| Size US |
Internal measure of the shoes (cm) |
Width of the shoe (cm) |
Measure of your longest foot (cm) |
|---|---|---|---|
| 40 | 26 | 10,6 | 25-25,5 |
| 41 | 27 | 10,8 | 25,6-26,5 |
| 42 | 27,5 | 11 | 26,6-27 |
| 43 | 28 | 11,2 | 27,1-27,5 |
| 44 | 29 | 11,4 | 27,6-28,5 |
| 45 | 29,5 | 11,6 | 28,6-29 |
| 46 | 30 | 11,8 | 29,1-29,5 |
| 47 | 31 | 12 | 29,6-30,5 |
Some trails just aren't the same if you can't feel them.
The Vivobarefoot Primus Trail Knit FG Grounding Men's combines the snug fit of its Knit upper with the grip of the Firm Ground outsole. Flexible, breathable and with plenty of room for your feet to move naturally across trails, dirt paths and uneven terrain.
They also feature Grounding technology designed to enable electrical connection with suitable natural surfaces.
It's not just about following the trail. It's about feeling it.
Barefoot trail running shoes to feel every step in nature
Imagine exploring a trail while feeling the ground beneath your feet, with the grip you need to move confidently.
The Vivobarefoot Primus Trail Knit FG Grounding Men's is designed for those who love running in the mountains, exploring new paths or walking through nature without giving up barefoot freedom.
They are an evolution of the well-known Primus Trail Knit FG, but with something that sets them apart: conductive Grounding technology designed to enable electrical connection with certain natural surfaces.
Their construction retains everything that defines Vivobarefoot's minimalist footwear: a wide, foot-shaped fit, zero drop and a flexible sole that allows your feet to adapt to the terrain rather than forcing them to follow the movement of a rigid structure.
But these shoes aren't designed just for walking. Their design combines barefoot ground feel with a lugged outsole prepared for trail running, hiking, fastpacking and functional training.
From running along forest tracks to spending a day exploring trails, the Primus Trail Knit FG Grounding lets you move with agility and feel what's happening beneath your feet. More freedom to move. More grip to explore. And a connection with nature that goes beyond the usual barefoot experience.

Knit fabric: a flexible fit that moves with you
One of the most interesting features of the Primus Trail Knit FG Grounding is its stretchy, breathable Knit upper. Unlike traditional hiking shoes, with rigid structures that restrict movement, this fabric adapts to your feet and allows greater freedom while walking or running.
Its construction features a stretchy sock-like collar that fits around the ankle, providing a snug feel and helping to reduce the entry of small stones, dirt and other debris when you're out on the trails.
This is particularly useful when running along gravel paths, forest tracks or terrain where loose debris can become uncomfortable. The fabric also promotes ventilation, allowing air to circulate around the upper part of your foot during physical activity.
The upper is made with 81% recycled polyester, combined with hotmelt nylon and elastane to create a flexible, adaptable structure.
The quick-lace system allows you to adjust the shoes with a simple movement, without stopping to tie and untie knots. A practical detail whether you're running or hiking in the mountains.
And, of course, the anatomical toe box provides the space your toes need to spread and contribute naturally to every step. Because when the terrain is constantly changing, your feet need to adapt, not be restricted.
Firm Ground outsole: trail grip and barefoot freedom
The outsole is one of the main features that separates urban barefoot shoes from those specifically designed for moving through nature. The Vivobarefoot Primus Trail Knit FG Grounding features the Conductive Firm Ground outsole, combining a flexible 3 mm base with 4 mm deep lugs.
These lugs are designed to provide traction on different surfaces, from compact tracks and dirt trails to rocky terrain and paths with wet sections. The result is a shoe that maintains excellent ground feel while offering a tread pattern better suited to outdoor activities than a purely urban model.
Its flexible structure allows your feet to adapt to uneven surfaces, with your toes contributing to stability on every step. The zero-drop design keeps your heel and forefoot at the same height, respecting the natural position of your foot and encouraging a freer way of walking and running.
That's why they're an interesting choice for anyone looking for barefoot trail running shoes for hiking and outdoor activities without the thick, rigid soles found in many conventional models.
However, it's worth remembering that these aren't waterproof hiking shoes, nor are they designed to provide high levels of cushioning. Their priority is grip, ground feel and freedom of movement.
Grounding technology: a different connection with the earth
The main innovation in this version is its Grounding technology, a conductive construction designed to allow electrical contact between the body and certain natural surfaces. To achieve this, Vivobarefoot incorporates conductive materials into both the outsole and the removable insole.
The Conductive Firm Ground outsole contains conductive components, while the insole incorporates carbon and other materials that form part of this system.
When conductive contact exists between your foot, the footwear and a suitable natural surface, such as soil, grass, sand or rock, these materials allow an electrical connection with the ground.
However, it's important to understand that grounding doesn't automatically work on every surface. Asphalt, for example, doesn't allow this connection under normal conditions. Wearing conventional socks may also interrupt conductive contact, so the technology requires suitable conditions to work.
Research into the potential health benefits of grounding is still limited, so this feature shouldn't be confused with a guarantee of therapeutic effects.
Beyond conductivity, the Primus Trail Knit FG Grounding retains one of the greatest advantages of barefoot footwear: allowing you to feel the surface beneath your feet and adapt your movements to its irregularities.
And this combination of ground feel, grip and conductive technology is precisely what sets this version apart from the conventional Primus Trail Knit FG.
From trail running to hiking: shoes made to keep you moving
The Vivobarefoot Primus Trail Knit FG Grounding isn't designed for just one activity.
It's a versatile option for those who enjoy different ways of moving: running on trails, walking along forest tracks, light hiking, functional training or simply spending time outdoors.
The Knit fabric provides flexibility and breathability, while the quick-lace fastening makes adjustments easier during activity. The Firm Ground outsole completes the design with traction suited to different terrains.
If you already wear barefoot shoes and want something more focused on the trails, you'll find a model that maintains the ground feel you're looking for while adding a tread pattern prepared for natural terrain.
On the other hand, if you're used to hiking shoes with plenty of cushioning, rigid plates or a significant height difference between the heel and toe, it's important to make a gradual transition.
Barefoot footwear requires greater involvement from the muscles, tendons and joints of the feet, especially when running or walking on uneven ground. That's why it's best to start with shorter routes, get used to the new sensations and gradually increase distance and intensity.
The Primus Trail Knit FG Grounding is for those who want their feet to be part of the adventure, not just along for the ride.
Technical features
- Men's barefoot shoes recommended for trail running, hiking, fastpacking and functional training.
- Stretchy, breathable Knit upper made with 81% recycled polyester.
- Stretchy sock-like collar that helps keep dirt and small debris out.
- Wide anatomical fit allowing natural toe movement.
- 3 mm Conductive Firm Ground outsole with 4 mm lugs for varied terrain.
- Zero drop (0 mm), with no raised heel.
- Grounding technology through a conductive outsole and removable insole.
- Quick-lace fastening with an adjustment system.
My size in the Vivobarefoot Primus Trail Knit FG Grounding Men's
To find your size, we recommend measuring your foot and using the link below the size selector. And if you don't get it right the first time, there's always a second chance. Our size exchange system is simple, quick and free if you activate the €1.99 exchange insurance (valid for mainland Spain and the Balearic Islands).
For more information about sizing and fit, check this link.
Care and maintenance of the Vivobarefoot Primus Trail Knit FG Grounding Men's
Materials: as they're made with Knit fabric and a flexible rubber outsole, we recommend removing mud and surface dirt after outdoor activities. Use a soft brush and a slightly damp cloth with mild soap, avoiding excessive scrubbing or harsh cleaning products.
Remove the insole to make cleaning and drying the interior easier. Allow the shoes to dry naturally at room temperature, away from radiators, tumble dryers, direct sunlight and other intense heat sources.
Care products: you can use products specifically designed to clean and protect textile footwear, helping to keep the shoes in good condition and maintain the water-repellent properties applied to the fabric. Remember that this treatment doesn't make the shoes waterproof.
You'll find different options in our barefoot footwear care and maintenance products section. For more information, check our barefoot footwear care and maintenance guide.
Data sheet
- Stack Height WITHOUT insole
- 7 mm
- Drop
- 0 mm
- Weight
- 110 g
- Minimalist Features
- Pura
- Use
- Todoterreno
- Vegan
- Yes
- Water-resistant?
- No
Specific References
- EAN13
- 5057794333260