Vibram Five Fingers KSO Review

Vibam Five Fingers have graced our feet for years now, but one of their first shoes is still going strong today. That shoe is the KSO, which stands for “keep stuff out“, and there’s a long list of good reasons they remain in heavy demand!

Vibram Five Fingers KSO Review
Like a true barefoot shoe, the Vibram KSO is full of functional fundamentals! For instance, the KSO perfectly compliments the natural shape and function of the foot. For instance, the shoes makes your toes fully usable for the benefit of stronger balance while allowing your foot’s muscles to work independently so they develop the strength that maintains.

What is more, the Vibram KSO was voted the most popular and most versatile out of all other Vibram models, and you too can expect great things from the shoe! Here’s why! 

Whats the KSO Good For?

Famous for its foot-shape design, the VIbram KSO is an incredibly lightweight package with near limitless versatility as the shoe isn’t just excellent for running and walking on smooth roads, semi-technical terrain and grass, the shoe is also a solid choice for obstacle course races and  backwoods trail hiking in dry or in wet, humid conditions.

The KSO is also great for Cross-Fit, lifting, kickboxing and karate, high intensity training, rock climbing (works just as well as any climbing shoe), golfing, soccer, whitewater rafting, swimming and for everyday casual use.

Vibram Five Fingers KSO Review
The barely-there feel makes the Vibram KSO an easy choice for long runs and speed work while the strong ground-feel from the super thin sole makes the shoe a terrific alternative to barefoot running!

Sole Specifications

The KSO sits on a zero-drop (completely flat), 3.5 mm thin, smooth rubber sole that supplies the foot with lots of ground-feedback to help you tease out bad mechanics so  you can work towards that more perfect forefoot running form!

Vibram Five Fingers KSO Review
The KSO’s sole is a good balance of stickiness and tread-clutchiness thanks to the strategically placed deep grooves to save weight and stops the tread from picking up mud. This is why the KSO is a wonderful trail shoe for a variety of off-road terrains! The deep grooves also provides extra flexibility, allowing your feet to function almost as if they were barefoot!

The contoured, razor-sipped tread pattern grips decently on wet, muddy surfaces and performs dependably in the dirt. Moreover, despite being remarkably thin and flexible, the KSOs sole  provides enough protection where trail debris doesn’t push into your underfoot.

Vibram Five Fingers KSO Review
The barefoot-feel of the KSOs makes everyday running comfortable and enjoyable!

The sole is what makes the KSO a high performance trainer because its plenty durable for high mileage and fast speed intervals on smoother surfaces, such as the track, grass and soft dirt trails.

The KSO also has a 2-mm EVA insole that provides a moderate layer of comfort and additional protection without taking away from the feel of the ground.

Upper Specifications

The KSO’s upper is a thin, airy, supple build of abrasion-resistant nylon and polyamide fibres that stretches out to adaptively bond to your foot like a sock. The toe sockets are also roomy and fully bend with your toes so the toes can do their part in putting you on stronger footing, especially when zipping over rugged terrain.

Vibram Five Fingers KSO Review
The upper is durable enough to handle harsh, tricky terrain and muddy conditions while the Velcro closure gives a dynamic fit while keeping debris out.

Better yet, Vibram prioritized durability on the KSO’s upper by making it out of  abrasion-resistant material to extend the shoes lifespan. The upper will really hold up for years! This is another reason the KSO is so prized for being a reliable OCR/trail running/hiking shoe.

Vibram Five Fingers KSO Review
Each toe socket on the KSO is capped with a rubberized rock guard that protects your toes from sharp objects on your path, making the shoe a superb choice for mud and trail running. The upper’s material also dries fast and is breathable enough to keep your feet cool in the heat.

The KSO’s upper employs a Velcro single hook and loop closure that’s  easily adjustable and does a great job at  locking the shoe snug onto your foot, so your feet won’t slip around inside. The Velcro straps also locks the shoe better in place onto your foot than regular water shoes.

The KSO’s upper also has a low shaft height, fitting just below the ankle, but higher up the ankle than the Vibram KSO EVO. The KSO’s also has more material density and way better durability than the KSO EVO. Lastly, the KSO is completely machine washable. Just let it air dry.

If you’re interested in the Vibram KSO, you can get them here! BUT, a sizing tip: since the KSO’s fit like a glove, its wise to get the next size up from your regular size.

If you’ve enjoyed my review, you’ll love my reviews on other barefoot shoes that does the necessary job at making you stronger and helping you move better!

If you’d like, you can support Run Forefoot and help keep it going by making a donation in any amount of your choosing:

Or, you can also support Run Forefoot by shopping at the following top minimalist shoes brands, and be sure to bookmark the links:

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Bretta Riches

"I believe the forefoot strike is the engine of endurance running..."

BSc Neurobiology; MSc Biomechanics candidate, ultra minimalist runner & founder of RunForefoot. I was a heel striker, always injured. I was inspired by the great Tirunesh Dibaba to try forefoot running. Now, I'm injury free. This is why I launched Run Forefoot, to advocate the health & performance benefits of forefoot running and to raise awareness on the dangers of heel striking, because the world needs to know.
Bretta Riches

P.S. Don't forget to check out the Run Forefoot Facebook Page, it's a terrific place to ask questions about forefoot running, barefoot running and injury. I'm always happy to help!

1 Comment

  1. Very interesting. First time I’ve heard of this and I thank you. I’d like to learn more. I’ve only been running for 5 years, my feet and especially my heels hurt very often. Also, I experience hip soreness on longer runs. Actually just finished my first marathon and am hoping to better my running technique. Thank you

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