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Adidas Adizero Boston 11: Backwards?
By Founder/Chief Editor Matthew Klein

The Boston series has always been a favorite of those that wanted a shoe they could train in that was also fast enough to race in. The originals were almost as light as the Adios series but featured more forgiving cushioning. This made them a frequent choice among elite and sub-elite marathoners given their uniquely combined comfort and speed. All of that changed with version 10, which saw a complete overhaul of the series. Boost was replaced with Lightstrike and Lightstrike Pro. Energy rods were placed along the length of the shoe for stiffness. The stack height maxed out, making for what many saw as a completely different shoe. The Boston 11 continues this with a redesigned upper but maintains the changes in the sole that divided many Adizero Boston fans. 

Price: $159.95 at Running Warehouse
Weight: 9.6 oz, 272 g (men's size 9), Women's Weights Not Provided
Stack Height: 39.5 mm / 31 mm
Drop: 8.5 mm 
Classification: Max Cushion Daily / Uptempo Trainer





RUNNING SHOE SUMMARY

The Adidas Adizero Boston 11 returns as a maximal stack height, firmer uptempo trainer. Featuring a brand new upper that provides more room at the forefoot and increased stiffness at the rearfoot for security and guidance. The midsole continues to be on the firm and stiff side thanks to the Energy Rods, taking extensive time to break in for the Lightstrike Pro to shine before it becomes a more versatile ride for both workouts and slower runs. Best for those who want a maximal stack height but stiffer/firmer shoe for mileage and uptempo efforts, the Adidas Adizero Boston 11 fixes some of the upper issues from the previous version while maintaining the taller and firmer ride.

FIT 

The Adidas Adizero Boston 11 fits me true to size in my normal US men's size 10. The width is normal to slightly snug in the rearfoot and midfoot while being slightly wider in the forefoot. Unlike the previous version, the forefoot is more open and does not have the strong taper it did previously. There are two suede pieces that are part of the toe guard that come up onto the toes. These did not cause me any issues and I forgot about them after the first run. The midfoot is slightly snug with a thin gusseted tongue that hugs the foot. The heel features a large and stiff heel counter with no padding. This combined with the slightly snugger fit locks the foot in the shoe well. I did not have any heel slipping and did not have to lace lock the shoe. The counter comes fairly far forward and provides guidance for the heel during rearfoot transitions. The drawback is that those sensitive to counters will not do well here. Although I have done mostly fine in this shoe, the stiffness will be divisive. Those who like stiff heel counters will do well here. Despite having a little more room in the forefoot, the upper material is stiffer than previous. This adds to security well, but the inner mesh is also scratchy. This is a shoe you should definitely wear socks with. Lastly, I could not figure out the adjustable heel tab. I kept it down and it did not get in my way, but I am not entirely sure what it is for...




PERFORMANCE 

The Adidas Adizero Boston 11 is a firmer, maximal stack height, rockered shoe. Like the previous version, it has taken almost 40 miles for the sole to break in and the Lightstrike Pro to begin to be noticeable. The ride overall is quite firm and stiff from the Lighstrike and full-length Energy Rods. The forefoot is particularly stiff with no flexibility up front. The 8.5mm drop feels about right and the solid rocker would normally unload the calf muscles. However, the forefoot stiffness requires a high level of calf strength to adequately push through. Combined with the toe spring, the Boston 11 feels better at uptempo efforts than easier paces initially. As the sole slightly softens and the rods loosen up (only slightly), it becomes easier to use at slower paces. Although also firmer and stiff at the rearfoot, there is a large posterior-lateral bevel that eases transitions far better than the forefoot. The rockered midsole helps offset some of the firmness along with a new weight drop to 9.6 oz (men's size 9). My US men's size 10 comes in at 10.5 oz, which is fairly solid for a daily trainer. However, its use as a daily trainer takes time for the shoe to break into. Starting out the firmer ride works better for uptempo workouts, but is still a little heavy for anything faster than tempo efforts. When the sole breaks in after 40-50 miles, the Lightstrike Pro becomes more apparent and faster efforts become easier. So like the ride, the responsiveness of the shoe improves as it breaks in.

Like the previous version, the outsole is extremely durable. I have 48 miles on my pair and have yet to put any major dent in my usual spot on the outsole. The traction is decent, making the Adidas Adizero Boston 11 an option for easier/tame trails. I have used this shoe on many road-trail efforts where high traction is not necessary and the firmer ride works better on softer surfaces. However, the true purpose of the Adidas Adizero Boston 11 is as an uptempo trainer on the roads, but it takes time to break in.

STABILITY 

The Adidas Adizero Boston 11 is stable neutral shoe with several methods of guidance present throughout the length of the shoe. The strong posterior lateral bevel at the heel guides runners in laterally, so those that need medial heel stability will do well here. The Lightstrike Pro acts as sidewalls on both the medial and lateral sides of the shoe. These run from the heel to the anterior midfoot. The sole is on the wider side as it should be for a maximal shoe which combined with some mild sole flare resists frontal plane (side to side motion). The most significant component resistant side to side motion is the incredibly stiff Energy rods. Particularly in the forefoot, these rods resist torsion and create a high level of stiffness. Those that also need a stable forefoot will do well thanks to this stiffness as well as the wider shape up front. Overall, the Boston 11 is a highly stable and guided "neutral" shoe from heel to toe. 





THOUGHTS AS A DPT / FOOTWEAR SCIENCE

We have discussed stiffness in footwear previously, the incredibly stiff ride of the Adidas Adizero Boston 11 makes this a worthwhile topic to revisit. Although carbon plates, shanks and other stiffening agents have been used in footwear for years (even in the 90s), the debut of the Nike Vaporfly dramatically increased the popularity of using full-length plates and rods in footwear. It was initially thought that the stiffer a shoe was, the more economical it was. That is only partially true and does not capture the full picture.

We have increasing evidence that longitudinal bending stiffness can be beneficial in footwear, but how stiff and the design of the stiffness plays a huge part. Mcleod et al. (2020) performed a great study that demonstrated that each individual has a unique level of stiffness they benefit from. Some people benefit from a stiffer shoe while others benefit from a more flexible shoe (Mcleod et al., 2020). Thus, a stiffer shoe will not work better for everyone and a great deal of how much stiffness will benefit each person depends on how the plate lines up with the mechanics of the toe joints (Agresta et al., 2022; Rodrigo-Carranza et al., 2021).

It is also known at this point that longitudinal bending stiffness is not the primary improver of running economy in many of these newer shoes. The plates/rods often serve to stabilize the softer foams, which are frequently what create most of the economy improvements in runners (Healey & Hoogkamer, 2022). This is why so many carbon-plated racing and uptempo shoes were released that did not perform to the level of plated shoes with super foams (Joubert & Jones, 2022).

A shoe that is too stiff may actually decrease economy and be incredibly uncomfortable. A stiffer shoe that goes beyond an individual's optimal stiffness can actually require more energy to get over, decreasing economy and potentially adding stress to different parts of the foot or lower extremity (Mcleod et al., 2020). For that reason, a shoe like the Adidas Adizero Boston 11 becomes an exclusive shoe that will work for those who need/want the highest level of stiffness or those who are patient enough to break it in. That also means it won't work for everyone.

References


Agresta, C., Giacomazzi, C., Harrast, M., & Zendler, J. (2022). Running Injury Paradigms and Their Influence on Footwear Design Features and Runner Assessment Methods: A Focused Review to Advance Evidence-Based Practice for Running Medicine Clinicians. 
Frontiers in Sports and Active Living4, 815675.

Healey, L. A., & Hoogkamer, W. (2022). Longitudinal bending stiffness does not affect running economy in Nike Vaporfly shoes. 
Journal of Sport and Health Science11(3), 285-292.

Joubert, D. P., & Jones, G. P. (2022). A comparison of running economy across seven highly cushioned racing shoes with carbon-fibre plates. 
Footwear Science, 1-13.

McLeod, A. R., Bruening, D., Johnson, A. W., Ward, J., & Hunter, I. (2020). Improving running economy through altered shoe bending stiffness across speeds. 
Footwear Science12(2), 79-89.

Rodrigo-Carranza, V., González-Mohíno, F., Santos-Concejero, J., & González-Ravé, J. M. (2021). The effects of footwear midsole longitudinal bending stiffness on running economy and ground contact biomechanics: A systematic review and meta-analysis. 
European Journal of Sport Science, 1-14.





RECOMMENDATIONS

There are some positive changes to the Boston 11. The upper fit fixes the heel slippage and tapered forefoot from the last version, providing adequate room and security. The midsole is far firmer than it needs to be or even should be for a stack height this tall. The ride is borderline uncomfortable unless you like really firm riding shoes and the Lightstrike Pro does not shine at all. Despite the great weight decrease, the Boston 11 needs to be softer. The lack of responsiveness and cushioning from this sole is confusing given the 39.5mm/31mm stack height.

Just like Nathan suggested with the last version, the Energy Rods may be too close to the foot or too stiff for a workout/uptempo shoe. On longer efforts, my feet often ache after running in these likely due to how stiff and firm these shoes are. The Lightstrike Pro is even less noticeable than the last version, which is the opposite direction from what we suggested. My two major suggestions are to reduce the stiffness of the rods and soften the sole, potentially with more Lighstrike Pro. The lower density foam will further decrease weight, bringing the mass down closer to the original Bostons. The softer ride will make this shoe more forgiving and more responsive, rather than harsh and stiff.

The above reasons are why I have graded the ride section lower than the Boston 10. The Boston 10 was a favorite of this team and I honestly think it is better than version 11. The newest version is far firmer and stiffer, to the point that the ride is almost uncomfortable. So unless you want a firmer ride and a wider fit in the forefoot, I would stick with the last Adizero Boston 10.

WHO THIS SHOE IS FOR 


The Adidas Adizero Boston 11 uptempo daily trainer for those who want an extremely stiff and firm ride in a rockered and maximalist shoe. The Energy Rods and Lightstrike create a highly stiff ride that takes a long time to break in, but along with several other features create a highly stable ride. The guidance is good enough that it will work for those with a variety of stability needs that don't respond well to traditional stability methods. The redone upper adds a high level of security while increasing the room in the forefoot. The upper is very structured, which contributes to the solid lockdown. Overall, the Adidas Adizero Boston 11 continues as a polarizing shoe that will attract those that want a firm and stiff ride. Our team really enjoyed version 10. While the upper has improved in version 11, the sole took a step back, despite having so much potential. There is opportunity here with version 12, but more work needs to be done to help make this unique combination of ingredients shine.



GRADING 

Matt
Fit: B+ (Stiff but secure upper with more room in the forefoot and a snug heel/midfoot)
Performance: 
B- (Max stack height, extremely firm and stiff. Can handle uptempo work but works better for daily and tempo efforts once it has broken in)
Stability: A [Stable Neutral] (Extremely stiff, guided and rockered sole. Excellent guidance for a neutral shoe)
DPT/Footwear Science: B+ (Continued stable neutral shoe with adequate room in forefoot. Unfortunately, this shoe is stiffer and firmer than it needs to be. Need a better balance between the rods and the Lighstrike Pro)
Personal: B (Stable ride that works with my mechanics, but way firmer/stiffer than it needs to be. It is slowly breaking in, but there are many better options that break in faster. I actually prefer version 10 to this one)
Overall: B/B+ 

SHOP | SUPPORT DOR

Price: $159.95 at Running Warehouse

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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 and Adidas 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.

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