PRODUCT REVIEW: Merrell Agility Synthesis Flex

Merrell Agility Synthesis Flex

I purchased the Merrell Agility Synthesis Flex trail running shoe because (much to my disappointment), both pairs I had of the Merrell All Out Crush started ripping on the inside of the shoe near the joint of my big toes.  Insert sad face because I truly love Merrell shoes and have owned them for years as a hiking shoe, backpacking shoe, and now trail runners in the mix.  While I loved the way the All Out Crush fit my foot– come to find out, it wasn’t a good shoe for my feet and my “abnormally high arches” as the doctors say.  I started to experience a collapsing arch, began pronating too far inwards (hence the ripping), and got a stress reaction from it all.  Doc said: switch your shoes and never wear minimalist shoes again.  Poof! Foot problems be gone!

So, I switched to the Merrell Agility Synthesis to see if it would help.  In addition, I also brought them into my sports doctor to review.  He gave me the okay saying they’d be a much better shoe for my feet.  These shoes literally are amazing.  They provide more cushion than the All Out Crush while still feeling like a minimalist shoe.  I’ve been going on training runs in them for a few months now but recently tested them out in a Spartan Beast.  Now that they’ve been OCR battle-tested, here are my takeaways:

  • Thin, synthetic protective toe cap (kept my toes safe from kicking rocks, and it even repelled mud.  Literally, I looked down at one point and my shoe was caked in mud…except the toe cap)
  • lightweight (weighs 1 lb, 9 oz)
  • stylish design and colors
  • comfortable
  • drains well
  • sturdy tread that grips well
  • vegan-friendly
  • removable footbed if necessary
  • antimicrobial agents to help reduce odor
  • able to move and flex feet easily as needed or stick into the ground for traction as needed
  • able to easily drag feet in the dry dirt and get the bottoms cleaned out quickly so I could use my feet on the rope climb
  • (my) doctor approved for high-arched folks
  • the laces stay put really well (I don’t feel a need to buy different laces).
  • costly since it’s a new shoe design. (Eventually, you should be able to find last year’s model for a fraction of the brand new, in-season cost).
  • I did feel my toe sliding slightly forward on descents and it was annoying at times, but nothing I was too bothered by to ditch the shoes.  This hasn’t been an issue in training runs, so it could have also been the steepness of the downhills and only situational.  If I encounter this again on a different course, I’ll update this to reflect that.
  • I had a hard time finding them in the stores and had to order them without trying them on.  I ordered from REI because I knew I’d at least be able to return them if I didn’t like them.  Luckily, I love them.  Plus, dividends! 😉  As they grow in popularity, this shouldn’t be an issue.



Yep! The pros definitely outweigh any cons and I absolutely recommend this product for OCR races!  I felt like I was able to just run the race, even in tight twists and turns of the single track trail and not worry about my feet at all.  Glorious!

EDIT: I wanted to update this post because I know you’re wondering – do I still love these shoes and/or race and train in them? Yes, even now (today’s 2/5/2021 y’all)! I still race and train in them.  I currently have FIVE pairs of this same shoe. Merrell for the win.

If you’ve got a favorite shoe, submit your review here for publication on our website.




Sidenote:  This is not a sponsored post.  Just a good ole’ review for your reading pleasure.

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