
Key Features
- Single-density Formax™ foam — lightweight with a low-profile fit for tight shoes
- Thermoformable — heat-mouldable in-clinic for a personalised contour
- Deep heel cup — stabilises the heel and improves shock distribution
- Longitudinal, lateral and transverse arch support — the teardrop shape supports all three arch areas
- Ultra-Fresh antimicrobial treatment — helps control odour from training
- Closed-cell foam — won't absorb sweat or moisture, stays light even on wet runs
- Designed to retain ground feel — thin enough to maintain proprioceptive feedback from the running surface
- Available in XXS–XL
- Made in New Zealand
Who Should Consider the Run Single?
The Run Single may be particularly suitable for:
- Road runners wanting lightweight arch support without changing the feel of their shoes
- Trail runners who value ground feel and terrain feedback
- Runners using low-volume shoes, race flats or carbon-plated footwear where internal space is limited
- Athletes who find thicker or dual-density insoles too bulky
- Runners transitioning toward lower-drop or minimalist footwear
- Runners who want a more structured alternative to the standard factory insole
The ideal insole depends on the runner, their footwear, training demands and individual foot mechanics.
Why Choose a Single-Density Running Insole?
The Run Single uses a single layer of Formax™ foam rather than the two-layer construction used in the Run Dual. This allows the insole to remain relatively thin and lightweight while still providing structured support through the arches.
This design can be particularly useful when:
- Your running shoe has limited internal volume
- A thicker replacement insole feels restrictive or changes the stack height
- You prefer more ground feedback and proprioception
- You want support without significantly changing the feel of the shoe
Which Formthotics Running Insole Is Right for Me?
Run Single
Best suited to runners wanting a thin, lightweight insole with structured support and good ground feel. Choose this if your running shoes are tight or low-volume, or you prefer a more direct connection with the ground.
Run Dual
Best suited to runners wanting additional cushioning and a more substantial dual-density construction. Choose this if you want more cushioning and structure than the Run Single provides, particularly for longer-distance running.
ShockStop
Best suited to runners wanting additional shock absorption and cushioning. Choose this if impact cushioning is a higher priority than the lowest possible insole profile.
Sizing
Available in XXS–XL. Trim guides are marked on the insole. Use the manufacturer's sizing chart and compare the insole against your running shoe before trimming. Follow the marked trim lines and ensure the finished insole fits securely without bunching or creating pressure points. See the Formthotics sizing chart to match your shoe size.
Frequently Asked Questions
What are the best insoles for running?
There is no single best running insole for every runner. The appropriate choice depends on your foot mechanics, running style, footwear and the level of support or cushioning you prefer. The Formthotics Sport Run Single is designed for runners who want lightweight, structured support in a relatively low-profile package.
Are these good running insoles for arch support?
The Run Single incorporates longitudinal, lateral and transverse arch support. It may be suitable for runners looking for additional structured support through the arch without using a thick or bulky insole.
What's the difference between the Run Single and the Run Dual?
The Run Single uses a single-density layer of Formax™ foam and has a thinner, lighter profile. The Run Dual uses two foam layers and provides a more substantial construction with additional cushioning and support. Choose the Run Single when low profile and ground feel are priorities. Consider the Run Dual when additional cushioning and structure are more important.
What's the difference between the Run Single and ShockStop?
The Run Single prioritises a lightweight, low-profile design and ground feel. ShockStop is designed with additional cushioning and shock absorption for runners who place a higher priority on impact protection.
Will the Run Single fit tight running shoes?
The Run Single is specifically designed with a relatively low-profile construction, making it suitable for many lower-volume and tighter-fitting running shoes. Always check the available internal space before replacing the original insole.
Can I use the Run Single in carbon-plated running shoes?
The low-profile design can make the Run Single suitable for performance and carbon-plated running shoes where internal space is limited. However, changing the insole can alter the fit and feel of a running shoe, so check the shoe's compatibility and ensure the replacement does not create excessive pressure.
Is the Run Single suitable for trail running?
Yes. The lightweight construction and low-profile design may suit trail runners who value ground feel and terrain feedback while still wanting structured arch support.
Are these suitable for minimalist running shoes?
The Run Single can be suitable for some lower-volume or minimalist-style footwear because of its slim profile. However, adding an orthotic or insole changes the characteristics of the shoe, so runners transitioning toward minimalist footwear should increase training gradually and consider their individual needs.
Can I use the Run Single for plantar fasciitis?
The Run Single provides structured arch support, which may be useful for some runners experiencing plantar heel pain. However, plantar fasciitis can have multiple contributing factors, and an insole should not be considered a guaranteed treatment. If you need maximum shock absorption at the heel, the ShockStop is designed for that. Persistent or significant heel pain should be assessed by a podiatrist.
Do running insoles help with overpronation?
Structured arch support can provide additional guidance for runners who overpronate, but whether this is necessary depends on the individual. Not all pronation requires correction. A podiatrist can assess whether a supportive insole is appropriate for your gait.
Do I need to get these heat-moulded?
No — they work out of the pack. Heat moulding by a podiatrist gives a closer, more customised fit, but it's optional. The foam will also gradually conform to your foot shape with wear.
How long do running insoles last?
With regular use, Formthotics running insoles may last approximately 12–18 months, depending on training volume, body weight, footwear and running conditions. Replace the insole when the foam has compressed and you notice reduced support.