The tried and true Altra Lone Peak is packing some updates in the 4.0 model. One of the biggest updates to the 4.0 model is the outsole. Made with a new rubber compound (still branded as Maxtrac), this outsole has better grip and more durability than previous versions. The lugs are more aggressive and less prone to being sheared off on sharp rocks or debris. The midsole of the Lone Peak 4.0 is relatively unchanged. The midsole tapering from the ball of the foot to the toes is now more aggressive, and the TPU StoneGuard rock plate replicates the bone structure of the foot (think independent metatarsals). The 25-mm stack height and foam firmness have been left unchanged.
The new mesh upper on the Lone Peak 4 is more durable and has functional stretch for your foot shape. Other changes to the upper include more ventilation, a tongue that is moderately padded and perforated, and a toe cap that has two drainage points.