Asics’ 3D-printed sandal offers post-workout comfort

The theory and practice of marginal gains is to find and fix hundreds of small things that, in aggregate, add up to something vast. Asics believes that there are gains to be made in what runners wear when they’re at home as much as what they’re wearing on the track. That’s the pitch for the Actibreeze 3D, a pair of 3D-printed sandals with a lattice structure designed to improve cooling and breathability. The idea is to stop your extremities from getting too sweaty and tense after a run, so you’re that much more prepared for your next one. I’ve been wearing a pair for a couple of days now, and while they do keep your feet cool and dry, they’re not perfect.

Taking them out of the box, you’ll first notice how heavy they are, with each sandal – although they’re more like slippers – weighing 350 grams (12 oz) for my size 11s. They’re a lot bigger than your average pool slide, too, thanks to the overbuilt sole and lattice going over the top of your foot. Obviously, this is to help get air flowing under your feet to cool them down after a long run, and I experienced this after a fairly intensive gym session. It helped that we’re enduring a climate change-enhanced heatwave right now, to really ram home the lack of sweating. It’s a far nicer experience wearing these than what I’d normally use, which is a $15 pair of Havaianas.

The 3D lattice is designed to provide the maximum amount of “step-in comfort” available, which means they’re pretty bouncy. Not in a I’m-walking-on-air way, but in that whenever you step, you can feel the sole compressing and bouncing back as you walk. I don’t know if the effect is more pronounced here than on other 3D-printed soles on the market, or if it’s magnified because you’re barefoot rather than wearing socks. Certainly, it takes a little mental calibration to compensate for the level of travel you’ll experience during each step. Maybe those folks who wear those novelty moon boots will find these no big deal, but if you’re coming from something flat, it is a noticeable change.

Here’s the issue – obviously 3D-printed stuff is made of springy plastic, but it’s still plastic, with its mostly hard, not-particularly-yielding structure. Wear these for an hour and the soles of your feet will look like you’ve been standing on a colander, the skin covered in a grid of little squares. Whatever benefits your feet are getting on the macro level, it requires you to tolerate the small annoyance of having your skin fed through a mesh. And, on a similar theme, because it’s a hard, waterproof plastic, it’s not the ideal surface to put your feet in close contact during a heatwave. That’s perhaps the one area that my $15 Havaianas have the edge, since there’s so little material coming into contact with the top of my feet. But if you're only wearing these for the two or three hours after you've had a running session, that shouldn't be too much of a problem.

Asics’ Actibreeze 3D are listed on the company’s website for $80, although they are currently not out for delivery. The company tells me that the stock will be available in selected markets once again this Autumn.