Mizuno Wave Mujin 9 Review: Back to the Wild

The Intro

MICHAEL: In Marvel’s Captain America, Steve Rogers intends to join the armed forces and do his part to defend the US of A. Unfortunately, Rogers’ stature wasn’t mighty, and it’s not until he’s injected with some secret sauce that the military deems him ready to fight. At this point, you’re probably already asking, what do America’s first superhero and the Mizuno Wave Mujin 9 have in common?

To put it bluntly, Mizuno has had about as much influence in the trail shoe market as our lil’ man Steve Rogers did in the war against Hydra before he got juiced. The similarities don’t stop there, though, because just like our buddy Steve, Mizuno has been experimenting with some secret chemicals in the lab, resulting in new midsole compounds and a promising new future for a brand previously thought to be slowly dying away in a lost era of running shoe technology.

At TRE in December, Mizuno dropped one of the most exciting, wildest plated racers we’ve seen in a while, leaving us anxiously anticipating the trickle-down of the technology into the company’s underpowered and often downright non-existent trail line. As Mizuno slowly resurrects its lineup with the not-so-secret-serum of new midsole compounds like Enerzy and Enerzy Lite Pro, the Wave Mujin 9 has returned as a sort of all-purpose general workhorse, built for daily mileage on technical trails.

Will Mizuno’s first venture back into the woods suddenly contend with the rest of the trail shoe market? Read on to find out.

The Good

MICHAEL: First, we’ve got to talk about some general strides Mizuno is taking as a brand. The Wave Rebellion Pro turned our heads at TRE, and that’s something Mizuno just hasn’t done in a long time. With the introduction of new midsole compounds, Mizuno might be the next Asics of the running shoe world, just waiting to turn out multiple exciting models in the next few years. The excitement is real, and that’s something you have to give Mizuno credit for.

Let’s get the elephant out of the room, the outsole of the Wave Mujin 9 is wild. It carries the personality of the shoe and sets the tone for the rest of the jagged styling throughout. The TPU wrap, midsole, outsole, and even the styling above the name all communicate that this shoe is built to eat up the most rugged trails. I think it’s a great design statement for Mizuno. In one sense, it looks like every other shoe, but there aren’t many shoes whose outsoles could mesh together like gears. Thankfully, it’s no gimmick, as the outsole both met and exceeded my expectations.

The rubber compound here comes from Michelin, which happens to be the same company that produces the outsole for Speedland. I’m not sure if the outsole compound on the Wave Mujin 9 is the same as the OCX3 compound on the SL:HSV, but they performed similarly, which we can be happy with. The outsole gathers more points here for being full coverage. While this may contribute to the weight of the shoe and ultimately take it out of contention for running fast miles (more on that later), it provides loads of extra protection and confidence and leans into what this shoe is built for.

We find more goodness in the relatively new Enerzy midsole foam directly above the outsole. I recently reviewed the Wave Rider 26 and have put nearly 100 miles on that shoe around my neighborhood. As the miles ticked by, I’ve realized I love them, and it’s all because of the full Enerzy midsole. This foam feels light, responsive, and surprisingly durable, given that it’s an EVA blend. While it’s not necessarily the same super flashy compound you might find in Mizuno’s new Wave Rebellion Pro, I think it’s the perfect pick here.

Further up, we run into a different EVA blend from Mizuno, dubbed U4icX. Before you sit for too long trying to figure that one out as I did… it’s pronounced “euphoric.” Clever, right? While I wasn’t exactly a fan of this foam being placed directly underfoot, it does provide some utility in the shoe. Similar to the Hoka Tecton X or the Mafate Speed 4 (two of our favorite trail shoes last year), the firmer U4icX EVA helps stabilize and protect the foot, while the soft, plush Enerzy foam provides comfort.

We’ve seen great success with this dual-density approach in the aforementioned Hoka models, but interestingly enough, Mizuno swaps up the order on us, putting the firm, supportive U4icX on top of the Enerzy and not the other way around. While this didn’t exactly pan out on the run, it did provide a pretty unique feeling of a stable yet adaptive ride, and you have to give Mizuno credit for trying out a dual-density midsole here and not just throwing a good ol’ hunk o’ foam in there and calling it a day.

Rounding off the shoe, the upper is well-constructed, with substantial and comfortable padding throughout. The upper mesh breathes fine, and I didn’t have any issues with overheating or lockdown. The tongue is well padded, too, offering comfort over the long haul, and it’s certainly worth mentioning that the sock liner and upper lining are both made from 90% recycled content, which is pretty sweet. Overall, I’d say this upper just works. It didn’t exactly wow me, but it wasn’t terrible, either.

On the run, the Mizuno Wave Mujin 9 provided a very stable, welcoming ride for daily mileage. The forefoot is substantially wide (but not quite Lone Peak levels), providing accommodation and stability for just about any runner. It simply performed well as a good ol’ trail shoe, great for tackling technical terrain and being ready to handle pretty much anything you throw at it. The protection from the U4ic foam and full coverage outsole worked together to provide a pretty nice underfoot sensation, with a good mixture of protection and trail feel.

The vibes here are overwhelmingly Brooks Cascadia, and while that can stir up some areas of critique for the Wave Mujin 9, we’re going to leave it in the good column. If you’re a runner or hiker looking for a stable, dependable shoe with a very nice blend of protection and trail feel and some gnarly grip, the Wave Mujin 9 might be right for you.

The Bad

MICHAEL: Unfortunately, the results from the super sauce injection into Mizuno’s revamped line are not all gains, as there are still some significant kinks to be worked out in the Wave Mujin 9. For starters, let’s talk about the weight of this shoe. During my first run in the shoe, I expected something light for this category, like somewhere in the ballpark of, say, the Lone Peak 7 or the Brooks Cascadia 16.

After all, the spec sheet for the shoe said 8.1 oz, which I figured to be indicative of a smaller size shoe than the standard US M9 or M10 listed on spec sheets, but I still got my hopes up. Turns out, they must have weighed Robbe’s pair before they were sent out because my US M9.5 came in at a mean 12.6 oz. TWELVE POINT SIX, folks. It’s a shame because this significantly narrows what this shoe is good for. That weight takes this shoe from Cascadia 14 territory back into Cascadia 13 territory and breeds a host of issues with this revamp. If this shoe’s midsole was more like a Hoka Stinson or Brooks Caldera, boasting tons of plush cushioning underfoot, then the weight may be justifiable, but such is not the case.

The Wave Mujin 9 is protective but is not exactly plush. It’s a bit unexpected, honestly, coming from a shoe that boasts a substantial stack height, but like Arnim Zola in SHIELD, there’s an old spy lurking around Mizuno’s lab. You guessed it… it’s that pesky U4icX midsole foam. I’m not sure whether it’s because the foam is placed directly underfoot or that it’s just an outdated, lousy compound, but the stuff really sows seeds of heavy and dull in what may have otherwise been a lovely field of Enerzy sunflowers. While the new, light, responsive foam is down there workin’ hard, doin’ its thing, the U4ic is right there on top, suppressing any sort of liveliness underfoot, with a two-punch knockout of weight and firmness. It’s honestly a shame.

On the spec sheet, Mizuno lists Enerzy as being 17% lighter and 15% more responsive than U4ic but decided to place a nice sheet of U4ic underfoot. In the next iteration, I just hope Mizuno doesn’t mess around and just throws in a full stack of Enerzy, or at least makes the part of the midsole that’s supposed to offer more protection lighter as well.

The full-coverage outsole already does a sufficient job in the underfoot protection department, and making this midsole full-Enerzy would not only lighten up the shoe but also make it more comfortable over the long haul. A similar adjustment was made in the Wave Rider 24 vs. the Wave Rider 25 and 26, and I think it was really for the better. It’s time for Mizuno to really let go of those old vices of weight and stiffness… bright days are ahead.

While the outsole of the Wave Mujin 9 really hosts the personality of the shoe, it has some downsides of its own. Similar to the SL:HSV, the Michelin man certainly adds some weight here, probably not without the help of those talons running along the sidewall (which I found to scrape up my calves from time to time). Also, the outsole is very flat, both in longitude and latitude. While this makes the shoe uber-stable, it really detracts from the liveliness when trying to pick up the pace. This shoe does NOT accelerate quickly.

Last but not least, the sizing ran long for me, and while the upper was nice and accommodating, the fit was just a bit too roomy for my liking.

Mizuno Wave Mujin 9 Conclusion

MICHAEL: While the Wave Rebellion Pro was a serious slam out of the park, the Mujin 9 turned out to be just a solid double. Despite its setbacks, it gets the job done in reinstating Mizuno’s trail line with some promising hope for the future. Besides the weight of the shoe, there’s really not too much to complain about.

Sure, I lamented the U4ic foam a bit, but Mizuno has all the right materials at play, and with a few more iterations, I think we could have something on our hands that is truly competitive with the Brooks Cascadia and Saucony Peregrine of the world. Unfortunately, some of Mizuno’s old friends, like weight and clunk, are still hanging around the block and somehow finding their way to sneak back into HQ and crash the party on a promising future.

For now, at least, this revamped super soldier will likely be stuck performing in shows rather than making its way onto the battlefield to contend with the rest of the trail shoe market. Kudos to Mizuno for getting back in the game, we are excited to see what comes next.

You can pick up the Mizuno Wave Mujin 9 for $150 at Fleet Feet by using the shop link below.

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