I have mentioned many times here that I have a special thing for lightweight trainers. I like their versatility to be able to handle high mileage and be able to drop the pace at a moments notice. The Adidas Adizero Boston 7 is a great example of that and takes it a step further. If you watch high level road races, you will notice the Adidas athletes wear a smattering of shoes. Currently you will see plenty of Adios, Takumi Sen, Sub2s.... and Bostons. Why? Because this shoe is fast. Fast, cushioned and perfect for the marathon or long distance race. Many elites get away with lighter shoes, but more still opt for that additional protection. I was very confused when I saw a few of the top runners at the LA marathon racing in these, until I talked to them afterward. Kenyans I have learned are notorious for only training on dirt (when possible). The athletes I have treated have repeatedly told me that they do not want to deal with the pounding unless they have to in a race. So it makes sense that many would opt to use a shoe that has a bit more protection, but still feels very fast. I would describe the current Boston as a slightly better fitting Adios with more protection. Lets dive into the details a bit more before you take my word for it.
Specifications (per Running Warehouse)
Weight: 8.6 oz (mens size 9)
Stack Height: 26mm / 16mm
Drop: 10mm
Classification: Lightweight/Performance Trainer
FIT
The mesh of the upper has increased flexibility compared to version 6, but the Boston 7 continues to fit on the narrow side. Although it does fit true to size, I found that the snug fit is best for workouts or racing as holds the foot well. Individuals with wider forefeett will likely find the narrow and shallow toe box a little too much over longer distances. I have found that many Adidas Adizero shoes feel better going up a half size (the tempo is also a great example) and although I went with my normal size, for daily training a half size up may be better. For that snug racing flat fit, true to size is best. This shoe is available in Japan in a wide version (which is the Japanese wide, meaning more room in the forefoot), so that might be a good alternative.
The heel is held by a somewhat flexible heel counter but the remainder of the upper is a light breathable mesh. As always, the three stripes provide a secure hold on the midfoot. With additional miles, I found that the shallow fit relaxed a bit and broke in. I did use this shoe sockless for shorter miles and did not get any hot spots or chaffing, even during strides. The mesh and inner liner are that smooth that I didn't have an issue. Without socks it fit perfectly, but I used this shoe with socks most of the time because I did not want to push my luck. However, I will say again the Boston 7 has a narrower forefoot that did not bother me during workouts, but did a little during easy runs. I am very curious to try the Wide version from Japan (like I did for one of the older versions of the Tempo) and may have to order a pair.
RIDE
The Boost and 10mm drop provide a good amount of protection, which when combined with the speed makes this a great shoe for workouts or long distance racing. The Boston 7 does feel like it has a lower drop, despite being listed as a 10mm drop shoe by Running Warehouse, Runners World and Adidas. This further contributes to why this shoe feels fast over almost every distance. The forefoot is somewhat firm and stiff for sprinting due to more EVA up front, whereas the additional Boost in the back makes for more bounce if you land farther back. The additional Boost in the shoe provides an advantage over the Adios as it has a far more forgiving ride and a similar speed. The torsion system is present as usual, but is integrated fairly well into an almost full ground contact outsole. It is close enough to the ground that I did not notice any difference in the transition, which is still super smooth and fast. The toe spring and heel bevel also contribute to the smooth ride without being over controlling. Those combined with the additional stiffness and toe drop seem to provide additional stability and protection that kept my calves fresh over longer workouts.
As mentioned previously, this is a lightweight shoe that is protective but begs to go fast. It seems to work best on road thanks to the additional protection and the AdiWear outsole provides plenty of additional grip. This was also present during the track workouts I used these for as I was able avoid any slipping despite a workout in the rain.
SPEED
The Boston 7 is one of the faster long distance lightweight trainer/racers I have tried. It has the speed to run fast 400s on the track as well as long tempo runs and races up to the marathon. For those that like the Adizero Adios but want more protection, this is the shoe for you. It begs to go fast and made me want to get back to racing long distance (currently my fellowship schedule is killing any chance of that thanks to classes and clinic every weekend). This shoe responds VERY well to pace changes and I have used this shoe for every type of workouts. Fast Long Runs, Intervals, Fartleks, Hill Repeats, Short Reps, Tempo runs, Steady States. It shines everywhere. The only place I have not used this shoe is for a race, but it would be my first choice for a marathon any day. This is due to the protection from the Boost in the heel, the firmer forefoot that lends to a fast transition and the feel of the Adios with more space between you and the ground.
DURABILITY
This is an Adidas shoe, which means a solid amount of Continental® rubber on the outsole. Like most Adidas shoes, the outsole is very durable and I have seen little to no wear despite all my miles being quite hard in this shoe. I have not used this shoe on aggressive trails due to the smoother outsole, but for groomed trails (dirt tempos) I have seen no additional wear. As per usual, the Boost maintains the ride and I expect to get a very high number of miles out of this shoe. For those looking for a more cushioned racing shoe, this is a great deal as it will last for quite some time.
THOUGHTS AS A DPT
A firmer ride means better proprioception. Partially because you can feel the ground and partially because the increased forces into the joint(s) activate mechanoreceptors that better engage the muscular around the joint (which ultimately protects it more) I found the Boston 7 to have multiple personalities. The heel is cushioned enough that moderate to uptempo paces still feel protective, but the forefoot is firm enough that I pop off the ground and get up on my toes when I sprint or do speed work. I have heard a few people comment that the forefoot feels a bit dead and this may have to do more with you that the shoe (not completely, but give me a second).
Individuals with stiffer muscular and joints will tend to seek out softer cushioning. Why? There increased stiffness means they do not have good shock absorption. They have great stability from the stiffness, but impact attenuation is the trade off. Individuals with looser muscular and joints will tend to seek out firmer cushioning. This is due to the fact that the increased loading increases proprioceptive input, which helps better turn on the muscles which gives them the stability they seek. However, those with looser muscular and joints will attenuate shock better because they have more room to move! That is not always a good thing of course if that looseness means instability. Extremes of motion are not usually good, whether too much or too little. Just like what I have discussed on the extra stiff side of the equation, where too little shock attenuation means an potential increased risk of stress fractures and bone related issues.
This may be one reason that some people prefer softer versus firmer cushioning. As someone with a large amount of joint mobility, I tend to do better in stiffer/firmer shoes because the extra input helps me stabilize my joints. There are many other factors that play into this, including the strength of the body's propioceptive centers (foot, pelvis, neck), footwear history, training history and more, but this is something to be aware of. It may explain your preference for footwear. So this may partially explain why some people may find a shoe to feel dead, but others may find it to be very responsiveness. Part of this is obviously the shoe, but don't forget your own biomechanics and neurophysiology!
CONCLUSION
For those looking for a bit more cushioning for long distance racing or just want a lightweight trainer that can do everything, check out the Adidas Adizero Boston 7. It has a traditional drop but still feels like a racing and has the cushioning/responsiveness to handle long miles and speed. This is a great example of a lightweight performance trainer. Able to still handle daily training but also able to handle that last fast 400 repeat. I really like the upper update, but wish there was a bit more room up front to accommodate the toes and mild swelling over long miles. Hopefully Adidas adds this upper with a bit more room the the Tempo 10 and I look forward to further progression fit wise. Overall one of my favorite lightweight trainers for some time and this is a strong contender for any longer races I have coming up (if my weekend class and clinic schedule allows).
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.
Dr. Matthew Klein, PT DPT OCS
Doctor of Physical Therapy
Board Certified Orthopedic Clinical Specialist
Kaiser SoCal Manual Therapy and Sport Fellow
Doctor of Physical Therapy
Board Certified Orthopedic Clinical Specialist
Kaiser SoCal Manual Therapy and Sport Fellow
***Disclaimer: These shoes were provided free of charge in exchange for a review. We thank the people at Adidas for sending us a pair. This in no way affected the honesty of this review. We put at least 50-75 miles on trainers and 10-25 miles on racing flats prior to reviewing them. Currently I have 54 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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