Description
Formthotics Sport Run Single – Lightweight Running Insole for Natural Ground Feel
The Formthotics Sport Run Single is a single-density running insole designed for runners who want arch support and alignment without extra bulk. Its slim, lightweight profile fits inside tighter-fitting running shoes — including race flats, trail shoes and minimalist footwear — where a thicker insole simply won't work.
Made from thermoformable Formax™ foam in New Zealand, the Run Single can be heat-moulded by a podiatrist for a fully custom fit, or worn straight from the pack. The closed-cell foam resists moisture and is treated with Ultra-Fresh antimicrobial protection to manage odour over long training blocks.
What Makes the Run Single Different
Where the Sport Run Dual uses two foam layers for extra cushioning and structure, the Run Single uses a single layer of Formax foam to keep the profile as thin as possible. That means better ground feel and proprioception — useful for trail runners who rely on terrain feedback, or road runners transitioning toward lower-drop shoes. If you need more cushioning and shock absorption for longer distances on hard surfaces, the Sport ShockStop adds a dedicated impact layer at the heel and forefoot.
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 absorption
- 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
Who the Run Single Is For
- Runners wanting arch support in tight-fitting or low-volume shoes
- Trail runners needing ground feel and proprioceptive feedback
- Runners transitioning toward minimalist or lower-drop footwear
- Athletes who find dual-density insoles too thick for their preferred shoes
Sizing
Available in XXS–XL. Trim guides are marked on the insole. See the Formthotics sizing chart to match your shoe size.
Frequently Asked Questions
What's the difference between the Run Single and the Run Dual?
The Run Single is a single-density insole — thinner, lighter, and better suited to tight shoes. The Run Dual adds a second foam layer for more cushioning and motion control. Choose the Single for ground feel and low-volume shoes, or the Dual for extra structure and support on longer runs.
Can I use these for plantar fasciitis?
The Run Single provides arch support that many runners with plantar fasciitis find helpful, but if you need maximum shock absorption at the heel, the ShockStop is purpose-built for that. If your heel pain is persistent, it's worth seeing a podiatrist for a diagnosis alongside using supportive insoles.
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.
Will these fit in carbon-plate race shoes?
Yes — the single-density, low-profile design is specifically suited to shoes with limited internal volume, including race flats and carbon-plate shoes where a thicker insole would change the stack height.
How long do Formthotics insoles last?
With regular use, most runners get 12–18 months from a pair, depending on training volume and body weight. Replace them when the foam has compressed and you notice reduced support.