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August 27, 2009

Vibram FiveFingers KSO Review

(Admin note: this is the second of a two-part review of Vibram FiveFingers footwear. If for some reason you missed my very glowing, but admittedly long-winded introduction to the product line, check it out here.)

Among the four versions of FiveFingers currently offered by Vibram, the KSO has become the model of choice among runners seeking the biomechanical, musculoskeletal, and psychological (yes, really) benefits of barefoot running without fear of the various hazards that keep most of us grounded in traditional shoes.

One key to the success of the FiveFingers (often referred to as “VFFs”, or sometimes “Fives”) line – in addition to everything I mentioned in the previous post – is that Vibram does a remarkable job of welcoming customer feedback and incorporating it into updated versions of their product. When early adopters began running in the FiveFingers, they reported that the upper didn’t always feel secure; that led to the strap feature found on the Sprint. When trail runners reported that dirt sometimes slipped into the shoe, Vibram added a thin mesh layer underneath the strap which became the KSO.

(And when KSO users reported that the KSO wasn’t warm enough for extremely cold conditions, Vibram created the Flow – but that doesn’t really pertain to this review. I’ll try to stay focused on just one model from this point on, I promise.)

VFFs are also called "gorilla feet" by users ... for obvious reasons

From a spec standpoint, here’s what you get with the KSO: the upper combines a thin, abrasion-resistant stretch nylon and breathable mesh upper that wraps your forefoot to "Keep Stuff Out." A hook and loop closure sits comfortably above the mesh and helps secure the fit. Underneath, a non-marking 3.5mm performance rubber Vibram outsole is razor-siped for traction – more on that in a bit. The outsole material actually extends around the front of the foot, which is a very cool design feature for improved scuff protection to the tips of your toes. There is a 2mm EVA midsole to provide just a touch of comfort without diminishing the barefoot feel. The entire shoe weighs 5.7oz, which barely seems like anything at all when you’re on the run.

VFFs don't Keep all Stuff Out; your feet will still get dirty through the mesh

The main caveat for first-time users to beware of with FiveFingers is in the sizing. Vibram uses European sizing, but since this is a form-fitting garment, you can’t make a straight conversion from your US shoe size to pick the VFF equivalent. You actually need to measure your foot, and match your foot length with the size chart on Vibram’s website. If you purchase FiveFingers from a store, the salesperson should have a specific Vibram foot ruler to determine your proper size.

My primary aim was to wear the KSOs on trails as much as possible, for a couple of reasons:

1) Although I’m improving my pain tolerance and increasing my duration of barefoot running time on asphalt roads, I still find running trails barefoot to be quite painful. I’m not nearly up to dealing with jagged rocks and knotted roots and pesky thorns quite yet – and whenever I do venture that way, it’s at an absolute snail’s pace.

2) I’m pretty sure I’ve mentioned this once or twice before … but I love trail running. That’s my thing. If being a barefoot runner means I can’t enjoy the trails, I’m having no part of it. Also, given my background in ultras, I’m curious as to whether the VFFs might be a viable option for running super-long distances over the rugged terrain I’m accustomed to seeking out someday.

(And before someone points it out: yes, I’m aware that the super-guru of the barefoot running community just ran the Leadville 100 in VFFs. But he’s Barefoot Ted, and I’m Idiot Donald. There’s a difference.)

So that’s exactly what I started doing. I wore the KSOs on all of my normal trail routes: over big climbs, narrow single track, loose rocks, steep canyons, and brush-covered hillsides. With a few exceptions, the FiveFingers handled all of these conditions quite well.

High above the Salinas Valley; you can barely tell that there's anything on my feet

It only takes a few strides to realize that you have to change your running form while wearing the VFFs; without any cushioning, your heels will get sore in a hurry if you insist on using the same heel striking gait that you do while wearing shoes. Coincidentally, heel pain is one of the most common complaints from beginners wearing FiveFingers.

(For this reason, and several others, many barefoot experts recommend that you don’t try VFFs until you’ve practiced pure barefoot running for a while; having a completely naked foot forces you to use proper form immediately, while VFFs allow you to “cheat” a bit, which could lead to injury.)

Although the outsole provides protection from the trail, you’re still able to feel every bump and contour of the ground underneath your feet. You can tell the size and shape of pebbles you step on, note the relative softness of various types of mud, and feel the change in texture from dirt to leaves to wood chips or anything else you encounter. You can even feel temperature changes from shady areas to exposed sections of trail. Perhaps this new sensory input becomes diminished over a long period of time (it’s a normal accommodation mechanism of your central nervous system, like the way you don’t notice a clock ticking in the background after a while) but I kind of hope that it doesn’t: it’s a very cool awareness that makes you feel more connected to the Earth somehow.

The VFFs are blurry, but the view is great; that dark sliver of land way off in the distance is the Monterey Peninsula stretching into the bay (click to enlarge)

The altered biomechanics and lack of cushioning will definitely slow you down a bit, but not nearly to the degree that running barefoot does. Theoretically, since your feet are lighter than when you’re wearing traditional shoes, you should be able to run faster than usual, but this is definitely a long-term adaptation. After several weeks of using VFFs, I’m able to climb steep hills almost as fast as I can in shoes; on level ground, I’m probably 30-60 seconds per mile slower than normal. It’s on the downhills that I’m still quite slow, attributable to two factors.

Wearing normal footwear, it’s on the down slopes that people place the most impact through their heels – therefore, it’s these sections where the lack of cushioning is most noticeable with the FiveFingers. It requires some major adjustments (and constant reminders) to shift your weight forward and use a midfoot strike on long downhill stretches of trail. I’m normally someone who likes to go “bombs away” down steep hills, so this is an especially challenging change for me to make.

The other limiter on my downhill speed is the traction - or lack thereof - of the outsole. For 90% of my running, the grip is fine, but I’ve noticed that on steep descents - especially if there are loose rocks or gravel to contend with - I experience a lot of slipping from the VFF. Since my standard trail shoes are La Sportivas, whose sticky rubber and angled lugs set the gold standard for traction, the difference is even more noticeable when I wear FiveFingers. It’s probably equivalent to wearing a road running shoe on technical trails: most of the time you can get away with it, but in some situations, you might find yourself in trouble.

Going down this hill was pretty sketchy

(Remember how I said that Vibram applies customer feedback so effectively? The traction issue is supposedly going to be addressed with the upcoming Trek model, designed specifically for trail running with a more grooved outsole and more durable upper. Needless to say, I’ll be VERY interested to check that one out someday.)

The only other drawback worth mentioning is kind of an odd one: many people report that the VFFs stink a lot. Since you don’t wear socks with the VFFs, and since most users don’t rotate pairs like people do with traditional running shoes, the funk potential is pretty high. FiveFingers are built with an antimicrobial footbed, and they are machine washable (but not dryer safe; they need to be air-dried) - but these are people’s feet we’re talking about, so I imagine that the situation could get kind of nasty. I haven’t experienced this phenomenon with my VFF yet, but perhaps I just haven’t used them enough.

I need to work on this pose, or come up with a new one. Is it normal to be unable to raise one foot higher than the other knee?

Honestly though, if a little bit of stink is enough to deter you away from FiveFingers, I feel badly for you. This really is a wonderful product to own, with large benefits for both traditional footwear users and the dedicated barefoot (or “minimalist”) crowd. You need to start slowly, and you need to build up your use of FiveFingers gradually to let your legs and feet adapt to the different demands placed upon them – but once you get to that point, they could provide you with some of the most uniquely enjoyable experiences you’ll ever experience in running.

The Vibram FiveFingers KSO retails for $85 from TravelCountry.com. If you have any interest at all in the barefoot movement, you owe it to yourself to try a pair of Vibrams; it could potentially change everything you know and feel about running.

See other product reviews on sidebar at right. If you have a product you’d like reviewed, contact me at info@runningandrambling.com.

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GRETCHEN 8/27/09, 9:32 PM  

Ooh, you just gave me full license to refer to you as Idiot Donald from here on out. Sweet! (Too bad I'm too nice to take you up on it.)
And yes, you do need to work on your 'Karate Kid' pose there.

Jon (was) in Michigan 8/28/09, 4:22 AM  


I've been wearing KSO's for about 300 miles now. I definitely have to wear the socks, because without them I get blisters like crazy. Wash the socks, and no stink problems. :)

Also, running on surfaces with alot of small rocks is extremely painful for me. I can run on a dirt road, but it has recently been "resurfaced", forget it. You definitely need to be careful of stone bruises in the VFF's.

Love the VFF's though. Nice review, Donald.

shel 8/28/09, 5:09 AM  

nice review Donald, i'm with you on the excitement over the treks. too bad they don't make a women's model, though!
it is so enjoyable to wear these "shoes" and i'm looking forward to many injury free years wearing them :)

Ray,  8/28/09, 7:33 AM  

Great observation about the sensory feedback involved with different types of trails...
Running in the dark one VERY early morning, I realized I had turned down the wrong trail from the feeling of the ground alone. I thought to myself "I did NOT run down a trail THIS soft on the way out!". It was a really cool experience. And it immediately made me realize how much I was missing with mmy normal trail shoes!

Makita 8/28/09, 7:48 AM  

Great review, Donald! I want to buy a pair now - soon, very soon. I agree with Shel, too bad they don't have a woman's version.


Donald 8/28/09, 8:04 AM  

Makita - all of the current VFF models, including the KSO, come in a women's version. Shel is referring to the forthcoming Trek model, which apparently doesn't have a women's model scheduled for release yet. But like I said, the KSOs should be fine for the vast majority of running situations.

Anonymous,  8/28/09, 3:23 PM  

At the opposite end of the spectrum (rigid instead of free like VFF), would you consider reviewing something like SOLE insoles?

smilinggreenmom 8/28/09, 4:22 PM  

This is so cool! Thanks for info :) To Jon (or anyone dealing w blisters or sore feet) I love the Topricin foot cream as it is great for my sore feet, blisters and even inflammation! This is just too cool.

Grellan 8/29/09, 7:31 AM  

Hi Donald. I have used a pair of sprints on and off for the last year and a half and find them great to run in. I agree that downhill running is the most challenging as I'm afraid to release the brakes - because the only way of reapplying them is to use my heels (a big no no). I've never had an odour problem with them (then again it's hardly a problem). I don't do much trail running but have stood on the odd sharp stone which can be painful.

Your intro on the development of the four versions is very like a fastforward version of the development of the shoe itself. First we had animal skins tied around our feet to protect them and keep them warm. then over the millenia we progressed to more durable leather soles for better protection, uppers to KSO and finally thicker cushioned soles for more comfort (I don't know where high heels fit in th grand scheme of things). There is a danger that the process could go full circle.

Womans version???. Have women different feet to men?

Rainmaker 9/6/09, 7:20 PM  

Once again, another awesome review write-up. I hadn't even considered some of the rougher terrain (such as that downhill segment) until you brought it up with that photo.

turkeyssr 9/12/09, 8:07 PM  
This comment has been removed by the author.
turkeyssr 9/12/09, 8:09 PM  

One correction, Donny. I was looking on the website to determine if they work for people that have a Morton's foot. In your article, you mentioned they (Vibram) uses Euro sizing. This isn't correct: Sizing:
I wear US/Euro size “X”; what does that convert to in FiveFingers size?
Because FiveFingers require a precise fit, we do not convert standard US or Euro sizes to our products, although in Euro they may coincidentally be the same. Instead, we measure the foot in inches per the instructions below...
Oh, and they don't guarantee a proper fit for those of us with a Morton's toe. So sad. I suppose should start running barefoot before I worry about that!

pergs77 9/13/09, 11:19 AM  

Hi - great review. I have issues with small or sharp rocks.. I'm hoping my feet get tougher soon! On the treks.. BOYCOTT THEM! They added kangaroo skins to the uppers. Booo! Absolutely no need to kill animals for some protection!! Vibram - we expect more!

Anonymous,  9/15/09, 10:14 PM  

Just got my pair of KSO's in the mail today and fell in love the second I put them on.

Wore them around my college campus, which has the ground covered in pebble-like cement stuff (wish I knew the proper term). While I could feel each bump, it didn't hurt at all.

Decided to go running a little bit later in the day and had a blast. I ran across all kinds of surfaces ranging from grass to roads and had no problems. Nothing hurt.

I was able to correct my heel striking quickly, and flew at a very fast pace up and down hills (I'm a track sprinter).

I dunno if I just have hard feet or what, because no surface I've ran on made me feel any kind of pain. Not even the torn up parts of the road with tons of loose gravel and rocks.

JSL,  9/20/09, 7:23 PM  

I've been running in VFFs for a couple of months now, 1-2 miles after a 5-6 mile run. I find that my fastest miles now are the last 1 or 2 run with the VFFs on!

Jason 9/20/09, 7:59 PM  

Excellent review; look forward to reading a review of the Trek's, if you get the chance.

@pergs: no need to cry boycott. they don't 'kill animals for some protection'; Kangaroo is widely used meat source (no differnt than cattle in the US), so harvesting the skin for use in clothing/shoes creates no additional 'killing'.

That being said, I'm awaiting arrival of some black Trek's this next week. Can't wait to go for a run!

the Dread Pirate Rackham 9/21/09, 8:49 PM  

hi donald,
so glad you've done this review! so much useful info!

well, as I said, I'm waiting for my pair of KSOs eagerly. can you direct me to any source of information that offers a prescriptive progression on how I should go about wearing them and working them into running? my normal shoes contain orthotics - this is a big shift, i expect it'll be slow...


Rana 9/22/09, 8:44 PM  

Womans version???. Have women different feet to men?

On average, women tend to have narrower heels relative to the front of their feet than men do on average.

But those are the averages. Large-footed women and small-footed men would be fine with wearing shoes meant for the other gender, from everything I've read.

Choice of colors may also be a factor. I have to say that some of the women's colors are damn fugly! :P

Anonymous,  10/24/09, 6:40 PM  

very excellent review. I'm still learning a lot about barefoot running though, and you mentioned that wearing VFF's before barefoot running is cheating, im not sure I get why, I thought that it would help train you before barefoot running. Can you direct me to that information please.

I do get that the heel strike is important but after I started wearing the vibrams I noticed i didnt do the normal heel strike at all.

Also, have you tried the sprints. I read this review on sprint and kso's and was wondering what you guys would recommend.

Derrek 10/26/09, 1:24 PM  

Question: I find these shoes intrueging, but if they are so great why is it that no elite level athletes like Dathan Ritzenhein, Kara Goutcher, or Ryan Hall are running in these?

Donald 10/26/09, 8:18 PM  

A couple of interesting comments lately - thanks!

Anon: there's a popular opinion within the barefoot running community that having any protection, even a very thin Vibram, emboldens you to place more impact through your heel, because you diminish the negative feedback (pain) that is quite acute when running barefoot. That's what's meant by "cheating": you can get away with a gait pattern that doesn't completely mimic true barefooting.

Derrek: the footwear of those elite athletes you cite is probably much closer to Vibrams than the traditional shoes most runners wear. Track runners pretty much invented minimalist footwear; when the elites race track 5K or 10K, their "shoes" are little more than a few millimeters of outsole protection (with spikes for traction) with a super lightweight upper. The weight of a racing flat is very close to the 5oz that VFFs weigh. The main difference is the toe structure, of course, but that's probably more a comfort preference than a structural advantage one way or the other.

camper223 10/29/09, 4:11 PM  

Donald thank you so much for your review.
I went with my 2 kids to purchase running shoes and saw a sign for the KSO five fingers and thought they looked awesome.
I finally decided after years of know exercise to start walking so I thought I had bought a good pair of running shoes within my budget.
I'm always bare foot so shoes seem so restricting.
On the first day I wore heavy socks and walked 2 miles (I know but its a start)
The second day I wore thinner socks walked the 2 miles but ended up getting blisters on my forefoot under my toes across the whole pad.
Not wanting to give up on the third day wore heavier socks again.
Changed shoes more blisters.
Today I ended up walking the last 1.5 miles in sock feet.
I have tried adding pads, wearing just shoes no socks,
I realized I must walk more on the front of my foot rather then my heels.
I have fat wide feet so since I only want to walk and eventually someday work up to light running
what are your recommendations?
because of the cost of the 5 fingers would it be worth the investment?
Thank you for all your help, information and your time,

Paul Carter,  12/23/09, 5:50 AM  

Just got a pair of KSOs - they're FINALLY available in South Africa - and had my first run this morning. I can only say "spectacular"! Nervous that I might get blisters, I took them off halfway through my run and changed them for my usual trail shoes: wow, they felt like lead! I think I may be an instant convert ;) Your area looks cool Donald - any time you're in Cape Town you're welcome to run on our beautiful mountain...

gumrol 12/28/09, 2:02 PM  

Hi Paul - I'm also Cape Town based & am keen to know where you got your KSO's. I've only found the classic and sprint so far.

Anonymous,  4/16/10, 3:52 PM  

I doubt that many folks will honestly consider boycotting this shoe due to the use of Kangaroo leather! I would like it a little better if it offered MORE leather protection to my feet!

That said, the size 47 is too small, I really need the 48, and even it might not work for me. I wear a 16-17 in a traditional shoe and have a harder time finding gloves.

Tracy 4/24/10, 2:08 AM  


I've just spent over an hour reading all your minimalist shoe reviews, and they're wonderful. Here's the thing: even before reading this review, I was ready to buy some Vibram KSOs. However, when I read the sizing information prior to purchase, it said that if your second toe is longer than your big toe by more than 1/6, then you probably won't be able to find a suitable size.

My second toe is a good half inch or more longer than my big toe. I never actually thought about it, but that's probably why all my toes curve inward toward my 3rd toe instead of being straight. Shoes aren't made for long second toes. :S

Anyway, it seems the Vibrams are out of the question. Since you've worn so many minimalist shoes, I was wondering what would be your second choice?

I'm primarily a road runner, although the shoulders on these roads tend to be narrow, and I often end up jumping into sharp rocks to avoid being hit by motorists. My current minimalist shoes are... I forget, LOL, Mizunos of some cross country racing variety, which I love, but are way too narrow.

Any suggestions? I'm currently marathon training and use the minimalist shoes on interval days and recovery days.

I also realize this is an old post and you might not reply, but it can't hurt to ask.

Thanks so much.

runnswim 1/15/11, 3:21 PM  

I've been running in KSOs now for 3 months. About 25 6 to 16 mile runs, over dirt trails and asphalt. They are wonderful. I've had no problems with blisters, at all. I wear them barefooted, without socks. Just wear them in the shower with me, once a week, then take them off and rinse them out well and hang them up to dry. I've had chronic knee pain for 30 years, before I switched to the KSOs. Now -- none, nada. It's entirely wonderful. The only problem has been occasionally landing on the balls of my feet on a sharp stone. Definite "ouchy," which makes me tend to look down more than I otherwise would. For this reason, I just bought a pair of Bikilas to use for training on surfaces where sharp stones are a potential problem. The latter shoes have more of a structured, "running-shoe" feel. I'm a bit apprehensive to see if my knee pain comes back, wearing the Bikilas. For an upcoming half-marathon, entirely on asphalt, I'm going to wear the KSOs, which are just a tad lighter in weight (every little bit counts) and which I know won't injure my knees.

- Larry Weisenthal/Huntington Beach, CA

Anonymous,  7/12/11, 6:19 AM  

I know this is an old post, but I love my VFF KSO shoes, but they smell so bad... what can I do... I washed them and let the air dry...Help

Donald 7/13/11, 6:42 PM  

Anon: there'a a whole variety of advice out there - Google search something like "removing Vibram odor" or "cleaning Vibram FiveFingers."

lolamako 11/29/11, 6:56 PM  

Best advice, in regards to the odor issue, that I heard was to smear some deoderant and/or anti perspirant on the bottoms of your feet before you put your Vibrams on. I use a "natural" deoderant, and also put a mix of 1 part tea tree oil to 1 part alcohol (mixed in a bottle with a small nail polish style brush) to each toenail, as a fungus preventative. That being said, both my Bikila's and KSO Trek's fell apart with less than 100 trail miles on them... :(

runnswim 1/30/13, 5:42 PM  

For the odor problem, just soak them in dilute bleach for an hour or so and then rinse well. This will change the mesh from black to gray, but it will keep the shoes odor free for a decent interval, until you need to do it again. I'm still wearing my original KSOs. I have a new pair which I wear to work and also two pairs of Bikilas. I like the KSOs better than the Bikilas, but both are entirely wonderful shoes. They cured my chronic knee pain. The only injuries I've had wearing them were a really bad case of shin splints, caused by very fast downhill running on hard concrete, and a very temporary case of Achilles tendinitis, which resolved with 10 days of pool running and hasn't recurred, and I'm 65 years old a formerly injury prone. - Larry Weisenthal/Huntington Beach CA

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