BUILT into the soul, er, sole of two flagship basketball shoes is one common element — atomic number seven, the gas that makes up almost four-fifths of the air, the big ‘N’ in the periodic table: nitrogen.
But the way Nike’s LeBron 19 and Anta’s KT7 use it is an illuminating look at the tech arms race of midsole cushioning.
A new Wall Street Journal video sizes up both shoes, framing them with a US-versus-China lens as it tackles how the Chinese sportswear giant is ramping up its ambitions to go global. But with interviews from basketball shoe reviewers Zhang Hanwen and Zach Thomas (a.k.a. Foot Doctor Zach), it also dissects the technology behind both shoes, and how they use different applications of nitrogen gas to deliver tip-top cushioning.
How nitrogen is used in LeBron 19, KT7
The Nike LeBron 19 is built on decades-old tech called Nike Air. First developed in 1987, it uses a polyurethane membrane filled with pressurized nitrogen gas. Nike then slots this air bag inside a shoe’s midsole.
For LeBron James’ signature shoe, there’s actually two Air units: a massive Air Max membrane on the heel, and then a more agile Air Zoom on the forefoot. The Air Zoom has tensile fibers lined up inside the membrane like ribs, which the Swoosh says helps add more spring.
Connecting the two Air units is a little tunnel so that the pressurized nitrogen gas can circulate freely as the sole gets sandwiched between your feet and the floor.
Anta, on the other hand, uses nitrogen a little differently, in tech the Chinese shoe brand first introduced in the KT7.
“In simple terms, it’s using nitrogen and mixing it with foam material,” Zhang told WSJ. The nitrogen forms a matrix of miniature bubbles within the midsole foam that compresses and expands as you move through the court.
The flexible and deformative qualities of the foam help explain the signature black “wings” that run across the sides of Klay Thompson’s seventh signature shoe. They’re there, says Zhang, to help the midsole foam keep its shape.
Nitrogen-injected soles are not a technological innovation that’s exclusive to Anta. In 2021, running shoe brand Brooks also introduced DNA Flash, a sole built on much of the same principles as Anta’s new cushioning. But Anta is clearly happy with their midsole innovation — the WSJ video says that it plans to roll its "Nitrogen Technology" to 75 percent of its footwear line by 2025.
Elsewhere in the video, WSJ also takes a look at the budding business rivalry between the two brands, as Nike seeks to cement its foothold on a country with a $50 billion sportswear market, while Anta tries to expand its footprint overseas.
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