Barefoot Shoes

Review of Vibram Five Fingers KSO (Keep Stuff Out)

Comprehensive review of the Vibram Five Fingers KSO barefoot shoes — Keep Stuff Out — the do anything, full coverage toe shoes from Vibram, and the most popular men’s model out!

I have been seriously enjoying my KSO Vibram Five Fingers — my second pair. The “KSO” is an acronym that stands for “Keep Stuff Out.” I had previously purchased and reviewed Vibram FiveFinger Classics back in May 2008, and as a result, John from KayakShed had gotten in touch and graciously sent me a pair of the “Taupe/Palm” Vibram Five Fingers KSOs. That color combo is more of a “grey/green” with gray rubber Vibram soles, as you can see here fresh out of the box (For all KSO colors, see the definitive guide to KSO Vibram Five Fingers):

Vibram FiveFingers KSOs out of the box and onto my feet!

Design Differences — The difference between the Five Fingers KSOs and the Five Fingers Classics (Here is a picture of the Classics)is that the KSOs have an ankle-sock-like elastic seal, fully cover the top of the foot (these two work to keep stuff out of the inner parts of the VFFs), and are secured via a velcro strap that tightens over the top of the foot. The strap runs behind the heel, which allows you to tighten up the KSOs at the back of the foot, as well. This design makes for an all around snug (and quite comfortable) fit.

Another point of difference to the Classics is that the Classics use an elastic band/bungee cord that can be cinched and tightened at the heel. On the plus side for the Classsics, this design allows for a minimal amount of foot coverage and makes the Classics the easiest to put on — sort of like the “flip flop” of the Five Fingers line-up. Unfortunately, when cinched, the band on the Classics can put pressure on the front top of the foot, which may be irritating on longer periods of wear (Again see the Classics picture for reference).

The primary drawback to the KSO design, which is unavoidable, is that the covered top forces a smaller entry point for your foot, making navigating toes into toe holes trickier. Having said that, after probably ten “wearings” it became easy to put the KSO Vibram Five Fingers on, and of course, the benefit to having a more cumbersome entry point is that the KSO design affords greater security on the foot. Once your KSO Vibrams are on your foot, they stay on — Keep Stuff Out, Keep Vibrams On!

Some have asked me if the KSOs are hot — they are not. The mesh covering seems to breath well and the regular Five Fingers fabric is ultra-thin.

Functionality — All of the typical FiveFinger benefits you find with the Classics apply to the KSOs and then some. That means you can run, sprint, play, workout, jump, etc., in the KSOs just like the Classics. Like any FiveFingers, KSOs afford the freedom of effectively being barefoot but with the added protection of a thin, non-supportive-but-protective, flexible Vibram rubber sole. Thanks to the more robust velcro-based tightening mechanism, the KSOs inspire confidence — moreso than the Classics when running sprints or dashing up or down stairs. Whereas the Classics sometimes feel like the heel might flip off, the KSOs (and the Sprints for that matter) are completely locked onto your feet.

As for the “Keep Stuff Out” part of the KSOs, they work pretty well—mind, they could have really gotten nasty on the ankle seal by employing a beefier elastic band, something akin to what cycling socks use. However, this would have been overkill for many, considerably less comfortable, and would have impaired the improved stylishness.

Style — Here I model the KSOs, note the turn in the middle (I know, I should be a professional foot model!):

Here I model my KSOs wearing jeans, like you would a normal shoe! And turn ...

Herein lies perhaps one of the greatest benefits of the KSOs over all other varieties of Vibram Five Fingers: they actually look more like normal footwear — particularly when worn with pants. Of course, they are still FiveFingers, which means that everyone will still be staring at your birthday shoes thanks to the articulated toes. But the full-foot covering of the KSOs makes them much more palatable from a style standpoint, and I have frequently worn mine around town. This, in combination with the added security provided by the KSOs, that makes the KSO model the number one selling VFF — particularly for men. And of the color combinations, VFFers everywhere love the KSO Five Fingers in black.

I actually love my Classics and probably get more “wear time” in them than the KSOs due to their ease of entry and overall maximized minimalist feel (See my detailed thoughts on why the Classic Five Fingers are awesome here).

What can you do in KSO Vibram Five Fingers?

Just about anything. KSO Vibram Five Fingers are the “do anything” Vibram model.

Go hiking. Run a marathon or a 10K. Mountain bike or attend a football game. They’re good in the water, too. This hardly scratches the surface of what you can do in KSO Vibrams. For 70+ user-based photo stories, take a look at the comprehensive page dedicated to KSO Five Fingers.

Sizing — Generally, KSOs size one down from Classics and Sprints though in my case, I actually wear the same size across both KSOs and Classics. You might have guessed it, but sizing VFFs is tricky. I recommend consulting the sizing methodology Vibram provides, which is covered in great detail at the birthdayshoes wiki, so make sure you consult it and get the right Five Fingers size! It’s also useful to consult before going into a retailer as often times the employees don’t know the nitty-gritty complexities on sizing VFFs (and there are differences between genders — a M40 isn’t the same as a W40 and women’s sizes, which men can wear and vice versa, generally are slightly more narrow).

Conclusion and Summary — Simply put, the KSOs provide:

  • more versatility than any other VFF. The KSO can do anything the Classic or Sprint can do and much of the same things the Flow can do (it’s just less warm),
  • a solid tightening method via the velcro strap, which both inspires confidence and is comfortable, and
  • the full-foot coverage makes the KSOs more stylish (particularly with pants). This seemingly trivial difference is actually very important because more stylish VFFs make you much more likely to wear your birthday shoes out in the world at large. More wear means freer, stronger, healthier, and happier feet. And that’s the whole point, right?

So even though they are around $10 more than the Classics, I think the KSOs are worth the added expense for most individuals — particularly if you are going for functionality more than comfort. You can get them at KayakShed here.

See our post on “Barefoot Running Shoes” to see where KSOs fall on our Barefoot Running Shoes Continuum.

Questions? Comments? Be sure to leave feedback below!

By Justin

Justin Owings is a deadlifting dad of three, working from Atlanta. When he's not chasing his three kids around, you'll find him trying to understand systems, risk, and human behavior.

20 replies on “Review of Vibram Five Fingers KSO (Keep Stuff Out)”

Good review of the KSO’s. I picked up a a pair yesterday after reading an article about toes which led me to one about how shoes are bad. There was a discussion on slashdot and someone posted about the five fingers. I started reading more about them, more about being barefoot and barefoot running and then decided to buy me a pair of KSO’s (same color as yours!)I’ve only had them a day now, but am liking them very much. Look forward to reading more about my new birthday shoes here on your site.


Glad to hear you’ve picked up some KSOs! I look forward to hearing more after you’ve “broken them in” (I say this tongue-in-cheek because the break-in time on VFFs is effectively *zero*).

I thought that DailyMail article was pretty excellent and blogged on it the other day here. I just wish they hadn’t given Nike an easy out with their Nike Frees.

Speaking of free and feet, feel free to shoot me a photo of you sporting your new kicks and I can throw it up on the photo section!

06 June 2009 I just picked up my first pair of FiveFingers and I went with the Blue KSO’s and they are so comfy!

Once I got them on, yes as everyone says it takes a bit if it’s your not use to toe seperation, I very quickly felt the comfort in my stride walking about the store like I was barefoot but not!

I ripped the tags off the FF’s I was wearing, the very pair/color my wife dared me to come home with! Wore them out of the store and headed home in them driving. Ends up FF’s are pretty comfy for driving too! Before I got home I stopped at the home depot real quick and I made it out alive! People were checking out my FF’s for sure but no riots or violence over my FF’s!

I came home wore them inside and out and back and forth through the moist soggy overgrawn & dog-land-mines lawn and into the shed with no fear!

So it was six hours later I took them off and my feet still feel great! None of my usual aches and pains are brewing in my goes and feet! My feet are happy all around!

These will be my everday relaxing, wash the car, stream exploring, gardening, at the park, frisbee, fishing, boating, downey ayshun hun on da bordwalk, playing and living in shoes!

I think I’ll have to get some FF Flows when the weather gets colder, and keep my feet warm with neoprene and maybe those crazy toe socks too. Maybe a black pair for around the office? Who knows!

Most comfortable ‘shoe’ I’ve ever worn is now the Five Finger KSO! More comfy than my Crocs which surprises me to say and hey are so much more useful at the same time…

Try them you’ll like them!

Thanks for the comparison….i’ve been going back and forth on whether to get the classics or kso’s and your review convinced me that the kso’s are the way to go. Now i just gotta decide between the brown and black ones.

Thanks for your review of the KSOs!

I picked up a pair a few weeks ago and have been running in them constantly. So comfortable and I love the feedback they provide to your feet. Definitely adds a whole new level to running.

Where do I start, I pick up my KSO (Blue) before I want on vacation to Jamaica. I decided to take them off rode you can say. My wife and I did the Dunes River Fall tour. It was quite nice, you go up the fall walking in water. Along the way up there are pools that you can swim in. As you walk you come across rocks that you need to step or climb over. Remember I’m in the water which means things are very slippery. You can point the people out who aren’t wearing any thing because they are the first ones to fall. You know how many times I fell or slipped. None, all thanks to my KSO. What a shoe, it truly is the next thing to being barefoot. They are so comfortable and yes an eye catcher indeed. So what ever your outdoor adventurer is the Vibrim Five Finger KSO is the way to GO.

I received my kso’s today and they are nothing short of amazing. The instructions say to break them in but they really dont need to be, I walked for hours in them at the art festival. The main thing I have to get used to is people stopping me to ask me what kind of shoes they are…

KSOs are lousy for hiking because of their limited traction. They also have lousy traction on wet sidewalks.

But the worst thing is that they DO NOT last. In 6 months at only about 6-7 miles of walking and hiking per week the soles have worn through on both sides right at the ball of the foot.

I have also had lousy luck with the Treksport with the crosses or nubbies peeling off.

Barefooting is great but fivefingers are not durable and are quite expensive. I have hiking shoes with Vibram soles that have lasted forever, so it is quite a disappointment to spend $95 to $115 for fivefingers.

I bought my KSO’s about a week ago after wearing Filas skeletoes for a few weeks. what a difference. I quickly ousted my Filas and have been wearing these everyday since. The best thing about them is the fit, I love how true to my foot they feel, they bend with my foot very naturally. the only thing is my right pinkie toe doesnt quite fill the pocket whereas the left one pretty much does. I’m looking into getting a pair of classics for around the house but I’ve definitely given Vibram my barefoot loyalty.

I love the KSOs, but it seems like Vibram may be phasing them out…any word on if that’s true? I say that just because they seem to have limited size and color availability on their site…

In response to the above comment – I sincerely hope that they are not phasing out the KSO. When my current pair wear out I will definitely wanting another pair. I think if they did phase them out there would be howls of protest from loyal fans.

I have to say my experience is very different to nkvball. I bought my KSOs 2 years ago and they are still going strong. I’ve used them for running, walking, hiking and used them on all surfaces. The only downside is they don’t grip in slippy mud on a hillside, but a greater degree of serration would mean a loss of ground feedback and flexibility. i’d take ground feedback and flexibility anyday. Mine have been incredibly durable and incredibly versatile and utterly life-changing. I no longer suffer terrible foot or knee pain.

i just got my pair of KSO’s today and i need some advice

my feet measure about 9.72 inches and i ordered womans 40 because they were the closest to it, but they feel pretty tight on the front, so i was wondering if thats normal and if they will stretch out after a while or if i should return them and get a pair in male 40


The women’s have a slightly more narrow last for the same length as the men’s — so if your foot is tight on the sides, men’s might work better. IF your toes are ramming the ends of the caps, you might try sizing up.

@Justin Owings

Thanks Justin. Maybe I’ll just look for 2nd hand VFF/KSO sold online and peel the logo off then use it on mine…lol ^_^


When I bought my VFF, the salesman advised me to always buy it 1 size bigger. Because eventually, it will have a tight/snug feeling on the toes when walking. The advice was accurate. I am comfortable with my KSO. ANd besides, you can always adjust and tighten the strap if ever you find it too loose.

So when my dad bought his very 1st KSO Treck last week, he did the same and bought his, 1 size bigger. (Men size)

Hello. Just got my first pair of VFFs, a pair of KSOs bought online on ebay India.
Everything else seems ok and as per description (new item), but I find stitching under all my toes, and part of the upper scrunched up below my toes. It gives me a disconcerted feeling.
I also find glue marks on the outside of some toes.
Have I been saddled with a fake?


Thank you so much for the many many reviews about barefoot shoes and sandals, your site helped me navigating through the dozens of shoes but I feel I finally get closer to the decision.

May I ask which one would you recommend: the KSO or the EL-X?
Everyday use, running, water, dirt, anything else. Which one has the better barefoot experience?
I’ll definitely buy Gladsoles as well but I just love the feel of the separated toe bags. 🙂

Thank you in advance!

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