Mizuno Wave Sky 4 vs 3 Comparison Shoe Review

by Sportitude
16 Oct 2020

Josh reviews the Mizuno Wave Sky 4, a max cushioned shoe in Mizuno’s high mileage running shoe family with an even plusher underfoot sensation than its predecessor, the Mizuno Wave Sky 3.

A fresh addition to the stable neutral category, it caters to a variety of runners including neutral and supinated (high arched) foot types and mild overpronators (flatter foot types) that prefer more subtle support.

Built upon the same outsole configuration as its predecessor, it offers hard-wearing rubber under the rearfoot for heel strikers and a balance of support and flexibility from the flex groove set-up.

The midsole is where the magic is in the Wave Sky 4. A bottom layer of responsive Enerzy Foam, top layer of plush U4icX cushioning and XPOP running virtually the entire length of the shoe creates an energy-returning ride that’s soft yet snappy.

It offers a consistent, secure fit through the upper, allowing the midsole technologies to get to work uninhibited. Choose from the lightweight and breathable engineered mesh upper of the standard model or the Waveknit upper for a more durable feel.

Check out the review with full transcript below.

Hey guys, Josh here from Sportitude and it’s shoe review time. Today we're going to be talking all things Mizuno Wave Sky 4.

This shoe is their premium high mileage neutral running shoe and it has had a little bit of an update on the Mizuno Wave Sky 3. It doesn't look like much has changed within this shoe but there is quite a bit of magic that Mizuno have put into this midsole which we'll get into in today's review.

Like all my shoe reviews, we’re going to talk all things outsole, midsole and upper. We’ll compare it  to the previous version which is the Wave Sky 3, profile the foot that could be considering this shoe and give you information at home that might make this your next shoe for your mileage running. Let's get stuck in.

Runner Profile

First things first, let's profile the foot that could be considering the Wave Sky 4. Technically it's a neutral running shoe so we’re looking at a foot that would potentially have a high arch which means there’s a little bit of air between the ground and where the arch starts.

Most of the pressure would be either through the central part of the foot or towards that lateral column so if someone happens to supinate, the foot will tilt out through their gait cycle. These neutral or supinated foot types can consider the Wave Sky 4.

However, like all stable neutral shoes it may have success fitting that runner that does mildly overpronate with a flatter foot from a static position. As they come through to midstance the foot may ever so slightly tilt towards that first metatarsal on to toe-off to get out of their gait cycle.

There's a lot of runners out there that have a foot shape like this that don’t like support systems, whether it’s a dynamic support system or some form of dual density structure because it works against them. They are absolutely fine running in a shoe that is stable neutral and that is exactly what the Mizuno Wave Sky 4 is.

It's a versatile shoe that can cater for a neutral to supinated foot type that rolls out or a mildly pronated foot type.


Let's talk all things outsole with this shoe. It won't take me long because there is nothing that has changed between the Mizuno Wave Sky 3 and Wave Sky 4 in the outsole.

Mizuno do this from time to time. They'll keep some engineering systems the same and they have done the exact same with the outsole of this shoe.

You've got your high impact rubber in the lateral part of the heel on that first point of contact for heel strikers. It’s a nice durable rubber and as you're coming through to the forefoot we have five flex grooves on offer.

The middle three flex grooves don’t go the whole way to that medial side of the foot. If you look at the rubber it just gives a little bit more support on that last phase of your gait cycle. It doesn't slit the whole way through where it would become too flexible on toe-off.

In my opinion it works better with this new midsole configuration because it is a softer midsole than the one they had previously made in the Wave Sky 3. So yes, the outsole is the same but the shoe flexes completely different than what it did last year, mainly due to the midsole.


Let’s talk all things midsole now and start off with the heel-to-toe drop. We are on a 10 mm heel-to-toe offset in both men's and women's. That's a 33mm measurement through the heel and a 23mm measurement through the forefoot for an offset of 10mm.

As I touched on in my intro, most of the change in this shoe is in the midsole. Let's get talking about this midsole because there's a bit going on.

Mizuno have they've used their new Enerzy Foam. On their reports, it's an extremely soft and responsive foam. The bottom layer of this midsole, the white component of the Wave Sky 4 is the Enerzy Foam and the top layer which is the orange and yellow component in this specific shoe is their U4icX cushioning system which is pretty darn soft as well.

U4icX last season was the softest foam that Mizuno have ever made and manufactured. They’ve now rolled out the Enerzy Foam which is that really soft, responsive foam as well, but it doesn't just stop there.

We've got the XPOP which is that polyurethane responsive system that Mizuno have introduced into the Wave Sky 3 last year. You can see that yellow component in the mid shank and the same thing goes with the Wave Sky 4.

The XPOP essentially sits from the back of the shoe and it runs right through just before your metatarsal heads. That system is a nice, responsive foam that they've introduced to complement what they're trying to achieve with the Mizuno Wave technology.

Mizuno Wave technology is similar to what they've ran for a couple of decades with all their technologies having that Wave Plate that splits two density midsoles. The Mizuno Wave sits together and when you compress the actual shoe it works together. You've got a soft density and firmer density that's going to assist in compressing on the vertical plane, which is the force coming down on the foot.

As you come through to your midstance to toe-off phase, the Mizuno Wave technology works on the horizontal plane to potentially reduce your ground contact time and to assist getting you through and out of your gait cycle.

It is a nice system underneath the foot and it certainly feels a lot softer than last season which I personally like. That was a nice soft shoe on the foot as well.

On your first step in you'll notice you've got a max cushion shoe on your foot, that is for sure. As we touched on, it is a neutral shoe so on the medial side of that midsole, there is no arch support that's been built into this running shoe.

There's no dual density system, there's no dynamic support system on that medial side. It is neutral meaning it's pretty similar on that lateral side and the medial side. That's essentially what a neutral shoe is all about.


Let's talk all things upper. I personally feel this shoe fitted almost exactly the same as last season with regards to widths on the foot. For the men's we're looking at a D standard and a 2E for a broader offering. The ladies’ comes in a B standard and a D which is slightly broader as well.

Just note that there are different colours for the width offerings and there is a link to the individual product pages below and the Mizuno Wave Sky page so you can have a look at the width offerings.

Regarding the fit up top, I didn't find it to fit totally different but there's a bit more magic going on in the upper of the Mizuno Wave Sky 4.

Let's talk about the heel counter. It’s still an internal heel counter and it still has that nice memory foam around the back. That internal lining is the same as the previous Wave Sky.

There's not a lot of change with how your foot sits inside the shoe and the support you get around the back of your heel. It’s still a soft and very comfortable first step in.

As you come through to the midsection there is a little bit of a change. Mizuno have called it out by these colours on the upper. The colour forms almost like an upside down V on the lateral and medial side. That's an extra welding system that has interlocked to the upper and comes down to the midsole.

As we come around the eyelets you can see that little extra V that drops down on the medial and lateral side. If you think about your foot sitting inside this shoe, you're getting more security from the back heel that comes right up around the arch.

When I said I didn't notice a change at all, I don't think anyone's going to notice much of a change. However, this system is going to play true when you look at the halfway point of the life expectancy of this running shoe towards the end. It'll give your foot a little bit more support through the whole duration of the life of this shoe versus what they did previously which fitted quite well.

The couple layers of mesh on top on the Mizuno Wave Sky 3 fitted quite snug and secure. There was some feedback early days about having a bit too much of a gape on that medial side, being a little airy through there. With this system of the Mizuno Wave Sky 4, on that medial side it just pulls the upper over your foot a little more to give more support.

The whole point of the upper is to keep your foot on a nice consistent, stable transition through every single step of your running cycle and letting the midsole do what it does best, providing support, cushioning and response. It’s a really good execution on the upper, I like what they've done.

As you come through to the forefoot, I wouldn't say it's a deep toe box but it's a nice secure fit. If you're a Mizuno Wave Sky runner, you'll probably recall the Wave Sky 2 which was the last of the traditional Wave Plate technologies that Mizuno had. That was a slightly boxier fit up through the front half of the shoe.

The Wave Sky 3 went to a slightly shallower fit which was a nice personal touch. I like that because you get a bit more security and lockdown on that forefoot. However, there's just enough wriggle room there for the runner that requires a little bit of toe space.

In talking about the upper, it's worth calling out that the Wave Sky 4 comes in a knitted version as well.  For the Mizuno Wave Sky 4 Waveknit, the midsole and the outsole set-up are the same as the standard model, the only change is the upper.

It's a knitted technology that feels a lot more durable. It wraps the foot quite nicely and this is the shoe that I did my testing in. I wasn't able to get my hands on the engineered mesh version which was on offer from Mizuno.

I did my testing in the Waveknit which was absolutely fine and I liked it. If I happened to choose myself I would definitely go for the mesh offering. It's marginally lighter and it's going to breathe a little better.

If I’m looking at these two on the wall and someone asks, “Why should I go with the knit?” or “Why should I go with the open mesh?”, it's going to be more of a comfort factor.

If you like the feel of the knit on top of your foot or if you're a walker and you want something more casual, that might be more applicable to your requirements. If you're running I would certainly offer the engineered mesh system before the knit but that's just my opinion.

To wrap up the Wave Sky 4, it’s a high mileage neutral running shoe from Mizuno. There's a lot to like about this running shoe. It has a good combination of your soft dampening cushioning system in conjunction with that responsive feel which is what Mizuno customers like about their running shoes.

Other than the little tweaks in the upper, I like what they've done with the lockdown. It's still a very popular shoe for customers wanting a really cushioned shoe underneath their heel and podiatrists that are seeking some assistance with an orthotic.

If you have any questions about the Mizuno Wave Sky 4 or if you've been a Mizuno Wave Sky 3 runner and have some feedback, please contact our Sportitude shoe experts.

Please subscribe to the Sportitude YouTube channel if you haven't done so already and we'll continue to bring as much running information to you at home as possible.

Until next time guys, stay safe and happy running. We’ll see you on the road. Take care.


  • Support: Neutral
  • Upper: Mesh or Knit
  • Midsole: Mizuno XPOP Foam, Mizuno Foam Wave, Mizuno Enerzy, Mizuno U4icX
  • Heel Height: 33mm
  • Forefoot Height: 23mm
  • Offset / Drop: 10mm


  • Weight: 325g / 11.5oz
  • Width: D (standard), 2E (wide)


  • Weight: 275g / 9.7oz
  • Width: B (standard), D (wide)