The Infirmary | Fixing Broken Endurance Athletes

Simon Marshall trained the brains of endurance athletes for a living, and in this conversation he makes the case that the mental side of sport is the part most of us skip — right up until it costs us a race. Recorded during the pandemic and shared again in Simon's memory, the episode digs into what actually decides how race day goes: why everyone walks to the start line a little terrified, why you...

Swim improvement is slow, frustrating, and worth every minute — and this episode is proof of that. Chris walks you through Alex W.’s amazing 2:35 to 1:52/100 threshold pace improvement in today’s episode: what wasn’t working, what Chris prescribed, and how Alex took the reins and put in the hard work. We track her development step by step: the front quadrant breakdown that was costing her propulsi...

The difference between a well-trained bike-to-run transition and a poorly trained one is up to 10% of your run performance — and most athletes have no idea why it happens or what to do about it. In this episode, we look at four peer-reviewed studies on the physiology of brick runs, covering the nervous system disruption that starts before you even dismount, the fueling and breathing problems that...

Joe Friel — author of the Triathlete's Training Bible, co-founder of TrainingPeaks, and one of the most influential coaches in endurance sport — joins Chris Bagg for a conversation centered on durability: what it is, how it is built, and why it matters more than most athletes realize. Joe explains how he developed the concepts of heart rate decoupling and efficiency factor in the early 2000s — mor...

One of the issues with the established training zone systems out there is that, very often, there are more zones than we need, particularly for multisport training and racing. When zones were first established, most of the data came from road cyclists, who have more dynamic events and different demands placed upon them while competing. In a triathlon—even a short course triathlon—the goal is a ste...

Sports scientist and triathlete Tash Cooper-Smith from Precision Fuel & Hydration joins The Infirmary to demystify one of endurance sport's most confusing topics: fueling and hydration. Tash breaks down sweat testing, sodium concentration, carbohydrate intake, gut training, and the actual science behind cramping — and why the answer to most athletes' fueling problems is rarely as complicated a...

Most athletes swing between two bad options when things get hard: they back off because something in their brain, body, or heart says “too much,” or they panic, push too hard, and blow up. In this episode of The Infirmary we name the productive space between those two poles — the growth zone — and give you a practical tool to train your ability to stay there. Chris draws on his own racing career,...

Ryan Bolton is an Olympian, competing at the first Olympic Triathlon in 2000, and he is also a long course champ, winning Ironman Lake Placid in 2002. He coaches America’s top-ranked short-course triathlete, John Reed, and coaches or has coached Olympic Morgan Pearson, triathlon legend Ben Hoffman, recent star Sam Long, and many, many others. Ryan and I talk about a huge range of topics, including...

Coaches and athletes talk about the semi-mythical “flow state” a lot, but there is precious little information about how to achieve flow state. Those same coaches and athletes seem to leave it up to chance, but as you all (I hope) know, hope is not a strategy! In today’s episode, which is the companion piece to the guided meditation just below this one in the feed, we talk about ways to practice p...

The companion piece to Episode 40, this is is a guided meditation that will help you discover what your brain and body wants to do during a difficult interval or during a race. Practice this meditation to improve your ability to maintain a wide, soft, presence that improves your chances of accessing flow state in your training, racing, and life. Book a free training consult with Chris here : https...

Endurance coaching legend Gordo Byrn joins us to discuss his return to racing after a 10-year break. The 2002 Ultraman World Champion and author of From Lemon to Legend breaks down his training philosophy that led to a 9:03 at Challenge Roth. We explore why consistency matters more than any specific workout protocol, how he rebuilt his aerobic base starting with workouts so easy he didn't believe...

For well over the first half of my professional career, I was labeled an “emotional athlete.” That label seemed to mean, well, something else . In this case that “something else” appears to have been “undisciplined,” if the describer was being nice, or “riding like a stupid asshole,” if the describer wasn’t concerned with hurting my feelings. Faced with this description, which wasn’t ever really e...

David Tilbury-Davis coaches or has coached triathlon household names such as Ashleigh Gentile, Lionel Sanders, Skye Moench, Corinne Abraham, Cody Beals, and Matt Hanson, and he’s been doing so for three decades. In this episode, David explains his “evidence-led” in contrast to “evidence-based” approaches, how he gives athletes autonomy within structured training blocks, and why understanding your...

Overtraining syndrome is rare, serious, and can end your endurance career if you're not careful. In this episode, we break down the differences between functional overreaching (proper training), non-functional overreaching (under-recovery), and true overtraining syndrome (OTS, and again, it's really rare!). You'll learn the warning signs that separate temporary fatigue from something far more conc...

Canadian pro triathlete Cody Beals opens up about thoroughly burning out, wondering if his triathlon career was over after Ironman Chattanooga, and what happened when he took his first real break in over 25 years of school, athletics, work, and professional endurance sport. We discuss the difference between intellectual understanding and actual practice when it comes to rest, why so many endurance...

What if the most sophisticated training tool you have isn't your power meter, but your ability to feel the difference between sustainable and unsustainable effort? Kolie Moore launched Empirical Cycling in 2015 after noticing a gap in how coaches approached endurance training. With a background in biology, biochemistry, metabolism, and physiology from Boston University, plus his own experience as...

I am joined by professional triathlete and cyclist Rach McBride to review their 2025 season, which saw them shift focus from professional triathlon to Elite UCI Gravel World Championships qualifier. We chat about the realities of racing at the world championship level—the different (but sensible!) call-up system, competing independently against fully-supported national teams, and what it felt like...

“Zone 2” training has become incredibly popular in endurance sports, but most athletes misunderstand what it actually does and why it feels so frustratingly slow. In this episode, we debunk the misconceptions to explain how this training intensity establishes your aerobic infrastructure, why comparing yourself to professional athletes derails your progress, and how to embrace slow work now so you...

Endurance journalist and author Brittany Vermeer joins me to discuss her book, The Complete Guide to Your First 70.3 Triathlon . Brittany has been in endurance media for 17 years, writing for Ironman, Triathlete , and Outside Magazin. Brittany shares the most common mistakes athletes make when tackling their first middle distance race, from nutrition mishaps to pacing errors, and we go beyond trai...

Over the past six weeks, Norwegian athletes have take four of the six podium spots at the Ironman World Championships in Nice, France, and Kailua-Kona, Hawaii. We sat down earlier this year to talk with Brad Culp, author of The Norwegian Method: The Culture, Science, and Humans Behind the Groundbreaking Approach to Elite Endurance Performance. Brad points out both in his book and in this interview...

One of the athletes I work with, Robin Cummings, asked a deceptively simple question about heat training that opened up a much larger conversation: which training adaptations actually last, and which ones disappear the moment you stop training them? The answer reveals your body's efficient "last hired, first fired" approach to fitness —and changes how you should think about periodization. In this...

Josh Monda raced as an age grouper for 17 years before turning professional at 40—displaying a patience you don’t often find in endurance sports. Josh’s story includes a five-year hiatus from the sport, personal struggles with addiction, and a long-term approach that eventually unlocked elite-level performance. Now racing for the On Your Left Professional Triathlon Team, Josh shares the training,...

Choosing an endurance coach might be one of the most important decisions you'll make as an athlete, yet most people approach it completely backwards. This episode of The Infirmary breaks down how to choose and endurance coach who matches your goals, communication style, and budget, because not everyone needs the same thing in a coaching relationship. We start with the biggest but oft-ignored quest...

Chris sits down with retired professional triathlete Lauren Brandon. An elite swimmer to triathlete success story, Lauren shares how her NCAA All-American swimming background and 2008 Olympic Trials qualification shaped her approach to professional triathlon training and racing. Lauren talks about swimming misconceptions, focusing on the critical catch and pull mechanics that most age-group athlet...