Jason Cork has spent the last two decades quietly shaping some of the most successful athletes in American cross-country skiing. As the longtime coach of Jessie Diggins and a key figure behind multiple Olympic medals, World Championship podiums, and Crystal Globes, Cork has built a reputation as one of the sport's sharpest minds. In this rare long-form conversation, he joins Andy Newell and Brian Halligan to discuss his journey from coaching juniors in Colorado to leading athletes on the World Cup stage, the lessons he's learned along the way, and why simplicity often beats complexity when it comes to endurance training.

The conversation dives deep into the training philosophies that guided Diggins from a talented high school graduate to one of the most decorated skiers in history. Cork explains why consistency matters more than hero workouts, how he approached building training volume over the long term, the role of threshold training in elite performance, and why he believes many athletes make the mistake of training too hard too often. He also shares stories from Diggins' early years, her remarkable resilience, and the qualities that made her stand apart from the crowd long before she became an Olympic champion.

Andy and Brian also pick Cork's brain on some of the hottest topics in endurance sports today, including the Norwegian double-threshold model, speed development, training intensity distribution, and what a truly effective training week should look like for endurance athletes. Whether you're a skier, coach, or serious endurance athlete, this episode is packed with practical insights, thoughtful debate, and a behind-the-scenes look at what it takes to build championship-level performance over the course of a career.