Mizuno Wave Musha 4 First Impressions:

Last year I reviewed the Mizuno Wave Musha 3 and was impressed by how fast and comfortably it ran. In fact, I set a new personal best in the 5K with the Wave Musha 3. So I had big expectations for the Wave Musha 4 when I learned that Mizuno did a complete update for the shoe.

Immediately noticeable to me was that the Wave Musha 4 has a considerably more curved last than the Wave Musha 3. A curved last is usually found on neutral shoes and I was a bit apprehensive about it. Nevertheless, I took the Wave Musha 4 to a 5K held on the same race course that I ran the Wave Musha 3 on. The results were not exactly what I’d expected.

But first, let’s review the changes made to the Wave Musha 4 in more detail.

Mizuno Wave Musha 4 Upper:

The Wave Musha 4 has a very similar overlay pattern to the Wave Musha 3 but closer inspection reveals some key changes to address fit. Previously the heel overlay wrapped around the entire shoe but now it ends right past the mid foot on the lateral aspect and right under the arch medially. This serves to free up flexibility in the upper where the forefoot bends and reduces a potential spot of irritation. To help ensure that the foot doesn’t slide off the platform, Mizuno slightly beefed up the toe box overlay and there are now two more robust overlays connecting the eyelet row to the toe box overlay.

The only carryover design I could find is the tongue and laces. The iconic Runbird logo is now of the same material both medially and laterally. On the Wave Musha 3, the Runbird was fashioned from a very light material on the medial side and a heavier, more decorative material laterally.

The colorway on the Wave Musha 4 is still electrifying in a dazzling lime green, blood red and black. If anything, the shoe makes an even brasher visual statement than before. Mizuno is still using highly breathable mesh for the upper albeit in a slightly different weave.

Mizuno Wave Musha 4 Sole Unit:

The Wave Musha 4 also gets a completely re-engineered midsole beginning with an all-new design for the wave plate. Mizuno is unique in that they are the only company to engineer their shoes around a plastic plate sandwiched into the midsole foam. These wave plates act as a “suspension system” and can be configured to deliver varying amounts of support and shock attenuation. The Wave Musha 4 gets a plate that extends farther forward than before both medially and laterally. In fact, on the medial side the plate stops right at the forefoot flex point-doubtless a design to provide a bit more rigidity through foot strike.

Mizuno has now introduced their AP+ foam formulation to the Wave Musha series. According to Mizuno, AP+ improves cushioning, energy return and durability over previous AP foam designs.

The last has undergone a dramatic change from semi-curved to a full on curved last. While this does improve transition in a shoe it also makes it more narrow in the mid foot and can compromise stability. Countering this is a new AP foam sock liner featuring a higher arch profile than before.

Mizuno’s X10 carbon rubber is still found in the heel while blown rubber is located in the forefoot. Additionally, the Wave Musha 4 is now available in a women’s specific model.

Mizuno Wave Musha 4 Opinion:

Previously I said that my first race in the Wave Musha 4 yielded some unexpected results. Well, not only did the Wave Musha 4 meet my expectations-it shattered them! I cut almost 30 seconds off of my previous best 5K time during my testing of the Wave Musha 4. Needless to say, I was thrilled. I finished fourth overall in that race and I expect that the sheer speed and thrill of the Musha 4 helped me along. It is an excellent shoe for 5-10K distances for a runner like myself. I have very flexible feet and I need built in support in any shoe I run in but I still want to enjoy the feel and good looks of a fast racing flat.

Runners without support issues could very well make this a marathon distance shoe. Also, the Wave Musha 4 could find a spot in a minimalist runner’s shoe rotation.

The Wave Musha 4 is slightly heavier than before. I can only attribute this to the new sock liner and it’s also possible that the AP+ foam is denser but I can’t say for sure. The new curved last could have some runners feet sitting too far in medially. Otherwise the fit remains close in the heel, snug in the mid foot while opening up slightly in the toe box.

At any rate, the shoe still moves hot and fast and is at its best when run aggressively. The ride is textbook Mizuno; powerful and explosive. The shoe lets you put all your energy into the ground while providing enough protection to get you through the race and on to your new personal best.

*Author’s note*

I also found another use for the Wave Musha 4. As an exercise physiologist I am always aware of the need for runners to strengthen their lower limbs through various exercises. Because of its highly proprioceptive feel, the Wave Musha 4 is equally at home in the gym when performing foot and ankle stability exercises such as on a wobble board. See photo.