Updates to Altra Lone Peak 4.0 Mid RSM

  • The Lone Peak 4.0 Mid RSM is a trail companion that’s part of Altra’s All-Weather Series (AWS). This shoe is meant to handle all kinds of weather conditions, improving confidence when traversing the trails at any time and in any season. The upper unit features the eVent®, a breathable, multilayered technology that is also waterproof.
  • Cushioning is the responsibility of the recycled A-Bound™ foam and ethylene-vinyl acetate (EVA). These full-length midsole compounds are also meant to attenuate impact shock. A StoneGuard™ layer protects against sharp objects on the trail. The DuraTread™ rubber offers traction over different kinds of terrain, even wet ones.

Size and fit

The Altra Lone Peak 4.0 Mid RSM is smaller than the usual measurements, so runners are encouraged to get a pair that’s a full size bigger than their preferences to enjoy an accommodating in-shoe experience. When it comes to width, the available options are D – Medium for men and B – Medium for women.


DuraTread™ is a rubber compound that’s responsible for protecting the foam midsole from wear and tear. It is also crafted to provide traction over the surfaces. Omnidirectional nodes offer trail-optimized clamping for precise movement over irregular topography.

The TrailClaw™ technology involves several gripping lugs that are placed right underneath the metatarsals of the foot. These protrusions are constructed to heighten traction and surface control, particularly when tackling upward and downward traversals.


A-Bound™ is a full-length cushioning unit that provides immediate support to the underfoot. It is made using recycled materials. It is resilient and long-lasting.

Ethylene-vinyl acetate (EVA) is an industry-standard foam. Its job is to attenuate shock and transition the foot smoothly towards the toe-off. It is also flexible and responsive.

StoneGuard™ is a thermoplastic polyurethane sheet that is placed between the EVA and the A-Bound™. This layer is tasked with protecting the foot from any sharp objects that may piece the cushioning platform.

A 5-millimeter footbed is placed on top of the primary cushioning system. This add-on has a contoured design that supports the curves of the foot-pad.


The upper unit of the Altra Lone Peak 4.0 Mid RSM is composed of the eVent®, a multilayered textile that is waterproof. It has a Direct Venting Technology that disperses heat from the foot-chamber, allows air to enter, and stops water completely.

The mid-cut design of this RSM (rain, snow, mud) model encompasses the ankles and the bottom part of the lower leg. Such a configuration helps in securing the foot and staving off any debris or water from entering the interior compartment.

The 4-point GaiterTrap™ is a loop-and-secure system that holds external gaiter attachments. Such a feature further protects against any potentially invasive element on the trail.

Facts / Specs

Terrain: Trail
Weight: Men 12.9oz / Women 10.7oz
Drop: 0mm
Arch support: Neutral
Base model: Altra Lone Peak 4.0
Forefoot height: 25mm
Heel height: 25mm

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Jens Jakob Andersen
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.