Flux Footwear Adapt Trail Runner Review: Improvise, Adapt, Link Yourself to the Earth

Introduction to the Flux Footwear Adapt Trail Runner

JOHN: This review is a real treat for me because I’ve wanted to run in Flux for a long time. Also, an added benefit — it’s a trail shoe. I first learned about Flux from an ultra runner I look up to for being a tough guy and just an all-around dude, Wes Faulk. Wes is a Marine and is always doing something badass, like being an early ambassador with Flux. He told me great things about them, but unfortunately, I never got to try a pair for myself.

But, as I’m sure you’ve seen (if you’re familiar with this brand), Flux’s marketing focused on telling people to “ditch your Altras,” taking quick shots at the biggest name in the lowest drop. It’s yet another thing that’s wild about the zero-drop running scene.

However, the way I learned about Flux was very similar to how I learned about other zero-drop brands like Xero (meeting an ambassador on a 100 miler). I like trying all the different zero-drop brands, so I’m knowledgeable on the overall scene. Many of the people I run trails with love Topo or Altra, and I love introducing them to smaller companies and broadening our collective horizons. So, where does Flux stack up to Altra? Should you ditch your Altras? Is this shoe a Delorean? A Cybertruck? Let’s get Back To The Future 4 all the details!

REESE: I’m coming at this review very differently than John. Before running in this shoe, I’d never heard of the brand Flux Footwear. I saw the pictures of the shoe and decided I needed to try it out, and then I took a closer look at the brand. It feels like the brand could be featured on Ben Greenfield — perfect for someone trying to biohack their existence.

I’m not into biohacking. However, I’m into tracking biometrics and understanding how my body is doing. I honestly don’t know if my health is in such peak condition that hacking will bring me the marginal gains biohackers are after, but at least I can look at the numbers.

That being said, my background is in science, and I do love to dig into the science (or sometimes pseudo-science) behind all hacking claims, so this shoe piqued my interest. Flux claims that its Earth-Link tech, featured in the sole of the shoe, offers a grounding sensation that can reduce inflammation, lower stress, improve sleep, and increase HRV, so obviously, I had to test that out. Luckily, I have an Oura ring that measures all of those metrics with actual data, too. To the trails!

What we like about the Flux Footwear Adapt Trail Runner

JOHN: Great Scott! The Flux Capacitor!

Weighing in at 11.3 oz, this shoe is about half an ounce heavier than the Lone Peak and about the same weight as a Topo Ultraventure, so honestly, it’s very comparable to other trail shoes out there.

Moving down, I like the grip of this shoe. The Trinity Tread is highly versatile and gives you grip on multiple surfaces. It’s not overkill but not underkill either — it’s a good balance to tackle lots of trails. If you have to run on some road to reach the trailhead, it also doesn’t feel bad there. I primarily ran on dirt, but I also used this one on a trail here that has other stuff on it, and it did well.

The toe box is roomy and comfortable, and I found my US M11.5 to fit true to size. I’m going to list the removable AdaptSol insole that includes “over 100 nodes that massage your feet and provide comfort with every step” as something I like, too, but it has some caveats. It certainly wasn’t bad, but I don’t know that it did any of what it said above. It’s one of those features that’s interesting, and I kinda see what it was after, but I still have my doubts.

I definitely felt that if I used this shoe on a 50k, that insole might blister the bottom of my foot because it’s bubbly and rubs at times. It feels fine on runs up to around 14 miles, but I’m not sure I would use it for anything longer. I kept laughing to myself that the rubbing was just the comfort process or something like that. With all that said, if you look at how the entire insole works with the rest of the midsole it is interesting. I just question the bubbles on the removable insole on longer runs.

Finally, I like the look of the Adapt Trail Trainer. I guarantee if you wear this shoe on the trail you will pick up friends because people love talking about Altra and zero drop and how they switched to Topo but aren’t totally sold yet. It’s like dating or something, but my point is the shoe looks good and people will want to talk about it once they hear it’s zero drop.

REESE: Before I get to the biometrics, I’ll focus on the shoe itself. There is a lot to like about this trail runner. The first thing I noticed was the sole inside the shoe. That is where the Earth Link tech is housed. Flux claims that the carbon-infused rubber and metal-coated webbing and stitching electrically ground you to the Earth. I’m not sure if that’s true, but it reminded me of the Adidas bumpy slides I wore back in the ’90s. I loved those slides.

Back in the present, I loved the bumpy feeling of this shoe. It was legit comfortable and pleasant — it felt like my feet were getting a little massage while walking and running, and I’ll take that over an abrasively stiff ride. The toe box is quite wide and roomy, which was nice while walking. Running, not so much, but I’ll get to that later. I think if you’re a fan of Altra, the large toe box will be welcomed.

The outsole is the real star for me. For a brand that is just dipping its toe into the trail world, the traction is quite lovely. As John mentioned, the Trinty Tread provides a lot of stability and traction on several surfaces. Flux notes that the rubber is non-marking, which caught my attention, too. I’m not sure if any of my trail shoes have ever marked rocks, but now I need to look into that. This perhaps matters less while outside (although don’t mark or graffiti any rocks anytime soon, okay?) and matters more if you’re in a gym.

What we don’t like about the Flux Footwear Adapt Trail Runner

JOHN: I found the Flux Footwear Trail Runner very hard to put on, and I feel like this is due to the anti-debris collar, which, in theory, is a good idea. After all, Hoka utilizes a similar feature on their shoes that works well. Once you get in the shoe, it’s fine, but I found getting the shoe on is cumbersome. Even more annoying, after all that effort to get the shoe on, debris still got in.

REESE: Maybe something is wrong with me, but I want my feet locked into a shoe. Like a corset, but you know, not as terrible and patronizing. But seriously, I look for a shoe with a locked-down heel, support and stability through the midfoot, and a little wiggle room in the toes. Not a lot, but just enough. The toe box was way too roomy for me, and although the upper is breathable and comfortable, it didn’t provide the stability I wanted from a trail shoe. On any sort of lightly technical sections, I found my foot flopping around inside. Maybe that’s how I’ll be grounded — I’ll fall flat on my face.

Now, to the grounding claims. I didn’t have a standard protocol to test this since Flux doesn’t indicate how it measured these results or what the measurable results were, so I’m not sure how long you need to wear the shoes to experience the claimed gains. I decided I’d wear the shoes and track my stress metrics throughout the day, along with the HRV measurements that my Oura takes in the morning, but it’s worth noting that your HRV fluctuates a lot throughout the day. Long story short, my results were not consistent with Flux’s claims, and I’d like to know how Flux tested these claims so I can more accurately replicate their protocol.

I’ll also note that I wear sole inserts in my shoes. It’s nothing crazy, just Spenco inserts that I cut to make sure they’re the same length as the shoe. These inserts work in all of my other shoes, but the toe box in the Adapt Trail Runner is so wide that it doesn’t fill out the whole shoe. It’s not a deal breaker for some, but for me, I have to run with those little things; otherwise, it’s injury city.

Final thoughts on the Flux Footwear Adapt Trail Runner

JOHN: We still don’t have hoverboards, but the Flux Footwear Adapt Trail Runner is a reasonably priced shoe that feels good on most trails and not bad on towpaths or roads if you encounter them in the wild. Is it a Resident Evil-like mutation of Altra, Hoka, and others? Absolutely. Is that bad? No, I think Flux is on to something, and I encourage zero-drop enthusiasts to try it. I honestly feel like the Adapt Trail Runner does more good than bad, and I would totally use this as a rotation training run shoe.

REESE: This shoe feels like a great shoe for someone who just did a gym workout and wants to casually hit the trails or a great travel shoe because it’s very comfortable. I’m wearing this shoe as I prepare to hop on a plane. It is roomy, it’s got those fun massaging (or grounding) bumps, and chances are when I get to wherever I’m going, I’ll need to go outside, walk, maybe walk on a trail, and these shoes would be perfect for a mellow cruise. I’d like to see some stats behind Flux’s claims on the grounding stuff and see this shoe get a more robust and stable upper.

You can pick up the Flux Footwear Adapt Trail Runner for $149 by using the buttons below.