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Brooks Adrenaline GTS 21 Review

     The Brooks Adrenaline series has been aptly named the "Go To Shoe" (GTS). As one of the top selling shoes in running retail, it has remained a staple stability shoe. Over the last few years as the concept of stability has advanced, the Adrenaline series evolved with it, ditching posts in favor of GuideRails in 2018. While this may have been a shock to many long time Adrenaline wearers, the Adrenaline continues to be one of the (if not the best) best selling stability shoes. This take on stability has continue with continued improves of integration of these GuideRails but now we have a few extra additions on the Adrenaline GTS 21 that are worth checking out. 


Specifications (per Brooks)
Weight: 10.4 oz (men's size 9), 9.1 oz (women's size 7)
Stack Height: Not Provided
Drop: 12mm
Classification: Moderate Stability Shoe


Matt: The Brooks Adrenaline GTS 21 continues as a staple stability shoe with a new DNA Loft midsole and an updated adaptable engineered mesh. While the updates are primary refinements, the GTS 21 now features an even smoother ride and more upper security while still being adaptable. The GuideRails continue to provide versatile stability and the "Go To Shoe" continues to live up to its name.


Matt: The Brooks Adrenaline GTS 21 fits fairly true to size in my normal men's size 10. Previous versions of the Adrenaline GTS have fit me slightly short, but was manageable. The Adrenaline 21 has a tiny bit of extra room up front and fits far more true to size. The fit is secure and slightly snug throughout the length of the shoe. The heel is very locked in with a significant heel counter and the origin of both the medial and lateral GuideRails at that point. There is plenty of cushioning between the heel counter and the calcaneus (heel bone) and the heel counter sits a little lower than most shoes, so I had no issues with sensitivity. The midfoot is normal to slightly snug, secondary to a slightly additional overlays on the upper and a great lock from the laces. The security of the upper is good enough that I did not have to lace lock the shoe. Even on turns, my feet stayed locked on the platform. The forefoot is a little snug, with a little pressure on my big toe initially. However this went away a few miles into the first run as the engineered mesh is quite adaptable to the foot. The tongue is connected to both sides of the upper and does not move. The mesh is also decently breathable, but not enough to cause heating issues. Overall the upper is secure and adaptable, but fits a little on the snug side (which adds to the security).


Matt: The ride of the Adrenaline GTS overall is fairly bouncy, stable and noticeable smooth through the midfoot and forefoot. The overall ride is slightly soft with a little bounce from the DNA Loft, which travels the full length of the shoe along with BioMoGo DNA. This feeling is a bit more soft in the heel and a bit more responsive in the forefoot thanks to the stack height differences. The heel drop is over 12 mm and is noticeable. The transition from the midfoot forward is extremely smooth and landing there feels very natural. The omega flex grooves in the forefoot provide awesome flexibility forward. This is combined with some toespring, which further adds to an extremely smooth toe off. The heel is a bit bulky, which is the trade off for being so stable. The lateral crash pad is significant and compresses somewhat during landings. There is a very mild heel bevel, but landing at the rearfoot is a bit clunky. Those used to the Adrenaline will feel right at home, but those new to the series should be aware of this. Overall the ride is extremely stable (see Stability) with a super smooth mid/forefoot and some clunkiness in the rear.


Matt: The Brooks Adrenaline GTS 21 is primarily a daily training shoe. The DNA loft midsole does have some responsiveness to it, but the significant heel drop and slightly softer heel make it better for longer runs and daily mileage. The smoothness up front does make it a great choice for uptempo work and some fartlek workouts if you land farther forward, but the Ravenna or Launch GTS (coming soon) are better options for speed work. This is not a slow shoe, but a consistent one.


Matt: The Adrenaline is all about stability. While there is no post, the GuideRail system, full ground contact outsole, overlays around the midfoot and secure fit provide a very stable and guided ride. The heel has a great deal going on. While the ride is a bit clunky in the rearfoot, it certainly is stable. The GuideRails are present on both the medial and lateral side so for the rare person that may need some guidance from the lateral side (or thinks they do), this shoe has it. The medial GuideRail travels fairly far forward and can be felt only while standing. While running, the GuideRails seem to integrate really well and it feels like a very stable ride. There is also medial, lateral and posterior sole flare in the heel. While there is a mild bevel, the combination of all of these do make the heel extremely stable to the point of being clunky. Those who need a ton of rearfoot stability without an obtrusive post will do very well in this shoe. Those used to posts may almost feel naked, but the GuideRails do their job well. While there are no rails or posts in the forefoot, the Omega Flex grooves do a great job of facilitating forward motion and the mild sole flare medially and laterally do a great job of keeping things in line.


Matt: The durability of the Adrenaline GTS 21 is slightly above average. I have over 40 miles in my pair and am only seeing very mild wear at the posterior lateral heel. The upper has no signs of wear and the GuideRails have remained consistent. I expect the normal industry standard of mileage out of these.


Matt: I was impressed some time ago by Brooks and their transition away from posting. That takes guts to drastically transition such a staple shoe in the world of running away from tradition. 3 years in it continues to be a success in the running retail world. However, I would like to discuss some claims regarding the GuideRails. Brooks reports this design was to control motion at the knee. I have discussed on here previously that assuming that pronation is a risk factor for knee pain is garbage. Trying to control motion at the knee with the foot completely ignores the other major contributor to transverse and lateral plane knee motion: the hip. The glute and deep hip rotator muscles are far larger and have better lever arms for control of the femur, and thus 50% of the knee, compared to the foot and ankle muscles. We also know that pronation is often a method of shock absorption, which in certain cases may be protective against knee pain. That is not a blanket statement, as there are some people who do move a bit too much at the ankle and may have issues at the knee joint. Is it everyone? No, that is a very specific population. Also, if the goal is to protect the knee joint, why would you have such a large heel drop? There is nothing wrong with that overall, but that does pitch the knee forward. In the running gait analysis I do, a knee that is to far forward compared to the foot during the transition from initial contact to midstance is a risk factor for anterior knee pain due to strain on the patella, quad and patellar tendon (for more information and references, see my post on Running Movement Impairments: Knee Anterior Translation). I am not trying to bash Brooks on this. My only point is that you should be careful with blanket statements. Depending on the person, foot motion can either be protective or problematic for the knee joint. Sometimes it can occur totally independently. This thought process is still a bit erroneous thinking that attempting to control motion at one area will fix problems elsewhere. Only when you take into account the entire lower extremity will that even be remotely possible. 


Matt: Based on my above comments from above, my two suggestions would be to lower the heel drop slightly (10mm), increase the bevel slightly or further decrease the density of the foam around the crash pad. This may smooth the ride out in the rearfoot. Outside of that I might suggest a little more room in the forefoot, but that is a personal bias on fit. 


Matt: The Brooks Adrenaline GTS 21 is for those looking for a moderate to high level stability shoe with a traditional heel drop, extremely high stability in the rearfoot, a smooth toe off and a slightly snug fit. Those with normal to narrow width feet will enjoy the very secure fit. People sensitive to posts for stability will enjoy the GuideRails and locked down upper for a stable ride.The GuideRails feel better integrated than previous versions, but there is still a lot going on at the rearfoot (which makes things a little clunky). This is made up for by a really smooth ride up front, so even people who land farther up there will enjoy the ride. Overall Brooks continues to make progress on concepts in stability and I am very excited to see the other new "GTS" shoes that are coming to market soon!



Fit/Upper      9  /10 (Slightly narrow fit but extremely secure and supportive)
Ride/Midsole  8 /10 (Super smooth mid/forefoot but clunky heel)
Stability          9.5 /10 (Moderate to high level of stability.).
Speed              8 /10 (Clunky Heel gets in the way of faster efforts)
Durability       9 /10 (Good Upper and midsole durability. Slight wear on heel)

TOTAL: 87% (M)


Dr. Matthew Klein is a 150 lb male with notable PRs of 14:45 for 5k 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 and close to the ground shoes, but can handle a little cushion when he gets beat up. IG handle @kleinrunsdpt

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.  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 40 miles 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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