Flux Footwear Review: I Tried the Adapt Runner and Trainer

Before I started taking running seriously, I never investigated what I needed in a running shoe.

There’s so many different brands, styles, materials, thicknesses, weights. But I didn’t know what I needed. 

Less cushion? More wiggle room? Lighter weight?

I put almost a hundred miles into my tennis shoes from high school before it dawned on me that this discomfort isn’t normal.

My feet had blisters, my quads were sore, running was painful. 

“Tennis” shoes are running shoes, I naively thought.

I couldn’t have been more wrong, and my feet hated me for it. 

Running as an activity seemed simple to me at the time, given that you really only need a pair of athletic shoes to get going. It didn’t occur to me that perhaps the benefits of the right shoe were a little more nuanced. 

So, I went out to a running shoe store, spoke with a specialist, and put a few miles on some proper shoes.

Here’s the truth: You need to invest in the right pair. Your shoes should work for you, and not the other way around.

Knowing what I do now about how proper athletic shoes work, I wanted to see if a style like Flux’s would be the right fit for me. 

What Is Flux Footwear?

Flux Footwear is a Nebraska-based brand that set out with one mission: create a shoe that allows the foot to move like it was naturally supposed to.

The brand prioritizes comfort and delivers shoes that cater to athletes’ specific needs, incorporating unique technology like the proprietary Adaptread™ outsole and the removable Adaptsol™ insole.

They make three models of shoes tailored for different activities.

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In this review, we’ll be testing the Adapt Runner for runs of all distances and the low-top Adapt Trainer for CrossFit and weight-training workouts.

Flux also offer the Adapt Trainer in a high-top version, which is more for more intense training and bodybuilding.

Things to Consider Before Buying

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Each model in the Flux lineup carries a zero-drop sole, meaning the thickness of the sole is even throughout the length of the shoe. This is meant to allow your foot to go through the full range of motions, rather than having your shoe direct your foot’s movement.

This style of sole is relatively unique among the wedge-shaped runners found in the market and may not be for everyone.

Changing styles of sole can take some getting used to, so be sure to take it easy at first for those considering these as a permanent addition to their workout gear.

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If you’re unhappy with your Flux shoes for any reason and they’re still in like-new condition, the company offers a 30-day money-back guarantee.

Also, if it’s within one year of purchase and there are manufacturer’s defects, Flux will replace your shoes free of charge. This is some nice peace of mind given this is a relatively new brand.

So, does Flux live up to the performance-minded persona the brand takes on? 

I picked up the Adapt Runner and Adapt Trainer to see if they do as I train for my upcoming half marathon—talk about perfect timing.

My Hands-On Review

Adapt Runner

First Impressions

The presentation of the shoes really stood out to me while unboxing.

The runners themselves come wrapped in branded tissue paper with a blueprint-like design that lets the customer know these shoes have gone through some serious R&D.

The appearance of the Adapt Runner is sleek. Flux designed this model with a fluid profile. Smooth curves and understated branding give them a premium feel, which I find to be a plus as hyper-branded athletic shoes are everywhere nowadays.

Sole

Flux Footwear takes a lot of pride in the soles of their shoes, so I was eager to see how these stack up with my other running shoes.  

When buying a pair from Flux, there is one non-negotiable, and that is the zero-drop sole that all three models of shoe in their shop have.

If you’re someone looking to transition to a minimalist sole (where only a very thin layer of material separates the foot and ground), this might be a good option for you, as the zero-drop sole is the stepping stone between minimalist soles and wedge-shaped ones.

Back in the good old days when we were crouching above the tall grass with spears in hand, we didn’t have a layer of cushioned foam under our feet to keep the foot fatigue at bay as we tracked our next meal for miles. Our feet were just tough as nails. 

That’s where the benefit of the zero-drop sole comes into play. 

The decreased thickness and even height across the footbed recruits muscles in a way that closely resembles our natural gait. This design has been shown to develop better performance and avoid posture-related issues associated with sloped runners.

While all of this sounds great, it’s best to experiment with different types of soles before you commit to this transition as everyone responds differently to changes in their shoe.

Flux also includes removable AdaptSol™inserts that feature their signature cushion pods to decrease impact. And remember, there’s the 30-day money back guarantee if this just isn’t for you.

I found that the zero-drop sole took two running sessions of three to five miles each before I began to adapt to closer ground contact. The tactile feel of a thinner sole allows more control than a thick, foamy sole that buffers the changing terrain of my trail runs—my calves could surely tell.

Because of the transition from wedge sole to minimalist, my legs were sore for the next few days.

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Construction Quality

The quality of the Adapt Runners speaks for itself. I’ve had issues in the past with the bonding between the soles and upper panels of the shoe—loose stitches, beads of glue sticking out, or a creased seam after only a few sessions. 

None of that was noticeable at all on my pair. 

My running shoes up until this point have multiple panels of material stitched to the sole or rigid panels of thicker material that make up the exterior. I’ve noticed that these are usually what cause the upper to separate from the sole, allowing water to enter and eventually lose stability. 

The reinforced mesh upper flexes with the bowing of the shoe during a stride, allowing me to not worry about corner creases in the future. I was always a bit sceptical of sock-like runners, but the quality seen on this pair definitely opened my mind to them.

But if you need a lot of support in your running shoes, these may not be for you. The “minimalism” in the Adapt Runner is definitely apparent.

Fit and Sizing

For context, I wear a US Men’s size 11.5. Sizing shoes can be unpredictable, but I decided to go with my true size and they fit like a glove (and not just because of the reinforced stretch knit upper).

As someone with wide feet, I knew going into the testing period that the wide toe box would be comfortable.

Narrowness near the toe is the most common reason for a running shoe not fitting me right the first time. But not only are these shoes wide enough, they allow enough room for my foot’s natural desire to spread out while running. 

If you have a narrower foot, I recommend sizing down ½ a size if your true size is too wide in the front.

You want enough room in the front for your toes to spread freely, but not so much that your foot can twist left to right inside the shoe. 

Support

Like I said earlier, I was never a proponent of the sock runner because a fabric construction wouldn’t be able to keep my foot in place like a more firm material would. 

Despite this upper being made of mesh, I wouldn’t describe it as flimsy. It’s elastic and dynamic. Previous shoes I have tested resulted in a bit of pain and a tight sensation after a long run. These weren’t so bad, and I think I know why.

I recently find out our feet actually get larger as we progress through a run due to the increased blood flow to the foot.

A running shoe that is too firm can trigger discomfort due to this natural swelling, so Flux’s use of this material certainly helped with my post-run comfort.

I’m sure it’s safe to say we’ve all had a nasty heel blister from a new pair of shoes.

The designers of the Adapt Runners must’ve had this in mind when designing the contoured heel-lock that pads the inner opening.

The additional support material is soft and maintains a secure embrace around the ankle to avoid unwanted friction, leaving me without a single abrasion after my first use. 

Break-in Period

While trying these out, I was in the final weeks of training for the Brooklyn half marathon. My training plan had consisted of two 4-6 mile runs per week followed by a 7-10 mile long run over the weekend. 

The zero-drop sole definitely took some getting used to. All the smaller muscle strands in my foot were sore after my first 5-mile run, as they weren’t used to the absence of springy foam my other trainers provide.

The age old saying goes: “no pain, no gain”. My feet were just using some muscles it wasn’t used to.

The form-fitting walls of the shoes also don’t require as much activity to respond to the unique shape of the foot—a plus for customers that are running with a zero-drop sole for the first time.

By the time I completed run #2, I felt accustomed and I continue to put miles on them with no issues.

My Overall Thoughts

All things considered, the Adapt Runners are great for those looking to try a shoe designed for the foot’s natural movement and can get them closer to a minimalist sole.

I’m not sure if I’d be able to do any run over 10 miles in these, simply because our feet do need more support the more miles we go in one run. So, be mindful of what your training schedule looks like.

If versatility in style is important, these might not be the best option as the wide toe box and mesh upper give them a true athletic appearance, unlike running shoes that deliver a casual, sneaker-esque silhouette.

Flux Adapt Trainer

First Impressions

Flux’s Adapt Trainer compliments its runner counterpart nicely with a more casual style without sacrificing any of the athletic benefits incorporated into their footwear. 

Comfortable, easy to dress, and great for anaerobic exercise make this model an approachable introduction into the Flux brand.

Sole

The AdaptSol™ technology that supports the Adapt Runner is featured on the Trainer as well, and let me just say, it looks amazing.

Flux maintains a simple color scheme on their products, but they include a subtle hit of their fluorescent blue behind the honeycomb-shaped cells that give the tread on these shoes so much flexibility. I loved this detail and I hope they use this color in a bolder way soon. 

If you stay fit by lifting weights or other high-impact exercises, the zero-drop sole could come in handy.

For lifting, the sole is flat and provides good traction and for HIIT workouts, the honeycomb pattern offers flexibility I haven’t seen in many other trainers. Think movements like pushups or sprints where the foot needs to move naturally. 

Construction Quality

The quality with the Trainers was a different story than the Runners, but still solid overall. The mesh upper has a nice feel to it, and the eyelets (built into the upper as opposed to the plastic brackets that the Runners have) are sturdy. 

The downside with the Adapt Trainer is its lack of removable insole similar to the one found in the Runner. It would be nice if the sole could be taken out since over time, the inside material will absorb moisture and odor.

Coming in at over $120, I would expect a bit more functionality wise. The low-top body of the Trainer offers less ankle support than conventional trainers such as the New Balance Fresh Foam 3000 v6 or even the Chuck Taylor All Star Classic, which is actually quite popular among serious lifters because of its barefoot feel. Both of these are priced less than the Adept Trainer. 

I also noticed hanging pieces of plastic on the midsole that must have been left over from the injection molding process.

While these do not pose any structural issues and are easily removed by hand, they were noticeable out of the box and indicate some tweaks that could be made to control quality.

Fit and Sizing

With these trainers, the wide toe box isn’t as pronounced. However, the low tops still leave plenty of room to accommodate the foot’s range of motion despite the familiar shape of the shoe. My advice is to go true to size with the trainers and sizing down if they are too wide.

When not worn on my leg days in the gym, I like to style mine with a pair of light-wash denim and a crisp denim shirt with some no-show socks—they’re a pretty effortless summer outfit fit. 

Support

Similar to the Runners, the flexible knit upper does a great job at keeping feet stable with the added benefit of breathability and comfort. 

One thing I will add is that if you intend to wear these shoes out and about, make sure the weather is nice. The breathability comes with the tradeoff of being quite water absorbent.

Luckily, Flux made these shoes to be easily washable in the event that your daily travels happen to include a muddy puddle. 

Break-in Period

Frankly, I did not have any noticeable break-in period with the Adapt Trainers.

The Trainers served me well for a week of commuting around the city, along with a few lifting sessions and they didn’t ever inhibit what I needed them for. 

My Overall Thoughts

These trainers are fantastic for those interested in the technology Flux has to offer without being pigeonholed to the Runner silhouette. 

The universal appeal of the Trainer’s silhouette makes these approachable to just about everyone. They’re also surprisingly capable for more active situations such as hiking or jogging.

While not suited for wet conditions, their easy-care instructions make washing and drying simple should you get them wet.

What Do Other Reviewers Say?

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Reviews of Flux seem to have a pretty consensus view: Flux is great for a wide range of activities, but if you have very specific needs there are probably better options.

A popular fitness YouTuber had this to say about the Adapt trainers:

“If you’re looking for a model to wear all day, maybe take to the gym for some casual training, and just whatever other activities you are doing, this is a pretty good model to be doing that in.”

Other reviewers appreciated the flex in the sole, stating that minimalist brand competitors often don’t provide much versatility, but Flux offers a nice balance between protection and movement.

One other thing people have noticed is that because of the grooves in the sole, small pebbles or objects may get stuck in the gaps. Be careful what kind of terrain you’re walking in.

My Thoughts Overall

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