The RW Takeaway: Big updates to the 17th version make the Inspire a moderately responsive and durable workhorse that offers mid-level stability for overpronators and plush cushioning for heel strikers.
- New Enerzy foam is softer and improves energy return in the heel.
- The air mesh upper boosts breathability and has a wider fit in the women’s model.
- A redesigned outsole increases ground contact for a smoother ride and better grip.
Price: $135
Type: Stability Road
Weight: 10.9 oz. (M), 9.2 oz. (W)
Drop: 12 mm
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Sad news first: Mizuno has been trimming its lineup to make room for fresh blood. (Moment of silence for some of the retired standouts from the RW testing lab, like the Prophecy, Shadow, Elixir, Hitogami.) The good news is that the shoes Mizuno has kept around are standouts that have time and time again performed. One such model is the Inspire. This 17th version continues to be the brand’s trusted go-to for stability, providing a soft experience much like the popular Wave Rider but with a more supportive midsole for overpronators.
Pros
- Heel cushioning is softer and more responsive than in the Inspire 16
- Full rubber outsole offers high-mileage durability
Cons
- Heavier than previous versions
The Inspire uses a reshaped zig-zagging TPU wave plate to help stabilize the underarch; it won’t stop your foot from rolling inward, but it helps curb those pronation forces to keep you steady. That plate sits between a fresh wedge of Mizuno’s new Enerzy foam in the heel and a full-length top layer of U4ic. Both foams are EVA-based, but Enerzy is the more premium of the two materials and feels significantly softer underfoot. Conversely, a firmer ride from the U4ic topsole offers more snap than plushness on toe-off.
A Soft, Stable Ride for Heel Strikers
Of our testers that enjoyed the Inspire the most, the majority were heel strikers. That’s not especially surprising since most runners are, but it makes a lot of sense based on the changes to the ride that Mizuno implemented in this version. (And it also explains why the shoe was received a little less fondly by forefoot strikers.) Those who hit the pavement heel first noticed more of the moderately springy ride from the new Enerzy foam; those who touched down closer to mid and forefoot instead encountered mostly Mizuno’s older U4ic cushioning, which is less adept at absorbing impact. While the softer Enerzy foam does compress a bit, making the 12mm drop feel slightly lower than previous models, that offset still felt off-kilter and foreign to mid and forefoot strikers.
Long-Awaited Wiggle Room
A too-narrow forefoot was a common struggle for many testers in the Inspire 16—enough so that some runners dub the Mizuno toebox “notoriously small.” Thankfully, this version brings some much-needed room upfront. The women’s model increases the volume in the upper overall and adds 2mm of space around the ball of the foot, where most of us experience hot spots in a shoe. More comfort also comes from the new air mesh upper with larger perforations for ventilation. Though the Inspire still hasn’t adopted the inner gusset style like its more premium stability sibling, the Horizon 4, it has added a thicker, more secure tongue. This appeased testers who had issues in the 16 with the thin tongue bunching and folding in on itself.
What Our Wear Testers Said
Melinda L. | Tester since 2017
Arch: Flat | Gait: Overpronator | Footstrike: Heel
Rated this shoe: 7 out of 7
“I loved this shoe. It met and exceeded all of my expectations. At first, I was a bit concerned about the stiff forefoot, but in the long run (pun intended), the Inspire felt perfectly supportive and I had no issues with hot spots or numbness in my toes. I most liked the snug fit of the heel cup, the secure and supportive—but not too tight—upper around the midfoot, and the wide toebox. I have a wide forefoot and I am always happiest with extra room. Due to the Inspire’s ample cushioning and support, it is perfect for ‘Church of the Sunday Long Run.’ But, because of its heavier weight, I would not recommend this shoe for speedwork or racing.”
Jeremy G. | Tester since 2017
Arch: Flat | Gait: Neutral | Footstrike: Midfoot
Rated this shoe: 5 out of 7
“For me, the Inspire was just above average. My runs were anywhere from 4 to 12 miles in length, and this shoe had a good balance of cushioning and stability for those distances. The heel cushioning is plush but not spongy so that it feels unresponsive or like your foot is completely sinking in. This shoe compares to the Brooks Glycerin GTS in terms of stability, but the Inspire felt higher in the heel. The toe spring is also very flat compared to the Glycerin GTS where the forefoot rolls upwards, so the Inspire did not feel as smooth. Instead, I felt like I was slapping down more on the firm forefoot.”
Morgan is a gear editor who has been with Runner’s World since 2017. She started as an intern ghostwriting The Warmup, a bygone version of the daily RW newsletter. Now, she tests and reviews anything you might find on runners’ feet-from crew socks and compression boots to carbon-plated super shoes.
A lifelong runner and shoe geek, Morgan has been chasing the perfect pair of kicks since she joined her grade school cross-country team. Since then, she ran as a Division I walk-on for the cross-country and track & field teams at the University of Delaware, where she studied English and Biology. She has one full marathon under her belt, and has raced more halfs and 5Ks than she can count.
