Endurance Icons

In this episode of Endurance Insights, I’m getting real about a recent mistake in my Eugene Marathon build that led to an Achilles issue, and exactly what I’d do differently so you can avoid the same setback.

From there, I break down three of my favorite legendary workouts—the Mona Fartlek, The Michigan, and the classic 800m session—and how to use them effectively depending on your level.

We also dive into key training insights for this time of year, including:

• Why triathletes need to prioritize time in the aero position before heading outdoors

• The biggest mistake athletes make after signing up for a race And why the real work happens in the 99% of training no one sees

I wrap things up by sharing some of the podcasts and books I’m currently loving so you can keep learning and improving alongside your training.

In this episode of Endurance Insights, Coach Mark Cullen breaks down several common myths and misconceptions in endurance training—from why runners shouldn’t cover the full marathon distance in training to why VO₂ max and heart rate are often misunderstood metrics. Mark explains how building consistent weekly volume, developing durability, and progressing through different training intensities creates a stronger aerobic foundation than chasing extreme workouts or metrics promoted by influencers.

He also dives into practical performance topics including marathon fueling strategy, why most runners shouldn’t change their natural foot strike, how lactate thresholds actually work, and why fractional utilization matters more than simply having a high VO₂ max. The episode closes with a discussion on the limits of heart-rate training and why pace, power, and perceived effort remain the most reliable metrics for training and racing success.

In this episode I cover three common mistakes that hold endurance athletes back. We talk about why elite runners often train and race without headphones, why pace, power, and RPE are usually more reliable than heart rate zones, and why many athletes miss their time goals by trying to train at goal pace before their fitness is ready. If you focus on awareness, the right effort, and building fitness patiently, your performance will trend toward and often beyond your goals.

In this episode, I dive into the best marathon-specific long run workouts used by competitive and elite runners, how to structure them properly, and how super shoes and shoe rotation fit into the equation.Let me know in the comments below your thoughts or topics you want covered!

In this episode, I break down where to place your strength training in relation to your endurance training each week, and why hills are one of the most underrated tools in endurance training. Whether you’re a runner, triathlete, or hybrid athlete, hills can act as sport-specific strength work that builds resilience without adding gym volume.Let me know in the comments what you think or if there is other topics you want to see covered

In this two-part episode, I break down why I feel heart rate training is overrated, and why focusing on RPE combined with pace or power leads to better training and racing decisions. We’ll cover why heart rate data can be misleading, how elite athletes actually train, and where heart rate does provide real value for long-term progress and recovery.

In Part 2, I talk about practical winter running advice, sharing simple strategies to reduce injury risk when conditions are crap, from treadmill use and pacing adjustments to warm-ups, footwear, and smarter decision-making.

The world’s best athletes train easier than most recreational runners think.

Drawing lessons from Kenyan training culture, insights from Into Thin Air on Ethiopian runners, and the performance mindset explored in Carrie Soto Is Back, we explore why truly easy days are non-negotiable, how environment and patience shape long-term success, and why confidence is earned through consistent preparation.

If you’ve ever felt guilty running slow, questioned whether your easy days are “easy enough,” or struggled to balance ambition with sustainability, this episode will challenge how you think about training and help you race better by doing less on the days that matter least.

Lessons from Kenya & Ethiopias Marathon Success + How To Avoid Bone Stress Injuries

In this episode, Mark breaks down one of the most overlooked performance metrics in endurance sport: running economy, how efficiently your body uses oxygen to run at a given pace. The research is clear: improving running economy can lead to massive performance gains without increasing fitness in the traditional sense.

You can improve running economy, by including:

• Hill sprints & short maximal sprints for neuromuscular efficiency and leg stiffness

• Plyometrics that boost tendon elasticity and reduce ground-contact time

• Heavy strength training to increase maximal force and rate of force development

• Super shoes

• High volume of running

Discover how Arthur Lydiard, the self-taught New Zealand coach, created the endurance training system that shaped modern running. We cover his famous 100-mile weeks, hill circuits, Olympic champions, and how his principles still apply to today’s runners, triathletes, and hybrid athletes.