Our verdict

As per our observations, the iconic Ultraboost line by Adidas has long been co-opted by the masses as more of a sneaker than a running shoe. However, we found that the 23rd shoe in the series, the Ultraboost Light, marks a return to its roots with an updated midsole that made our daily runs feel as comfortable as our walks around town.

Pros

  • Cushy and responsive ride
  • Good for easy runs and long distances
  • Ideal for heel strikers
  • Suitable for wide feet
  • Effective stability elements for mild pronation
  • Snug and secure lockdown
  • Durable toebox and heel
  • Outsole built to last
  • Ready for winter runs
  • Works as a comfy walking shoe
  • Sustainably designed upper

Cons

  • Thin forefoot cushioning
  • Could be lighter
  • Slippery on wet surfaces
  • Not for speedwork
  • Average at best breathability

Audience verdict

89
Great!

Who should buy

We recommend the Ultraboost Light to:

  • Casual runners who want a stable neutral road shoe
  • Heel strikers looking for added rearfoot protection
  • Runner who enjoy long distance efforts 
  • Those looking for a daily runner that doubles as a comfy sneaker
  • Runners with mildly pronating strides

Adidas Ultraboost Light 1

Who should NOT buy

While heel-strikers have plenty of plush foam to land on, the midsole provides much less cushioning at the forefoot, so mid/forefoot striking runners will find the shoe to feel much more firm underfoot. We recommend the ASICS Gel Nimbus 25 as an alternative that's well cushioned throughout.  

Contrary to what the name suggests, the Ultraboost Light is relatively heavy. While this isn’t an issue for short to mid-distance runs, the shoe did prove quite burdensome  during the latter half of our longer test runs. 

The sock-like fit of the Ultraboost Light lends the shoe a comfy lockdown that’s secure enough for most purposes. It’s only when we picked up the pace that we began to notice some foot movement within the shoe that brought on some uncomfortable hot spots. For a daily trainer that sports a more snug, racer-like fit, we recommend the Brooks Levitate 6.

Adidas Ultraboost Light cut up

Breathability

To test how breathable the Ultraboost Light is we pump the shoe full of smoke and observe how it dissipates through its upper material. As you can see the smoke does manage to escape the shoe, though mostly through the sides and toebox while the tongue seems to trap it in. This leads us to give the shoe a breathability score of 3 out of 5. 

Compare that to how the Saucony Triumph fared in the same test. With a perfect score, it virtually disappears in a fog of smoke that emerges almost as soon as it is pumped in. 

Inspecting a backlit section of the upper gives us a better impression of how insulated the shoe is, with almost no light shining through any section of the shoe. 

Our closeup shots of the Ultraboost Light also explain the shoe’s lackluster breathability. We can clearly see that the material that makes up the upper knit layer is thick and tightly braided, while the mesh that lies below is dense and not porous enough to allow heat to escape efficiently.

Adidas Ultraboost Light micro 1

Adidas Ultraboost Light micro 2

Test results
Ultraboost Light 3
Average 3.8
Compared to 189 running shoes
Number of shoes
1
Breathability
5

Durability

Toebox durability

We tested the durability of the Ultraboost Light’s toebox by applying our dremel to it with a force of 3.2N at 10K RPM for four seconds. While we were able to tear clean through the shoe’s knit upper, the mesh below remained relatively intact, which leads us to give the toebox a durability score of 4 out of 5. 

Adidas Ultraboost Light toe result

This is a marked improvement from the Ultraboost 1, which stood no chance against our dremel and was left with a gaping hole in the aftermath of the same test.

Test results
Ultraboost Light 4
Average 2.2
Compared to 123 running shoes
Number of shoes
1
Toebox durability
5

Heel padding durability

The Ultraboost Light’s heel counter proved to be an even more worthy contender against our dremel. After four seconds at the same parameters as the previous test, the dremel barely left an imprint on the shoe’s heel collar, leaving it looking about as it did before the test! We therefore score the shoe’s heel padding a perfect 5 out of 5. We can safely predict that the Ultraboost Light will still have most of its padding intact well beyond 500 miles of use. 

Adidas Ultraboost Light Heel padding durability

This is also an improvement from the original Ultraboost's heel collar. 

Test results
Ultraboost Light 5
Average 3
Compared to 119 running shoes
Number of shoes
1
Heel padding durability
5

Outsole hardness

We pressed our durometer against the outsole of the Ultraboost light to test how hard it is and got a reading of 76.8 HC. 

This is slightly softer than our current lab average, but still in that sweet spot between hard and durable versus soft and grippy.

Adidas Ultraboost Light Outsole hardness
Test results
Ultraboost Light 76.8 HC
Average 80.3 HC
We use an average of four tests. The photo shows one of those tests.
Compared to 241 running shoes
Number of shoes
55.5 HC
Outsole hardness
92.8 HC

Outsole durability

To simulate extreme wear and tear over time, we once again fire up the dremel to 10K RPM and apply it to the shoe’s outsole with a force of 3.2N but for twenty seconds this time. The result of the visually anticlimactic test was a loss of only 0.71 mm of rubber. This makes the Ultraboost Light much more durable than average, and further supports our prediction regarding the longevity of this shoe. 

Adidas Ultraboost Light Outsole durability
Test results
Ultraboost Light 0.7 mm
Average 0.9 mm
Compared to 101 running shoes
Number of shoes
0.0 mm
Outsole wear
2.0 mm

Outsole thickness

The shoe’s outsole is only 2.4 mm according to our caliper measurements, but, as the previous test demonstrates, the durability of the rubber means that this isn’t an issue as there was more than enough rubber left to run our dremel against it three more times. 

By skimping on rubber in this instance, Adidas is able to keep some much needed weight off this already hefty shoe. 

Adidas Ultraboost Light Outsole thickness
Test results
Ultraboost Light 2.4 mm
Average 3.2 mm
Compared to 261 running shoes
Number of shoes
0.0 mm
Outsole thickness
6.6 mm

Weight

While this may be its lightest iteration so far, tipping the scale at 10.75 Oz (305g), the Ultraboost Light simply isn’t as light as the name implies. The shoe is about as chunky as it looks and quite a bit heavier than our current lab average. 

Adidas Ultraboost Light Weight
Test results
Ultraboost Light 10.76 oz (305g)
Average 9.42 oz (267g)
Compared to 261 running shoes
Number of shoes
5.26 oz (149g)
Weight
12.56 oz (356g)

Cushioning

Heel stack

We measured the prominent heel stack of the Ultraboost Light to be 30.1 mm which is almost exactly as advertised by Adidas. While this makes the shoe’s stack ever-so slightly shorter than our lab average, heel strikers will have more than enough cushioning underfoot for a protective and comfortable ride. 

Adidas Ultraboost Light Heel stack
Test results
Ultraboost Light 30.1 mm
Average 33.5 mm
Compared to 260 running shoes
Number of shoes
7.6 mm
Heel stack
42.7 mm

Forefoot stack

With a forefoot stack measuring 21.7 mm according to our caliper, the Ultraboost Light is only 1.7 mm taller than officially stated by Adidas, and also falls just shy of our current lab average. While this stack height gives forefoot strikers a good amount of ground-feel, it does come at the expense of impact protection, which feels inadequate for longer runs. 

Adidas Ultraboost Light forefoot stack

As the video below demonstrates, forefoot strikers won’t savor the cushioning of the shoe’s midsole as much as their heel striking counterparts. For a shoe that boasts more foam at the forefoot, we suggest checking out the ASICS Gel Nimbus 25 instead.

Test results
Ultraboost Light 18.2 mm
Average 24.7 mm
Compared to 260 running shoes
Number of shoes
7.6 mm
Forefoot stack
34.8 mm

Drop

The difference in our two stack measurements leave us with a drop height of 11.9 mm, which classifies the Ultraboost Light as a high-drop shoe. This steep drop definitely favors runners with a heel striking stride as it promotes good heel-to-toe transitions. 

It must be said that high drop shoes put more strain on our knees and hips which can increase the likelihood of injury, especially for forefoot strikers. Check out this helpful guide for more information that will help in choosing the right drop height.

Adidas Ultraboost Light Drop
Test results
Ultraboost Light 11.9 mm
Average 8.8 mm
Compared to 260 running shoes
Number of shoes
-0.8 mm
Drop
16.1 mm

Insole thickness

We measured the insole of the Ultraboost Light at a meager 2.8 mm which is a fair bit thinner than our current lab average. 

Adidas Ultraboost Light Insole thickness
Test results
Ultraboost Light 2.8 mm
Average 4.4 mm
Compared to 256 running shoes
Number of shoes
1.5 mm
Insole thickness
9.8 mm

Midsole softness

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

The midsole of the Ultraboost light is decidedly plush. With a reading of 15.5 HA according to our durometer, the shoe’s midsole is much softer than our current lab average. 

Adidas Ultraboost Light midsole durometer

While this may be the case, the midsole has a lot of bounce to it and doesn’t bottom out when weight is applied to it, rather quickly springing back to shape. This means that the Ultraboost Light boasts a ride that is not only cushy and comfortable, but energy-efficient enough to support our long distance runs as well. 

On the other hand, while it is possible to pick up the pace in this shoe; the sheer lack of foam at the forefoot meant that our toe-offs weren’t poppy enough to support tempo runs. For a daily shoe that’s more capable of high pace running, we recommend the Adidas Adizero SL which provides performance on a budget .

Test results
Ultraboost Light 15.5 HA
Average 23.6 HA
We use an average of four tests. The photo shows one of those tests.
Compared to 242 running shoes
Number of shoes
6.5 HA
Midsole softness (soft to firm)
52.5 HA
Note: a low durometer measurement equals a soft material, whereas a high measurement means it's firm.

Midsole softness in cold

Note: a low durometer measurement equals a soft material, whereas a high measurement means it's firm.
Adidas Ultraboost Light Midsole softness in cold

Difference in midsole softness in cold

We popped the Ultraboost Light in our freezer for twenty minutes to simulate exposure to cold weather and re-tested the shoe’s midsole with our durometer. With a reading of 19.8 HA, the Ultraboost light remains remarkably soft in the cold compared to the average shoe. 

This, in conjunction with the shoe’s toasty upper, makes the Ultraboost Light a great choice for winter running of those living in colder climates as it remains cushy and plush no matter the weather. 

While these results make the Ultraboost Light about as consistent as the average shoe under the same conditions, stiffening up by 27.4% in the cold; we must bear in mind that the shoe’s post-freezer midsole is still softer than the average midsole at room temperature!

Adidas Ultraboost Light Midsole softness in cold
Test results
Ultraboost Light 27.4%
Average 26.3%
Compared to 241 running shoes
Number of shoes
0%
Difference in midsole softness in cold
125%

Stability

Lateral stability test

The Ultraboost Light feels incredibly stable underfoot. Shifting our weight from side to side, our feet felt well planted into the ground despite the shoe’s high heel stack. 

Torsional rigidity

The Ultraboost Light put up a fair amount of resistance as we torqued and twisted it in our hands, giving the shoe a score of 3 out of 5 for torsional rigidity. This helps to offset any instability brought on by the high heel stack while still being flexible enough to adapt to the shape of our foot rather than forcing it in place. 

Test results
Ultraboost Light 3
Average 3.2
Compared to 238 running shoes
Number of shoes
1
Torsional rigidity
5

Heel counter stiffness

The heel counter felt moderately stiff as we squeezed and manipulated it, giving it a score of 3 out of 5 on our subjective scale. This level of stiffness means that the shoe does a good job holding our heel in place and helps to prevent too much rolling from side to side. 

Test results
Ultraboost Light 3
Average 2.7
Compared to 222 running shoes
Number of shoes
1
Heel counter stiffness
5

Midsole width in the forefoot

We measured the midsole with our caliper to be 117 mm wide at the forefoot. This is significantly wider than our current lab average, and gives us an extremely steady, if somewhat firm, platform to land on for forefoot strikers. 

Adidas Ultraboost Light Midsole width in the forefoot
Test results
Ultraboost Light 117.0 mm
Average 113.4 mm
Compared to 261 running shoes
Number of shoes
100.5 mm
Midsole width in the forefoot
126.5 mm

Midsole width in the heel

The midsole is also wider than average at the heel, measuring 93.7 mm according to our caliper. This gives heel striking runners more than enough surface to ensure stable landings 

The overall wide midsole of the Ultraboost light gives us an added sense of stability that is often lacking in high stacked shoes. This means that the shoe will also benefit runners with a slightly pronating stride.

Adidas Ultraboost Light Midsole width in the heel
Test results
Ultraboost Light 93.7 mm
Average 90.3 mm
Compared to 261 running shoes
Number of shoes
74.9 mm
Midsole width in the heel
106.6 mm

Flexibility

Stiffness

We test the flexibility of a shoe by securing it to our workbench and measuring how much force is required to torque the shoe to 90-degrees. With a reading of only 18.6N the Ultraboost Light is much less stiff than our current lab average. This definitely contributes to the ease and comfort we felt when testing the Ultraboost Light; with the shoe moving with the natural motion of our foot instead of fighting it.

Test results
Ultraboost Light 18.6N
Average 29.0N
We use an average of four tests. The video shows one of those tests.
Compared to 244 running shoes
Number of shoes
2.2N
Stiffness
94.4N

Difference in stiffness in cold

We repeated the stiffness test after leaving the Ultraboost Light in the freezer for twenty minutes and got a reading of 24.4N. This makes the Ultraboost much more flexible than our lab average under the same conditions, and means that the shoe will remain extremely pliable even during the frostiest winter runs. 

These results mean that the Ultraboost Light only stiffens up by 31.3%, making it much more consistent than the average shoe between warm and cold conditions. To further contextualize just how remarkably flexible the Ultraboost Light is in the cold, it rivals the reading of a great bulk of shoes we’ve tested at room temperature! 

Test results
Ultraboost Light 31.3%
Average 38.8%
Compared to 244 running shoes
Number of shoes
0%
Difference in stiffness in cold
148%

Grip / Traction

The outsole provided us with sufficient traction across most surfaces we came across with the exception of a patch of cobblestone, soaked by a nearby sprinkler, that proved to be a challenge for the shoe’s grippiness. 

Adidas Ultraboost Light grip

Size and fit

Toebox width at the widest part

We measured the toebox at its widest point to be 102.9 mm. This makes the shoe quite a bit roomier than average and means that runners with wide feet will have no issues with fit in the Ultraboost Light. 

Adidas Ultraboost Light Toebox width at the widest part
Test results
Ultraboost Light 102.9 mm
Average 98.2 mm
Compared to 262 running shoes
Number of shoes
89.5 mm
Toebox width at the widest part
109.1 mm

Toebox width at the big toe

Moving down to the big toe area, we measured the toebox to be 81.6 mm. This is also wider than the average for shoes we’ve tested in the lab, which means that our toes have more than enough room to splay naturally without being constricted by the shoe. 

Adidas Ultraboost Light Toebox width at the big toe
Test results
Ultraboost Light 81.6 mm
Average 77.8 mm
Compared to 134 running shoes
Number of shoes
67.6 mm
Toebox width at the big toe
90.4 mm

Toebox feel

The knit upper is nice and stretchy, which combined with the wide base, meant that the upper comfortably wrapped itself around our foot with enough elasticity to lock the foot down with minimal movement. 

Runners with very narrow feet, however, might find the Ultraboost Light to be a little too roomy. We therefore recommend that those runners look into sizing down as the shoe does run a little long as well.

Adidas Ultraboost Light Toebox feel

Heel feel

The heel cup on the Ultraboost Light is well padded and shaped in a way that snugly squeezes the heel while avoiding putting too much pressure on the Achilles.

Adidas Ultraboost Light Heel feel 2

Tongue: gusset type

The Ultraboost Light is sock-like, which means that the tongue is an integral part of the upper with no separation from it. While this contributes to the shoe’s comfort, it’s not tight enough to provide adequate midfoot lockdown for tempo training. 

Adidas Ultraboost Light Tongue: gusset type

Test results
Ultraboost Light Sock like

Comfort

Tongue padding

The padding in the tongue area of the shoe’s upper is only 1.3 mm thick based on our caliper measurements. While this is quite meager compared to our lab average, the plastic overlays adorned with the Adidas logo that hold the laces keep them from cinching down too tightly around the instep; so lace bite was never an issue during our test runs. 

Adidas Ultraboost Light Tongue padding

Adidas Ultraboost Light tie

Test results
Ultraboost Light 1.3 mm
Average 5.7 mm
Compared to 258 running shoes
Number of shoes
0.5 mm
Tongue padding
14.2 mm

Heel tab

The Ultraboost Light doesn’t have any traditional heel loop to speak of; but the heel counter does extend slightly to form an elf ear tab that helps pull the shoe on, as well as providing some added support around in the rearfoot area. 

Adidas Ultraboost Light Heel tab
Test results
Ultraboost Light None

Removable insole

The insole of the Ultraboost Light is removable, making the shoe suitable for custom orthotics if needed. 

Test results
Ultraboost Light Yes

Misc

Reflective elements

With no reflective element whatsoever, the Ultraboost Light completely disappears in the dark. We therefore advise keeping to well-lit areas or taking the appropriate precautions when running at night. 

Adidas Ultraboost Light Reflective elements
Test results
Ultraboost Light No