We spent 9.3 hours reading reviews from experts and users. In summary, this is what runners think:

8 reasons to buy

  • Many testers considered the Merrell All Out Crush Tough Mudder 2 BOA to be comfortable right out of the box.
  • A few purchasers said that the shoe is flexible.
  • The majority admired the shoe’s BOA system; they said it remained tight and easy to adjust.
  • Based on several reviews, the All Out Crush Tough Mudder 2 BOA has a wide toe box.
  • Several runners noted that the traction of this running shoe was reliable, especially on technical terrains.
  • The shoe is durable, said a few runners.
  • Most were satisfied with the shoe’s drainage system.
  • The mesh in the upper is breathable and has a quick-drying feature.

2 reasons not to buy

  • A few users noticed that the laces became difficult to adjust when a small amount of mud got stuck in the BOA system.
  • The arch support is lacking in this shoe, according to some wearers.

Bottom line

The Merrell All Out Crush Tough Mudder 2 BOA is a tough partner when it comes to trail running. Based on the number of compliments it received, the shoe was able to satisfy most runners. Most feedbacks were about the shoe’s traction, comfort, and BOA lacing system. Though a few expressed displeasures about the wear experience, most of its users found that the shoe delivered on its promise.


Terrain: Trail
Arch support: Neutral
Weight: Men: 8.3oz | Women: 7oz
Heel to toe drop: Men: 6mm | Women: 6mm
Pronation: Neutral Pronation
Arch type: High arch
Material: Vegan
Strike Pattern: Midfoot strike
Distance: Competition
Heel height: Men: 23mm | Women: 23mm
Forefoot height: Men: 17mm | Women: 17mm
Brand: Merrell
Type: Low drop
Width: Men: Normal | Women: Normal
Price: $120
Colorways: Orange
Small True to size Large
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A top 2% best Trail running shoe

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  • The Merrell All Out Crush Tough Mudder 2 BOA is an update to a fresh series of off-road shoes that are meant for muddy obstacle course events such as the Tough Mudder. It features a new upper construction, utilizing open-weave mesh and printed overlays to deliver a breathable and secure coverage. The unique BOA® lacing system makes it easier to adjust the fit.
  • Underfoot cushioning is provided by a full-length foam midsole. It’s meant to keep the foot save from impact and other hazards on the trails. A pad is placed in the platform for additional protection. Multidirectional gripping lugs on the outer side of the sole unit ensure traction over dry and sloshy surfaces.

The men’s version of the Merrell All Out Crush Tough Mudder 2 BOA is half-a-size smaller than the regular measurements, but the women’s iteration is true to size. Males should get one that’s half-a-size bigger to have an accommodating in-shoe experience.

The width profiles are B – Medium and D – Medium for women and men, respectively. The form-fitting façade and last welcomes the natural curvature of the human foot.

The M Select™ GRIP is an outsole compound that’s meant to protect the rest of the underfoot platform from the abrasive nature of the trails. It is also the one responsible for doling out surface grip. This outsole material has been used in almost all Merrell running shoes.

Aggressive gripping lugs make the All Out Crush Tough Mudder 2 BOA more traction-ready. The multi-directional construction of these protrusions permits a well-rounded experience on the trails, especially when handling slopes and muddy paths.

A full-length unit made of ethylene vinyl acetate or EVA offers underfoot cushioning. It has a soft nature that keeps the foot comfortable. Its responsive nature enriches the toe-off and tempers the force of impact during the landing phase.

An EVA footbed has been integrated above the last of this shoe. Its goal is to bring a soft feel for the foot-pad. It isn’t removable; it won’t slide around the interior chamber during obstacle course racing.

The BOA version of the Merrell All Out Crush Tough Mudder 2 makes use of Synthetic Mesh as its main upper component. It has a traditional open-weave design for breathability and water drainage, as well as multiple layers to heighten durability and support.

There are thin synthetic overlays to bolster the structural integrity of the façade. These thin add-ons also help in providing a secure coverage.

A toe cap protects the forefoot section from abrasion. It also prevents the toes from boring holes through the fabric.

A Lycra lining brings a smooth wrap for the heel, thus preventing hot spots and blistering.

Running in low-light conditions becomes safer with the reflective detailing that’s added to the upper. Such a feature is helpful when deciding to run at night.


Jens Jakob Andersen

Jens Jakob is a fan of short distances with a 5K PR at 15:58 minutes. Based on 35 million race results, he's among the fastest 0.2% runners. Jens Jakob previously owned a running store, when he was also a competitive runner. His work is regularly featured in The New York Times, Washington Post, BBC and the likes as well as peer-reviewed journals. Finally, he has been a guest on +30 podcasts on running.