The Infirmary | Fixing Broken Endurance Athletes

Episode 46: Fixing the Brick—Four Studies on Running Off the Bike

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 peak in the first seven minutes of the run, and the biomechanical breakdown that results in the dreaded “Ironman hunchback.” You know you’ve seen that out there in the wild. You'll learn why long brick runs are a waste of training time, how riding with high variability hurts your transition runs, and exactly what a productive brick workout looks like. Practical, research-backed, and we got it in under 30 minutes! Links mentioned in this episode: Millet & Vleck (2000), British Journal of Sports Medicine — cycling-to-run transition adaptations Bonacci (2011), Sports Biomechanics — neuromuscular control in elite triathletes Walsh (2019), Sports — elite short course triathlon and transition efficiency Zwetsloot et al. (2022), BMC Sports Science, Medicine and Rehabilitation — prolonged cycling and running mechanical efficiency Campfire Endurance Coaching: campfireendurance.com [https://campfireendurance.com]

Episode 45: Durability and Fatigue Resistance with Coaching Legend Joe Friel

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 — more than fifteen years before sports scientists gave durability a name — and walks through the three-phase training structure he uses to build durable athletes from the ground up. The conversation covers zone one and zone two training, the discipline of race-specific pacing, AI's role in coaching, and Joe's revised edition of Fast After 50, due out in June. If you work with long-course athletes, or if you are one, this episode covers the ground that determines who holds on late in a race and who doesn't. Links mentioned in this episode: Joe Friel's website: joefrieltraining.com [http://joefrieltraining.com] TrainingPeaks (decoupling and efficiency factor tools): trainingpeaks.com [https://www.trainingpeaks.com] Fast After 50, revised edition — coming June 2026 (available wherever books are sold) Kolie Moore / Empirical Cycling: empiricalcycling.com [https://empiricalcycling.com] Serious Training for Endurance Athletes [https://www.amazon.com/Serious-Training-Endurance-Athletes-2nd/dp/0873226445] by Rob Sleamaker and Ray Browning Campfire Endurance coaching: campfireendurance.com [https://campfireendurance.com]

Episode 44: Triathlon Only Has Two Zones

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 steady, moderately-hard effort that you can hold for a long time. In this monologue episode of The Infirmary, I make the case that triathletes need just two training ranges: endurance and speed. I talk about how training actually works — oxygen delivery, blood volume, capillary density, mitochondrial function, muscle fiber recruitment, metabolic efficiency — and show why the moderate and heavy exercise domains can and should be collapsed into a single endurance range for multisport athletes. I also address why a seven-zone system can actually hurt your training as a triathlete, why "anaerobic threshold" is a misleading term, and why your threshold intervals shouldn't be killing you—they are part of the endurance side of things, NOT intensity. We wrap things up with a practical breakdown of how to apply perceived exertion and training intensity distribution across a season. Links mentioned in this episode: Jesse Dukes' one-day "How to Get Good Tape" Los Angeles Workshop: https://jessedukes.com/good-tape-how-to-get-it-2/ [https://jessedukes.com/good-tape-how-to-get-it-2/] Kolie Moore FTP test and threshold discussion [https://open.spotify.com/episode/13CpjXnclQvjLe9VBT7B5I?si=e5dd8220c83b4690] Ryan Bolton metabolic efficiency episode [https://open.spotify.com/episode/6mSDYTLlTvWgolS05jdcdP?si=d839a79dee4f472e] Book a free training consultation: https://tinyurl.com/mu8d8tux [https://tinyurl.com/mu8d8tux] Join the Campfire Discord community: https://discord.gg/3Uq989QFX4 [https://discord.gg/3Uq989QFX4] 2026 Bend Camp waitlist [https://campfire-endurance.kit.com/b23e940f6d?utm_campaign=feed&utm_medium=referral&utm_source=later-linkinbio]

Episode 43: The Science of Sweat | How to Actually Fuel and Hydrate for Endurance with Tash Cooper-Smith

Sports scientist and triathlete Tash Cooper-Smith from Precision Fuel & Hydration [https://www.precisionhydration.com/us/en/?srsltid=AfmBOorl01X0P6O2cHqmjdXJvYT69TQCy2l2U5ShiSywY-sWFviTvaUS] 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 as they make it. She also shares the story of her own athletic journey, from competitive gymnastics to Kona qualifier in four years, and what that experience taught her about personalizing nutrition for performance. Links mentioned in this episode: Jesse Dukes' one-day "How to Get Good Tape" Los Angeles Workshop: https://jessedukes.com/good-tape-how-to-get-it-2/ [https://jessedukes.com/good-tape-how-to-get-it-2/] Precision Fuel & Hydration: https://www.precisionhydration.com [https://www.precisionhydration.com] Precision F&H free sweat rate calculator and spreadsheet: precisionhydration.com Follow Tash on Instagram: @tash.cs Follow Precision F&H on Instagram: @precisionfandh Book a free 20-minute video call with a Precision F&H sports scientist: precisionhydration.com [http://precisionhydration.com]

Episode 42: Stress + Rest = Growth: A Guided Breathwork Session for Mental Toughness

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, including a painful lesson from Ironman Canada 2012, to explain why learning to sit with discomfort is a crucial and trainable skill, not a personality trait. The episode ends with a three-round guided breathwork session designed to put you face-to-face with that exact discomfort, so you can practice handling it before you're in a race or in a tough workout. Links mentioned in this episode: Campfire Endurance Substack: campfireendurance.substack.com [https://campfireendurance.substack.com] Bend Camp [/training-camps] 1:1 Coaching with Chris: campfireendurance.com [https://app.acuityscheduling.com/schedule/f0ceda55/appointment/63067352/calendar/any?appointmentTypeIds[]=63067352]