Mizuno Wave Sky 6 Review: Keeping Steady
By Matthew Klein, Bach Pham, David Salas
Premium daily training shoes are an incredibly variable bunch. While all bring high-quality uppers, midsoles and durability, how those are executed specifically vary a great deal. While many are becoming borderline lightweight trainers, others are staying true as high-mileage, high-performing workhorses. The Mizuno Wave Sky 6 fits into the second category, balancing out the integration of some newer foams while still being a solid shoe for easy and recovery miles. While updates have been made, this shoe continues on at a consistent pace similar to the one that feels best while running in it.
Price: $169.95 at Running Warehouse
Weight: 10.7 oz, 303 g (men's size 9), 9.1 oz, 258g (women's size 8)
Stack Height: Not Provided
Drop: 8mm
Classification: Premium Daily Training Shoe
RUNNING SHOE SUMMARY
Matt: The Mizuno Wave Sky 6 is a premium neutral daily training shoe. A new recycled upper that provides enough room despite a toe box taper. While not the lightest shoe, the ENERZY CORE and ENERZY midsole provide a moderately cushioned, protective and comfortable ride. This is a shoe best for easy and recovery miles where cruising is the goal.
David: The Mizuno Wave Sky is a premium daily trainer in the neutral category. The shoe builds upon a lot of the groundwork they have already laid down with the Sky and Horizon models. The shoe features a more refined upper and greater security on foot. The midsole is Mizuno Enerzy Core and Enerzy to provide a bouncy ride throughout, though still a little bit of a firmer feel. This is a workhorse for easy day mileage.
Bach: The Mizuno Wave Sky 6 is Mizuno's premium neutral trainer. This year's version is a mild update, featuring a new recycled upper that cleans up last year's version a bit. The shoe also feels more even balanced despite minimal changes, providing moderately high cushioning with some decent stability.
SIMILAR SHOES: ASICS Nimbus 24, Hoka Bondi 8, Nike Vomero 16
FIT
Matt: The Mizuno Wave Sky 6 fits me true to size in my normal US men's size 10. While the toe box tapers, there is plenty of room at the forefoot and the upper does provide some mild stretch. The midfoot is fairly normal in width. The tongue is the perfect balance of thickness (moderate), sitting comfortably against the top of my foot. The rearfoot fits normal to slightly snug thanks to additional heel collar cushioning. There is a solid heel counter in the rearfoot that I almost did not notice thanks to the large amount of padding there. Those with sensitivities should be a bit cautious, but I had no issues. The heel lockdown is quite good and I did not have any security issues (no lace lock required). The new upper is a stretch woven material that adapts well yet stays secure. This creates a unique combination of being comfortable and relaxed, yet still providing a solid lockdown. The upper also breathes surprisingly well. I have used it during many 80-90 F runs lately and have not had any issues with overheating. Based on that, those with normal, slightly wide and slightly narrow feet should do well in the upper of the Wave Sky 6.
David: The Mizuno Wave Sky 6 fits true to size in my normal men's 9.5. The shoe does seem to run a tad on the long end, but the other dimensions are quite sound. The width in the heel and midfoot are normal with a slightly forefoot that tapers into the toe box. The upper material itself is on the plush end throughout and runs a little bit thicker than a lot of other training models. With that said it still is breathable and decently streamlined for how much material there is. The tongue is padded pretty well and would be right in between moderate and plush. The laces seem to lock down pretty well and I did not seem to have too much issues with slippage or translation. There is a padded heel counter present that seems to hold the structure well throughout without being irritating in any way. Overall a good upper that could probably be shortened up just a little bit.
Bach: The Wave Sky 6 fits true to size. The toe box is a bit tapered, but I had a standard amount of room around the toe box. There's a moderate amount of cushioning around the heel and a lightly padded tongue that does a nice job of providing both comfort and decent lockdown. I didn't feel the need to lace lock the shoe as the laces do a fine job as is. Though there's some room for me into the midfoot, I was able to lace down well without any concerns. The overall fit is very relaxed rather than fitted, making the shoe feel most suited for easy-paced running. The upper looks built out, but breathes well. I had no trouble in the humid summer weather during testing. As is, the Wave Sky 6 is built to fit without fuss for a large range of foot types.
PERFORMANCE
Matt: The Mizuno Wave Sky 6 is a highly cushioned daily training/mileage shoe. The ride is protective, but on the firmer side initially. As I have broken the shoe in after 50 miles, the ENERZY CORE and ENERZY midsole have provided a slightly softer and bouncy ride. This is not a plush ride, but a comfortable one. This platform is best for someone who wants more cushioning, but does not do well with extremely soft platforms. There is a heel bevel, but it is angled slightly medial. This initially caused an awkward heel transition for me, but then the lateral aspect breaks in to form a crash pad. It still feels a bit better to land farther forward, but the heel does transition better after break-in and compresses nicely on the lateral side. The forefoot transition is a little stiff at first, but the flex grooves break in to create a smooth transition off the toes. The lack of major bounce from the shoe and the slightly heavier weight (10.7 oz) makes it a great option when you are plodding along. I have enjoyed this shoe during recovery and easy runs where pace is not a priority and I just want to pound the ground for some miles. The Mizuno Wave Sky 6 is extremely durable and has handled my pounding well. Despite 50 miles on my pair, I have barely made a dent in the outsole (even in my usual spot). Thus, the Sky 6 is a tank of a shoe best for plodding along and getting miles in.
David: The Mizuno Wave Sky 6 is a premium daily trainer in the neutral category. This means, in theory, a plush and highly cushioned shoe to handle easy days. This is mostly true. The shoe has plenty of cushioning underfoot to run as far as you would like. With that said, the foam is not the most plush. The Mizuno Enerzy and Enerzy Core in combination with the outsole actually provide a somewhat firmer ride. The foam still has resilience and bounce to it. It just does not feel super soft. In a lot of ways this could be a maximum cushioned shoe that someone who struggles with softer platforms may be interested in looking into. The ride has a decent amount of bounce at toe off with mild to moderate forefoot flexibility throughout. The platform has some rigidity to it but the flex grooves in the forefoot help with giving some flexibility to the region when the shoe is loaded. This will be talked about more in the stability section, but I do find that I trust this shoe in a larger variety of terrain than just road or packed dirt. The shoe has good security throughout with enough firmness and traction to feel confident in most situations. The shoe still carries a good amount of weight and certainly leans towards an easy day and recovery shoe. The Enerzy Core has some bounce to it which gives some life to the shoe, but it handles best at more controlled paces.
Bach: The Wave Sky 6 is a moderately high cushioned trainer that does a fine job at easy day runs. The forefoot outsole is fairly grippy and makes its presence felt, slightly firming the shoe a touch. Though in the max cushion category within Mizuno, it sits more as a moderately high cushioned shoe; less than the Triumph, More v4, or other high stacked trainers in the market today. The Wave Sky 6 sits under these popular options to provide what is best described as a slightly above average cushioned daily trainer.
The midsole itself is fairly traditional feeling and less modern than its competitors. The Enerzy Core does provide a touch of pop and bounce, especially as the shoe warms up into the second/third mile. While it can log a longer effort, I personally felt the shoe was a touch weighty for a long run shoe. Though it has less cushioning, the Wave Rider and Wave Neo Wind's nimbleness make them feel a bit more versatile. The Wave Sky 6 is best for logging everyday mileage and recovery runs. The Enerzy Core's bounciness does allow the shoe to pick up for minor strides, but otherwise the diversity is on the lower end here.
The outsole has been fairly durable after 30 miles, with absolutely no wear for me. It does have a bit of an aggressive grip that could be dialed back a touch to help emphasize a bit more softness. The shoe is built like a tank though, and I have no doubt it'll last miles and miles on end based on past experience with Mizuno shoes.
STABILITY
Matt: The Mizuno Wave Sky 6 is a neutral shoe. There is a decent amount of sole flare and the lateral component felt way more prominent. This initially pitched my ankle inward. However, as the shoe broke in, both the medial and lateral sole flare do keep the transition somewhat centered. The mild flexibility of the forefoot and rocker allows for a solid transition forward. Combined with the wider shape, this shoe has some mild guidance, but is still a neutral shoe.
David: The Wave Sky 6 is a neutral shoe in the premium category. Normally I don't expect much for stability in this category, but the Wave Sky 6 does do some things well here. First is that the upper lockdown and security is quite good for a maximum stack height shoe. Second, the foam itself isn't pillowy soft and makes you still feel like you are grounded pretty well. Third, the traction is actually pretty decent underfoot as well. Everything combines here to add up to a pretty trust worthy shoe in most situations. There is no posting or major sole flaring (though there is a little bit) to make this a stability shoe. This is a just a well constructed neutral shoe that would fall in that stable neutral category we talk about sometimes.
Bach: The Wave Sky 6 has a few elements that helps add some stability to this otherwise neutral shoe. There's a decent amount of midfoot width that provides a large landing zone. The shoe has some mild guidance through their layered midsole. The crash pad and tapered toe also helps provide some forward movement. The bottom midsole being a bit more rigid also helps prevent some collapsing while the denser forefoot outsole definitely keeps the front end feeling stable. The sole overall is still just soft enough that it runs fairly neutral as a result.
Comparatively, the Wave Sky 6 is about on par with the Saucony Triumph 20 stability-wise and less stable than the Endorphin Shift 3. The rearfoot has just enough bevel though to make it feel a bit less clunky than the Brooks Glycerin 20.
THOUGHTS AS A DPT / FOOTWEAR SCIENCE
Foam Compliance
By Chief Editor Matt Klein
A large number of new foams are coming out. A large variety of extremely bouncy foams are now being seen in daily trainers and not just faster racing shoes. While we are seeing these foams continue to get softer, which is what human beings tend to gravitate toward, their type and degree of softness varies greatly between models and companies. Much of this comes from the purpose and design of the shoe, but other variables can influence this. There are a few definitions and clarifications that may help with further understanding the feelings of these evolving footwear components.
A compliant foam or midsole is one that compresses. This refers to how much the foam (or how much it feels like) deforms under the load of the foot and human body. Foams that are less compliant sometimes feel stiffer, while those that are more compliant tend to feel softer and more cushioned (sometimes). This can be measured as a rate of deformation under load. This rate does not always match exactly with how a person perceives this, likely due to differences in how individuals perceive changes in pressure, joint movement, acceleration, internal tissue movements and more.
A resilient foam is one that not only compresses but also rebounds/reforms. These are the foams that are often associated with shoes that have higher energy return. The material compresses, but then "responds" to the initial loading force by creating a higher resultant force in the opposite direction. People often refer to these foams as bouncy or responsive. They are often used in shoes where the user wants to either run faster or be more efficient.
Which one each individual wants will depend on what that person is looking for in a shoe. Compliant foams are often soft and compress well, but don't usually bounce back. This can make them great for recovery days/easy runs where the goal is just to have a cushioned shoe on foot. A resilient foam is often better for faster days where you want the force you put into the shoe to help push you forward more. We are seeing the lines blur between these types as newer foams come out. One isn't better than the other overall as they have specific areas and individuals they will work better for. Like any other property of shoes, this is something you should be aware of and may further help guide your next shoe decision based on your goals, purposes and preferences.
RECOMMENDATIONS
Matt: The Wave Sky 6 is continuing to move in the right direction. The shoe is getting lighter and it has a bouncier midsole than the previous one (version 5 felt dead to me). Based on the current market trends, both these things need to be amplified. I think Mizuno should keep the shape of the shoe, but should experiment with lighter and bouncier foams. ENERZY Lite and its variations should be considered to create a bouncier ride while further reducing weight. Outside of that, I would like to see a slightly more anatomic toebox, but the stretch woven mesh does a solid job of adapting to the toes after a few miles.
David: I like where the Wave Sky 6 is going here. This is my favorite version of the shoe so far. I do think the shoe runs a little on the long side and the sizing could be worked out a little bit. Even though this is my favorite version of the shoe so far, I would like to see them playing with some softer and bouncier materials so there is no major overlap with the other training models they offer. Other companies are having highly compliant and bouncy foams in their premium trainers and then have a middle line where the Sky would slide into. Mizuno has Enerzy Lite and I think it would be interesting to see that in a max stack midsole as well.
Bach: With the Wave Horizon 6 getting softer and lighter year to year, there's a point where the Wave Sky and Horizon series could collide at this rate. With the Wave Neo Ultra introduced, I'd like Mizuno to consider elevating the Wave Sky to be a more complete max cushion shoe with a higher stack and a bit more softness. A few ways the Sky 6 could achieve these stats are with the outsole. A flatter, less aggressive forefoot outsole could help emphasize a smoother ride. The new Mizuno Enerzy Lite would also help propel the Sky forward and aid in lightening the shoe. Finally, Mizuno could toy with a Pebax insole to help further emphasize softness.
WHO THIS SHOE IS FOR
Matt: The Mizuno Wave Sky 6 is a premium shoe for those who want a durable, high-mileage shoe with a large amount of cushioning that isn't mushy. It features an adaptable fit, so those with normal, slightly narrow or slightly wide feet should do well. Those with wider feet may have to be a little patient as the toe box breaks in. The ride is slightly firmer at first, but breaks into a reliable and balanced ride. Those who do not want excessively soft shoes, but still want one with a large amount of foam underfoot will enjoy this shoe. Its weight and ride make it best for those who want to pound the pavement and get miles in at easy and recovery paces. The Mizuno Wave Sky 6 stays true to its roots as a traditional premium high-mileage trainer, so those looking for a consistent ride and fit that isn't crazy new will find this a great option.
David: The Mizuno Wave Sky 6 is a daily training shoe for those that want to have a maximum cushion shoe to hit easy mileage in. The foam itself runs on the firmer end, though it does have a decent bounce at toe off. Because of the good lockdown, firmness, and traction of the shoe this can also dabble in a little bit of off-roading if you would like it to. The shoe is pretty versatile to terrain on easy days, but still a little heavy to turn over on the faster days.
Bach: The Mizuno Wave Sky 6 is a solid shoe for those wanting a bit more cushion and a durable neutral trainer. It's one of the safer bets for anyone wanting a solid, no-fuss fit. For Mizuno fans, the question will be whether you want a premium easy day trainer in your rotation, or a shoe which can do a little bit of everything. If the latter, the Wave Rider may still be the go-to, but if value and durability are your priorities, the Wave Sky 6 is worth a look. For those who want to splurge, the Wave Neo Ultra is definitely a consideration that improves what is here in just about every way except price.
GRADING
Matt
Fit: A- (Normal fitting, adaptable upper that is comfortable on the run and for casual use. Toe box tapers, but adapts quickly)
Performance: B (A cushioned ride for pounding the pavement in. On the heavier side, so best for easy/recovery runs)
Stability: B+ [Neutral] (Stable for a neutral shoe, but not stable neutral. Wider base and midsole design help keep motion forward)
DPT/Footwear Science: B (Points for sustainability but nothing new in terms of design)
Personal: B+ (Although not the most exciting shoe, it has been surprisingly dependable for me during recovery runs where I don't want a crazy bouncy shoe. Also an excellent shoe for all-day walking.)
Overall: B/B+
David
Fit: A- (Solid dimensions and usage of space and materials, though still runs a little long)
Performance: B (A good shoe to log easy miles in, though still a little heavy to do anything else in)
Stability: A (Solid stability throughout for a max cushion shoe in the neutral category)
DPT/Footwear Science: B (There is nothing revolutionary here, though I do like that they streamlined the Sky model and improved the security on foot)
Personal: B (Smooth transitions throughout, good versatility on terrain, a little heavier than I normally like to run in, a little less responsive than what I normally like to run in)
Overall: B+ (A well executed neutral daily trainer in the premium category though still nothing overly revolutionary)
Bach
Fit: A (Solid, no-fuss fit that simply works)
Performance: B (A slightly higher cushioned ride that is suitable for easy day, and not much else)
Stability: B+ (Classic Mizuno dual density design and width helps give it a bit more stability than normal)
DPT/Footwear Science: B- (Not a huge departure from last year's model besides a recycled upper)
Personal: B (A fine mileage eater, but lacking in the wow factor department. There's nothing wrong with a dependable, no-frills trainer though)
Overall: B
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