Inov-8 F-Fly Performance Review

It was a nice surprise to see the Inov-8 F-Fly appear on our doorsteps.

Inov-8 has a storied history in the functional fitness world, though in recent years brands like NoBull have rapidly taken the spotlight (and the CrossFit Games sponsorship) and newer brands like TYR have exploded in popularity with their initial forays into footwear (including here at WearTesters, where we’re huge fans).

But the athletes who love Inov-8 are some of the most faithful. We’ve been looking for the right shoe to see just what the company has been up to in the cross training space and the Inov-8 F-Fly is the perfect opportunity.

So, does Inov-8’s latest hyped trainer live up to the buzz or will it be one we’d wish had more, uh, innovation? Keep reading to find out more.

Please note that while Inov-8 sent us pairs of the Inov-8 F-Fly, the company had no involvement in this review, didn’t receive an advance look at it, and has not attempted to influence it.

How do the Authors Train?

Arune Singh (age 42, 5’11”, 210lbs): Trains daily with functional fitness programming provided by Deadboys Fitness, founded by Colby “Seth Rollins” Lopez and Josh Gallegos, along with logging 30-40 miles of running per week. He also has a medical history of Sleep Apnea and Myasthenia Gravis, meaning Arune’s focus is on lean muscle mass.

Drew Whitcomb (age 42, 6’6″ 195lbs): Trains daily with a focus on running, strength training, and mobility. He writes the majority of our running shoe reviews and runs a lot of miles due to testing needs and his growing affinity for long-distance races. He regularly competes in marathons, half-marathons, 10k, and 5k races. His strength training and mobility regimen center around maintaining flexibility and lifting heavy to build power as a counterbalance to all the running he’s doing. His number one focus is staying injury-free so he can keep up the sweet gig of reviewing shoes for a living.

What is the Inov-8 F-Fly?

Inov-8 describes it as:

A lightweight gym shoe to tackle any workout – meet the F-FLY. Designed to give superior cushioning and bounce during treadmill running and cardio sessions, the F-FLY is also versatile enough to be worn for weightlifting, functional fitness movements or wherever your workout takes you.

Feel light and bouncy thanks to the combination of a POWERFLOW PRO midsole and BOOMERANG FOOTBED. These work together to give you the cushioning and energy return during high impact exercise, whether that’s running or jump squats. At the same time, we’ve designed the POWERFLOW PRO in such a way that you can still feel the ground, for that more natural feel when you train.

Training

Arune: One thing you need to keep in mind is that the Inov-8 F-Fly is closer to a barefoot training shoe (like Xero Shoes) than it is to more cushioned trainers (like the Nike Metcon 9).

And it’s pretty much the perfect shoe for anyone considering the transition to barefoot training.

I was genuinely shocked at how this felt when I put it to the test with some heavy lifts, given it’s a light and relatively minimal shoe with a 4mm drop. The combination of the Powerflow Pro midsole and Boomerang footbed provides some incredible stability when you drive into the ground with those heavy lower body lifts, whether you’re doing heavy squats or stability-focused lifts like RFESSs.

The outsole bites every surface I tried it on. That means you can safely focus on form with any kind of lift you have in mind because you’re always going to feel connected to the ground. 

While this isn’t a shoe I’m going to want to use outside the functional fitness training I do, I think there was no version of my training – Olympic lifts, HIIT, bodyweight Metcons – that this shoe didn’t excel in.

I think a truly exceptional training shoe is one you don’t think about while training because you’re focused on the work and the Inov-8 F-Fly is one of those shoes.

The F-Fly is made to take time with those heavy lifts and to move quickly when you’re doing something like burpees. That aforementioned Boomerang insole really is aptly named, as I always felt like any energy I put into it truly got returned back to me in a very noticeable fashion.

Drew: As Arune mentioned, the Inov-8 F-Fly feels initially like a minimalist training shoe but is so much more than that. It’s the most and best cushioned minimal gym shoe currently available. The Powerflow Pro is the perfect blend of impact protection and ground feel. And that ground feel makes it easy to recruit every bit of your body, starting with the toes, and channel it all into lifting heavier.

The grippy outsole also keeps the feet planted to the floor. The outsole makes it easier to stay stable when heavy weight shifts around while held above the head or shoulders. The high end power transfer and stability make the Inov-8 F-Fly a desirable option for lifting aimed at logging big PRs.

Cardio

Arune: We always remind readers that training shoes aren’t running shoes or court shoes, so we’re always grading this section on a curve as a result.

Let’s start with running, since the Inov-8 F-Fly purports to deliver “superior cushioning” during treadmill runs and I think that’s an important distinction. I did NOT enjoy road running in these shoes but they were surprisingly solid on a treadmill for both sprints and steady state cardio. The heel and forefoot cushioning kept me moving on the treadmill and it felt like a much more natural gait than trying to run in some of the more padded, big brand training shoes.

The flexible construction of the shoe is also a blessing with rowing, as it really allowed me to get up on my toes and then push through from my heels.

I also really liked the feel of these shoes with some shadow boxing and jump rope splits, where my feet took a real beating but never felt as sore or tired as with most barefoot shoes or anything even in their orbit.

Drew: When I first picked up the Inov-8 F-Fly I was dubious of the shoe’s ability to stand up to cardio. Like Arune, I felt they didn’t work well for running on pavement or asphalt. There’s just not enough foam underneath the foot. As a result, the impact protection wanes as your body smooshes the cushioning into the pavement. Running outdoors, I’d say a 200m sprint is the limit. 

But on the treadmill? I ran a several miles without issue. The Inov-8 F-Fly can handle 3 miles on the treadmill, and though the experience won’t be as good as in a running shoe with ample stack height, the F-Fly gets the job done without the need to change shoes. The 4mm drop may be a bit too low for some people with balky achilles or calves, but otherwise it’ll be fairly clear sailing.

The midsole and upper are extremely flexible and running feels natural. Other drills or exercises like plyometrics, agility ladders, jumping rope, or skater jumps also feel natural. One leg exercises feel highly stable and powerful. There’s a complete confidence that the F-Fly is going to do what your foot wants it to do and never fight against your natural motion or induce a movement path you don’t want. That makes it a highly reliable gym companion.

Comfort

Arune: If you’ve never worn barefoot shoes, I think you’ll find the Inov-8 F-Fly a bit shocking. But keep in mind that there’s a LOT more cushioning here than in anything truly minimal.

These shoes allow for full toe splay and were quite accommodating for my Hobbit feet, but I think I’m at the upper end of the foot width that can fit in these shoes.

We’ve talked about the Boomerang insole and the Powerflow Pro midsole, which not only provide great stability but are pretty comfortable too. I’ve worn these shoes casually for up to eight hours in one day and had no real complaints.

How did these feel for you, Drew?

Drew: The Inov-8 F-Fly is going to be one of my key recommendations for people looking to transition to a more minimal shoe experience. Rarely is cushion this reliably plush in a shoe that emphasizes ground feel. That cushion and the 4mm drop make the F-Fly the perfect shoe to start down the minimalist shoe path.

The upper is engineered mesh, and while it isn’t going to the most durable (especially if you use it to climb ropes), it’s comfortable and soft all around the foot.

Fit

Arune: I went with my standard 9.5 size here and overall I’m happy with the fit, though it felt a smidge short at times.

I’d say TTS (true to size) to what you wear in other training shoes should work for most people. If you have a super wide foot, going up a half size might work but you’ll need to try the F-Fly to make sure it works for you. 

Drew: I went true to size and while the Inov-8 F-Fly is slightly short lengthwise, it’s not enough to change sizes. It tightens nicely around the midfoot while allowing plenty of room in the forefoot and heel to accommodate a bunch of different foot types. This build is part of what makes the stability so good and the F-Fly so good at compound lifts.

Aesthetics

Arune: I got the all black pair and it’s a perfectly non-descript training shoe that fits every fitness environment you have in mind.

They’ll also transition to your chores quite nicely, especially the white and gum sole pair that feel made for folks wanting to look a bit more fashionable when they’re on the go.

Drew: The Inov-8 F-Fly’s looks are uninspiring. It’s a basic looking engineered mesh pattern with some vinyl overlays to improve lockdown and stability. It works, which is the most important thing, but it’s not a shoe I’ll be wearing around often.

However, I don’t hold it against Inov-8. It’s extremely difficult to make a shoe with a low profile midsole look good. Our brains are so used to thick midsoles with crazy designs. We expect big and chunky and when we don’t get it, it just doesn’t seem right.

Price

Arune: At $130, this is well below the median $150 price of training shoes and is a more versatile training shoe than many others on the market. This might not be everyone’s cup of tea given how close it is to a barefoot trainer, but I think it’s an absolutely great value.

Drew: At $130, the Inov-8 F-Fly is a no-brainer over many cross training shoes that cost $10-$30 more. It can do pretty much anything you need it to in the gym and feels great on foot while doing it. It’s not a casual banger but it delivers performance more than commensurate with its price point.

Inov-8 F-Fly Final Verdict

Arune: 2024 continues to be an exciting year of new training shoes and Inov8 has a winner on their hands. The Inov-8 F-Fly is a versatile training shoe that is great for nearly all fitness levels and ambitions.

Drew: The Inov-8 F-Fly will make an appearance on our Best Cross Training Shoes list, Best Weightlifting Shoes list, and Best CrossFit Shoes list. It’s just as good as many of our current picks but offers a different, more low profile, and flexible experience.

I love that the Inov-8 F-Fly exists because it gives gym goers a new and different option. If you thrive when your foot is supported yet still free to flex as needed, the Inov-8 F-Fly is likely a great option. It’s a high performer without the clompiness or clunkiness that can plague modern cross training shoes.