• Terrain


    Shoes best for road, track and light gravel. See the best road shoes.


    Shoes best for trail, off road, mountains and other unstable surfaces. See the best trail shoes.

    Good to know

    As long as you stick to the road or path, and if you want just one running shoe, buy a road running shoe.

  • Arch support

    Neutral / cushion / high arch

    Shoes for runners who do not need any additional arch support (Around 50% of runners). Best for people with normal, high or medium high arches. See the best neutral shoes.

    Stability / overpronation / normal arch

    Shoes for runners who need mild to moderate arch support (Around 45% of runners). Best for runners with a low arch. See the best stability shoes.

    Motion control / severe overpronation / flat feet

    Shoes for runners who needs a lot of arch support. Best for runners with flat feet. See the best motion control shoes.

    Good to know

    - Rule of thumb: If in doubt, buy neutral shoes to avoid injuries.
    - More about arch support in this video.
    - Find your arch type by following steps from this video.

  • Use

    Daily running

    Cushioned shoes for your daily easy running. Great comfort. See best shoes for daily running.


    Lightweight shoes good for races, interval training, tempo runs and fartlek. Here are the best competition running shoes.

    Good to know

    If you want just one pair of shoes, buy a shoe for daily running.

  • Price
  • Weight
    Men: 8oz
    Women: 6.7oz
  • Heel to toe drop
    Men: 6mm
    Women: 6mm

    The height difference from the heel to the forefoot, also known as heel drop, toe spring, heel to toe spring or simply drop.

    There are many opinions about what a good heel drop is. We do not recommend any in particular. Lean more in this video.

  • Heel height
    Men: 22mm
    Women: 22mm
  • Forefoot height
    Men: 16mm
    Women: 16mm
  • Width
    Men: Normal
    Women: Normal
  • Release date
Show more facts


Expert Reviews

Experts are runners, who post reviews at youtube, directly at RunRepeat or at their own websites. Each expert is categorized from level 1 to level 5 based on expertise. See stats on expert reviews and how we calculate scores here.

Are you an expert? Apply to contribute here.

80 / 100 based on 1 expert reviews

  • 80 / 100 | Rocket Runner | Level 2 expert

    Four stars for Tough Mudders only.

Become an expert

  • Merrell’s All Out Crush Tough Mudder 2 is vegan-friendly. It uses 0% animal products while still delivering sturdiness, comfort and style.
  • On the heel area, a Lycra Neoprene lining was added to supply the runner with additional comfort during trail runs.
  • An extra layer between the midsole and the outsole was added for extra protection. The layer is called Trail Protect Pad, and its main purpose is to shield the bottom of the foot rocks and other debris a runner can step on during trail runs.
  • The outsole is made of a material called M Select Grip. It supplies enough grip to conquer different terrains. Runners don’t have to worry about slipping even when running on wet trail. The design is also self-cleaning, with strategically placed lugs.

The Merrell All Out Crush Tough Mudder 2 is available in regular sizes. Runners will be able to purchase the shoe in their usual size preference. In terms of width, the shoes come in the standard B-medium and D-medium measurements.

On the outsole is Merrell’s M Select Grip which is a durable rubber that’s wear and tear resistant. Aside from its durability, it grips on both wet and dry ground and adapts to terrain that’s uneven. This is made possible by the strategically-placed lugs which can grasp unto the ground easily. This Merrell technology is also placed in the outsole of the popular Merrell shoes for running.

How the semi-aggressive lugs are placed, plus the additional rectangular ones on the side complement the M Grip when it comes to producing in enough traction needed for different terrain conditions, including ones that are more technical. Because the lugs are spaced properly, particles won’t easily get stuck underneath the shoe. The design is also self-cleaning, so runners don’t have to worry about debris getting stuck at the bottom.

Several Flex Grooves have been incorporated into the forefoot area of the outsole to promote flexibility. This design feature allows the forefoot to bend and prepare for the propulsion phase of the running gait cycle. Because the forefoot can move naturally, runners can move forward optimally.

The midsole is made of Ethylene-Vinyl Acetate or EVA. It runs the shoe’s full length and its main purpose is to provide cushioning and shock attenuation throughout the run. It delivers sufficient responsiveness, allowing the runner to feel energized with every stride.

To protect the foot from debris and other objects that a runner can step on while trail running, a pad called Trail Protect was added. It sits between the outsole and midsole. Its thickness complements the cushioning of the midsole and robustness of the outsole to lessen the impact of debris on the trail.

An EVA footbed was integrated onto the platform. It is mainly for additional cushioning and enhanced comfort underfoot.

The upper is made up of a material called mesh. It’s stretchable, molding to the shape of the foot and delivering a custom feel. It’s also breathable, easily permitting air to pass through to keep the foot cool and dry at all times during the run.

To strengthen the mesh material on the upper of the Merrell All Out Crush Tough Mudder 2, it was reinforced by a material called Thermoplastic Polyurethane or TPU.  It is a material that’s resistant to oil, grease and abrasion. As it protects and reinforces the mesh material, it’s flexible enough to allow natural movement.

On the heel is a Lycra Neoprene Heel Lining which was added to improve the comfort delivered on the heel. Generally, Neoprene is a material used in wetsuits. However, in this shoe, it acts as an impact protector on the heel that’s resistant to tearing or cracking.

The All Out Crush Tough Mudder 2 has a traditional lace up closure. Tightening up the laces will secure the fit on the midfoot and prevent the shoe from accidentally sliding off during a run.