Nike FlyKnit Trainer Part 2 | Function

Yesterday I broke down the Form of the Nike FlyKnit Trainer in Part 1 of my series Form, Function & Philosophy. Today I am going to discuss the Function of the revolutionary shoe.

As I discussed yesterday this product is a shoe I have been anticipating for a very long time, as I believe it changes how athletic footwear will be designed and manufactured for years to come. But what I want to discuss today is does the Function of the shoe change how I will run for years to come?

First let me start out by saying I run six days a week between 2.5 miles to 6 miles during each run. When I do my 2.5 miles it is a sprint for me while all the other days are a more consistent speed. If my app is correct my average mile is an 8:13. I tell you this to give you an idea of what type of runner I am, which is not a marathoner, not a half-marathoner and maybe a 5ker but definitely an “I want to stay in shape” runner. So if you are looking for a legit runner who probably has been running his whole life and not consistently since he was 22 then you should look elsewhere. With that being said lets discuss the Function of the FlyKnit Trainer.

What I look for in a running shoe is lightweight stability. I am a huge pronator, while at New Balance the biomechanics team there actually shot slow motion video of how bad my pronation was. Literally I was the test example to see if any posted shoe works. I have also dislocated both my knees at separate times in high school sports, so I have that going for me as well. With all of these ailments I absolutely hate and refuse to use an overbuilt and overweight stability shoe for a few reasons. One, they are generally ugly as hell; two, they make me feel old and three; I don’t believe that pronation is a bad thing but that is a whole other conversation.

For the past four months I have been running to much delight in my first generation LunarEclipse. They are quite comfortable and meet all of my stability needs. So switching to the FlyKnit Trainer is huge. It weight’s dramatically less, my LunarEclipse comes in at 12 ounces so the Trainer weights a total 3.6 ounces less or nearly three quarters of the weight of my LunarEclipse, at 8.4 ounces. This feels basically like loosing fifty pounds off my feet, as I barely feel the shoes during my runs.

The upper of the LunarEclipse is minimal for its time. The shoe features Flywire skin and welded synthetics that work in connection with a very large TPU heel counter to provide a secure fit. These features made it one of the lightest stability shoes on the market in 2010. Again though, the FlyKnit Trainer is the exact opposite of this as the only thing it has remotely in common on the upper is the Flywire. Except that the Trainer features the updated “Dynamic Flywire” that isn’t welded between TPU. So basically these two shoes couldn’t be further a part on the comparability scale.

I have run in the Trainers a total of three times now, once for 3.3 miles, once for 3.5 miles and the next for 2.5 miles. I did my running around my neighborhood on a combination of asphalt and concrete sidewalks, no off road running.

Literally the only thing I felt on my foot during my runs in the FlyKnit Trainer is the sole unit under me. The upper was nearly invisible to me by the time I started my third run. The upper felt tight, secure and most importantly lightweight. I was concerned that the knitting might cause for me to roll over the top of the midsole because it might stretch too much but that wasn’t the case at all. I never once felt like I would loose my footing. I should point out though, that my runs have very little sharp turns and is pretty much all straightforward movement. So unless I hit an unexpected undulating surface I rarely have to worry about instability under my foot. I do think if you are a runner that is on a course that has a lot of turns at high speeds it could be an issue of you going over the top of the midsole because there is no stability piece but I think if you were wearing this shoe for that type of running then you are in the wrong shoe.

This shoe was clearly built to be the Trainer to the Racer. Meaning that the FlyKnit Trainer is meant to be the shoe you train in for months to prepare for a race and then you switch to the FlyKnit Racer, that is less in weight; for the big day. Since I didn’t buy the Racer I can’t tell you if there are any major differences in the two shoes but a couple of close friends have informed me that the upper is the same materials but the weave is executed differently which in return provides a completely different fit. From the way they explained it the fit is much more flexible and lighter as opposed to the firm and supportive feel the Trainer provides helping to shed weight from the shoe. Right now the Trainer comes in at a weight that is just a little heavier then typical racing shoes. So Nike has really advanced what Training is going to become. Especially if the future FlyKnit Racer sheds some serious weight, which is possible since most of the weight is in the sole unit.

The only aspect that I would change about the shoe is something that I touched on yesterday and that is making a Lunar version. The Trainer has a forefoot and heel Zoom Air bag in it that feels nice and is responsive. What I would like to see is it become is ground contact Lunar foam with a lower drop from heel to forefoot bringing you just a couple millimeters closer to the ground. This could also give you your more advanced racing version, as I am sure it would be much lighter in weight as well. But more importantly, it would also provide me with a more firm and consistent feel under my foot while still having a high rebound.

Overall I will continue to run in the Trainers on a regular basis. It won’t become an everyday running shoe for me because it doesn’t have the amount of support I need for my ailing knee but it will work great for my 2.5-mile sprints. I think as Nike explores various knit constructions in the future we could get a whole new look as to what a stability shoe could be.

What if they found a way to weave the TPU counter into the knitting process…..wait, wait, wait! You have to come back tomorrow for my Philosophy on the future of FlyKnit!