Tech Profile: The Trail Breaker running top

Forwards. That’s where the Trail Breaker is engineered to go. Swiss-engineered for all-weather alpine adventure or wild runs pretty much anywhere, this lightweight performance running top is made to be the shield you need for running head first into adventure – whatever the weather forecast says. 

It’s with this fearless forward motion in mind that the front panel and sleeves of the Trail Breaker features the most protective elements of its zonal fabric construction. The PFC-free water-repellent fabric feels like a force field against wind and rain and comes into its own on steep downhills where it acts as a barrier against the rush of fresh mountain air. 

Made with the mountains in mind, the Trail Breaker is also developed to prevent you overheating when on tough ascents or longer runs where the weather improves. As a result, the fabric on the back of the top is a ultralight mesh that delivers increased airflow for ultimate breathable comfort. 

In combination, this zonal system of a more protective front panel and the ventilating mesh panel on the back helps keep your temperature in the comfort zone, even if the weather, or your run, is pushing your limits. 

Performance? Check. 

When you’re out in technical terrain, details matter. So the team in the On Lab found a way to pack them into the Trail Breaker without compromising its minimalist design. Take the watch window in the sleeve, for example. This lets you keep the protection of your long sleeves but still access the data on your watch – great when you’re trying to move fast but also stay warm. And thumbhole cuffs ensure that those sleeves don’t ride up. One less thing to think about, one more reason to stay out there. 

Ultrarunner Approved.

During development, The Trail Breaker has been put to the test in harsh environments. It’s also been proven to perform when pushed to the limits by elite On ultra-trail runners Katie Schide and Germain Grangier. 

The Trail Breaker was also a go-to piece of kit for the pair when they embarked on an epic 188km cross-border mission to traverse the Alps on foot.  

“When we want to move light and fast in the mountains, we care about the weight and how packable a layer is,” Germain explained. 

“The Trail Breaker doesn’t take up space in my backpack and protects me from all conditions up there.”

According to Katie, the Trail Breaker is also the perfect choice if your mountain adventure includes more than running:

“Another great thing about the Trail Breaker is that it has the half zipper, so you don’t have the deal with the zipper crossing the hip belt on a backpack, but it’s also big enough that you can even take it off over a mountaineering or bike helmet. 

“We packed the Trail Breaker on our traverse between Cervinia (Italy) and Chamonix (France). We used it a lot in the sections between Zermatt (Switzerland) and Chamonix. 

“We brought it with us because it’s light and protects from the wind on the glaciers, but it’s not too warm when we’re trying to move fast.” 

So there you have it: Swiss-engineered, tested in the Alps and endorsed by elite mountain runners. The Trail Breaker is the performance running top developed specifically so that whatever the weather has in store, you can break new ground. And it’s ready when you are. Run wild.

Pair up for Added Protection

Pair the Trail Breaker with these other items engineered to lock out the elements and you can be sure you’ll outpace Mother Nature.