What if the grid-foam-soled shoe, as pioneered by Nike via the “Nike Free x.0,” somehow copulated with a pair of toe shoes?

God forbit it but what would you get? Well, you don’t have to think too hard because Fila has done just that. Allow me to introduce The Skele-Toes Voltage: a four-toed Frankenstein toe-shoe-slash-sneaker-slash-Nike-Free-wannabee. Take that in for a minute. Are you horrified? All your worst nightmares in shoe design made reality? While it’s easy to gasp at the site of these monstrosities — the “marshmallow shoes” we all know as Nike Frees turned into toe shoes — is this yet one more example of Skele-toes “innovating” by mashing together winning concepts from other brands? We’ve certainly seen plenty of Nike-Free-wannabes — Reebok RealFlex being the most popular, but also Skechers GoRun — I’m sure there are others, too. And we all know Fila is being sued by Vibram over intellectual property rights involving toe shoes (See our original Skele-toes review here; the Skele-toes 2.0 review here). Is the Skele-toes Voltage just something to be derided by minimalist footwear and toe shoes fans, alike, for being nothing more than a thick, cushion-y ugly mess? Nope. It’s actually got some redeemable qualities — nay, it may actually be even better than the Nike Free! Read on for a bit of history on the Nike Free marshmallow “barefoot” shoe, grid-soled shoe functionality, and how the Skele-toes Voltage stacks up and actually beats the competition, in many ways. You could call this a case study on marshmallow shoes and toe shoes. Read on after the jump!

A precursor: What of the “barefoot” Nike Free

It’s impossible to talk about the Skele-toes Voltage without first talking about the Nike Free. Basically, the Nike Free line universally (I think) features a cut-up, foamy grid-sole design. It’s as though you took a thick sheet of foam and diced it up into little cubes. The function from this form is that you get a more flexible, dynamic sole — with a lot of cushioning. That plush ride plus the resulting look of the white Nike Free soles leave them looking like you glued a bunch of marshmallows to the bottom of your shoe. That’s why Nike Frees are often called “marshmallow shoes.” Seriously though, the grid-cut, thick foam sole really is an improvement, I think, over the alternative; it really does increase the flexibility of the sole to have lateral and vertical cuts; indeed, it’s one of the reasons toe shoes are more flexible at the front versus regular shoes; more movable parts means a mo dynamic shoe. Long-time readers may know that I’ve yet to review the Nike Frees on BirthdayShoes.com. This is despite the fact that a) there is a huge fan-base of the Nike Free line: people really like their marshamllow shoes! Match that up to b) the fact that Nike markets the Free as being close to barefoot. It’s common knowledge among minimalist footwear enthusiasts that Nike Frees were born out of Nike having studied barefoot running. The Nike Frees were Nike’s first “barefoot shoe.” To wit, Chris McDougall wrote about the birth of the Nike Free in Born to Run. You can read that excerpt below if you’re interested in the history behind the Free (it’s fascinating to me):
Bowerman had died by the time the barefoot uprising was taking hold in 2002, so Nike went back to Bowerman’s old mentor to see if this shoeless stuff really had merit. “Of course!” Arthur Lydiard reportedly snorted. “You support an area, it gets weaker. Use it extensively, it gets stronger. . . . Run barefoot and you don’t have all those troubles.” “Shoes that let your foot function like you’re barefoot—they’re the shoes for me,” Lydiard concluded. Nike followed up that blast with its own hard data. Jeff Pisciotta, the senior researcher at Nike Sports Research Lab, assembled twenty runners on a grassy field and filmed them running barefoot. When he zoomed in, he was startled by what he found: instead of each foot clomping down as it would in a shoe, it behaved like an animal with a mind of its own—stretching, grasping, seeking the ground with splayed toes, gliding in for a landing like a lake-bound swan. “It’s beautiful to watch,” a still spellbound Pisciotta later told me. “That made us start thinking that when you put a shoe on, it starts to take over some of the control.” He immediately deployed his team to gather film of every existing barefoot culture they could find. “We found pockets of people all over the globe who are still running barefoot, and what you find is that during propulsion and landing, they have far more range of motion in the foot and engage more of the toe. Their feet flex, spread, splay, and grip the surface, meaning you have less pronation and more distribution of pressure.” Faced with the almost inescapable conclusion that it had been selling lemons, Nike shifted into make-lemonade mode. Jeff Pisciotta became head of a top-secret and seemingly impossible project: finding a way to make a buck off a naked foot. It took two years of work before Pisciotta was ready to unveil his masterpiece. It was presented to the world in TV ads that showed so many barefoot athletes—Kenyan marathoners padding along a dirt trail, swimmers curling theier toes around a starting block, gymnasts and Brazilian capoeira dancers and rock climbers and wrestlers and karate masters and beach soccer players—that after a while, it was hard to remember who does wear shoes, or why. Flashing over the images were motivational messages: “Your feet are your foundation. Wake them up! Make them strong! Connect with the ground. . . . Natural technology allows natural motion. . . . Power to your feet.” Across the sole of a bare foot is scrawled “Performance Starts Here.” Then comes the grand finale: as “Tiptoe Through the Tulips” crescendos in the background, we cut back to those Kenyans, whose bare feet are now sporting some kind of thin little shoe. It’s the new Nike Free, a swooshed slipper even thinner than the old Cortez. And it’s slogan? “Run Barefoot.”
Millions of people have now bought the Nike Free in some shape or form. You’ll note that the Frees come in varying thicknesses at the soles, which result in their names like the Nike Free 5.0 (photoed above) or the Nike Free 3.0 (these are the two versions I have). The irony of the Nike Free, which is so well known (and bemoaned) by barefoot- or minimalist-running enthusiasts is just how far the Nike Frees are from being barefoot. There is hardly anything “barefoot” about the Frees, even in their most minimally soled iterations. Oh the gnashing of teeth these shoes have caused us! The truth is that Nike Frees have been popular for very good reasons: the cut-up foam sole does do a great deal to decrease the block-like, brick shoe feel of more plush sneakers. People like shoes that don’t utterly rob their feet of their natural function. People like footwear that is comfortable. Like it or lump it, the Nike Frees are comfortable shoes to many, many people. It’s the success of Nike’s Free line that has spawned a slew of copy-cat designs or riffs on the “marshmallow shoe” concept (some of which are noted above). Thus it was only a matter of time before Fila jumped on the bandwagon; they just decided to go the distance and articulate the toes.

Meet the Skele-toes Voltage

Given the Nike Free and a pair of four-toed Skeletoes (this is a pic), it’s incredibly easy to imagine what a toed Nike Free would look like; well, with the Voltage, all the guesswork has been eliminated. Just take a look at the Skele-toes Voltage and you’ll have to agree — it really is the bastard lovechild of the Free and a pair of toe shoes:

How do they work?

If you’ve worn a pair of the Nike Frees, the Voltage doesn’t feel all that different. It’s a plush ride with a notable heel-to-toe differential. The rear thickness of the sole is about 25mm vs. what looks like half that at the forefoot or about 12.5mm (as measured using skinfold calipers; I’ll do some comparisons to other shoes below). 12.5 mm allows for a surprising amount of ground feel at the front of the Voltage; of course, your biomechanics are going to be degraded dramatically by the elevated heel (which is the ultimate downfall of this design). Thanks to the foot-shaped design of the Voltage last, they’re both easy to put on and don’t cramp my toes. The upper of the Voltage is “tongue-less”, too, utilizing a speed-lacing system (like Vibram’s Bikila LS, though the idea didn’t originate with Vibram, it’s still kinda funny). In short, they’re pretty comfortable. Meanwhile, the articulation of the toes actually works to make these shoes more dynamic. This is how they set themselves apart from the Frees and Free-wannabes, after all, but in the case of the Skele-toes Voltage, articulating the toes isn’t just a gimmick to catch the eye; separate toes on a marshmallow shoe make for a more dynamic shoe. And really, that’s sorta interesting, don’t you think? It makes sense and it’s one of the reasons toe shoes work in the first place: adhering the sole to your foot across the toes makes the shoe move more in concert with your foot. It’s really that simple.


I actually like the look of these but the blasted heel lift just takes the completely off the table.
I actually like the look of these but the blasted heel lift just takes the completely off the table.
Ahh … there’s not a ton to say here. My personal feelings are so clouded on the Voltage thanks to my general derision for marshmallow shoes — something I feel not because I find marshmallow shoes to be completely horrible, but because they’re marketed so loudly as “barefoot” when they’re hardly barefoot at all. My gut reaction to the Voltage was … revoltage! I couldn’t help it, sorry. Yet they really aren’t that ugly, if I can set aside my bias. Case in point, my wife actually remarked that they didn’t look that bad, which I had to ask her to repeat a couple times; apparently ,they sorta look like normal sneakers on first glance. Your mileage may vary, but as seen above with jeans they look pretty ok, no? I’ll let you be the judge. Here are some casual photos of me wearing the Skele-toes Voltage. Pay particular attention to the dorsiflexing; that’s some serious toe flex for a pair of marshmallow shoes!

Concluding thoughts

I haven’t spent a lot of time in these shoes. I’ve not run in them. I’ve not walked miles in them. So this “review” can’t go in-depth about their pros and cons. Why? Well, despite my surprised delight in finding toe articulation could make the marshmallow shoe more functional, the elevated heel and major heel-to-toe drop immediately kills my interest in the Skele-toes Voltage. If messes with my natural biomechanics by encouraging me to strike at the heel too soon (my foot catches the ground too early in my stride). Meanwhile, my posture is negatively impacted as my heel elevation changes my balance. Knowing these issues, why would I subject myself to wearing them regularly? I love this site but not gonna do it! There may be a place for transitional footwear as people rehabilitate their feet from years of walking and running in “high-heeled” sneakers and try to move to a more minimally soled, natural and biomechanically neutral shoe (should such a shoe exist); however, over a centimeter in drop as with the Voltage is probably too much. That said, perhaps you could do worse …

Skele-toes Voltage vs. Nike Free 5.0, 3.0 and Reebok RealFlex

From left to right, the Nike Free 3.0, Nike Free Run+ or 5.0, Reebok Realflex, and Fila Skele-toes.
From left to right, the Nike Free 3.0, Nike Free Run+ or 5.0, Reebok Realflex, and Fila Skele-toes.
(How’s that for a segue?) In the event you’re angling for a pair of marshmallow shoes, well, you’ve got some options. I’m going to keep my comparisons of the Skele-toes Voltage to the Nike Free Run+, Nike Free 3.0, and Reebok Realflex, as I have these shoes (and maybe will review them one day — any interest?). Skele-toes Voltage vs. Nike Free Run+ 5.0 The Nike Free Run+ or 5.0 measures about 27mm thick at the heel and about 18mm at the forefoot. The foam rubber sole of the Free Run 5.0 is markedly, incredibly more rigid than the Voltage. It’s also more narrow at the forefoot than the Voltage. The Nike Free Run+ is also not nearly as comfortable worn with bare feet despite using a similar, sock-style upper; it’s too narrow in the forefoot. The Voltage does have a more prominent arch to it, but overall it’s no comparison way more comfortable to wear. Better ground feel and more dynamic flexibility in the toes, which have plenty of room to wiggle. Aesthetically, I like the Frees better. Winner: Skele-toes Voltage. Skele-toes Voltage vs. Nike Free Run 3.0 The Nike Free 3.0 is more flexible bending the shoe vertically than the Skele-toes Voltage but unbelievably stiff to bend laterally (the 5.0 is similarly hard to bend laterally across the forefoot). The Free 3.0s are measuring about 24mm thick at the heel and around 18mm thick at the forefoot, which is the same forefoot measurement as the 5.0s. When I got the 3.0s they were the most minimally thick-soled of the Frees available, but this was a couple years back, so not sure if that is still the case or not. Like their heftier cousins, the 3.0s also aren’t a pleasure to wear on my barefoot and there’s a lot of pressure from the upper against the top of my feet in them. Biomechanically, the 3.0s are definitely better due to a lesser heel-to-toe drop than the Skele-toes. Meanwhile, the Voltage has a roomier toed toe box than the narrow 3.0s. The 3.0s feel better through the arch. Winner: Voltage, barely. Skele-toes Voltage vs. Reebok Realflex I was surprised to find that I really like the Reebok RealFlex upper. It’s pretty comfortable on the sockless foot; yet the Voltage actually is more comfortable. However, style-wise I like the minimal styling of the RealFlex. The sole flexibility of the RealFlex is improved laterally over the Nike Frees, but not quite as good when compared bending from heel-to-toe; overall, the Skele-toes Voltage sole is more flexible. The RealFlex foam rubber is a bit stiffer than the Voltage, too. I could see that being a pro or a con depending on how you look at it. The main drawbacks of the RealFlex are it’s narrow last cramping the toes and it’s fairly thick sole; I’m measuring it at about 33mm thick at the heel and 26mm at the forefoot. The RealFlex simply puts your foot very high off the ground compared to all the other marshmallow shoes listed here; meanwhile, it also has the most narrow sole (see the lead sole comparison photo above); combine the toe and I find the RealFlex unstable — when I pronate just walking around it’s like my foot is suddenly on a lateral seesaw. The first time I tried them on I felt completely unstable. For me, wearing the RealFlex would lead to a rolled ankle in short order. They do have a less pronounced arch; I think they just need to chop off 10mm off their soles (at least). Winner: Skele-toes Voltage. I’ll wrap the comparisons up with two more comments: one; you’d be better served picking up a pair of the original New Balance Minimus or the Merrell Bare Access (or the Altra Instincts!) over any of the above shoes because they’re all neutral from heel-to-toe while still providing some of that crack cushioning that’s so hard to give up. The Minimus Zeros are a better, choice, too. Cushioning needs ignored, why buy a shoe that touts the benefits of barefoot while putting your foot nearly 2cm at best from the ground that puts your heel even higher? All the toe articulation and foam sole slicing in the world won’t fix an inherently non-barefoot design; and yes, marshmallow shoes are better than so many other sneakers sold out there; but they’re still pretty flawed beasts, toe articulation or not. If you’re just itching to get the Voltage, well, the good news is that apparently they’re on a fire sale over at FinishLine for something like $30, which I just about guarantee is less than FinishLine paid for them (and a lot less than the $75 bucks I paid — yes, I paid for these!). Here’s a link to the sale.


If video is your thing, well please excuse the overly rambling long video I made of the Voltage below. It does include some video comparisons; one of which is that the Voltage soles actually allow my toes to dorsiflex easier than the Bikila LS rubber sole (foam easier to bend? foam cuts? Not sure why). Watch it if you dare …

Wow this post is long.

Why did I write such a long-winded post about the Voltage? Mainly because I think it’s fascinating that Fila could actually, unintentionally, create a shoe that is competitive if not better than the types of shoes it’s (effectively) copying (the marshmallow shoes) simply by adding toes. Adding toe articulation to a pair of shoes improves their design. Toe shoes work better.