Mizuno Wave Inspire 20 review

We recommend the Mizuno Wave Inspire 20 as a great choice for:

• Overpronating runners in need of a comfy and stable daily trainer with a spacious toebox
• Heel-striking runners looking for a well-cushioned shoe that's protective and responsive enough for long-distance and marathon training.
• Those who prioritise reliable traction and want a shoe that can tackle some off-road activities
• Year-round runners in the market for a shoe that's breathable but performs consistently in the cold

The Wave Inspire 20's 12.4 mm drop might prove to be a little too steep for runners with a forefoot striking stride. We recommend the Saucony Tempus (8.5 mm) or the Hoka Gaviota 5 (2.2 mm) as more suitable alternatives for their strike pattern. 

While the Wave Inspire 20's toebox is accommodating enough to provide a comfy fit for those with normal to wide feet, it will likely prove a little too roomy for those with narrow feet. We recommend checking out the ASICS Gel Kayano 30 for a more snug and locked-in feeling at the forefoot. 

Stability shoes tend to be on the heavy side and the Wave Inspire 20 is no exception at 10.7 oz (302g) according to our scale. For runners who prefer a more lightweight ride, we recommend the Saucony Guide 16 (9.70 oz/275g) or the Hoka Arahi 6 (8.89 oz/252g).

Those with a rearfoot strike pattern will love the Wave Inspire 20's beefy heel stack which we measured with our calliper to be 37.7 mm thick. This is significantly higher than our current lab average and means that we have plenty of foam underfoot for well-protected heel landings while testing this shoe. 

Apart from being beneficial for heel-strikers, this feature is excellent for long-distance running where fatigue can affect our running form and cause midfoot/forefoot strikers to revert to heel striking as the miles wear on. 

The Wave Inspire 20's stack isn't as chunky at the forefoot, measuring 25.1 mm thick according to our caliper. This amount of foam underfoot effectively mutes out the harsh road below by allowing our feet to sink into and savor the midsole cushioning from landing to toe-off. 

The difference in our stack measurements leaves the Wave Inspire 20 with a drop height of 12.6 mm, making the 12 mm offset stated by Mizuno quite accurate. While this might sound like a given, our findings in the lab so far have turned up quite a few disparities in manufacturer-stated heel drops as we explore in this article. 

High-drop shoes like the Wave Rider 20 are generally more advantageous for those with a heel-striking stride or those with lower leg issues. That said, we found that the midsole's SmoothRide rocker geometry promotes smooth transitions that even midfoot and forefoot strikers can appreciate. 

For runners who prefer shoes with less drastic offsets, we recommend looking into the Saucony Tempus (8.5 mm) or the Hoka Gaviota 5 (2.2 mm) instead. 

We pressed our durometer against the Wave Inspire 20's Enerzy Foam midsole and got a reading of 22 HA. This is about as soft as our current average for road shoes. 

This level of softness is exaggerated by the shoe's healthy stack, allowing us to really savour the shoe's cushioning as it dampens the impacts of our landings. At the same time, the Wave plate embedded in the midsole prevents us from sinking into the midsole too much which contributes to the shoe's comfy yet stable ride. 

The Enerzy Foam also has a pleasant and responsive rebound with a slight springiness to it that felt great whether we were out for an easy recovery run or testing our gas tank with a marathon training session. 

To test the effects of cold conditions on the midsole, we placed the Wave Inspire 20 in our freezer for twenty minutes. Once appropriately chilled, we pressed our durometer against the Enerzy Foam once more and were impressed to find that it only became 14.2% firmer. This makes the Wave Inspire 20 more consistent than the average road shoe under similar conditions and, with a reading of 25.1 HA, means that the shoe should still provide a balanced and comfy level of cushioning during the winter months. That said, with its relatively high breathability, we recommend pairing the Wave Inspire 20 with a pair of warm socks to avoid frosty feet on particularly frigid days. 

At 5.5 mm thick according to our caliper measurements, the Wave Inspire 20's insole is a little thicker than our current lab average. This gives us a nice and cushy footbed to sink into as the midsole works its cushioning magic. 

Using our calliper, we measured the Wave Inspire's toebox to be 101.6 mm wide at its widest point. This is significantly wider than our current lab average and means that the shoe will provide an accommodating fit for runners with broad feet. What's more, the added internal real estate gives us some space for our feet to swell without being constricted by the upper during our longer runs. 

However, this might prove to be a little too roomy for those with narrow feet. For a more snug alternative, we recommend checking out the ASICS Gel Kayano 30 instead. 

The toebox is also roomier than average in the area around the big toe at 78.9 mm wide according to our caliper measurements. As such, we had plenty of room for our toes to splay out naturally while testing the shoe without worrying about painful hotspots or blisters. 

Despite the Wave Inspire 20's chunky stack, the shoe feels incredibly stable during our test runs. Rather than using rigid medial posts to achieve this, Mizuno opts for its signature Wave Plate embedded in the midsole (and visible through the cutouts) that lends the shoe its moniker. 

The Wave Inspire 20's heel is bevelled in a way that allows us to land on the outside of our foot and smoothly transition to the forefoot. The Wave plate embedded in the midsole also helps evenly disperse the force of impact in tandem with the cushy Enerzy foam. 

Additionally, its positioning under the arch of our foot feels incredibly supportive and makes the Wave Inspire 20 a good choice for those with flat feet. 

Further adding to its confidence-inspiring ride is how the midsole flares upwards to form sidewalls at the shoe's rear and medial side. This means that our feet feel cradled within the foam rather than perched precariously atop the Wave Inspire 20's high stack. 

The aforementioned Wave plate lends the shoe a relatively high level of torsional rigidity, leading us to give the Wave Inspire 20 a rather stiff score of 4 out of 5 in this manual assessment. As such, the shoe resists the excessive lateral movements of our foot during our test runs. This not only helps us maintain a more neutral gait but leaves us with a nice and steady landing platform for a surefooted and stable ride. 

The Wave Inspire 20's heel counter also feels quite stiff as we squeeze and probe at it, leading us to give it a subjective score of 4 out of 5. This limits the lateral mobility of our rearfoot and helps us achieve a secure lockdown without putting too much pressure on our tendons. 

At 115.5 mm wide according to our calliper measurements, the Wave Inspire 20's midsole is slightly wider than average at the forefoot.

This gives us more than enough of a base to ensure stable landings and toe-offs without the shoe feeling too blocky when taking corners.  

The midsole is significantly wider than average at the heel, measuring 94.2 mm wide at the forefoot. This further confirms how well-suited the Wave Inspire 20 is for heel-striking runners as it gives them a very broad landing platform that's conducive to their stride. 

While it has a relatively high level of torsional rigidity, we found that only 20.7N of force is needed to torque the shoe to 90 degrees in our stiffness test.

This makes the Wave Inspire 20 more flexible than average in a longitudinal sense. This contributes to the shoe's comfortable ride as it conforms with the natural flexion of our foot with relative ease. 

Becoming only 8.1% stiffer, the Wave Inspire 20 displays an impressively consistent performance as we repeat the flex test after leaving the shoe in our freezer for twenty minutes. As such, despite being well-suited for warm weather, the shoe will feel just as flexible and forgiving on the foot as temperatures drop. 

Tipping our scale at 10.7 oz (302g), the Wave Inspire 20 is on par with the average stability shoe which tends to be on the heavier side when compared to most road shoes. That said, thanks to the rockered and responsive midsole, the Wave Inspire 20 never felt overly burdensome during our test runs, even when we pushing the mile markers. 

For runners looking for a more lightweight stability shoe that can also gobble up miles, we recommend checking out the Hoka Arahi 6. 

The Wave Inspire 20's tongue is semi-gusseted on both sides. We found this to be a welcome feature as it further contributes to our foot's locked-in feeling within the shoe while also preventing the tongue from slipping at higher paces. 

Despite a slow start in our breathability test, the shoe is suddenly engulfed in a haze of smoke that steadily filters through the entire upper. This leads us to give the Wave Inspire 20 a respectable 4 out of 5 in this assessment which indicates a good amount of airflow that allows heat to escape the shoe quite easily. 

As we can see from inspecting a backlit cross-section of the upper, the light is able to shine brightly through the mesh at the toebox while the more reinforced lateral section blocks it out almost entirely. This more insulated portion is what prevents the shoe from achieving a perfect breathability score. 

Looking at the toebox under our microscope, we see that the mesh is made up of a multi-layered network of braids with lots of little gaps for airflow that open up to form larger gaps that go all the way through the toebox. This explains the shoe's breezy nature which makes it a good warm-weather companion. 

Shoes with breathable mesh uppers don't usually do too well in our durability test but we were very impressed with how well the Wave Inspire 20 stood up to our imposing Dremel. 

After withstanding four seconds of abrasive force simulating extreme wear and tear, we found that the toebox was left with only a small rip in the upper outer of its mesh. This earns the Wave Inspire 20 a toebox durability score of 4 out of 5 which is excellent for a road shoe. We, therefore, have added confidence taking this shoe off-road as an accidental bump on a rock of snag on a bush isn't likely to compromise the toebox. 

The heel collar proved to be even more resilient in the face of our Dremel which wasn't able to bite into the lining material, with its abrasive element skating off it rather impotently during the four-second test. 

Apart from a minor scuff, the Wave Inspire 20 escapes essentially unscathed with the padding within fully intact. This leads us to give it a perfect 5 out of 5 in this assessment and means that we don't expect any issues with rearfoot comfort or lockdown throughout the shoe's lifetime. 

The Wave Inspire 20's outsole is comprised of the brand's proprietary X10 carbon rubber that's marketed as providing excellent traction as well as high wear resistance. Giving us a slightly harder-than-average durometer reading of 84 HC bodes well for the outsole in the shoe's final face-off with our Dremel

With high expectations for the X10 rubber, we fired up our Dremel to 10K RPM and set it against the outsole with 3.2N of force. After twenty-two seconds of grinding, we used a tyre tread gauge to measure the indentation and were somewhat surprised.

With 0.9 mm of material lost from the outsole, the X10 didn't deliver the performance we had anticipated. Instead, it's just average. This isn't necessarily a bad thing, though, as we still think that this shoe will last the predicted shelf life of 400 to 500 miles of use, even if used on mild trails occasionally. 

The Wave Inspire 20's outsole falls in line with our current lab average at 3.2 mm thick according to our caliper measurements. This amount of rubber gives us a deep enough tread for solid traction as we tested the shoe on various surfaces without adding too much weight underfoot. 

The Wave Inspire 20's X10 outsole features a wavy tread pattern that stays true to the shoe's name and covers the major points of contact with the grounds. This provided us with excellent traction on roads and pavements during our test runs. Even a smattering of rain that left the roads wet and slippery didn't compromise the shoe's grippy nature. 

What's more, the outsole's mini lugs allowed us to tackle some mild park trails and activities on dewy grass just as confidently as on the asphalt. 

With no reflective elements to be found on the shoe, we don't recommend using the Wave Inspire 20 on dimly lit routes at night without additional high-vis gear. 

At 7.1 mm thick according to our caliper measurements, the Wave Inspire 20's generously padded tongue is thicker than our current lab average. As such, the shoe feels very comfortable across our instep and allows us to achieve a secure midfoot lockdown with no trace of lace bite during testing. 

The Wave Inspire 20's tongue is semi-gusseted on both sides. We found this to be a welcome feature as it further contributes to our foot's locked-in feeling within the shoe while also preventing the tongue from slipping at higher paces. 

The Wave Inspire 20's insole isn't glued in so replacing it in favor of an aftermarket alternative or a custom orthotic is possible where necessary.