Using the Stryd footpod, the zoom fly is consistently showing an elevated "leg stiffness" metric versus 2 other brands I have tested...in theory, that is a good thing...especially keep power that same for those comparison runs. It's more interesting than anything right now.

Any chance more being released next week?

More?

a new batch of 4% flys?. even the Ebay stocks are drying up....

Damn, you were one of the lucky ones! I ordered them the second the Vaporfly 4% came out on that Thursday and was hoping to get them overnight on Friday for a quick little run before Placid on Sunday, well Nike delayed my order and told me they won't get shipped until the 31st. Well i was not going to be in Placid anymore so I asked them to change the shipping address to my home address and was told no worries, then the next day, they just outright cancelled my order and would do nothing for me. They sent me a 20% coupon and told me to reorder them and the only sizes that were left were 4.5, 5, and 5.5. Gee, thanks. I ended up calling a local running store and they had my size and I bought them and can't wait to race in them at Kona!

interesting indeed.
can you also see/graph a change in speed/pace for the same power output?

Based on my testing with Stryd footpod (reviewing shortly), it would be hard to attribute any change in pace/power to the sneakers. The margin of error and the difference in footwear is too small to reliably make such a statement. The leg stiffness was significant enough to attribute to the shoes and consistent enough.

Speaking a bit out of my expertise, since the Leg spring stiffness was higher, it would mean that you should be able to hold a given pace at less effort, so you would be more efficient. This is a relatively new metric so I'm not about to derive any absolute conclusions from it, but I'm confident to say there was a difference using the Nike compared to other shoes at nearly every pace I tested.

I think you did okay without them.

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Dimond Bikes Superfan

Recently grabbed one of the discounted flyknit racer since Nike changed the back of the lunaracer and it is now curving back inside towards the Achilles, which is an issue for me.
I love these shoes and do all my runs in them (I'm barely above 140lbs). Also the elastic upper part of the shoe around the ankle makes it very forgiving for the AT.
They're basically a slightly stiffer lunaracer, so perfect. For me anyway.
Can find them for $100 on RWH.

fascinating
does the causation lie in the shoe or is it a mere correlation, that would be a great question to get answered...
in other words would i see the same leg stiffness improvements because of the shoe or is it your stride that benefits from using the nike?
if the latter and significant, this would be a great protocol to make individual shoe choices at retail.
if its the former, of course great bragging rights for nike.

I just read Phil Knight's book Shoe Dog...I am slowly joining the cult.....

Keeping in mind this wasn't a controlled study, but simply a controlled test by myself keeping as many factors constant as possible, I'm confident to attribute the leg stiffness to the shoe alone based on repeated results and comparisons with 3 different shoes. I was able to keep pace/cadence/power nearly the same over these tests at different speeds and the results were the same...Obviously this is a N=1 and ideally we have better testing equipment (not to take away from the Stryd footpod) but I am satisfied...the question remains is it relevant???

It would be interesting to test versus their model with the carbon insert to see if there is a difference as maybe it is the foam as well, and not the carbon insert...in that case, Adios shoes with their foam may be an equal test.

still your test comparing different shoes does not yet prove that its the shoe in isolation (vs the combination of the shoe and your stride) to cause the benefit.
and yes it would be interesting to test the same set up with several runners and then also add the shoe with the carbon plate and see if its worth its money...
i have a zoom fly coming and will repeat your test. do you plan on getting the 4% when available?

I should have added that my avg. stride for the intervals was nearly identical. As for the 4%, if you are willing to buy them for me, I'll test them right away ; ) otherwise, it may be a bit for I'm ready to drop that type of money for another set of shoes.

haha. ok, i buy yours, if you buy mine...
maybe you are willing to run someone else who has the same size run in your zooms and find out if they can measure the same leg stiffness improvement.
i will do and let you know what i come up with.

I got a pair of the 4% last week in the dark grey. I am happy as I wanted a different looking pair to the Zoom Vaporfly in the light blue. Has anybody removed the glued in insoles for orthotics?. I am a bit scared . a very expensive shoe to make a horrible mistake with. I use the currex sole in neutral.

finally i got around to replicate your test comparing the fly zoom (not 4%) to my hoka clifton3 over a 40' tempo run.
my test seem to confirm your findings as my leg stiffness turns out to be 2% higher then with the cliftons (10 vs 9.8)
now the question is if the delta is relevant enough... but since our "n" now already equals 2 it might be worth pursuing...

I picked up a pair a few weeks ago.

The shoes are terrible. Especially if you are in the male, 50-54 Age Group and race in the mid-west. Actually all of the Zoom Fly's were cursed by a witch and will 1. Cause your feet to fall off and 2. Will give you everlasting impotence.

Again, if you race in the m 50 - 54 age group I WOULD NOT recommend these shoes.

You have been warned!