Flexibility is an interesting thing in trail running shoes. There are those who love the agility of a flexible shoe and it’s ability to rock-hop and make quick adjustments on the run. Then there are those who look for the snap or pop of a more rigid shoe that will give a more active ride. The shoe that we’re looking at today is named for its flexibility but is it really that flexy and, if so, how does that influence the ride? After some solid miles in the Merrell Agility Peak Flex, I certainly have some things to say!



The first thing you notice about the outsole of the Agility Peak Flex is the distinctive skeleton-esque lug pattern. Made from M Select Grip+, these aggressive lugs are deep enough to get a handle on some pretty technical terrain (~5mm deep). As you can see from the image of the outsole below, the lugs mimic the metatarsals and phalanges and are broken up by full-width flex grooves in the front half of the shoe. The rear half of the shoe maintains the same rubber and lugs though here they’re in a more traditional, directional layout.

Merrell Agility Peak Flex Review | Gearist

While I’ll get into this more below in the MIDSOLE section, I’ll say that the outsole is clearly where the flexibility of this shoe begins. The flex grooves are generous and leave plenty of spacing in the lug layout so that mud and debris clears reasonably well though not great. The grip of the outsole I found to be very good on all terrain, enhancing the cornering and agility on both flat but turn-y trails and on rocky, technical stuff. From a durability standpoint, I’m very impressed as I see almost no significant wear over my ~45 miles in this shoe.


The midsole of the Merrell Agility Peak Flex brings even more tie-in to the way the body is built. While the outsole features skeletal influence, the midsole FLEXconnect EVA foam gives a very strong nod to the musculature of the body. The foam is molded to look like muscle fibers in the rear of the shoe and connective tissues in the from half. In the front half of the shoe we see a set of sidewall flex grooves which line up with their siblings on the underside of the shoe. Here there give a visible nod to the fact that this shoes doesn’t stop its flex grooves at the bottom of the shoe only but rather, cuts in on the top and bottom of the shoe to give even more flexibility. Also living in the 33.25mm heel / 27.25mm forefoot is a front and rear rock plate which, as you’ll see later, plays into the overall ride of the shoe.

I really enjoy the feel of this shoe and while the ground feel isn’t super present, I do feel quite in touch with the ground. The rock plate does a good job of protecting the foot from pokey bits which is a big reason for me that this shoe can handle more technical stuff. Now, those flex grooves which are cut in the top and bottom of the midsole present an interesting thing to me; on the one hand, they should produce more flex – and I’m sure there are plenty of shoes that are more stiff. However, due to the rock plate in the midsole, these don’t feel THAT flexible to me – they just feel as though they have a normal amount of flexibility. So to me it’s kind of a non-thing and my feeling about the flexibility is pretty neutral except to say that this is a good way to keep a rock plate from making the shoe overly stiff.



Since the rest of the shoe has al the references to the human body I’m curious about the design printed on the upper. The only thing I can come up with is that it’s a theoretical representation of the nervous system(?). Not that it matters to the rest of this review but I’d love to hear other ideas in the comments!

The upper pf the Merrell Agility Peak Flex is a mix of mesh, TPU overlays and a bit of microfiber fabric here and there. The aforementioned, synapse-laiden mesh covers the large majority of this upper. I found it to be supple and quite breathable but still burly enough to hold up to some very rough treatment. The bonded TPU overlays are well placed and plentiful keeping the foot held nicely in place. These overlays run all the way from the midsole junction up into the lacing system for further reinforcement of heavily stressed sections of the shoe.

Speaking of the lacing system, Merrell uses something called their Omni-Fit™ lacing system which they’ve used in plenty of other models of running shoes. In the case if the Agility Peak Flex the Omni-Fit™ system is a series of secondary laces which go only between eyelets opposing one another (see image) with there being four of these in total. These secondary laces are a closed loop and each is attached to the middle of the tongue which both locked them in place and prevents tongue slide. The actual laces are routed through the ends of these loops in a pretty traditional way. I found these to allow for quite a bit of customization with lacing tightness and the like. I’m not one who needs specific parts of the lacing to be tighter/looser than the next typically but for the sake of testing I tried it to good success in this shoe.

At the rear of the shoe is a VERY substantial, rigid TPU brace called HYPERLOCK which aims to hold the heel in place and does a great job of it. The bonded overlays which support the general structure of the upper move forward and into a more beefed-up overlay as a toe cap. The foam in the collar around the achilles is a pretty puffy amount but it is comfortable and didn’t get in my way. The tongue – which isn’t gusseted for some reason – is pleasantly thin without being harsh on the top of the foot when combined with the laces.

Merrell Agility Peak Flex Review | Gearist


I found the Merrell Agility Peak Flex to fit nicely to my standard size 11 without a problem. In my digging around some customer reviews here and there I saw where a few people complained of the shoe being a bit narrow. I can see what they mean but at the very worst I’d say that the shoe is on the narrow side of very normal

At the rear of the shoe, the amount of foam around the collar as well as the HYPERLOCK definitely kept my heel well in place with no slipping even on steep ascents. The midfoot fit me very well and gave me a nicely locked-down feel – probably a byproduct of the fit and the lacing system. For forefoot of the shoe was comfortable across the metatarsal heads but is a bit more slim than I’d like to see in the toe box. The from third of the shoe is actually where I’d say any perceived narrowness would come into play but it wasn’t a hug deal-breaker for me.


Merrell Agility Peak Flex Review | Gearist


One of the first things I talked about in this review was the flexibility of this (and other) shoes. Since flexibility is part of the name of this shoe I expected a ton of flex but I never quite found it. Now, this isn’t a bad thing and for me I believe that the rock plate is what counteracts the inherent flexibility in the midsole bringing it from what would likely be a VERY flex shoe, to one that is fairly standard (though on the flex-y side of standard). If the rock plate were articulated like the rock plate used by Top Athletics I can see much more room for improvement in that area.

As for performance, I had a blast in this shoe in everything from longer, slogging distance to shorter, poppy miles. The traction in the Agility Peak Flex is certainly one of my favorite parts of this shoe and while I do acknowledge that it could be a bit of placebo effect, the way that this shoe worked with my foot in cornering or hopping was excellent. For me the ride of this shoe and its construction is such that it’s a good daily driver – assuming your trails are actual trails and not simply fire roads.


Merrell Agility Peak Flex Review | Gearist


The initial price tag of the Merrell Agility Peak Flex was a fairly expected $130 – which isn’t cheap but I don’t have a problem with it for a shoe that should get you a lot of fun miles. However, if you check the links in and below this review you can get your hands on this shoe for about $90 which makes it a no-brainer (and even at $130, it’s a solid buy).

The Agility Peak Flex isn’t quite as flexible as the name implies but the resulting pop and fun from a bit of resistance makes it a shoe that brought some very cool miles my way. If you’re looking for a solid, all-around trail shoe, this is one to look at for sure.


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