Mizuno Wave Inspire 21 Review
By Matthew Klein
Mizuno Wave Inspire 21Price: $139.95 at Running Warehouse
Weight: 10.3 oz, 292 g (men's size 9), 8.8 oz, 249 g (women's size 8)
Stack Height: 38 mm heel / 26 mm forefoot
Drop: 12 mm
Shoe Purpose: Moderate Stability High Drop Daily Training Shoe
Pros: Wider Comfortable Secure Fit, Rare High Drop Ride, Great Walking Shoe, Centered Well-Integrated Stability
Cons: Boring Ride, Slightly Clunky Heel
RUNNING SHOE SUMMARY
The Mizuno Wave Inspire 21 is a high drop, moderate stability training shoe for those who want a more traditional and now rare ride with a wider forefoot. The upper mesh fits low volume but wider in the forefoot for those who want a close fit but more width. The ride is slightly clunky in the heel but has a smooth forefoot for those who want a rare 12mm heel drop shoe. The medial stability is prominent in the heel and midfoot, providing a solid amount for those who need it. While not a responsive shoe and limited to slower paces, the Mizuno Inspire 21 is a (now) rare option for those wanting an easy running and walking, high-drop stability shoe.
PAST MODEL: Mizuno Wave Inspire 20
FIT
(To learn how a shoe should fit, check out our full podcast on fit by Matt Klein.)
Matt: The Mizuno Wave Inspire 21 fits me true to size in my normal men's US size 10. The full-length Jacquard Air Mesh provides a wider but slightly lower volume fit. There is some stretch to the upper, which provides both a secure and accommodating fit for those with normal volume feet. The forefoot is wider, providing room for toe splay without feeling sloppy. This transitions into a normal width and secure midfoot. The tongue is moderately thick and strongly gusseted, which locks the foot down well. I did not have to tighten the laces down at all to get a secure fit. However, the lower volume creates a lower instep, so those with a higher instep may not do well or will have to really loosen the laces. The heel fits normal in width with moderate heel collar padding. There is a stiff counter in the rearfoot, although there is a little extra padding in the center of the counter that offset the stiffness and it didn't bother me for the most part. Those with sensitive heels will not like this but those wanting a stiff counter will do well. The security is quite good for a shoe that fits a bit wider, although that mostly comes from the lower volume and midfoot lockdown. I have not had slippage even turning in this shoe. The inner liner is quite comfortable and I have been able to wear this shoe sockless for several miles. The toe guard, while flexible, does create some abrasion; therefore, I would still suggest socks for most people.
Typical Size: Men's US Size 10
Shoes that have fit Matt well: On Cloudboom Strike, Asics Gel-Nimbus 27, Xero HFS, Topo Cyclone 3, Adidas Adizero Evo SL
Shoes that have fit snug: Hoka Arahi 7, Brooks Launch 11, Diadora Mythos Vigore 3
Shoes that have fit large: Salomon S/Lab Phantasm 2, Adidas Agravic Speed Ultra
Doctors of Running Checklist
Is This a Good Shoe for Walking: Yes
Is This a Good Shoe for Standing: Yes
Is the Forefoot Flexible: Somewhat Flexible
How Flexible is the Shoe: Stiff Rearfoot, Somewhat Flexible Forefoot
Is This a Good Heel Bevel: Somewhat
Recommended for Haglunds: No
Is This Shoe Orthotic Friendly: Yes
Recommended for Sockless: Yes
Durability Expectation: Normal to Above Average
PERFORMANCE
Matt: The Mizuno Wave Inspire 21 is a daily training running and walking shoe. The midsole features ENERZY NXT in the rearfoot and ENERZY in the forefoot. Combined with the wave plate that travels from the heel to the midfoot, this provides a slightly snappy but firmer ride in the heel and slightly softer ride in the forefoot. The weight is down from the prior version to 10.3 oz. This weight makes it feel like a solid daily trainer that isn't too light or too heavy at daily training paces. There is a 12mm drop that is noticeable. It is great for walking around (especially right now with a slightly irritated but improving Achilles tendon). The heel bevel is moderate in side but centered. This makes for a slightly clunky heel transition. The midfoot transition is a little stiff but transitions into a smooth and comfortable forefoot. There is flexibility to the forefoot, so those with toe mobility issues will not find enough stiffness for them but those wanting a little flex will enjoy it.
With the slightly clunky heel and smooth forefoot, the Inspire works best for those who land a little farther forward or want a higher heel drop. The foam is not the most responsive but is consistent, feeling best for easy and longer runs. This shoe does not do well with pace pick ups as I found even strides to be a struggle. Anyone wanting to run fast will need to look to a different shoe but for the majority of mileage the Inspire 21 may work for those with the above unique needs. The traction is fairly good on both wet and dry surfaces. The gap in the midsole is mostly shallow but rocks hitting the plate feels a little weird. I would keep this shoe on the road but the mild lugs on the outsole can grip mild smooth trails. Durability-wise wise the foam is holding up well, and there is barely any wear on the outsole after 30 miles. I therefore expect this shoe to last slightly above average compared to most shoes as there is still a tiny bit of wear at this few miles but it should hold up well like many other Mizuno trainers.
Further Thoughts, Bach: Being a bit more forward of a runner than Matt, I'm able to get past the clunky heel a bit better and enjoy the best part of the shoe with the smoother forefoot. The foam is still relatively on the less responsive side though. It loses some of the Wave Rider feel that version 20 had between that version's fit and midsole, despite losing some weight in version 21. The Wave Inspire 21 is best for easy miles and for those who want a healthy amount of rearfoot stability. This will have less pop or cushion feeling of the last couple of versions. Those who want a little more grounded feel will maybe like this middle of the road option. Runners who do want a high, high drop though will find this as one of the few remaining options to choose from in the stability shoe arena (and it definitely still feels high).
Additionally the shoe's stability did not irritate my flat feet.
STABILITY
(Learn more about stability in our full guide)
Matt: The Mizuno Wave Inspire 21 is a moderate stability shoe. Rather than traditional methods, the Inspire series has also used the wave plate and its medial "waves" to create resistance to motion. This provides some level of adaptive stability. On foot, the large medial wave provides noticeable pressure into the medial midfoot and medial heel with collapse. On the run, this is significant but well integrated, keeping consistent but smooth medial stability that is most noticeable in the midfoot. In addition to the plate, the heel is somewhat wide, the medial midfoot is filled in more than the lateral side and the forefoot has a decent amount of sole flare (more lateral than medial). All of this creates more medial stability in the heel and midfoot with late medial push from the lateral sole flare in the forefoot.
Thoughts as a DPT: Posterior Tibialis Irritations and High Drop Stability
By Matthew Klein
While there is some benefit to most shoes moving to a more moderate drop, the almost total loss of 12mm drop shoes has created a gap for certain individuals who do benefit from them. We know from research that those who benefit from using stability running shoes include those with a history of pronation-related injuries (Willems et al., 2021). One type of pronation-related injury is irritation of the Posterior Tibialis muscle. This muscle sits deep to the calf muscles and acts to both plantarflex and invert the ankles. This really means it supports the medial arch, helps with push off/propulsion and helps control pronation movements. Given that it helps both with pronation and plantarflexion, a shortened position for the muscle would be in a high-drop stability shoe. Not surprisingly, many people with a posterior tibialis tendinopathy or strain do really well in these shoes as they reduce the range of motion/stretch this muscle experiences.
Even in shoes with stability, a lower to moderate heel drop may still put this muscle on too much stress for some people early in healing phases. While appropriate rehabilitation, mobility and strength work shoe precede an appropriate and timely return to running, many people do not take the time realistically and having a tool that support them in their goals of motion may be helpful. The Mizuno Inspire 21 is one of the few shoes left that fits this besides the Brooks Adrenaline 24 (although not for long as the Adrenaline 25 is 10mm drop). Not every shoe needs to be low drop and not every one needs to be high drop. Having more things in the middle is probably best, but having a few outliers is a good thing as it helps create unique tools for people that may need them.
RECOMMENDATIONS
Matt: I am thankful for the opportunity to test this shoe, although it sounds like the new version is coming out soon. Therefore, my recommendations may not have a purpose as the next version will be debuted by the time most people read this. While the higher drop makes the heel a tiny bit clunky, I would not change the drop. Instead, I would encourage progressing the midsole foam as Mizuno did with the Rider 29 but use the lighter foam to maintain the wider sole (keep the midfoot wide) and continue with the wave plate stability mechanism. I would bevel the heel more appropriately, with the heel bevel facing laterally rather than being centered/medially facing as it currently is. Outside of some small geometry changes and updating the foam to today's standards, I would not change other things. The wider forefoot is really comfortable, the higher drop is unique and provides not just an option for runners but a clinical option for those of us looking for options for patients. Making a shoe that is like everything else on the market is a waste and I hope Mizuno continues the great traditions of the Inspire while still updating things like the midsole.
WHO IS THIS SHOE FOR?
Matt: The Mizuno Wave Inspire 21 is a moderate stability, higher drop shoe for those who want this rare shoe type for daily training and easier miles. The fit will work best for those who have a wider forefoot but a lower volume foot overall. The ride will work best for those who either like a high drop shoe or have limited ankle mobility. The stability will work best for those who still like medial stability, especially in the midfoot. The transitions are still a little clunky and there is no pace versatility but those looking to get through their mileage will do fine. The $140 price tag is great given the more traditional ride and decent durability, which combined with the now unique set up makes this a solidly priced shoe. While this will not work for those with lateral stability needs or those with knees/hips sensitive to higher drop shoes, those with posterior tibialis problems may really benefit from this shoe for a time as they reduce their symptoms and begin reloading or continuing to appropriately load this important muscle. What will happen in the next version will have to be seen. The Inspire 21 is on the more traditional end of their line up, which has seen a massive shake-up and progression in recent times. How that will impact this long-standing (long-running?) stability shoe remains to be seen.
GRADES
Matt
Fit: A (Wider forefoot with secure midfoot/heel. Comfortable liner that is great for running, walking and standing. Slightly lower volume)
Performance: B- (Consistent ride with higher heel makes for slightly clunky rearfoot and smooth forefoot. No pace versatility and can only handle easy running/walking)
Stability: A- [Moderate Heel/Midfoot Stability] (Good medial heel and midfoot stability from the wave plate. Lateral flare a little excessive at the forefoot and creates medial bias but will stop over supination at toe off)
Value: A- (Decent durability and now unique ride at $140 is a great deal)
Personal: B+ (This has been a great walking shoe but is a little dull for running given the lack of pace versatility. Can still eat up easy miles but wish it had a little more versatility without sacrificing its core values)
Overall Design: B+
SHOP | SUPPORT DORPrice: $139.95 at Running Warehouse
Mizuno Wave Inspire 21
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FURTHER READING
Hoka's stability champion.
Altra's lightweight, 4mm drop trainer.
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