Physical Therapists Using Clinical Analysis To Discuss The Art And Science Behind Running and The Stuff We Put On Our Feet

Post Page Advertisement [Top]


Nike Air Zoom Pegasus 39 Review: Past Meets Present
By Senior Contributor Nathan Brown and Content Manager Bach Pham

The Nike Pegasus line has been in existence for a long time, hence version 39. In a world where even staple models are seeing substantial changes in stack height to meet the maximalist movement, the Pegasus stays consistent while adding a few elements to continue to improve its versatility. The Pegasus 39 drops some weight and changes some of the technology implemented in the shoe. Let's dive in to see how these changes affect the outcome of the shoe. 

Price: $119.95 at Running Warehouse
Weight: 9.5 oz, 269 g (men's size 9), 8.0 oz, 227 g  (women's size 8)
Stack Height: Unknown
Drop: 8mm
Classification: Classic Daily Trainer


Nathan: The Nike Pegasus 39 is a versatile daily trainer that gets a substantial upgrade that helps improve the overall running experience without compromising what people enjoy about previous Peg models. This is a neutral running shoe with a combination of React midsole foam (EVA) and two regions of Zoom Air in the heel and forefoot. The Pegasus 39 continues to run narrow, but does accommodate a bit over time as the upper stretches. 

Few shoes come to mind that have a legacy like the Nike Pegasus series. The Nike Pegasus 39 completes a trilogy of React midsole technology that started with version 37. Keeping many of the improvements seen in the 38, the Peg 39 refines the shoe further by stabilizing the heel with a new geometry and providing a pocket of Zoom Air in the heel for added cushion. The result is something that harks a bit back to the Pegasus 36 in shape and design, with the fun that this React/Zoom Air combo brings to the table.


The Pegasus line has continually fit on the narrow end, but would still be in the "true to size" category for me in my men's size 9. I saw true to size because I would not personally alter up or down a half size to improve my personal fit. The length gives about a thumbs width at the end, and the slightly more narrow construction works well for my foot. Compared to the previous version, the upper is stripped down, which helps it breath a bit more and shaves off a good chunk of weight. That said, it is still on the moderate to thicker end for trainers, which both adds durability and also a little heat retention on hot days. The engineered mesh is only mildly flexible through the toe box, but does seem to stretch out over time, which is nice to create a bit of space for the toes (because the volume of the toe box is quite low). The midfoot is reinforced by Flywire tech, which is a series of straps that go from the eyelets to the platform of the shoe. Overall, the heel is locked in nicely by the lacing system, more narrow fit, and padded/semi-rigid heel counter. Overall it's a comfortable upper that is a crossover between a trainer, due to the thickness, and performance trainer, due to the more snug construction.

Bach: The Nike Pegasus 39 fits true to size for those with medium to narrow feet. The general identity of the shoe fits on the snug side initially, slowly expanding and molding to your feet over time. The result is ultimately a very comfortable fit. Those who have wider feet will likely have to go at least a half size up. The upper also feels very premium compared to prior editions: soft on the inside and breathable on the exterior. It is a touch on the thick side, but despite wearing some thick socks I was able to run in them comfortably on recent super hot, humid days in South Carolina recently with no hotspots or any issues. The shoe sneakily breathes fairly well. I did have to lace lock the shoe to feel dialed in though. My first run with just regular lacing left the shoe feeling a little loose. Lace locking solved the problem and I've had no issues since.

There is a moderately rigid heel counter that I found to be very comfortable and supportive. There is also a minor, but pleasant amount of heel padding in the collar. Finally, the insole is removable.


Full disclosure, I didn't get all the testing in on this shoe that I would have liked. I just got done with my second round of COVID, which has limited some of my distance running that I wanted to test out. That said, I did still get 5 runs in, which included both recovery and tempo paces. I've personally never found the ride of the Pegasus to be anything extremely remarkable -- and that isn't necessarily a bad thing. The foam is moderately soft, but not squishy, there isn't any extreme geometry or rockers, and there is nothing from a structure standpoint that pushes the foot. The result is a consistent trainer that can come along for whatever you want to do that day, making it very versatile. The Pegasus' construction doesn't dictate what type of run you do, unlike shoes like the NB 1080 that shines for easier runs or the Endorphin Speed that functions best a bit faster. Instead, the platform that the Pegasus 39 is built allows you to dip into easier runs while also being able to put a bit of effort in (even more than previous thanks to the drop in weight). The major addition here was the Zoom Air in the heel, which honestly I haven't quite felt at all on the run. I can, however, continue to feel the Zoom Air in the forefoot, but it has not been bothersome, and actually feels like it gives a bit of a pop to push-off. Ultimately, the Pegasus 39 remains rather similar to the 38 (though I'll hit some differences in stability later), but just feels lighter and a bit more versatile.  

Bach: Versatile is the first word that comes to mind with this edition of the Peg. Unlike the Pegasus 37 - the last version I personally spent a lot of time in - the Pegasus 39 feels good at a larger variety of paces, from easy to uptempo. I felt the Pegasus 37 had a bit of a steady, slightly uptempo state it excelled at with little room in-between. Here, I've taken the shoe on everything from easy and recovery runs to uptempo days, and found the Pegasus 39 more than capable and comfortable at the job. I would still reach for a performance trainer for a hard workout, but for newer runners who just wants a neutral runner to get started with, one that can handle a little bit of everything, this is definitely on my shortlist of recommendations.

The ride of the shoe is a combination of moderately soft with the React and Zoom Air and firm with the waffle outside adding some rigidity which feels really good when pushing off. I didn't really notice the Zoom Air in the heel, but I did find the shoe to ride more balanced throughout compared to the Pegasus 37. The shoe feels much more in tune with itself than the past iterations which all felt more bottom heavy, the upper here providing a much better integration with the midsole to help bring unity. The forefoot's flexibility has been opened up a bit further as well which definitely helps make it a little lighter and easier on the landings for those easy day paces. In summary, it's a slightly softer shoe than the past two iterations with a more flexible forefoot and nice, balanced transition. I wouldn't say it excels in any category over any competitor in the market, but it feels really solid and reliable. For those who want a very traditionally built running shoe that's soft-leaning, but not mushy, this checks that box well.

The outsole is classic Pegasus; it performs well on road and light trails admirably and provides excellent grip and durability. Additionally, the shoe feels great for walking - the one time I do feel the air in the heel as I spend more time there.


Nathan: The Pegasus 39 is a neutral shoe that does not have any structure built in for people who may prefer guidance in one direction or another. However, there are a few changes that create a bit more structure than the 38. The main difference is the filling in of the heel with rubber. The groove/crash pad is filled in quite a bit compared to previous, leading to a slightly firmer feel in the heel and less compliance to the foam. This leads to a less wobbly sensation in the heel. The other major difference is some convex shaping on the inside of the midfoot. This also resists compression of the foam in that region, also decreasing the capacity for the shoe to compress more on one side versus another. These changes create a more balanced shoe from inside to outside, but still is firmly in the neutral category. Those who had issues with previous Pegasus models being unstable for them might want to try this one out if you were loving all the other elements of the shoe. 

Bach: The stability in the heel of the Pegasus 39 is greatly improved. New geometry adds a little width to the heel along with a slightly firmed up feeling as Nathan noted. I found this to be much more stable than the 37 from the midfoot back. The shoe doesn't do anything dynamic for stability, but it also isn't unstable either. A full contact outsole along with a crash pad and minor guidance line providing some centering helps give the design some inherent stability. The rigidity of the waffle outsole alone helps provide some minor landing stability, while the reinforced, structured upper holds the foot in nicely. This is still very much a neutral shoe, but deceptively okay as far as stability goes for a neutral trainer. That being said, React itself is still a softer midsole, and those with higher stability needs should check out other shoes like the Nike Structure or other stability footwear first.

Additionally, I found the shoe to do well with lateral movement for some light basketball and other work. The upper's hold does a good job of locking you in for this type of movement.


Reconstructing the Heel of the Peg
By Senior Contributor Nathan Brown

The Pegasus 39 made some subtle changes to the construction of the shoe that really affected how the components of the shoe worked together. One of these subtle changes was what was talked about in the "stability" section about the outsole rubber in the heel. As stated above, the heel is more filled in and covers more of the surface where most people strike the ground. Nike has stated that this new foam is a "softer" material of React. However, the running experience is not only dependent on foam. The interaction of the insole, the foam (or other elements such as Zoom Air), the rubber, and the glue that holds all these things together all change our perception of how soft or firm a shoe is. Therefore, I found the heel of the Pegasus 39 to feel a bit firmer than the 38 despite having a "softer" foam.

It also cannot be overlooked how the midsole is shaped even in areas where the foam is not touching the ground. The Pegasus 39 has a new convexity rib build into the medial aspect of the midfoot. Although this part of the midsole does not contact the ground, it provides more cross-bridges for the foam to "hold on to" as the foam is loaded. This resists compression and can sometimes act as a guidance feature, or at least prevent an unnecessarily unstable surface. Another shoe that utilizes this technique is the NB Rebel V2, which helps take an extremely soft foam and add some structure that makes it work really well for more runners.

The final change for the Pegasus 39 that likely changes the sensation in the heel is the addition of Zoom Air in the rear foot. Although I could not necessarily feel the air pockets, the spanning of air and ability for air to move within the confined area depending on where it is loaded may help "personalize" the landing experience for runners. Additionally, if the chamber holding the air is of a durable material, the landing experience may be more consistent over a longer period of time.


Nathan: I sometimes feel silly offering recommendations for Nike shoes, but here we go. I think the volume of the forefoot could be opened up without compromising the slight performance bend of this shoe. That, or I'd like to see the upper have a bit more stretch through the forefoot. 

Bach: I agree with Nathan. Nike has a history of accommodating narrower feet - a lot of that goes in with their design decisions around the traditionally slim silhouette for the Peg series - but there's no doubt that more width would help accommodate many more runners. I think the upper can be just slightly more breathable as well, along with a very slightly tighter heel to help fully lock the foot down. 

In a more theoretical territory, like every Nike fan I'd like to see some kind of ZoomX implementation. One of the ones that I have been curious about is the new trend of utilizing cores to give that super shoe sensation, but in a more stable package. A ZoomX core to provide that softness and bounce while the React helping to stabilize the shoe? That could be a fun experiment.  


Nathan: The Nike Pegasus 39 is a versatile, neutral, and narrow daily trainer that shaves some weight from its predecessor and will be a hit for those who have loved previous versions. Some of the structure in the heel with increased rubber coverage, a convex rib in the midfoot and the Zoom Air may make this shoe just structured enough for those who found previous versions slightly unstable. The Pegasus 39 maintains much of the character of the 38, but has subtle changes that make it even more approachable and versatile. 

Bach: The Peg is back, and better than well, recent iterations. The 39 brings versatility back to the Pegasus line, along with one of the most balanced designs since the 36. Anyone looking for a do-it-all trainer primarily for everyday training and some moderate workouts, this is a great pickup. For more advanced shoe nerds, the Peg can fill a lot of roles from easy to recovery to steady long runs, but that is where you have to weigh what your preferences for those roles may be. You might want an even more cushioned shoe for those easy to recovery paced runs, or a performance trainer or super shoe for your workouts and long runs. In that case, the Pegasus 39 might not be the shoe that fills that void.

Most of all, the Pegasus 39 is for runners who just want to run in a slightly stabler neutral shoe that is  versatile for everyday activities and sports that involve some lateral motion. The classic continues to be one of the very best for that in the running shoe market.



Fit: A- (Nice lock down, a bit low volume in the forefoot)
A- (Versatile trainer, nice and smooth transitions, a little thick on the upper made it warm on hot days)
Stability: B [Neutral Trainer] (More structure than previous, but still more narrow platform and no stability elements, which isn't a bad thing)
DPT/Footwear Science: A (I appreciate the changes in rubber coverage and shaping of the midsole)
Personal: B+/A- (I have more I want to do in this shoe, I was just limited by COVID. I think a little warm for my taste in the summer and a bit narrow in the midfoot for me to maximize my use)
Overall: A- (Versatile, reliable trainer, but nothing flashy -- which is also okay)
Fit: B+/A- (Really comfortable, true to size fit, but does run more narrow than anything which will be a challenge for wider feet)
Performance: A-
 (Versatile trainer that can hit the mark for a lot of activities)
Stability: B+ (Much improved heel helps balance shoe greatly)
DPT/Footwear Science: A- (Redesigned heel was unexpected for a third iteration of this React edition of the Pegasus, but a welcome one)
Personal: A (Thoroughly enjoyed this Peg and will continue to have it my line up and for everyday activities)
Overall: A- (Versatile, comfortable, and a solid price point. The Peg is back)


*Using the link to purchase helps support Doctors of Running. Thanks so much!

Check out Gear We Love
Ultraspire Fitted Race Belt: The best way to carry your phone and goods on the run. No bounce and various sizes for waist
Skratch Recovery, Coffee Flavor: Mental and physical boost post run. Coffee flavor is excellent and goes great straight into a fresh brewed cup
Feetures Socks: Massively grippy socks that will make you feel more one with the shoe
Huma Chia GelNatural and goes down easy. Powered Contributor Nathan Brown to his marathon
Trigger Point Foam Roller: Help get those knots out post-run and feel better for tomorrow
Theragun Massager: This small version is great on the go for working tired legs
Ciele Hat: Our team's favorite running hat of choice!


Asics EvoRide 3 - 
A superlight workout trainer in the 7 oz range!
Zen Running ZR-01 - A fully sustainable rockered shoe for daily training
Mizuno Wave Horizon 6 - Max cushion meets max stability
Topo Athletic Ultrafly 4 - Low drop, medial posted stability
Saucony Tempus - Superfoamed stability!?

Find all Shoe Reviews at Doctors of Running here.

Thanks for reading!


Facebook: Doctors of Running
Youtube Channel: Doctors of Running
Instagram: @doctorsofrunning
LinkedIn: Doctors of Running
Strava: Doctors of Running
Podcast: Virtual Roundtable
Pinterest: Doctors of Running

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.

***Disclaimer: These shoes were provided free of charge in exchange for a review.  We thank the people at Running Warehouse for sending us a pair.  This in no way affected the honesty of this review. We systematically put each type of shoe through certain runs prior to review. For trainers and performance trainers, we take them on daily runs, workouts, recovery runs and a long run prior to review (often accumulating anywhere from 20-50 miles in the process). For racing flats we ensure that we have completed intervals, a tempo or steady state run as well as a warm-up and cool down in each pair prior to review. This systematic process is to ensure that we have experience with each shoe in a large variety of conditions to provide expansive and thorough reviews for the public and for companies. Our views are based on our 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.

Please feel free to reach out, comment and ask questions!
Contact us at

Mizuno Wave Horizon 6

Bottom Ad [Post Page]

// ]]>