Running With Knitting

What would the perfect running shoe look like for a knitter?

Adidas’ adizero PrimeKnit and Nike’s FlyKnit

It might look very similar to the perfect running shoe for a runner.

As it turns out, runners like their shoes as light weight as possible.  They also like shoes which offer support, comfort, and breathability.  Apparently, some runners would even prefer a running shoe which resembles a sock.

It’s not a huge surprise then, looking at the list of criteria, that two different sportswear manufacturers–Adidas and Nike–would create a running shoe with a knitted upper.  (The upper is the top part of the shoe, everything except the sole and the laces)

Nike did it first.  In February 2012, they introduced the Flyknit, a high performance running shoe with a highly engineered one-piece, seamlessly knitted upper.  The whole shoe only weighs 5.6 oz, and uses knitting techniques like short rows and intarsia to create an upper which has the support needed for running while still being lightweight and form-fitting.

Here’s Nike’s video introducing the shoe:

Very cool, right?

But then there’s Adidas’ shoe: the adizero PrimeKnit.

The PrimeKnit was introduced in July 2012, just a few brief months after the FlyKnit.  It also sports a one-piece seamlessly knitted, light weight upper.  The PrimeKnit is 0.4 oz less than FlyKnit, weighing in at a total of 5.2 oz.  (Just for comparison, the beef patty alone on a quarter-pounder is 4 oz, so there is a very good chance that either of these shoes weigh less than a fast food lunch.  In fact, I’m pretty sure I own pairs of plush socks which weigh more than this.)

The PrimeKnit also gets its very own cool video.  See below:

Small Tangent

Now, I’m not passing any sort of judgement on the shoes, but the Adidas video wows me with its coolness.  Showing me the knitting machines and shoe construction totally played up to my inner knitting-geekiness, especially in contrast to Nike’s animated depiction of knitting which does not happen to resemble the actual knitted process at all.

End Small Tangent

 So What’s The Difference?

Between the shoes?  Beyond the obvious facts that one is Adidas’, one is Nike’s, and the two are competitors, that is what the court is trying to determine.

In September, Nike went to court, filed for and was granted an interim injunction against Adidas for infringement on Nike’s patents for seamlessly knitted shoe uppers, of which they hold several for both flat and circular knitting.  (I know!  I want to see a circularly knitted running shoe too!)

Then about a week ago (October 23), the court decided that the injunction was not sustainable, and that Adidas would again be allowed to produce and sell the PrimeKnit.

Adidas then went a step further, filing for the cancellation of Nike’s patents on the argument that the technology using fused yarn to make shoe uppers has been around since the 1940’s.

So, any actual differences?

Yes and no.  As far as I can tell, both shoes are using roughly the same technology – flat knitting using some kind of manmade fiber which is then “fused” together to help add sturdiness and stability.  They have both been in the design process about four years, inspired by the 2008 Beijing Olympics and released in time for this year’s London Olympics.

There are some significant differences in design:  The FlyKnit includes wires woven into the knitted mesh which wrap around the foot for extra support, while the PrimeKnit stands as is.  The PrimeKnit has a deeper vamp.  The FlyKnit comes up higher on the sides of the foot.

Also, neither design is truly seamless the way I understand hand knitting to be seamless, as in without a single seam.  The FlyKnit has one seam running vertically on the heel attaching the left side of the upper to the right.  The PrimeKnit has one seam running horizontally across the top of the little toes, attaching the toe of the upper to the left side of the upper (on the left shoe, right side of the upper on the right shoe).  Granted, compared to the number of seams usually seen on a pair of sneakers, one seam is certainly a huge improvement.  But IMHO, one seam makes them almost seamless, not seamless.

To me, the placement of the seam is the largest difference between the two shoes from an actual knit standpoint.  For the FlyKnit to have the seam at the heel, one turn needed to be executed at the toe of the knitted fabric.  Technically for the PrimeKnit to have the seam across the toes, there should be two turns in the fabric: one at the toe and one at the heel; this trickiness is avoided by the shape of the shoe and by doing some gentle width increases where the heel is.

Which Shoe?

Eh.  I’m not a runner, so I have no idea which shoe actually functions better.  However I would suspect–given my experience with other high performance shoes–that a final choice boils down to personal preference, combined with what kind of feet a person has.  Some hard data I can offer is that the FlyKnit retails for around $150 online, while the PrimeKnit currently retails for about $350 if you can get your hands on them–so far they’ve only been released in a limited edition for the 2012 London Olympics.

As a knitter, I’m just happy to see knitting treated seriously.  It is not very often that someone tries to push the envelope of what can be done with knitting.  Both of these companies thought outside the shoebox to come up with these designs, and both achieved a lighter, more efficient running shoe. 🙂

Happy Knitting!

More Reading + One Video:

Here is where I’ve been following the story of the dueling knitted shoes.  Help yourself!


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