What does it really mean to train your “energy systems”—and how should you approach improving your weakest link? Many programmes talk about “conditioning”, but how do you know if you’re targeting the mechanism that matters most for your goals? In this episode, I’m joined by physiologist and CrossFit coach Evan Peikon to explore how recent advances in technology and research can help athletes and coaches make smarter decisions. We discuss how the outdated view of energy systems as isolated, sequential contributors to performance can lead to mistakes in training design. Evan shares what he’s learned updating his book Paradigm Shift, especially on identifying performance “limiters” in athletes—whether respiratory, delivery, or utilisation—and tailoring training accordingly. We also look at how practical tools like NIRS (near-infrared spectroscopy) can clarify what’s truly holding someone back, even for those without access to lab equipment. Whether you coach hybrid athletes or just want to better understand how to personalise your own training, you’ll find this conversation challenges assumptions and brings clarity to complex questions. In this episode, we discuss:00:00 – Opening and welcome in the new studio 00:11 – Introduction to Evan Peikon and his background 01:20 – Evan’s recent exit from Nox and current work in biotech and academic research 02:54 – Evan’s PhD focus on precision oncology and biodefence 04:14 – How skills transfer between human performance, medicine and technology 05:39 – Evan’s aims after completing his PhD 06:21 – Startups, academia, and the changing research landscape 07:31 – Why Evan returned to human performance and updated Paradigm Shift 09:23 – How his thinking on energy systems and control mechanisms has evolved 12:29 – Technology advances and making complex data more accessible 13:24 – The gap between wearable data and useful training decisions 15:20 – Types of physiological “limiters”: utilisation, delivery, respiratory 19:45 – How these limiters appear in different sports and athlete levels 24:27 – Impact of sport programming and selection pressures 26:56 – Interval training examples for different limiter archetypes 33:21 – Integrating limiter-based training into the overall training plan 36:58 – Real-world examples: adjusting perceived “muscular endurance” limitations 40:40 – Identifying limiter types without advanced technology 47:38 – Structural signs, posture, and their relation to true limitations 51:02 – Using NIRS data to inform programming: recovery, volume, and progression 56:49 – Why repeating effective sessions can be more useful than constant novelty 58:54 – Evan’s current work and how to find more resources TakeawaysNot all energy system “limitations” are created equal: Evan Peikon explains how an athlete’s performance may be limited by different physiological systems—muscular (utilisation), cardiovascular (delivery), or respiratory. Identifying these distinctions is critical: the problem is rarely just “conditioning” and the wrong focus can waste training effort.Interval structure and training adaptations depend on individual constraints: The same session can produce different results depending on a person’s limiting system. Coaches should tailor pacing, rest, and exercise order—sometimes using simple tools like performance curves or pulse oximeters—to address the root cause of underperformance.New technology aids, but practical interpretation still matters: While affordable wearables and NIRS sensors now provide more data than ever, Evan emphasises that progress comes from understanding trends and context, not chasing isolated metrics. Repeating and adjusting useful sessions, not constantly changing workouts, often yields better insights and adaptations. FOLLOW OUR PODCASTThe Progress Theory: @theprogresstheory Dr Phil Price: @drphilprice Evan Peikon: https://www.evanpeikon.com/ Resources mentionedParadigm Shift by Evan PeikonNIRS (Near-Infrared Spectroscopy) tech and muscle oxygen sensorsEvan Peikon SubstackTraining Think Tank (referenced in context of testing and applied coaching) Explore more episodes and resources at: https://www.theprogresstheory.com/ For all our other episodes and to get in touch, please visit www.theprogresstheory.com. Thanks for listening! This podcast is hosted by Captivate, try it yourself for free. KULT Media 2026 Mentioned in this episode: Podcast Produced By KULT Media Before we wrap up, I want to give a shout-out and my thanks to my production partner, Kult Media. If you are thinking of launching a podcast or want to grow your audience, head to www.kult.media to get started today. Kult Media The Science of Hybrid Training It was originally thought that you could not effectively train for both strength and endurance at the same time because they required different adaptations which were not compatible with each other. It was claimed that ‘an interference effect’, blunted the adaptations for strength if you simultaneously trained for endurance. However, recent developments in sports which require both strength and endurance have really challenged this idea, with hybrid athletes producing impressive performances in both strength and endurance sports together. This had led scientists, coaches, and athletes to rethink what is humanly possible and suggests the interference effect is not as influential as originally thought. But what is a hybrid athlete? What is the ‘interference effect’? And how can we maximize our training to improve at the same time our strength and endurance performance? In this book, Dr Phil Price provides insight into the misconceptions surrounding strength and endurance training by distilling the past 50 years of research and drawing on the conversations he had with great scientists, coaches, and athletes on The Progress Theory podcast. This book is essential reading for hybrid athletes and coaches who are looking to understand the key training variables and their effect on the simultaneous development of strength and endurance performance. Book
