Slow, cruising miles are some of my favorite miles to run. When you can put in some headphones, not worry about pace, and get lost in a run – there’s no better feeling.
But when slow cruising is your goal, you need a shoe that feels comfortable and doesn’t try to make you push the pace. This is where maximalist shoes fit into the rotation.
These max cushion shoes have grown in popularity in recent years. Now, Mizuno is throwing its hat in the ring with the Sky Prime.
With the tagline “cushioned today, crush it tomorrow”, it’s clear the Sky Prime is focused on comfort and shock absorption to help you perform your best on every run. But does it accomplish that goal?
Our review team is here to answer this question and more about the new Sky Prime. We’ll cover the specs, dive into all the technology, detail our road test results, and offer some comparable running shoe options.
Sky Prime Overview: Specs & Highlights
Before we go too in-depth with this review, let’s take a quick look at the specs, numbers, and tech that make up the Sky Prime.
- Designed as a neutral, max cushion training shoe for recovery days and easy mileage
- Stack height: 47 mm in the heel, 41 mm in the forefoot
- 6 mm heel-to-toe drop
- Weight: 10.4 oz (M), 9 oz (W)
- Midsole features a dual-layer construction. ENERZY NXT+ PEBA foam and ENERZY NXT EVA foam layers create a soft yet balanced ride
- Mild stability elements and geometry create a smooth, supported, and structured all-around feel
- Engineered mesh upper maximizes breathability, while the stretchy gusseted tongue keeps feet securely in place with fewer hotspots
- Carbon rubber X10 outsole is grippy and durable for long-lasting wear
- Constructed with recycled materials
- Price: $200
A Closer Look at the Sky Prime
As a brand-new shoe, we couldn’t wait to learn more about the Sky Prime’s innovative tech and features. Let’s dive into each of the shoe’s main elements, so you’ll know what to expect when you slide this trainer on for the first time.
Dual-Layer Midsole Construction
Mizuno separates its shoes into 5 key silos: speed, bounce, cruise, float, and trail. The Sky Prime falls into the float category, meaning it prioritizes plush cushioning for daily miles or recovery runs.
The Sky Prime uses a combination of two foams to achieve these floaty, ultra-soft landings. The top layer, ENERZY NXT+, is a nitrogen-infused PEBA/EVA foam that delivers maximum bounce and energy return underfoot. Closer to the ground, ENERZY NXT EVA foam maximizes stability and durability.
And of course, we also have to mention the sheer amount of midsole cushioning for unmatched step-in comfort and shock absorption. This new model boasts 47 mm of foam in the heel and 41 mm in the forefoot, offering one of the highest stack heights on the market today.
Shoe Geometry & Stability Elements
Max cushion shoes aren’t for everyone, in part because the incredibly high platforms often feel wobbly or unstable during runs. But this isn’t the case with the Sky Prime. This shoe takes steps to balance out the high stack height, incorporating mild stability elements and geometry into the design.
The Sky Prime has a moderate rocker geometry that subtly guides you forward without feeling like it’s pushing you to move faster during easy miles. The 6 mm drop also keeps your feet in a relatively natural position, helping you feel grounded throughout your longer runs.
The wide base and stable bottom layer also come into play, creating more surface area for smooth, stable, and efficient landings.
Upper Material & Fit
The upper design is a major highlight in the Sky Prime. It’s made from an engineered mesh material that optimizes breathability and airflow, with added cushioning around the heel for immediate step-in comfort and security.
The stretchy gusseted knit tongue adds more comfort and security, wrapping the foot without any added pressure or rubbing.
While the upper is stretchy and accommodating, the Sky Prime does have a snug, narrow fit. The narrow heel and midfoot and tapered toe box hug the foot, which may appeal to those who prefer a secure lockdown. However, the fit could feel too tight for anyone with wider, higher-volume feet.
Value & Durability
If there’s one aspect we can always count on in Mizuno shoes, it’s durability. The brand’s foam tends to hold up well over long-term use, and the reliable EVA foam in the Sky Prime’s bottom layer ensures just as much dependability and durability. The rubber X10 outsole provides even more protection and effective grip and traction during all your long runs.
The downside? The Sky Prime is bulky and relatively heavy at 10.4 oz for men’s shoes and 9 oz for women’s shoes. This added weight and material means there’s less versatility for more intense, fast-paced efforts.
At $200, some athletes might expect a bit more adaptability in their trainers. But if your goal is cushioning and shock absorption on runs, you’ll likely find the Sky Prime’s comfort and protection worth the higher price tag.
Primed and Ready to Run: Sky Prime Road Test Results
Now comes the best part of any review – the road test. Review team members laced up the Mizuno Sky Prime and set out for daily miles, track workouts, long runs, uptempo days, and more to fully understand how the new model performs.
On first impression, the shoe offered immediate step-in comfort. The engineered mesh upper securely wrapped the foot while providing ample padding around the heel and ankle. The stretchy knit tongue created a snug, almost sock-like fit across the top of the foot that felt natural both at rest and in motion during runs.
The upper is a highlight, but the unique midsole design is the true standout. Past Mizuno shoes, particularly daily training models like the Wave Rider, have been relatively firm underfoot. They deliver a consistent, comfortable, and well-balanced ride, but Mizuno isn’t typically known for their overly soft, plush running shoes.
So we were excited to hit the road with the Sky Prime and see Mizuno step out from its reputation and deliver a premium, soft yet stable max cushion running shoe.
With a 47 mm heel stack and 41 mm forefoot stack, the Sky Prime has lots of foam to absorb impact and keep you comfortable during long mileage. The Foam Wave midsole design incorporates softer Mizuno ENERZY NXT+ foam directly under the foot, with a firmer EVA foam closer to the ground. With each landing, this next-generation midsole makeup maximizes protection, energy return, and softness.
I also appreciated how, despite the large amount of plush foam, the shoe was surprisingly stable on runs. The wide platform ensured solid landings, while the firm base layer prevented the shoe from feeling too wobbly or unstable. The low 6 mm drop also kept feet in a natural position for a smooth ride.
The blend of softness and stability really shines during long, easy mileage. The soft underfoot provides optimal protection without creating the feeling of our feet sinking into the foam or moving around inside the shoe. And with premium materials and a durable outsole, this shoe has everything it needs to carry you for miles and miles.
But if you’re looking for a shoe to help you pick up the pace, you may want to consider another option. With its heavy-duty design, the Sky Prime excels when you want to cruise your way through each mile with less impact. However, with so much cushioning, it’s heavier and softer than many other daily trainers, and you may find it doesn’t adapt as well to speed workouts or uptempo runs.
Fit could be another area of contention for runners, walkers, and other athletes testing out the Sky Prime. The toe box is narrow and tapered, and while the stretchy upper offers some wiggle room, the Sky Prime is snug with a low-volume fit. Anyone who prefers a more spacious, high-volume running shoe will likely find the Sky Prime doesn’t fit the bill.
Overall, there’s a lot to appreciate about Mizuno’s new max cushion training shoe. It can be a bit bulky, but on long runs or easy miles, this extra cushioning comes into play for a smooth, effortless ride. It’s a great choice for anyone who wants more cushioning without sacrificing stability.
Sky Prime Pros and Cons
Throughout our road testing, we found both upsides and downsides with the Mizuno Sky Prime. While we went over a few of the key points in our road test results, here’s a quick rundown of the top pros and cons to consider when shopping for your next running shoe.
Pros
- High stack of foam delivers a blend of softness and energy return for a well-balanced cruising shoe, ideal for long runs and easy recovery days
- Engineered mesh upper is soft and breathable, with a stretchy, gusseted tongue and extra heel padding for maximum step-in comfort
- Inherent stability features, including a wide base and stable bottom foam layer, work alongside the upgraded midsole cushioning for secure, supported landings
- Premium materials and X10 outsole create maximum durability and longevity
Cons
- Narrow, low-volume fit and tapered toe box won’t suit athletes with wider feet or who prefer a roomier fit
- Relatively heavy and bulky, limiting its versatility and adaptability for uptempo runs
Sky Prime vs the Competition: How Does it Stack Up?
More and more max cushion shoes are popping up in the running shoe market. As someone who loves the feel of these ultra-cushioned shoes, it’s a trend I can easily get behind. But it’s also important to compare your options and understand what each distinct model has to offer. So while the Sky Prime felt fantastic on long runs, let’s take a look at some of the other comparable shoes worth considering.
First is another new running shoe model, the Asics Gel-Slowcush. Having just reviewed this model as well, I noticed many immediate similarities in the cushioning, ride, and overall feel between the Slowcush and Sky Prime.
The shoes have a similar stack height – 47/41 mm for the Sky Prime and 48/40 mm for the Slowcush – and a similar soft but bouncy feel. Both are also neutral shoes with some mild inherent stability elements for extra support.
The biggest difference here is in the fit. The Slowcush has a roomier toe box, with a high-volume fit that can easily accommodate wider feet. On the other hand, the more tapered Sky Prime is the better choice for those who prefer a more locked-in, narrow fit.
In the same max cushion trainer category, you’ll find the Puma MagMax Nitro 2. This Puma model is slightly more responsive than the Sky Prime and Slowcush, making it a bit more versatile. At $179.99, it’s also a slightly more affordable max cushion option. With that, you don’t get the same plush, luxurious comfort found in comparable running shoes.
Everyone has different preferences with fit, cushion level, and overall feel. Even within the same running shoe category, you’ll find everything from a firm, responsive feel to a super soft, spongy feel. The best choice for you ultimately comes down to your preferences and what you’re looking for in a running shoe.
The Finish Line: Try the Sky Prime and More at Marathon Sports
Our dedicated Marathon Sports footwear experts aim to understand every new running shoe model inside and out. To accomplish this goal with the new Mizuno Sky Prime, our review team tested out the new model on all types of runs.
Throughout rigorous road testing, we found that the Sky Prime was a great choice for anyone looking for a dedicated easy or long run shoe. It’s easy to see how, with so much cushioning, it lands in Mizuno’s “float” category. The large amount of soft, bouncy foam truly helps you feel like you’re floating through runs, with minimal impact and maximum comfort.
But everyone is different, and we always suggest getting a customized fitting at your nearest Marathon Sports and trying out the Sky Prime and other top running shoe options for yourself.
Our team will use the Right Fit process to get to know you and your feet, understand what you’re looking for in a running shoe, and curate a selection of running shoes that meet your needs. We’re excited to work with you to find the perfect shoe and keep you comfortable, happy, and supported through all your runs.
