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 Nike Air Zoom Alphafly NEXT% Review

    The Nike Alpha Fly Next% is finally on the market after some debate on legality for competing. After the sub 2 hour marathon effort from Eliud Kipchoge in the original Alphafly footwear began to go under much more scrutiny. The remaining rules (to my knowledge): a limit of 40mm stack height and 1 plate. This shoe fits the bill and is the new racing shoe seen on the feet of athletes like Eliud Kipchoge, Galen Rupp, and Jakob Ingebrigtsen. Is it worth the hype? Let's take a look. 



Specifications (per Running Warehouse)
Weight: 7.4 oz (Men's size 9)
Measured weight: (Men's size 9.5): 8.1 ounces
Stack Height: 40mm/36mm
Drop:4mm
Classification: Elite Racing Shoe


HIGHLIGHTS

    The Nike Alphafly Next% offers a shoe with elite level cushioning and responsiveness in the same package. The weight does come up a little bit from the Vaporfly Next% but this is a calculated move on Nike's part. The shoe offers more cushioning, a carbon fiber plate known as Flyplate, and 2 Air Zoom pods in the forefoot. The shoe feels very unique and responds well to high force exerted on it. The shoe is definitely a racing shoe worth considering for specific populations. 



FIT

    The Alphafly debuts a new upper that branches from flyknit updated as Atomknit. The knit upper is still incredibly breathable but feels a little more synthetic and less less sock like than the prior knit. The upper is incredibly light and also reinforced really well because of this. The shoe is slightly spacious in the forefoot with width and length but perfect for accommodating swelling over 26.2 miles. The heel is slightly wide but dialed in enough to prevent any slippage or translation. The midfoot is definitely narrow and held in medially. I thought this would irritate me as I ran but I ended up forgetting about it. Overall it's a good fit, but those with wider feet may not agree with the midfoot. The heel is "secure enough" but does have a small amount of translation. Upon donning (putting the shoe on) the shoe feels really snug through the heel collar but once your foot is in the shoe the fit is ok and mimics above. 



RIDE

    The Alphafly has a unique ride. High stack height with high levels of responsiveness. There is a catch to this shoe though. It is very plush and can feel a little mushy if you don't put meaningful force into the shoe. I found at slower speeds it kept me slow, but when I put the shoe to work it responded very well. I do notice the hoof and air pod under the forefoot when running. The shoe almost feels like it wants to respond and propel your leg from hip extension into hip flexion when advancing the limb. The shoe has a "pop" feeling. This is very different from the Endorphin Pro or Speed Elite that have more of rolling sensations. The shoe has a heel flare, though it is beveled really well. The foam is decently stabilized by the bevel and plate. The shoe can feel a little like a clog initially if you aren't used to the hoof or weight distribution anteriorly on the shoe. It took me a second run to really appreciate the ride of the shoe. Overall it is smooth from heel to toe with a sharp bevel and toe spring and propulsive plate and foam. The shoe feels smooth and not as aggressive as the 4mm drop the shoe has. The midfoot can be a little unstable for those who do not have sound mechanics.  


STABILITY

    For so much stack the Alphafly has a decent level of stability. Anytime the shoe is plush with a high platform the shoe is inherently going to be less stable. The weight of the shoe seems to be shifted anterior into the hoof and air pod sections of the shoe which actually makes the unstable heel want to transition into that forefoot quicker and subtly adds some stability. The upper is reinforced well and does not have much stretch allowing the runner to take turns a little harder than in prior models of vaporfly (though this is coupled with the high stack so turns are harder because of the stack as well, so... a wash maybe?). Traction is decent on road and should do just fine in most conditions. It isn't continental but doesn't need to be. The midfoot can be a little unstable for hard heel strikers transitioning over the platform, though Nike did a decent job of quickening the transition with geometry. 


SPEED

    The shoe weighs 7.4 ounces in Men's size 9. It has also been seen on world class athletes from 5k to Marathon. For me, I could see it being a potential race shoe below 10k, and a definite racer for half to full marathon. I took this through a longer tempo and through fartlek work ranging from 4:45 mile pace to 7 minute mile pace. The shoe likes to run fast and be pushed. Ironically for me it feels like a lot of shoe for such a short distance at 5k but definitely doable for those who like more shoe underneath them. It's fast and  wants to be worn fast. The shoe doesn't come alive unless pushed to some capacity though and some may struggle using it. 


DURABILITY

    After wear testing the shoe does have some visible wear, though minimal. I was concerned about durability initially after my first run but after further mileage there is a decent amount of outsole in the forefoot to burn through and just enough in the heel to last you a few marathons. For an elite racing shoe I think the durability is decent. It isn't a tank but it isn't designed to be. 


THOUGHTS AS A DPT 

    Everyone talks about the carbon fiber plates in today's super shoes. Today I actually want to talk about something else. I want to look into the forefoot and toe off transition that is felt so prominently in the Alphafy. The shoe feels like it has a pop through the forefoot and through toe off. The combination is a hoof configuration up front with the actual extended outsole, ZoomX foam in high stack, the Flyplate carbon fiber plate, Air Zoom pods, and a relatively sharp toe spring. This whole concoction of components make for one of the most "poppy" shoes I have ever worn, but does slightly change my mechanics. All of those components make for a fast and propulsive toe off, but what people don't realize is that as you push into the shoe and the shoe responds back, you are moving into terminal stance and end range hip extension in the stance phases of running gait. This shoe has enough pop that I almost feel my leg more forcefully moving into hip extension and then I have to gallop my foot forward in front of me (if I can't keep my own cadence or force output). This is why it is important that the runner is already biomechanically sound and does not lack motion in the sagittal plane. If someone does this could end up resulting in hip flexor or proximal hamstrings type strains down the line, especially with the load from the rocker design shifting force mechanics further up the chain and away from the foot and ankle. The design is fast and responsive but someone who isn't ready for fast might have a hard time with it. 


RECOMMENDATIONS 

    I like that the midfoot is held in this shoe pretty well, but I think the atomknit is reinforced well enough that the Alphafly can widen through the midfoot slightly so that the fit will agree with a much larger population. I think the heel lockdown can be improved a little bit but overall the shoe is very solid. 

WHO THIS SHOE IS FOR (Conclusion)

    The Nike Air Zoom Alphafly Next% is an elite racing flat for runners who are relatively efficient looking to put some pounding to the pavement. For some this may be a 5k racing flat and for others this may be a half to full marathon racer exclusively. This isn't a shoe that will feel the greatest to train in at slower paces and definitely a shoe you want to push for special efforts. It has a high amount of cushion, the highest stack height on the market, and a strong responsive sensation when pushed. 

GRADING

David
Fit                     9.5/10 (Atomknit solid and breathes well, narrow midfoot, mildly spacious through heel)
Ride                  9.75/10 (Highly responsive at fast paces, a bit clunky initially and at slower paces through midfoot to forefoot transition)
Stability            9.25/10 (Stable for a max stack height shoe. A bit unstable platform through midfoot)
Speed                9.75/10 (I have a hard time peaking at sprint speeds, but very fast for other distances)
Durability         9.5/10 (For the top of the line racing shoe, it will last a few marathons, good but not phenomenal durability)

Total Score: 96%

Thanks for reading!

TESTER PROFILES:

Dr. David Salas is a 135 lb male with notable PRs ranging from 3:54 in the 1500m to 1:08:36 for half marathon. He typically runs 40 to 50 miles per week and trains from about 7:30 recovery runs to fast shorter efforts at 4:30 pace. He normally prefers neutral shoes with a firmer ride, but is completely open to other types of shoes.  He is a footwear enthusiast at heart and will always appreciate a high quality shoe when it comes around. For updates on training or testing, IG handle: @docsofrundavid


Editor's Note: As always, the views presented on this website belong to myself or the selected few who contribute to these posts. This website should not and does not serve as a replacement for seeking medical care. If you are currently injured or concerned about an injury, please see your local running physical therapist. If you are in the Los Angeles area, I am currently taking clients for running evaluations.

Matthew Klein, PT DPT OCS FAAOMPT
Doctor of Physical Therapy
Board Certified Orthopedic Clinical Specialist
Fellow of the American Academy of Orthopedic Manual Physical Therapists

Nathan Brown PT DPT MS
Doctor of Physical Therapy 
Masters in Anatomy and Clinical Health Science
Movement Performance Institute Certified in Advanced Functional Biomechanics 

David Salas PT DPT CSCS
Doctor of Physical Therapy
Certified Strength and Conditioning Specialist

***Disclaimer: These shoes were purchased at full retail price from a local running store.  This in no way affected the honesty of this review. We put at least 35-50 miles on trainers and 10-25 miles on racing flats prior to reviewing them. Currently I have 14 miles (David) on my pair. Our views are based on my extensive history in the footwear industry and years testing and developing footwear. If you are a footwear rep looking for footwear reviews or consultations on development, we are currently looking to partner with companies to assist, discuss and promote footwear models. Partnership will not affect the honesty of our reviews.

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