ASICS Metaspeed Sky+ Review: Bigger, but is it also Better?
By Chief Editor Matthew Klein and Senior Contributor David Salas
The original ASICS Metaspeed Sky was a huge hit. The new generation racing shoe was seen on the feet of road racers and triathletes everywhere. Continuing on that success, ASICS decided to update this shoe, making a few tweaks to its DNA. The Metaspeed Sky+ has 4% more FF Turbo than the original Sky, but changes the geometry to maintain a lower weight. The plate design is a little bit flatter compared to the Edge + counterpart and is meant to support those that are "stride runners". The Sky+ is a new generation racing shoe focusing on increasing stride length rather than cadence.
Price: $250 at Running Warehouse
Weight: 7.2 oz, 205g (men's size 9), Women's Weights Not Provided
Stack Height: 39 mm / 34 mm
Drop: 5 mm
Classification: Distance Racing Shoe (Super Shoe)
RUNNING SHOE SUMMARY
Matt: The ASICS Metaspeed Sky+ is a lower drop, carbon plated, nylon-based superfoam distance racing shoe. Evolving into a completely different shoe from its predecessor, it features a more aggressive geometry, a slightly firmer ride and a now true-to-size fit. The low drop, high amount of forefoot cushioning and aggressive toe spring make it ideal for those who land farther forward or in the words of ASICS increase their speed by increasing their side length. A flatter plate sits closer to the foot, contributing to the slightly firmer ride that will excel for most from 5k to half marathon distances.
David: The ASICS Metaspeed Sky+ is a new generation racing shoe that expands upon the original Metaspeed Sky design. Using a nylon based FF Turbo midsole and carbon plate the Metaspeed Sky+ is designed to help with increasing stride length. The plate design is a little more flat than "spooned" and uses loading mechanics of the user to engage the plate. This a racing shoe in the "super shoe" category and will be seen on the roads for pretty much anything from 5k to marathon.
FIT
Matt: The ASICS Metaspeed Sky+ fits me true to size in my normal men's US size 10. The width is a little wider for a racing shoe and is slightly snug overall. The forefoot mesh has a little stretch, with some mild wiggle room. The midfoot fit slightly wider than I expected, which has caused some slippage that required me to tighten down the laces. I did not have to lace lock the shoe as there is a little extra padding around the heel collar which helped lock my heel in.. The mesh is a thin and breathable synthetic material that does start to stretch with time. The tongue is extremely thin and like the Metaspeed Edge+, folded on itself unless I carefully laid it down before every run. There is a flexible heel counter in the rearfoot that has not given me any trouble. Those sensitive to heel counters should be fine in this shoe. Like the Edge+, the upper is not one I would advise going sockless in. The upper mesh is a bit scratchy in the midfoot and forefoot, but this is easily fixed with socks. Overall the upper is comfortable and fits true to size. As long as the midfoot is locked down, it should do well for normal width feet over a variety of distances.
David: The ASICS Metaspeed Sky+ fits true to size in my normal men's 9.5. Overall, the dimensions are dialed in pretty well and there are no length or width issues. The heel is normal width, midfoot normal to slightly wide, and the forefoot and toe box normal to slightly wide for a racing shoe. The fit still locks down well and the lacing system seems to pull the material pretty well. The upper material is pretty consistent with the previous version having a more synthetic feel to it, though has a tiny bit more intrinsic reinforcement embedded in the material. There is a heel counter that provided no irritation for me and was lightly padded. The tongue is very lightweight and thin, but provides just enough protection from the laces. The laces are pretty slick in feeling but have texture throughout that keeps them from slipping. This is probably more the platform than the upper and fit, but I couldn't help but feel my midfoot falling off medially slightly more than the previous version. When they are side-to-side, the platform does seem to be a little more flush with the upper in the medial midfoot in the original Metaspeed Sky compared to Sky+. Other than that sensation the upper is really well done.
PERFORMANCE
Matt: The ASICS Metaspeed Sky+ is a max stack height, stiff, low drop racing shoe marketed as a shoe for those who increase their speed by lengthening their stride. Despite the increased stack height to 39mm/34mm (from the original being 38mm/33mm), the flatter plate that sits closer to the foot throughout the length of the shoe provides a slightly firm ride. At easy paces, it does not feel particularly inspiring, but once the pace picks up, the FF Turbo compresses more and provides a more resilient/responsive feel. There is a heel bevel that makes rearfoot transitions somewhat smooth. The toe spring is late and aggressive, which makes the shoe feel overly stiff and delays the transition off the toes at slower speeds. At faster speeds, transitioning quickly through this feels better, providing a snappier ride the faster you go. There is a 5mm drop, which feels even lower than listed. At times this has felt like a zero-drop shoe, particularly with how stiff the forefoot is due to the late toe spring and top-loaded plate. As a rearfoot striker, landing heel first compresses the sole and gives it more of that low drop feeling. Getting up on your toes feels better, especially since it provides a more stable and bouncy ride up front. Thus, those who land farther forward may do better in this shoe.
A question that has emerged since I used the original Sky for a trail race is what surfaces can the Metaspeed Sky+ handle. Given the narrow and smoother sole, I would keep this shoe exclusively for road. While the ASICS GRIP has remained unworn, I am tearing through the exposed FF Turbo. There is more exposed midsole than previous, so those who rip through outsoles like me may go through this shoe a little faster than the last version. Most people will find this shoe handles mileage well and will last an above-average number of miles for a racing shoe.
A pattern that emerges quickly is that the Metaspeed Sky+ works well at faster paces. Running slowly feels firmer, stiff and uninspiring. Once the pace quickens to tempo efforts and faster, the shoe begins to shine more. Due to instability issues in the midfoot and heel (see the stability section for more), I have had difficulty running beyond 10-12 miles in this shoe. It feels best at faster paces, particularly during quicker/shorter tempo runs and intervals. For most people, this shoe will likely be a 5k to maybe half marathon shoe. The harder you land in this shoe, the more bounce back/responsiveness you get. As soon as you slow down, the Metaspeed Sky+ slows you down more. Thus, those with efficient mechanics that put a high amount of force into the ground and can maintain their form for long periods will do well enough to take this shoe up to the marathon. Most people will do better at shorter to mid-distances and will enjoy the Sky + if they want a firmer, lower drop ride that responds better the faster you go.
David: The Metaspeed Sky+ is designed to be a top-shelf road racing shoe. The design feels a little different to me in the Sky+ compared to the Sky. There is more foam added into the Sky + compared to the original. The original sky had 33mm of stack in the heel and 28mm in the forefoot with the Sky + raising up to 39mm in the heel and 34 in the forefoot (including sock liner). The plate design is flatter and the toe spring starts much later in the forefoot, though much sharper. The feeling is much more elongating and bouncy rather than rolling.
The shoe feels best when running uptempo paces like it should. For me the shoe shines more in controlled efforts, as it feels the plate design almost fights me a little bit when digging down and trying to run faster than half marathon effort. I also notice I tend to shift back a tiny bit to make the geometry work for me. When loading from the rearfoot it feels like I get more out of the design of the shoe and design. That also increases my stride length concurrently. I am normally a heel striker, but more mild. I don't land super hard in that region and tend to gravitate more towards rolling shoes, and so the Edge+ felt a little more natural for me. The lower drop ratio is noticeable in the Sky+, but not so much it aggravates my calves. I actually noticed a little more work in my knees, but I think that was in part to some of the slight gait changes at the rearfoot. There is a slight heel bevel that works pretty well and the sharp toe spring still helps a little once you finally get up to the front of the shoe. The transitions definitely feel a little longer in the Sky+, but so does the stride length. I do think the toe spring probably could be started a little bit earlier, despite the stride length goal just to make that midfoot to forefoot transition feel a little less long. At slower paces, or when I was fatigued, it almost felt like I was climbing out of the forefoot a little bit. It's a good design overall though, that I am sure some people will like a lot. For me I just prefer the Edge+ for my own given mechanics.
STABILITY
Matt: The ASICS Metaspeed Sky+ is a neutral shoe with a medial bias. Those that tend to go too far medial will likely not do well in this shoe, while those that go too lateral will do extremely well. The midfoot and heel sole are both narrow enough that my foot was hanging over the inner side. There is a solid lateral sidewall that starts in the rearfoot and travels into the forefoot. There is a small medial sidewall in the far anterior midfoot and forefoot. However, it really doesn't do anything until you get to the forefoot. Like other max stack height carbon plated racing shoes, the forefoot is quite stable. There is a significant amount of midsole flare in both directions and the new plate sits right underneath the foot. This makes for a stable and guided forefoot, although these features are not present in the rest of the shoe. Transitioning through the heel and midfoot will require neutral or supinated mechanics, so those who need stability in either of those places for medial issues will not do well here. The Metaspeed Sky+ will work best for those with lateral stability issues or forefoot strikers, but is definitely a neutral shoe.
David: The ASICS Metaspeed Sky+ runs pretty stable for being a max stack height racing shoe. The platform is decently wide and the plate seems to stabilize the foam pretty well throughout. There is some sole flare through the forefoot that seems to be more than the previous model. The heel and midfoot width feel similar to each other. The upper locks down well throughout and provides good security. The platform through the medial part of the midfoot feels a little more inconsistent with the upper though. I think this may be in part due to shaping through the forefoot, but I notice a little more medial collapse through that region when running and loading through stance phase. Otherwise the sole flaring is strategic and feels good in the forefoot and the rear foot. Traction is pretty good underfoot as well and I had no problems with slippage when running. This is one of the few new generation road racing shoes I feel okay navigating some dirt or grass if I need to.
THOUGHTS AS A DPT / FOOTWEAR SCIENCE
On Plate Design
By David Salas
One of the interesting things about the super shoe boom in the last couple of years is that plate designs have been so unique. There have been several things companies have been doing to try and effect biomechanics and a ride that helps performance. There is still a lot of work to be done in this wild west of plate designs but the one thing we do know is that changing these designs does change the ride and what is being used from a muscle and joint perspective. Fu et al. (2021) found that plate design, even just isolated to the forefoot, can change biomechanical parameters at different joints. They found that differentiating between a segmented forefoot plate design and a full forefoot plate design showed an increase in peak plantar flexion velocity at the metatarsophalangeal joints and increased work at the knee without changes in longitudinal bending stiffness or energy return in the segmented design (Fu et al. 2021). ASICS did not do this specifically with their shoe, though they did change the angles of toe spring and the plate geometry between the Sky+ and the Edge+. There is so much to be done to quantify what these plates and their designs are doing, but having some research out there showing that it is indeed doing something is a step in the right direction.
References:
Fu, F., Levadnyi, I., Wang, J., Xie, Z., Fekete, G., Cai, Y., & Gu, Y. (2021). Effect of the Construction of Carbon Fiber Plate Insert to Midsole on Running Performance. Materials, 14, 5156.
Does the Sky+ Functionally Work?
By Chief Editor Matt Klein
The ASICS Metaspeed Sky+ is a different shoe from the original. The toe spring is far more aggressive, there is a little more foam underfoot, the plate is flatter and sits closer to the foot. The FF turbo foam feels firmer, but the additional firmness is likely from how closer the plate is to the foot throughout the length of the shoe. A variety of studies have looked at plate placement and how it impacts economy. The variations out there now appear to be bottom-loaded plates (plate close to the ground), top-loaded plates (plates right below the sockliner) or those embedded in the midsole (Ortega et al., 2021). Most plates designs out there are imbedded in the midsole and a curved plated design (seen in the Edge + and original Sky) appear to be somewhat more common. The flat plate design, which is almost a top-loaded plate in the Sky+, has been designed to let the foam compress under the foot. This is supposed to allow someone who uses a longer stride to compress the foam more and get more bounce. However, the current evidence has suggested that top-loaded plates may not provide economical improvements (Ortega et al., 2021). For some people it might, given that plate location and benefit is individual depending on how it lines up with each person's metatarsophalangeal joints. This goes back to many of the studies that have suggested that optimal longitudinal bending stiffness depends on individual factors AND speed (Mcleod et al., ; Oh and Park, 2017). On top of this (pun intended), it is important to remember that plates contribute only a small amount to economy at most. Their true function is to stabilize the softer resilient foams, which is still where I think the Sky+ misses the mark compared to the original Sky due to what also feels like a firmer FF Turbo foam (Healey & Hoogkamer, 2022).
References
Healey, L. A., & Hoogkamer, W. (2022). Longitudinal bending stiffness does not affect running economy in Nike Vaporfly shoes. Journal of sport and health science, 11(3), 285-292.
'McLeod, A. R., Bruening, D., Johnson, A. W., Ward, J., & Hunter, I. (2020). Improving running economy through altered shoe bending stiffness across speeds. Footwear Science, 12(2), 79-89.
Oh, K., & Park, S. (2017). The bending stiffness of shoes is beneficial to running energetics if it does not disturb the natural MTP joint flexion. Journal of biomechanics, 53, 127-135.
Ortega, J. A., Healey, L. A., Swinnen, W., & Hoogkamer, W. (2021). Energetics and biomechanics of running footwear with increased longitudinal bending stiffness: a narrative review. Sports Medicine, 51(5), 873-894.
RECOMMENDATIONS
Matt: While I am sure some may enjoy the changes to the ASICS Metaspeed Sky+, this shoe does not work well for my mechanics beyond shorter efforts. The upper sizing issues have been fixed, but other things that were working well were changed. The lateral sidewall will be great for those who supinate heavily, but the narrow midfoot/heel combined with that has my foot hanging off the medial side of the shoe. Combined with the almost zero drop feeling sole (it is 5mm, but feels low) and my tight calves, this drives me even further medially. The midsole only feels responsive at high speeds and feels firmer during others. This is a different shoe from the original and if given the choice, I will choose the original or the Edge+ every time.
Based on Dustin Joubert's initial testing, the Metaspeed Sky+ does seem to have a similar economical benefit compared to the original, at least for him. I think ASICS can still take some steps forward with the next version and learn something from this one. For starters, I would add sidewalls on both the medial and lateral sides. I am usually against biasing the foot in a single direction other than going forward as it tends to limit the population that can use it. I would also consider widening the midfoot and heel. Taller stack heights are inherently more unstable, so the shoe needs to have at least a somewhat wider base throughout. I also think from both a comfort and performance perspective, the foam needs to be softer and more resilient. The FlyteFoam Turbo in the original was awesome, so if ASICS can bring back that magic and some of the ideas above, version two (or three, not sure what is happening with the "+") will be a fantastic shoe.
David: I enjoyed my time in the ASICS Metaspeed Sky+ but I do have some recommendations. I think from a design standpoint the Edge+ fits my mechanics a little nicer, but I think to help with the stride length goal they can touch up a couple. The heel and plate design seem to work quite well and opening up the stride. I think the forefoot toe spring may still be a little too distal though. It doesn't feel like you are using it until the very last second at toe off, which seems too late for functional utility when working hard. If that was moved just a little more proximal I think that forefoot transition would come off much more bouncy and fluid. The midfoot is also a little unstable for me in this model and just integrating that platform with the upper would help improve the security in that region as well. Or increasing the sidewall slightly from the foam to give it a nice hold. This is still a very high quality racing shoe.
WHO THIS SHOE IS FOR
Matt: The ASICS Metaspeed Sky+ is a lower drop, slightly firmer, max stack height and stiff distance racing shoe for those who land farther forward or need guidance against excessive lateral motion. Although it uses the same FF Turbo midsole as the original, the flatter plate sitting closer to the foot provides a firmer ride that bounces more with a longer stride and more force through the ground. The toe spring is quite aggressive requiring high speeds to make it shine. The upper finally fits true to size, providing a snug but comfortable fit that needs some lockdown in the midfoot. The firmer ride that opens up with higher speeds makes this shoe better for faster runners who put a ton of force through the ground over 5k to half marathon distances.
David: The ASICS Metaspeed Sky+ is a high level racing shoe designed for road racing. The shoe is for those that use stride length as their main method of increasing running velocity. The shoe uses the same FF Turbo midsole seen in the original Metaspeed Sky+ and adds in a little more foam, a flatter plate design, and a little more sole flaring through the forefoot. The transitions in this model feel a little longer but does open the stride up. The Metaspeed Sky+ is a road racing shoe that is versatile enough for everything from 5k to marathon, though leans more half marathon to marathon for me personally due to the geometry and design.
GRADING
Matt
Fit: B+/A- (Comfortable, mildly snug, true to size fit. Midfoot a little baggy and requires additional lockdown)
Performance: B+ (Slightly firmer ride with stiff forefoot that feels better the faster you go.)
Stability: B- (Great shoe for those who go too far lateral due to lateral sidewall. Narrow heel and midfoot with medial bias will limit most to shorter distances)
DPT/Footwear Science: C+/B- (Aggressive toe spring and narrow heel/midfoot make the shoe far stiffer, less stable and more exclusive for certain people. Will work well for those who drift too far laterally or those who land farther forward. I can understand the longer stride idea, but this shoe is going to work against you when you fatigue)
Personal: C+ (Firmer ride due to close plate that only opens up at faster paces. My foot is hanging off the medial midfoot and heel, which combined with the low drop limits this shoe only to shorter efforts for me. Not my first choice and would choose the original Sky every time over the Sky +)
Overall: B-
David
Fit: A- (The fit throughout is dialed in well with good width throughout, though the medial midfoot feels like it collapses a little on the platform)
Performance: B+/A- (Good super shoe DNA, though transitions feel long and toe spring could probably be more proximal to smoothen out toe off)
Stability: B+ (Good stability throughout with nice sole flaring in the heel and the forefoot, midfoot has some collapsing medially I think due to shaping, sidewall, and upper integration. Otherwise good throughout.)
DPT/Footwear Science: A- (I like ASICS taking a crack at different designs. The geometry and plate design do seem to open up the stride and the sole flaring done well to accommodate for more stable landings in heel and forefoot.)
Personal: B+ (I enjoy the Metaspeed Sky+ but the geometry just seems to fight me a little bit at faster paces and at slower paces. At the tempo and marathon pacing it is pretty good, though some midfoot instability.)
Overall: B+/A- (A well done racing shoe that opens up the stride pretty well though could have a smoother toe off and midfoot stability.)
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