Merrell Long Sky 2 Matryx trail running shoes review: tear down tough, technical trails with confidence

Meet the reviewer

Julia Clarke

Julia Clarke is a staff writer for Advnture.com and the author of the book Restorative Yoga for Beginners. She loves to explore mountains on foot, bike, skis and belay and then recover on the the yoga mat. Julia graduated with a degree in journalism in 2004 and spent eight years working as a radio presenter in Kansas City, Vermont, Boston and New York City before discovering the joys of the Rocky Mountains. She then detoured west to Colorado and enjoyed 11 years teaching yoga in Vail before returning to her hometown of Glasgow, Scotland in 2020 to focus on family and writing.  

Merrell Long Sky 2 Matryx trail running shoes: first impressions 

We've been tearing down the trails in the Long Sky 2 Matryx shoes lately and found ourselves highly impressed with their grip, weight and stability and we're not the only ones – these trail running shoes won the 2023 ISPO award. An evolution of the Long Sky 2, which we tested back in 2022, these are lighter and stronger, and boast even more impressive traction, placing Merrell firmly in the conversation when it comes to trail shoes for elite runners.

In terms of weight, the Long Sky 2 Matryx shave nearly a third off their predecessors, which is nothing to scoff at when your days are long. The word "Matryx" refers to the upper, which is built using thin synthetic threads to create a single layer that the company says "is lightweight, with better breathability and abrasion resistance." As advertised, we could feel a cool breeze on our feet during hot runs and so far the uppers are holding up to rocky, technical trails and protecting our toes while they're at it. The real magic of these shoes lies in what's happening underfoot, however.

These shoes look quite a bit like the Skyfire 2s, which we tested last summer and found left a lot of midsole exposed to save weight and had us concerned about durability, but we were relieved to turn them over and see a good covering of Vibram Megagrip rubber. When we got them out on steep, rocky trails covered in dust and crumbly stuff, we were amazed at the grip we got.

Meanwhile, the FloatPro Foam midsole has great flex for an easy roll-through and gives excellent trail feel when you're moving fast on technical routes. A 4mm drop and a maximum stack of just 23.5 mm means we feel really stable in these. 

The traditional lacing system makes these easy to pull on and adjust for a snug fit round your heel and midfoot. The toe box leaves plenty of room for comfort over many hours, though we think these shoes excel best on technical runs than over long, rolling hills where you might want a slightly bouncier ride. Though the price is creeping up, they're still not up there with the priciest shoes and they could make your summer a lot more fun.

Merrell Long Sky 2 Matryx trail running shoes: in the field

I've had these shoes for a couple of months but between rehabbing a tweaky knee and a never-ending seasonal cold, I've mostly been admiring them from afar, especially since I've had so much luck over the last couple of years with Merrell shoes. Finally back in fighting shape, I decided to wear them on a recent hiking and trail running adventure in Gran Canaria, where I encountered warm weather, arid terrain, and steep, rocky trails, then again in the Lake District.

Here’s how they performed:

Sizing and fit

I tested a US 6.5, which is my usual half-size up to give my feet room to swell. When I compare these side-by-side with my Skyfire 2s, which are the same size, they look massive and while I do think they run a little large, but I love the fit.

There's lots of room around the toe box, which for some reason is becoming increasingly important as I age (maybe my feet are getting wider with gravity?). However, the traditional lacing system means I can secure them nicely around my midfoot (and you can tuck the laces away using the handy lace keeper) and I didn't get any movement even with steep downhills. 

Comfort and breathability

I don't have a narrow, wide or oddly shaped foot, and I found these super comfortable both out of the box, and across long days hiking and running on the trails, with zero rubbing anywhere. The uppers are quite thin and pliable, so I imagine that as long as you wear running socks, you shouldn't have any problems.

The breathability of these shoes is great, especially since I seem to have been mostly testing waterproof shoes recently. It was warm in Gran Canaria, but in many places a good breeze blew nearly constantly and I was relieved to feel the breeze coming through the uppers. I never experienced sweaty feet.

Weight and protection 

These aren't the lightest shoes I've tested – that distinction almost certainly goes to the Skyfire 2s – but they are very light and made a no-brainer choice when I was packing for my trip and didn't want to check a bag. Once on the trails, this means they're great for long days too.

Even though weight is saved by the light, thin uppers, there's plenty of protection around the toes and heels and I rammed my foot into plenty of rocks on the trail with no pain.

Responsiveness, grip and stability 

These shoes excel at trail feel over responsiveness, so I don't get a big bouncy ride out of them and would probably wear my Agility Peak 4s for a longer run, but they feel great on both steep and flat trails with the perfect amount of trail feel for me. For technical trails, however, the midsole is exactly what I want and I'm loving the absence of a carbon plate to let my feet flex properly.

The grip of these shoes was really the standout for me, however. I don't know about you, but I find those steep, crumbly trails that never see a drop of rain to be by far the most treacherous, and I ran a full 7 km down on the same trail used in the Transgrancanaria race without so much as a skid. I'll definitely be wearing these this summer during a longer hut-to-hut run I have planned in the Alps.

Finally, the low drop and stack means a nice, stable ride which kept my knees and ankles happy and is obviously just what you need from a shoe built for technical trails.

Merrell Long Sky 2 Matryx trail running shoes: the bottom line

These shoes deliver superior traction, breathability and stability on technical trails without sacrificing durability. If you're only planning on jogging over rolling hills or on flat gravel roads, look for something with a plusher midsole, but if you're planning on mountain running, you might love these shoes. If you want something technical but with more cushion, compare them with the Salomon Genesis.

• How Advnture tests products