Firefighters deal with extreme situations that go far beyond putting out fires. They not only have to deal with intense physical demands, but they also have to be able to perform emergency medicine and rescues under extreme mental pressures. That experience is a big part of what’s made Emma Cook-Clark such a force of nature on the ultrarunning circuit.

Cook-Clark is an ex-firefighter turned Arc’teryx ultrarunner athlete. She runs some of the longest and hardest trails and races in the world — and she runs them fast.

But she isn’t the kind of athlete who’s obsessed with numbers. She says she doesn’t have a defined “training schedule.” Instead, she has a random sequence of badass outdoor objectives she’s constantly pursuing. Cook-Clark couldn’t tell you how many kilometers she’d run in the last week, what pace she ran at, or what her heart rate was. She just goes; she just trains.

And it’s working out for her. The ultrarunner and mountaineer has represented her home country of Canada on multiple occasions. She ran at the FISU World University Games for Cross Country and the World Mountain Running Championships. She tied for first in the Skyrunner World Series, took second in the Hochkönig SkyRace, won the Ultra SkyRunning Madeira, and placed second in the Minotaur SkyRace.

So, it’s no wonder Arc’teryx wanted to sign this ex-firefighter as one of the brand’s ultrarunner athletes. Emma Cook-Clark (@emcookclark) is a beast in the mountains.