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

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Saucony Endorphin Pro Multiple Tester Review
By Chief Editor Matt Klein and Senior Contributors David Salas and Nathan Brown

First seen on the feet of Jared Ward and Parker Stinson and most recently on the feet of Molly Seidel (2nd place at the 2020 US Olympic Marathon Trials), the Saucony Endorphin Pro is finally coming to market. The Endorphin Pro is the racing model of the new Endorphin series including the Speed (lightweight trainer) and Shift (trainer). I was lucky enough to grab a pair early at the US Olympic Trials and was able to put a ton of miles on them while spectating, doing workouts while inspired by the competitors and more.

Saucony Endorphin Pro
(per Saucony)
Currently $99 at Running Warehouse

Weight: 7.5 oz (men's size 9)
Measured Weight Men's Size 10: 8.2 oz
Stack Height: (35.5mm / 27.5 mm)
Drop: 8mm
Classification: Marathon Racing Shoe
Release date: 07/01/2020


Matt: The Saucony Endorphin Pro features a full PWRUN PB midsole, an S-shaped carbon fiber plate and super light upper that create a faster and consistent long distance racer. The new Speed Roll will keep you going and fresh after fast and long miles alike. This is a fantastic and efficient racing shoe that excels at half to full marathon distances.  Coming in at 7.5 oz but riding much lighter, the Saucony Endorphin Pro has one of the smoothest rides out there.

David: The Saucony Endorphin Pro is a marathon designed racing flat that lives up to the hype.  This is the product of a lot of research, testing, and innovation. This all shows in the shoe. The Endorphin Pro is highly plush (PEBA based midsole) without any sinking feeling and also features a S shaped carbon fiber plate that helps with propulsiveness and stabilizing foam. The construction of the Speed Roll design also makes the shoe very fluid with cadence at any foot strike. With the big boom in foams, plates, and big ticket racing shoes, the Saucony Endorphin Pro is definitely worth looking into.

Nathan: The Saucony Endorphin Pro is a top end competitor to be crowned the "best marathon racing flat" that is able to work for a variety of runners. It was constructed using publicly-available research and implements evidence-based strategies for efficiency. The shoe boasts a smooth, fluid, and stable ride that is aided by the PWRRUN PB midsole, a full length carbon plate, and the Speed Roll shape design. One of the smoothest riding shoes out there is now on the market.  

Matt: The Saucony Endorphin Pro fits me true to size in my normal size 10. The upper is very light and comfortable, utilizing a single layer engineered mesh. It easily disappears off the foot when you start running. The mesh is very minimal and breathable, with only mild reinforcements throughout the upper. There is no heel counter, only thicker mesh at the rear of the shoe and the Saucony logo is used at the midfoot for additional lockdown. Combined with the attached tongue, the midfoot is decently secure. The fit overall is normal to even slightly wide. There is plenty of room in the midfoot and forefoot, with the usual slight Saucony taper at the lateral foot.  I had a little pressure on my 5th toe that went away after a few miles.  It should be noted this shoe fits similar to the Kinvara (in my opinion) with the major difference being the Pro having a much lighter and breathable. The tongue is thin but stays in place well. It is connected to the upper and stays in place well. The heel has a surprising amount of room for a racing shoe, so l had to lace lock the shoe as I experienced a little bit of heel slippage.

David: The Saucony Endorphin Pro appears to fit true to size, but does also work for me being a half size up. The toe box is wide when compared to most racing flats, but not overly wide. It is just enough to allow for toe splay and swelling late in the race. The same holds true for the midfoot with security. The hold is lightly snug with just enough to lock-down to not cause any problems and allows for accommodating swelling. The heel is a little more spacious on the sides, but lacing tightly clears this up. The heel counter is very flexible and just provides enough structure to prevent any translation, with the counter tapering off at the calcaneus to prevent irritation on the Achilles tendon. The upper is truly one of the best uppers in the game with breathability and providing just enough structure with only the minimum amount of reinforcement.

Nathan: I've been raving about the fit regarding the Endorphin line, particularly in the forefoot, and the Pro is no exception. There is a high volume toe box that accommodates well, yet the single layer (no-nonsense) mesh upper secures the midfoot extremely well. The heel does not have a rigid counter and is slightly wider (my only complaint about the fit). With lacing it down, I was able to get a solid lock of my heel. The tongue is razor thin, but there is no irritability from the flat, thin laces and the tongue stayed secure since it is attached to the rest of the upper. Breathability of the upper is top notch for race day as well. 


Matt: Smooth is the best word to describe the Endorphin Pro. The PWRUN PB midsole is made of a beaded Peba material that feels cushioned, slightly soft and very responsive. The Speed Roll (toe spring) and plate provide a very nice, responsive and easy toe off. Even during a long 17 mile run spectating the Olympic Trials, my calves did not fatigue or get sore. The Speed Roll creates a very efficient ride and noticeable forward roll that feels very natural. There is a decent heel bevel, so landings at the rear of the shoe are smooth. The midfoot transitions nicely as the full ground contact outsole provides a stable place to roll through. The PWRUN PB midsole is bouncy but on the slightly firmer end for Peba midsoles. It is still soft, but not as much as ZoomX or Floatride Foam. It feels cushioned, smooth and efficient combined with the Speed Roll but bouncy enough to pick up the pace easily. There is plenty of midsole underfoot to provide protection over long miles, however even with the amount of sole, the shoe feels lighter than the listed 7.5 oz. Thanks to the full length use of PWRRUN PB, that responsive, smooth and cushioned ride is consistent across the entire length of the shoe. The Saucony Endorphin Pro, more than any other shoe, has left me feeling fresh the next day no matter how much or how fast I hit the ground. This may be due to the shock absorption of the PWRUN PB combined with the Speed Roll.

David: The ride of the Endorphin Pro is unique even when compared to other PEBA or PEBAX based shoes. The density of the foam appears to be a little higher, providing a plush ride without any sensations of sinking into the foam. There is a S shaped carbon fiber plate running the length of the shoe as well contributing to a more "stable" midsole. The result is a responsive foam with big rebound, fluidity, and dynamic stability upon loading forces. The Speed Roll construction of the Endorphin Pro also makes the shoe very fluid from heel to toe off. The beveled heel is coupled with a toe spring and a wave like construction through the midfoot that makes the shoe feel so smooth at every transition point. The shoe absorbs shock well while still providing a smooth and responsive ride. One thing I appreciated was how well the shoe did with uphill/downhill running and with turns. Uphill the Speed Roll helps keep momentum forward and the firmer foam makes you stay aggressive without sinking. Downhill the midsole is just plush enough to keep you from hitting the plate really hard and having a hard landing and jarring forces up the chain. The great upper and traction in the forefoot helped maintain smoothly through turns.

Nathan: The best word to describe the ride of this shoe is smooth. But there is a bit of "hop" in there as well. The PEBA-based midsole is very bouncy, but also slightly firmer than some other "beaded" midsoles. The creates a very propulsive feel without feeling like you are sinking into the foam at all. What is so beneficial about that in this shoe is that the Speed Roll technology (which includes the toe spring) can really be felt since there isn't an excessive amount of deformation of the foam when you land. That said, given that it is a beaded foam, there is some deformation (cushion/shock absorption) on each step, which makes the 8mm drop feel lower than that. For those who prefer a lower stack for racing, you should be fine here. From heel strike to toe off, there are simply no hitches. Down hill, the heel gives great cushion. Up hill, the toe spring offers extra propulsion. The ride is just as smooth for me at marathon pace as it is at 10K pace.


Matt: The PWRRUN PB sole is slightly firmer than other Peba soles I have tried, which combined with the plate, full ground contact outsole and flared heel provide stability in the heel and forefoot. The bevel at the heel is centrally located but the sole is flared both laterally and medially, which may help center the foot with rearfoot landings. This creates a stable rearfoot for a shoe with this much stack height. There is no form of posting and the midfoot is slightly narrow, however the plate seems to stabilize this a little. The upper is very minimal and does not provide any additional support outside of the logo for lock down. The Speed Roll (toe spring and heel bevel design) also does a great job of keeping forward momentum rather than lateral motion, so those with stability needs may find this shoe works better for them than other peba/carbon fiber plated shoes.

David: For being a high stack and high cushioned racing flat the Saucony Endorphin Pro has a decent amount of stability built into it. The density of the PWRRUN PB is probably the most firm of PEBA based midsoles I have ran in so far, making the shoe plush and bouncy but leaving you with no sensation of sinking into the foam. The shoe is what I would call dynamically stable. Once you put load through the shoe the stability comes alive. There is small sole flaring both medially and laterally easing medial and lateral stabilizing forces that is also joined with the Speed Roll design that keeps your momentum linear. The carbon fiber plate keeps the foam from massive deformation upon loading forces as well. A full contact outsole also helps provide traction and grip on the road. There is some exposed midsole inferior to the calcaneus that could come off slightly as unstable upon landing, but with everything above listed it shouldn't be much of an issue with the plate and Speed Roll assisting.

Nathan: I had a real issue with rearfoot stability in the Endorphin Speed because of the "give" of the PWRRUN PB combined with a high stack. However, none of these issues were present for me in the Pro. The full length carbon plate stabilizes the bouncy PEBA foam in the heel, making it feel much more stable than it's trainer counterpart. In addition, the wider midsole last (compared to other comparable racing flats) and lateral flaring of the sole help make this one of the most stable high stack racing flats available. The appropriate shaping and beveling of the rearfoot also contribute to this stability as there is no excess torque being placed through the ankle at heel strike. Finally, the Speed Roll technology promotes forward progression and really seems to limit lateral movement of the foot. So although this is certainly a neutral racer, it has much to add in the area of stability.


Matt: The Saucony Endorphin Pro is a fun and fast distance racer to run in. It is not the fastest shoe as I personally did not feel like it responded as well as it could at 5k pace. For anything 10k pace and above the Pro really shines. Consistent is the word I would use to describe this shoe. The Endorphin Pro works better for longer repeats, tempo runs, steady states and there is enough cushioning for use as a long run shoe. The cushioning from the PWRRUN PB midsole, the stability from the S plate and the Speed Roll make it very easy to keep the pace consistent. Thanks to the firmer ride, it can handle sprints and faster paces, but again excels more at longer distance events partially thanks to the natural and propulsive toe off from the Speed Roll.

David: The Saucony Endorphin Pro is designed for marathon and long distance efforts. For that purpose it is very fast. The shoe runs much faster that 7.5 ounces and feels so light thanks to the supporting elements built into the shoe. Despite this though, it did feel like just a little too much shoe for 5k, and maybe even 10k efforts. It's doable, but the shoe shines so brightly with longer distances. Pace may be needed to take into consideration though. For me, my 5k pace is something I prefer to hit in spikes or minimally light racing flats, and so the shoe feels a little too cushioned and built up. However on tempo efforts I have done for 3 miles and 13.5 miles the shoe felt amazing. The shoe rides best for me at half marathon and marathon paces, but could be someone someone else's 5k/10k racing shoe as well if they need more cushion for these respective. One thing I like as well the shoe also works at slower paces, so it could easily be warmed up or cooled down in too.

Nathan: Certainly this shoe is smooth and fun, but how fast can it go? When I took it through my testing, I felt best at 10K to marathon paces. Anything lower than that and I felt the 7.5oz on my foot and couldn't find the rhythm as easily. This shoe wants to find a rhythm and stay there, and I found this to be true at my marathon goal pace (7:20-7:30 min/mile) as well as my 10K pace (6:15 min/mile). Those paces really seemed to allow the Speed Roll shaping to play into the stride, where anything faster felt like I was trying to get up onto my toe before the "shoe was ready". Given the smooth nature at marathon pace and even slower, this shoe can handle some long training efforts that have fartlek and recovery components. 


Matt: I have 30 miles on my pair at this time and have not observed any major wear on the outsole or on the upper. I was concerned about durability at both points, but the additional rubber on the outsole has held up well.  There is just the beginning bit of wear at the posterior lateral heel (only on the left side) but overall I expect to get far more miles out of the Endorphin Pro than other peba/carbon racers as it runs similar to a lightweight trainer (+300-400 miles for me). I was initially worried about the upper, but the light reinforcements around the lateral and medial forefoot seem to and will likely hold up well. The midsole and ride have not changed at all with the hard miles I have put on them. The Saucony Endorphin Pro is just as smooth at mile 30 as it was at mile 1. I again expect this to be one of the more durable carbon fiber/Peba shoes on the market.

David: I have Matt's pair. Between both of us I believe the shoe is around 70 to 80 miles of wear. The shoe is still holding up VERY well. The ride has not lost any pop and still feels very fluid with each pace. The plate helps maintain deformation of the PWRRUN PB midsole in the Endorphin Pro very well. The outsole also has minimal wear and has not been broken through yet. Under the heel and calcaneus there is some foam exposure that has taken a good amount of abrasion and mild tearing, but should still hold up very well over time. Besides the exposed heel, everything about this shoe is durable in every aspect of the word.

Nathan: So far so good. I have 20.4 miles on these shoes and there is no wear to the outsole at this point. Despite the relatively minimal rubber coverage, it is positioned very well and the rest of my exposed foam looks good so far as well. The midsole feels great without any signs of flattening (if there were signs of this at 20 miles I'd be concerned), and the firmer nature combined with the carbon plate makes me believe this midsole will handle a lot of miles. Upper is showing no signs of wear so far, but given how thin it is, I could see this being the first thing to go. But again, that is 100% speculation because it looks great so far (and is still clean!).


 One of the challenges for highly cushioned shoes is that the sole is so thick, it is difficult to have enough flexibility allow a normal forward transition.  This is particularly challenging in the forefoot, where most of the sagittal plane (front/back) motion occurs in the foot (ie the toes). Toe spring is something that has been used to combat this, but it is often not done well and feels artificial. Saucony has done a great job creating a very natural toe spring that combined with the plate and Peba midsole have a shoe that although pushes you forward, feels natural and doesn't get in the way. That is no easy feat. I suspect this comes from perfectly situating the toe spring as well as the S-plate being stiff but not aggressive.

The PWRRUN PB midsole is one of my favorite midsole foams. It is light, cushioned, very responsive but not too soft (like ZoomX). This is the first time I have tried it and look forward to trying other Saucony shoes with that material. Although everyone is excited about the S shaped carbon fiber plate in the Endorphin Pro, the research demonstrates that the magic really happens from the midsole foam. Hoogkamer et al (2019) demonstrated that the Peba midsoles have the greatest influence on running economy and is what is most responsible for the +4% improvement seen in the Vaporfly. However, while an improvement is seen from the plates, it is only in the realm of 1% (Roy & Stefanyshn, 2006). So while the plates may help, the majority comes from the special foams. There is further speculation that a majority of the performance enhancements come not from making runners faster, but in helping reduce fatigue via extra shock absorption. Hence why so many people report feeling fresher after running in these types of shoes either after hard workouts or races or at the end of them. This is only further emphasized with the Speed Roll in the Saucony Endorphin Pro, as good toe spring has been demonstrated to decrease load into the ankle and foot, which may decrease lower extremity fatigue (Ogsten, 2019). Research is still coming out on why these types of shoes help, why certain runners respond to them and how to make them better. Just know that there are many components, but at this time, the midsole foam seems to be the most significant influence. So kudos to Saucony on a great foam!


Matt: I have really enjoyed the ride of the Saucony Endorphin Pro and only have a few suggestions. If possible, I would like to see a little more security around the heel, but without the use of a heel counter. There is just a little heel slippage, although lace locking the shoe easily fixes the problem.  I would also suggest beveling the heel just slightly to the lateral side as this is where a majority of people land. I have not tried the Endorphin Speed yet, but since there is only a .5 oz listed different, the Endorphin Pro as the racing shoe could lose a little more weight from the midsole just to differentiate more between the two models.

David: The Endorphin Pro is a phenomenal shoe but there is always room for improvement. I agree with Matt regarding heel security. I am not opposed to perhaps a slightly more snug heel counter while still keeping it very flexible and minimal to avoid irritation. Minor reinforcement in the heel region could potentially also stiffen up the area for security without a counter. I would also like to see the exposed heel outsole covered just a little more on the lateral side to prevent major abrasion to the midsole.

Nathan: My one recommendation here is to snug up the heel a bit. My favorite racing upper and heel counter for security at this point is the Skechers Speed Elite. I'd love to see the continuation of a non-rigid heel, but either make it more narrow or shift the material inside the heel counter to promote better security to the heel with less slippage. 


Matt: The Saucony Endorphin Pro is a smooth, comfortable and consistent long distance racer. There is plenty of PWRRUN PB cushioning for long runs, long workouts and long races. The Speed Roll creates a nice roll forward that will keep you going for miles. The thin and breathable upper creates a very comfortable and slightly wider fit for a distance racing shoe that should accommodate any foot swelling. One of the most unique things about this shoe is that it does leave my legs fresher the next day no matter what the workout. From long hilly runs (watching the Trials) to tempo runs and hill repeats, the Speed Roll, plate and PWRRUN PB foam help create a cushioned, fast and protective distance shoe. For those who want a comfortable, cushioned distance racer for 10k upward, the Saucony Endorphin Pro should be on your list to try.

David: After a long process of development, the Saucony Endorphin Pro comes to fruition in so many right ways. It is the real deal. The PWRRUN PB midsole is plush, responsive, and keeps you fresh for miles. The Speed Roll design makes the cadence of the runner so smooth and fluid. The upper is breathable and provides enough room for swelling accommodation. If someone is looking for a half marathon, marathon, long run, or ultra road shoe this can be a very good option on the market to take a look at.

Nathan: Here we have another marathon racing flat for the masses. The Saucony Endorphin Pro is aggressive enough for the elite while being stable and smooth at slower paces for those looking to continue searching for their next PB in the marathon. This shoe is going to be as durable as you can get for a marathon racer, and could even handle training miles for some. If you want a smooth, responsive, and enjoyable ride for longer races, this is your shoe.


Fit/Upper       9.5 /10 (Very light and comfortable, -.5 for mild heel slippage)
Ride/Midsole  10 /10 (super smooth and consistent)
Stability          9 /10 (Firmer + Speed Roll + Flare helps stability, -1 for narrow midfoot)
Speed              9.5 /10 (Fast and consistent shoe, -.5 for bias toward longer miles)
Durability       9 /10 (Consistent sole, -1 for slight but normal outsole wear)

Fit/Upper       9.75 /10 (Very light, breathable, heel security could be slightly improved)
Ride/Midsole  10 /10 (That's about as good as it gets with LD racing flats)
Stability          9 /10 (Sole flare, plate, firmer PEBA all help give stability to a high stack shoe)
Speed              9.5 /10 (Incredibly fast for long distance miles, but top speeds in 5k/10k harder)
Durability       9.25 /10 (Above average durability for racing flat, normal outsole wear)

Fit/Upper       9.5 /10 (-0.5 for loose heel)
Ride/Midsole  10 /10 (incredibly smooth, consistent, and responsive)
Stability          9.5 /10 (very stable for racing flat with carbon plate giving extra stability)
Speed              9.75 /10 (Smooth and fast for everything but the 5K)
Durability       9.5 /10 (not much wear now, very durable for racing flat)

FINAL GRADE:  95.17 % (94% M, 95% D, N 96.5%)


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The Endorphin Pro 2 is out now! Visit our review of the update here.

Doctors of Running Youtube Review


Dr. Klein is a 140 lb male with notable PRs of 14:45 for 5k, 1:11:11 for the half marathon and 2:32:44 for the full marathon.  He typically runs 70-100 miles per week and trains at a variety of paces from 8min per mile recovery runs to 4:40 per mile 1k repeats.  He prefers firmer and responsive shoes with snug heels and medium to wide toe boxes.  He is particular to less cushioned shoes and close to the ground shoes, but can handle a little cushion when he gets beat up.  IG handle: @kleinrunsdpt

Dr. Nathan Brown is a 155 lb male with notable PRs of 18:18 5K, 39:25 10K, 1:29 half marathon, and 3:54 marathon. He typically runs between 20-40 miles per week at a variety of paces from 8-8:30 min/mile for recovery runs to 6-6:45 min/mile for tempo runs. He typically prefers shoes that provide some cushioning underfoot but still maintain a more firm and responsive feel. Current goals for 2020 are to break the 1.5 hour half marathon (CHECK) and 3:30 marathon. IG handle: @nate.docsofrunning

Dr. Salas is a 135 lb male with notable PRs of 3:54 1500m, 14:56 5k, 31:06 10k, 1:08 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

Thanks for reading!

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.

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 for their full US retail price ($200).  We thank the  people at Big Peach Running Company for helping us a pair early.  This in no way affected the honesty of this review. We put at least 35-75 miles on trainers and 10-25 miles on racing flats prior to reviewing them. Currently I have 30 miles on my pair. My 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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