Almost all of my running shoes fall into one of two categories: shoes for speed, and shoes for distance. It’s not every day that I find myself running in a shoe that meets both my fast-paced and slow-paced requirements. But then I was asked to test the Mizuno Wave Sky 4 Waveknit shoes, and let me tell you that these kicks are really suited for almost any kind of run.
The Mizuno Wave Sky 4 Waveknit design looks fairly identical to the Mizuno Wave Inspire 16 Waveknit I also reviewed for the 2020 SELF Certified Sneaker Awards. If you put the two next to each other, you really wouldn’t be able to tell the difference immediately. While visually alike, the two differ in that the Wave Sky 4 has Mizuno’s XPOP PU foam and Mizuno Enerzy, which gives this iteration a more cushioned feel than the Wave Inspire 16. (Editor’s note: Several shoe brands implement proprietary foam technology, all with varying degrees of cushion versus responsiveness. Per its website, Mizuno claims the Enerzy combines with the XPOP for a plush midsole experience.) It’s probably the biggest difference I noticed in the shoes during my runs.
How I Tested
Just like my other Sneaker Awards testing, I incorporated a mix of speed drills (one to two miles) and middle-distance runs (three to four miles) in these Mizunos. Again, I typically categorize shoes into two areas (speed or long distance), so I wanted to use my runs to determine into which category these Mizunos best fit. Unfortunately for my type-A personality, I couldn’t assign these shoes to just one category—because they honestly work for both scenarios!
My testing routine followed the criteria recommended by our experts. Read more about their criteria here, and check out my thoughts on how the Mizuno Wave Sky 4 fared for each of their criteria below.
Fit and Shape of the Shoe
These Mizunos are closely related to the Mizuno Wave Inspire 16 Waveknit in both of these areas.
It’s a flat shoe with decent wiggle room for your toes. The sides of the shoe basically hug your feet so that they feel secure without feeling tight. These shoes have a traditional lace-up style, with a shoe tongue that’s easily adjustable so you can really find a tight, custom fit. The ankle collar is slightly padded, so if you’re looking for a more minimalist feel, these might not be right for you. There’s also a fairly average drop, meaning the profile of the shoe isn’t too bulky and doesn’t add inches to your overall height. (A running shoe’s drop refers to the difference in height between the heel and the toe of the shoe. The drop on this Mizuno shoe is 10 millimeters.)
Other than those points, both the fit and shape of this shoe are pretty straightforward. That’s not necessarily a bad thing—it’s just that it looks and fits just like…most other running shoes.
Feel of the Shoe
Feel is where I’ll hammer in on the key differences between the Sky 4 and Inspire 16: the XPOP PU foam and Mizuno Enerzy. Particularly during the speed drills, the addition of the extra cushion becomes very pronounced. Instead of feeling like my feet and shoes were combining forces to hit the pavement, theses Mizunos felt more like my feet were running and the shoes were bodyguards against the impact—which my body very much appreciated on the days after my harder runs! Because my legs didn’t exert so much energy, I was able to push myself more than if there was less cushioning.