Our verdict

The Adidas Adizero Boston line saw a radical change with version number 10 when it got much bigger. As per our observations, the 11th iteration sees just a few differences and remains a maximal training shoe devoted to those runners who love a very firm ride and train for medium to long-distance races. We found it to be surprisingly stable, lighter, and much more durable. And thumbs up for including some recycled materials.

Pros

  • Very stable for being a high-stack shoe
  • Excellent grip
  • Breathable upper
  • Versatile for different workouts
  • Protective underfoot
  • Extremely durable outsole
  • Made with recycled materials
  • Attractive design

Cons

  • Definitely stiff and firm
  • Long breaking-in period

Audience verdict

83
Good!

Who should buy

Consider choosing the Adidas Adizero Boston 11 if you:

  • Struggle with stability and need a shoe that can handle a wide range of paces
  • Are looking for a durable shoe that can handle races and don't mind it being heavier than racing shoes
  • Seek a cushioned-yet-firm ride for long-distance training sessions

Adidas Adizero Boston 11

Who should NOT buy

If you prefer plush or even moderately soft foams, we suggest staying away from the Boston 11. The same advice goes for those in search of flexible running shoes, as this one leans towards firmness and rigidity with its Energyrods.

For moderate-to-slow paces, consider the ASICS Novablast 3. It's a fast-and-light daily trainer that comfortably handles a wide range of speeds. On the other hand, if a flexible speed trainer is what you're after, the Nike Streakfly could be your match. It's fast, agile, and incredibly soft while maintaining excellent flexibility.

Adidas Adizero Boston 11 parts

Breathability

The Boston 11 handles summer runs without a hitch. The moment we got our hands on the shoe and felt the upper with our fingers, we were impressed by its thin, breathable engineered mesh.

Despite this, we didn't give it a full 5/5 score in our jaw-dropping smoke test—we settled for a 4. You might be wondering why—the reason lies with the shoe's tongue.

While the toebox plays a crucial role in breathability, discomfort can arise if other parts of the shoe don't allow for heat and humidity to escape.

Though the medial part of the Boston 11 offers sufficient breathability—a fact confirmed by our light test—the tongue could potentially be a problem on the hottest days.

Adidas Adizero Boston 11 microscope

Even so, when it comes to breathability, let us be clear: this shoe is superb—99% of runs should pose no problem.

Adidas Adizero Boston 11 microscope

Our observations in the lab reinforced our initial impressions. Under the microscope, we found a strikingly thin mesh—a true testament to precise manufacturing—that allowed for extraordinary airflow.

Test results
Adizero Boston 11 4
Average 3.8
Compared to 222 running shoes
Number of shoes
1
Breathability
5

Durability

Toebox durability

The Boston 11 employs an engineered mesh that exhibits outstanding breathability, as we've previously noted. However, this material falls short when it comes to durability—it's highly susceptible to wear and tear.

Our dremel test, which applies a force of 3.4N for four seconds to every shoe in the lab, really put the Boston 11 through the wringer. The hyper-thin layer of mesh offered almost no resistance at all.

We strongly believe Adidas could up their game in this regard in the v12. Of course, a thinner mesh typically has less robustness compared to a thicker one, but consider the Nike Alphafly 2. This model also sports a thin, competition-focused and breathable layer, yet it doesn't compromise on durability.

Adidas Adizero Boston 11 Toebox durability
Test results
Adizero Boston 11 1
Average 2.4
Compared to 156 running shoes
Number of shoes
1
Toebox durability
5

Heel padding durability

Luckily, the Boston 11's heel padding is really great. This is good news for runners who often wear holes in this area.

Our tough Dremel test on the soft fabric that Adidas uses in this area showed it holds up really well.

Test results
Adizero Boston 11 3
Average 3.1
Compared to 152 running shoes
Number of shoes
1
Heel padding durability
5

Outsole hardness

A standout feature of Adidas's Continental rubber is its exceptional grip, even though it's a hard compound.

This is a rare quality, as most brands need to use softer rubber to ensure a good level of traction. Adidas and Continental shine in this unique, hard-yet-grippy approach.

Adidas Adizero Boston 11 Outsole hardness
Test results
Adizero Boston 11 86.3 HC
Average 80.4 HC
We use an average of four tests. The photo shows one of those tests.
Compared to 273 running shoes
Number of shoes
54.9 HC
Outsole hardness
92.8 HC

Outsole durability

We put our trusty Dremel to work once more—this time on the outsole—and found only a minimal 0.74 mm wear in the rubber. This is an excellent result pointing to the shoe's long-term durability.

This shoe truly stands the test of time. 

Test results
Adizero Boston 11 0.7 mm
Average 0.9 mm
Compared to 134 running shoes
Number of shoes
0.0 mm
Outsole wear
2.0 mm

Outsole thickness

With a thickness of 3.3 mm, the rubber on the shoe is pretty standard, but it's so sturdy that you're likely to wear out many other parts of the shoe before the outsole.

Adidas Adizero Boston 11 Outsole thickness
Test results
Adizero Boston 11 3.3 mm
Average 3.2 mm
Compared to 292 running shoes
Number of shoes
0.0 mm
Outsole thickness
6.6 mm

Weight

Sporting a thick midsole, we quickly realized we were dealing with a chunky shoe. Adidas tried to lighten the load with a simpler upper design, but it wasn't enough.

Disappointingly, the shoe still tips the scale over the mental barrier of 10 oz—it weighs in at 10.2 oz or 290g. Let's hope that Adidas improves this issue in the Boston 12.

Adidas Adizero Boston 11 Weight
Test results
Adizero Boston 11 10.23 oz (290g)
Average 9.38 oz (266g)
Compared to 293 running shoes
Number of shoes
5.26 oz (149g)
Weight
12.56 oz (356g)

Cushioning

Heel stack

With a stack height height of 39.1 mm, the Boston 11 just falls within the World Athletics regulation of 40 mm, making it a legal shoe for racing.

We think it's a good option for almost any heel striker that seeks a high-yet-stable shoe, but it's not a great competition shoe, though.

Adidas Adizero Boston 11 Heel stack
Test results
Adizero Boston 11 39.1 mm
Average 33.7 mm
Compared to 292 running shoes
Number of shoes
7.6 mm
Heel stack
42.7 mm

Forefoot stack

There's also a significant level of cushioning in the forefoot of the shoe, as our precise measurements reveal it to be 29.3 mm.

Adidas Adizero Boston 11 Forefoot stack
Test results
Adizero Boston 11 29.3 mm
Average 25.0 mm
Compared to 292 running shoes
Number of shoes
7.6 mm
Forefoot stack
35.8 mm

Drop

This leads to a drop that's typical for Adidas shoes—at 9.8 mm.

So, even though the brand's official numbers indicates an 8.5 mm drop, we discovered it to be slightly steeper. This feature makes the shoe particularly well-suited for heel strikers, as a higher heel-to-toe drop facilitates the transition towards the midfoot and forefoot.

Adidas Adizero Boston 11 Drop
Test results
Adizero Boston 11 9.8 mm
Average 8.7 mm
Compared to 292 running shoes
Number of shoes
-0.8 mm
Drop
16.1 mm

Insole thickness

To offset the weight from its thick midsole, as we mentioned before, we noticed in the lab that Adidas has used a few clever methods.

That's why the insole is leaner than those found in most other running shoes on the market.

Adidas Adizero Boston 11 Insole thickness
Test results
Adizero Boston 11 3.4 mm
Average 4.5 mm
Compared to 288 running shoes
Number of shoes
1.5 mm
Insole thickness
7.3 mm

Midsole softness

Note: a low durometer measurement equals a soft material, whereas a high measurement means it's firm.

The Adidas Boston 11 makes use of two distinct foams:

  • Lightstrike is a standard EVA foam that, to us, feels notably firm. It doesn't have much bounce, but it does contribute to a stable ride. 
  • Lightstrike Pro, on the other hand, is the premier foam in Adidas' arsenal, boasting impressive energy return.

We clocked the hardness of Lightstrike at 22.0 HA, but it felt significantly firmer to us during our test runs.

That's because Lightstrike is renowned for having a really long break-in period, so expect a very firm ride for a while.

Adidas Adizero Boston 11 Midsole softness
Test results
Adizero Boston 11 22.0 HA
Average 21.4 HA
We use an average of four tests. The photo shows one of those tests.
Compared to 220 running shoes
Number of shoes
8.5 HA
Midsole softness (soft to firm)
41.5 HA

Secondary foam softness

Note: a low durometer measurement equals a soft material, whereas a high measurement means it's firm.

Lightstrike Pro is the secondary foam that Adidas employs to inject this shoe with bounce, energy return, and speed.

Even though we measured its hardness at 23.5 HA, which is technically firmer than Lightstrike, it felt quite the opposite to us. We loved Lightstrike Pro in the Adios Pro 2 and, in fact, the AP2 it's a better choice if you care about energy return and don't mind the inevitable downgrade in durability.

Adidas Adizero Boston 11 Secondary foam softness
Test results
Adizero Boston 11 23.5 HA
Average 25.3 HA
We use an average of four tests. The photo shows one of those tests.

Difference in midsole softness in cold

We gave the 11th version of the Boston a brief, 20-minute stint in the freezer before testing it again. After this cold-exposure test, we found the Lightstrike foam to measure 29.5 HA.

That's a jump of 34.1% from its normal state. It's not as good as the typical shoe, but that makes sense considering EVA foam never do well in cold temperatures. 

For a deeper understanding of foams and the effects of temperature in running shoes, we suggest looking at both our guides!

Adidas Adizero Boston 11 Midsole softness in cold
Test results
Adizero Boston 11 34.1%
Average 25.6%
Compared to 219 running shoes
Number of shoes
0%
Difference in midsole softness in cold
100%

Stability

Lateral stability test

Despite its significant stack height, we find the Boston 11 surprisingly stable.

Torsional rigidity

This stability is due to its carbon plate, Adidas' fiberglass Energyrods, and the firm foam we mentioned earlier.

That's also why we rated this shoe at 4/5 in our torsional rigidity test. It really felt stiff to us.

Test results
Adizero Boston 11 4
Average 3.3
Compared to 271 running shoes
Number of shoes
1
Torsional rigidity
5

Heel counter stiffness

The same principle applies to the heel counter. Adidas is simply making an effort to increase stability, offsetting the high-stack height's potential side-effects.

Test results
Adizero Boston 11 3
Average 2.8
Compared to 255 running shoes
Number of shoes
1
Heel counter stiffness
5

Midsole width in the forefoot

In our lab, we found the midsole width to be 109.3 mm.

This measurement is less than what we initially anticipated for this shoe, but it still provides enough stability for runners who land on their midfoot or forefoot, even in the fastest tempo runs.

Adidas Adizero Boston 11 Midsole width in the forefoot
Test results
Adizero Boston 11 109.3 mm
Average 113.6 mm
Compared to 293 running shoes
Number of shoes
100.5 mm
Midsole width in the forefoot
126.5 mm

Midsole width in the heel

The heel tells a similar tale. Once again, it seems like Adidas prioritized weight savings. If they had made the shoe as wide as the average training shoe, it could have ended up 10% or 20% heavier.

The narrower design could potentially compromise the shoe's stability and comfort for some heel strikers.

Adidas Adizero Boston 11 Midsole width in the heel
Test results
Adizero Boston 11 84.9 mm
Average 90.5 mm
Compared to 293 running shoes
Number of shoes
74.9 mm
Midsole width in the heel
106.6 mm

Flexibility

Stiffness

By now, it's clear that we're dealing with a stiff shoe. However, we really LOVE testing shoes in our lab and wanted to put a number on it.

So, we performed a 90-degree bend test and got a higher-than-average result of 35.3N.

Test results
Adizero Boston 11 35.3N
Average 29.3N
We use an average of four tests. The video shows one of those tests.
Compared to 275 running shoes
Number of shoes
2.2N
Stiffness
94.4N

Difference in stiffness in cold

We also put the shoe's stiffness to the test after a freezer-cooling session, just like we did for the midsole softness.

The EVA-based Lightstrike foam, once again, showed significant change under cold conditions. This time, we recorded a stiffer reading of 50.1N.

This shows a substantial 42% difference between the two measurements.

The change is quite noticeable, leading us to conclude that this shoe might not be the best choice for running in colder weather.

Test results
Adizero Boston 11 42%
Average 36.3%
Compared to 275 running shoes
Number of shoes
0%
Difference in stiffness in cold
148%

Size and fit

Internal length

Coming in at 268.6 mm, it aligns almost perfectly with the Adidas size chart, which lists 270 mm. We're confident in declaring this a true-to-size running shoe.

Adidas Adizero Boston 11 Internal length
Test results
Adizero Boston 11 268.6 mm
Average 269.1 mm
Compared to 156 running shoes
Number of shoes
259.9 mm
Internal length
280.4 mm

Toebox width at the widest part

Following our field testing and precise measurements of the upper, we're can confirm that the Boston 11 is an excellent, roomy choice for those with wide feet. Thumbs up for those 103.7 mm!

Adidas Adizero Boston 11 Toebox width at the widest part
Test results
Adizero Boston 11 103.7 mm
Average 98.3 mm
Compared to 293 running shoes
Number of shoes
89.5 mm
Toebox width at the widest part
109.1 mm

Toebox width at the big toe

There's even more good news for those of us blessed (?) with wide feet.

From our in-depth evaluations, we can confidently affirm that the Boston 11 is an excellent fit for those whose toes do not have significant size variation, such as those with Celtic, German, or Roman foot shapes—forming a near-perfect match.

For a deeper understanding of foot shapes and uppers, we strongly encourage you to explore our guide about uppers.

Adidas Adizero Boston 11 Toebox width at the big toe
Test results
Adizero Boston 11 80.5 mm
Average 78.0 mm
Compared to 167 running shoes
Number of shoes
60.4 mm
Toebox width at the big toe
92.5 mm

Tongue: gusset type

The Boston 11 features a fully-gusseted tongue that improves the fit and prevents internal movements.

Although we might have preferred a semi-gusseted design for a more balanced feel, we're fine with this setup.

Adidas Adizero Boston 11 Tongue: gusset type
Test results
Adizero Boston 11 Both sides (full)

Comfort

Tongue padding

We found the tongue padding to measure 4.1 mm. This is a surprisingly pleasant result, particularly for a shoe that's specifically designed for tempo runs.

Most training shoes in the Adizero line, like the Adizero Adios 7 with its 1.8 mm padding, sport a much thinner tongue.

Adidas Adizero Boston 11 Tongue padding
Test results
Adizero Boston 11 4.1 mm
Average 5.6 mm
Compared to 290 running shoes
Number of shoes
0.5 mm
Tongue padding
14.2 mm

Heel tab

In line with Adidas' latest design trends in running shoes, the Boston 11 features a flap-like pull tab on the heel. This serves two purposes—it makes slipping your foot into the shoe easier and adds a unique aesthetic touch.

Adidas Adizero Boston 11 Heel tab
Test results
Adizero Boston 11 Pull tab

Removable insole

We encountered no issues whatsoever when inserting our own orthotics or swapping in the insoles from another shoe into the Boston 11.

Adidas Adizero Boston 11 Removable insole
Test results
Adizero Boston 11 Yes

Misc

Reflective elements

Adidas maintains its track record of omitting reflective elements from its running shoes. Although they've stayed consistent with their design approach, it's disappointing and concerning for us, particularly from a safety perspective.

Night runners really need those reflective components for increased visibility. We certainly hope Adidas revisits this aspect in the Boston 12.

Adidas Adizero Boston 11 Reflective elements
Test results
Adizero Boston 11 No