NIKE Men's Air Zoom Structure 21 Running Shoes

Product Information

In case if you found the last year’s Structure 20’s ride to be hard on your feet, consider the list of alternatives at the end of this review. PROS AND CONS The new midsole made Structure a few mm higher (while maintaining a 10mm drop from heel down to toe height), and ironically, I kept feeling like I wanted the shoe to be closer to the ground, before I even learned about this change.

Saucony Guide is 2mm lower in heel-toe drop with 8mm as opposed to Structure and GT-2000’s 10mm, with Adrenaline and Wave Inspire coming in at 12mm. The 21 is my first experience with the Structure line, so I asked a friend of mine who loved the 18th and 19th models what he thought of the 20. For reasons best known to Nike, the Zoom Structure has rarely had a plushly padded tongue or heel lining. Thankfully, the Structure 20’s tongue quilting is nowhere as bad as the Structure 18. There’s plenty of room in the toe-box and forefoot and the fit is true to size. The Structure also comes in multiple widths (2E and 4E) in case the standard D width fits narrow.The Structure 25 is more of a stability trainer than the 2 previous Structure versions. It has an extra heel clip, more arch support and it also has a firmer ride which results in less lean bias. The Nike Structure is all about balance. The upper has smooth interiors and fits well. The inner strapping system which was re-introduced on the Structure 20 finds its way into the 21, and that’s a good thing. The Flywire cords are restricted to the rearfoot, and this means that the midfoot is secured entirely by the straps.

The excessive outwards bias or lean of the older Structures (17, 19) is no longer present on the 21. The rearfoot has a bit of an outer bias due to the midsole groove and the beveled heel, but only slightly so. Changing the engineered mesh to a lighter and vented kind leads to a significant weight reduction. The Structure 21 is nearly an ounce lighter than last year (for a size US 10). Minor improvements have been made to the laces (flat instead of round) and the Flywire cord placement. LOWER PRICED ALTERNATIVE? When it comes to popularity, the Structure series comes nowhere near the likes of the Pegasus or the Infinity. I personally prefer the Structure to both the Peg and the Infinity because its upper is more padded and the cushioning feels more substantial but I think that most runners still think the Structure is an old school, traditional stability trainer. An inner sleeve is attached to the tongue, so the arch-band strap is sandwiched between the outer upper and the inner sleeve.A lower drop seems to encourage runners onto their toes while at the same time limits the range of motion of the Achilles.

The Nike Air Zoom Structure 22 is a running shoe designed for people with flat feet. It helps runners to train with appropriate support. Plantar fasciitis or flat feet problems can be treated by regular stretching but wearing a shoe that supports the arch and heel correctly is a more lasting solution and that's where the Zoom Structure 22 comes in. The product is also a good choice for anyone who trains daily with a view to covering longer distances as it its hard-wearing and offers good support over an extended period of time. Support On Hard Surfaces Structure 21 rides very similarly to the ASICS GT-1000 6, with a bit more flexibility in toebox upper fit; the heel fit also gives a touch more room. So all in all, the fit is closest to ASICS’ GT-2000 series. This update got rid of the overly skewed ride behavior of the Structure 19. The new design was also easy on the foot, as the under-arch lost the pointy feeling. Nothing has changed on the midsole this year as the Structure 21 carries forward the same design. The outsole rubber is laid out in a familiar format. The outer side has the ‘crash rail’ strip with multiple flex grooves, a design first used on the Pegasus 31. I’ve enjoyed running in HOKA’S, but for some reason a higher ride in this Nike never lost its awkward feel.When I walked around in the Structure 25 for the first time, it was noticeable how much more it felt like a stability trainer than the last 2 versions. There was a prominent arch sensation which wasn’t there since the Structure 19 but it wasn’t painful or uncomfortable. I could feel the airbag under the forefoot which has always been a characteristic of the Structure series. It was comfortable right out of the box and didn’t need any break in period. My podiatrist informed me that one’s preference in drop height of a shoe relates to one’s Achilles flexibility—but no two people are alike in terms of an exact “if this then that” diagnosis: you’ll have to try out a few different types to see what really works for you. Nike Zoom Structure 21 General Info Expect 400 miles of life from the Structure 21, with the wear and tear of the midsole cushioning and outsole happening in a gradual fashion. UPPER FIT AND FEEL The inner outsole is populated with a colony of pentagonal lugs. The rearfoot has a shallow cavity exposing the midsole foam; this extends to a transition groove which splits the outsole longitudinally. The forefoot has an internal Nike Zoom Air bag.

We had our work cut out for us last year because the Odyssey 2 was the perfect upgrade path from the Structure. This year, the Odyssey is gone so the only way is down. If you don’t require Structure levels of support, then you should look up the Nike Zoom Span 2. Structure is also a competitor to the Saucony Guide, Brooks Adrenaline GTS, and the Mizuno Wave Inspire. You’ll get a similar upper fit from these shoes, but the differences in offset provide varied underfoot experiences. The Structure 21 still has Flymesh (as did the 20), but uses a new and lighter version. Nike says that the new Flymesh uses mono-filament yarns which reduce weight yet retain structural strength. The weight claim is true – the Structure 21 sheds nearly a full ounce over the 20. The inner straps hug the foot closely, and the newly introduced flat laces pass smoothly through the eyelet straps. Flywire is restricted to the rear, so that takes care of the pressing sensation against the midfoot.The laces are now flat instead of round. These flat laces pass better through the strap-based cinching system. The Structure 21 uses a strapping system (or the internal ‘arch-band’ in Nike-speak) which was also used on the 20. The rest of the upper fits beautifully. The midfoot fit is far superior to the Flywire-based cinching of the Structure 18 and 19. The new Structure is nearly an ounce lighter than its predecessor, thanks to a new knitting technique, with the same magical balance of stability and cushioning—not too stiff but with the added support overpronators need. If you’re looking for a stable, relatively lightweight shoe that can handle a ton of miles, well, you don’t have to look any further. Runner’s World Wear Testers Say When it comes to support, the Structure 25 is currently the most supportive trainer in the Nike lineup. I’m a mild overpronator with flat feet and I find it stable but the prominent arch is a bit too overbearing. I think it will provide enough support for most overpronators but it’s more suited to runners with high arches. I know what Nike is trying to do with the Structure 25 and the latest InfinityRN 4: they want to push runners who need support away from the InfinityRN to the Structure and vice versa.