Function: Technical Outer Layer (For Running and Cycling)
Size: Extra Large
Reviewer: 6’0”, 160 lbs., Chest: 40”, Shirt Sleeve Length: 38”
Test Duration: 2 months of almost daily use
Test Locations: Alta Ski Area; Park City Mountain Resort; Wasatch Backcountry; Corner Canyon Trails; Moab, UT; Fruita, CO.
The Blast Long Sleeve Zip jacket, from Icebreaker’s Technical Outerwear line, is designed to be a comfortable, water-resistant, windproof, light insulator for cycling, running, or any other outdoor sports where you may be looking for a little protection from the elements.
I haven’t done a lot of running in the Blast jacket (unless you consider the countless trips to and from my car to grab forgotten necessities), but I have used this jacket a lot this spring for resort skiing, ski touring, and mountain biking.
Unlike nearly all other Icebreaker products, the Blast jacket does not use a 100% (or close to 100%) merino wool construction.
Because of the water-resistant and windproof goals of the jacket, Icebreaker instead uses a three-fabric layering on the areas open to the elements, including the chest, shoulders, and along the exposed portion of the sleeves. The three materials used to provide protection are a polyester outer layer for water resistance, a polyurethane membrane for wind resistance, and a merino liner for comfort and moisture wicking.
In the less exposed areas of the jacket, including the lower half of the back, side panels, and inside portion of the sleeves, the Blast uses a mixture of merino, nylon, and elastane (lycra).
Along the back of the jacket where the transition from “soft-shell” to the softer and more breathable merino/nylon/elastane lies, the fabrics overlap and provide a mid-back vent to help shed access heat from the upper portion of the jacket.
The Blast jacket uses incredibly smooth running and easy to grab YKK zippers for the full-length chest zip, two hand pockets, and an adequately sized chest pocket, which easily fits my Samsung Galaxy SII and features a small internal port to run headphone wires through.
Immediately upon donning the Blast jacket, it was clear that this jacket was designed with a focus on running. In a standing position, the XL jacket offers a comfortably slim cut over my thin build, with adequate sleeve length with my arms at rest by my side, or through the typical range of motion I would have while running.
This fit has been ideal while using the jacket as a light insulator under a shell while skiing at the resort, as well as while using the piece as an outer layer for the climbing portions while ski touring. The slim nature of the jacket fits nicely under a shell and offers a clean feel while wearing a backpack and hiking.
For cycling, however, the Blast jacket wasn’t nearly as ergonomic of a fit for me. While in the saddle, reaching for the bars reveals that the shoulder region of the jacket wasn’t quite roomy or stretchy enough, while the sleeves were also too short to provide protection all the way to the glove line.
With the snug-fitting sleeves being stretched in cycling position, it was also very noticeable that the interior seams bonding the soft-shell fabric to the softer fabric of the under arm are quite bulky. With a long-sleeve base layer, the seams weren’t much of a bother, but while wearing a short-sleeve base layer, the interior arm seams were definitely noticeable and made me wonder how this wasn’t noticed before the jacket went into production.
Thumbholes, or even a thin wrist gator, would also be a welcome addition to the Blast, in my opinion, especially for cycling, where forward movement combined with the sleeve opening translates to a cool breeze running up the length of the sleeve and into the torso.
While I have experienced exceptional breathability in my nearly 100% merino products from Icebreaker, the polyester/polyurethane/merino portion of the Blast jacket does seem to decrease the performance in this area on occasion—though for runners or those not wearing backpacks, the large back vent just under the shoulder blades does sufficiently dump heat and moisture as advertised during strenuous activity.
The only problem is that while wearing a backpack or hydration pack, the vent is ~50-75 percent blocked. In these scenarios (ski touring / cycling) I found myself relying on the front zipper to regulate my temperature and to keep the jacket from feeling a little clammy in the upper torso, shoulders, and mid/upper arm areas.
With that being said, I rarely have found myself needing to take the jacket off because I’m too hot or getting sweaty with a pack on my back. Not only has this been the case while touring with temps in the mid/upper 30s F (1 to 4 C), but even while mountain biking in Fruita, Colorado, when the temps rose into the 50s (teens C) by mid-day and most riders were dressing down to just a long-sleeve base layer.
With moderate exertion, it seems my body temp rises to the point where it is just about to break into a decent sweat, but with the front zip opened 50 percent and the sleeves pulled up slightly, I never cross the line into heavy perspiration.