About us

Providing you with the tools to get fitter, run faster and race smarter.

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The story starts in the Chamonix mountains with one mission, to help runners like you, break through your limitations and reach your greatest potential.

Whether you want to run your first ultra; earn that shiny 100-mile buckle; train for a personal adventure; or elevate your mental game, we understand where you’re coming from, and will support you every step of the way – wherever you are in the world.


Run with Mettle


A person’s ability to cope well with difficulties; someone who has spirit, courage and tenacity.

  • Mettle represents a dedication to continuous improvement by showing up, putting in the work, being healthy and having fun. Progress, not perfection.
  • Make no mistake, you will be challenged, every bit as deeply as we challenge ourselves, to do better than yesterday.
  • With a Chamonix HQ and a strong network of connections wired into the US trail and ultra running scene, you join a passionate community with an international outlook.
  • We’re brimming with positivity because we have a lot to celebrate at Mettle. Our athletes’ results and personal achievements, tell their own stories.
  • As for us, we’re doing what we know we do the best and love the most: empowering, supporting and educating runners like you, achieve your goals.

“Be curious, not judgmental.”

– Walt Whitman, American Poet


Dr Kaz Williams, Performance Psychologist, Certified Running Coach, Speaker, Ultra Runner. Striving to help people discover their mettle.

Hi, I’m Kaz. I founded Mettle to help you take on challenges you are curious about, whether that’s chasing a PR or a distance you aspire to run. Our purpose is to provide you with coaching plans, mental strategies and honest support to be the best trail and ultra runner you can be.

I love to run far. My trail running journey started in Chamonix, France with Marathon du Mont Blanc in 2010. Favorite adventures include Tahoe 200, Moab 240, Ouray 100, TDS (UTMB series), Across the Years (10 days), plus successfully completing 1 loop of The Barkley Marathons, and Last Annual Vol State, a 500K continuous and self-supported race across Tennessee.

I have met incredible people during these races, shared priceless moments and experienced boundless kindness. I am grateful to be part of this amazing community.

Head Coach, Dr Kaz Williams

Ready to take your fitness, your training or your mental game to a whole new level of running and success?

All you need to do is send us a message to arrange a coach call so we can learn about your running ambitions.

It may be the most important call you make this year.