Adidas Adizero Boston 11: A Step Back or Forward?
By Founder/Chief Editor Matthew Klein and Ryan Flugaur
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.
Editor's Note: Updated with Contributor Ryan Flugaur's thoughts on 11/1/22.
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
Matt: 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.
Ryan: The Adidas Adizero Boston 11 is a high stack, firm riding, tempo trainer best suited for faster effort days. It is a unique shoe that requires a break in a period of around 60 miles before truly feeling good. This is mainly due to the firm longitudinal bending stiffness of the shoe which requires a large amount of extra strength to push through as I will discuss later. I currently have around 130 miles on my pair and can still feel the ride improving. Knowing this, one must be committed to the shoe and log the “break in” miles before being able to truly appreciate the ride.
FIT
Matt: 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...
Ryan: The Adidas Adizero Boston 11 fits me true to size in my men’s size 9. The mid and forefoot have adequate space while the toe box expands providing ample room for the toes. I found the fit comfortable thanks to the upper providing a slightly snug, performance feel. As the upper provides very little stretch in the material, I typically wore a pair of ultra-thin socks to get the perfect fit as the midfoot felt too restrictive in anything too thick. The lightweight mesh upper is breathable and performs well even on hot summer days. As a bonus, Adidas claims the upper is constructed using at least 50% recycled content. The tongue is gusseted and very thin. It features a small piece of padding located just below the laces to help provide a secure lace lock without placing pressure over the dorsum of the foot. The heel counter features only a small amount of padding and does a good job keeping the calcaneus locked down. As the shoe is firm, I was initially worried about slippage, but after nearly 100 miles it continues to provide a secure and comfortable lockdown. Overall, I found the fit to be comfortable enough for all day use and frequently wore the shoes around the clinic and casual use as I enjoyed the firm midsole for general walking.
PERFORMANCE
Matt: 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.
Ryan: This was my first time running in a Boston shoe, but I was aware of the stiff energy rods and the need for a “break-in” period to help soften the firm ride. Without knowing this, it would have been easy to toss the shoes aside after my first couple of runs as they truly feel too firm and pushing through the stiff energy rods requires significant work. Near the 70-mile mark, the ride of the Boston 11 really improved as the energy rods began to soften and the Lightstrike Pro foam became more pliable. When initially running in the Boston 11, the forefoot felt overly stiff. This led to a feeling of pressure during push off under the plantar surface of my forefoot. This sensation quickly dissipated as the shoe began to break in but is very noticeable the first 30 miles.
The Boston 11 performs best during tempo work thanks to the longitudinal bending stiffness created by the energy rods. This stiffness helps keep the shoe moving forward and assists with giving the runner some extra pop with toe off. However, I also had no issue taking it out for a 10-minute pace cool down run once it was broken in. Slower easy runs were very uncomfortable the first 30 miles. Despite the Boston 11 being designed for speed, I found that The Boston 11 works well for both up-tempo and base training paced runs. I was able to successfully wear the Boston 11 for all my training coming back from a knee injury. This began with a run walk program and recently ended running a half marathon at an 8.22 pace.
A word of caution for those runners with weaker calves. When first running in the shoe I was able to feel a significant amount of gastrocnemius (calf) activation needed to push through the firm energy rods. For this reason, individuals with weaker calves may want to slowly transition into this shoe to prevent overuse or muscle strain injuries. (For reference, most runners should shoot for a minimum of 30 single leg calf raises for adequate calf strength).
STABILITY
Matt: 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.
Ryan: The Boston 11 falls into the stable neutral category for me thanks to the firmer ride and stiff energy rods. The newly designed upper does a good job keeping the foot planted on the footbed and guiding the foot forward. The lateral heel bevel works well for those individuals that pronate as it controls some of that inward motion. Those individuals that supinate may have the opposite feeling however, as the bevel may push them further to the outside of the shoe. Lastly, the wider last and well-done toe spring help with stability during push off. Overall, the Adidas Adizero Boston 11 should work well for those individuals with neutral or mild stability needs that tend to pronate more than supinate. Individuals that are sensitive to more firm shoes or that tend to have issues with a strong lateral heel bevel may want to look elsewhere.
THOUGHTS AS A DPT / FOOTWEAR SCIENCE
Shoe Stiffness Impact
By Chief Editor Matt Klein
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 Living, 4, 815675.
Healey, L. A., & Hoogkamer, W. (2022). Longitudinal bending stiffness does not affect running economy in Nike Vaporfly shoes. Journal of Sport and Health Science, 11(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 Science, 12(2), 79-89.
Rodrigo-Carranza, V., González-MohÃno, 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
Matt: 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.
Ryan: I would love to see the Boston 11 feel at mile 1 the way it feels after mile 70. Like both Nathan and Matt have said previously, softening the sole with more lightstrike pro foam or changing the placement of the energy rods may assist with this.
When speaking with other runners about how much I liked running in the Boston 11 many seemed to disagree. Many of them logged a few miles on the treadmill at the shoe store or walked around the store “testing” them out. When asked what they thought of the shoe, many replied it felt too firm and lacked the pop they look for in a runner shoe. Sadly, they will all miss out on the ride that comes following the 70-mile break in period.
WHO THIS SHOE IS FOR
Matt: 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.
Ryan: The Adidas Adizero Boston 11 is a firm, high stack shoe that takes a significant amount of time to break in. It does best with daily and temp work but can perform slower pace runs once the rods are softened slightly. Thanks to the wider last, stiff energy rods, and well-done lateral heel bevel individuals with neutral to mild stability needs, especially into pronation, should do well here. The upper is well fitting and the midfoot offers slightly more room to accommodate a slightly wider foot like mine. I still preferred ultra-thin socks to get the best fit as thicker socks placed some pressure over the lateral side of my foot. The Lightstrike Pro paired with the stiff energy rods create a firm ride for the first 50-70 miles, so runners need to be committed to the shoe before finding the sweet spot. From what I understand, the Boston 10 from last year was a team favorite and Matt feels this model takes a step back. As I have no knowledge of the Boston 10, I cannot compare but I can tell you that once the Boston 11 breaks in it becomes a very different shoe and I enjoyed the ride.
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+
Ryan
Fit: A- (Comfortable well-fitting upper with a slightly wider forefoot)
Performance: A- (Performs best at temp pace however can log some miles at slower paces following the break in period)
Stability: B+ [Stable Neutral] (Stable neutral shoe thanks to the wider last, stiff energy rods, and lateral heel bevel)
DPT/Footwear Science: B (Should we need to run in a shoe 70 miles before it becomes good? Other shoes offer a similar ride without the need for a break in period)
Personal: A- (One of my favorite tempo shoes this year after the break in period)
Overall: A-/B+
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