Does high intensity training really build the strongest heart, or is it time in Zone 1 and Zone 2 that truly drives cardiac adaptation?

In this episode, Dr Guido Claessen joins us to unpack a landmark longitudinal MRI study on endurance athletes that challenges common assumptions about HIIT and heart remodeling. They explore what actually builds the “athletic heart,” why low intensity volume matters more than most think, and what this means for polarized training.

They also tackle the harder questions lifelong athletes worry about including atrial fibrillation, coronary plaque, myocarditis, and how much endurance sport might be too much.

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Today’s speakers:

Prof Paul Laursen https://www.paullaursen.com/

Dr Guido Claessen https://www.linkedin.com/in/guido-claessen-936a18a9/

We sit down with Prof Guillaume Millet to get clear on what fatigue actually is, why durability became the new buzzword, and what really limits performance in ultra endurance events. We dig into central vs peripheral fatigue, why muscle damage matters so much in trail and mountain running, and how shock weekends can build the resilience you cannot fake on race day. We also talk heat, perceived exertion, field monitoring tools, and his new Zero to 100 project taking sedentary adults to a 100k mountain race in 18 months.

References:

https://pubmed.ncbi.nlm.nih.gov/22323647/

https://pubmed.ncbi.nlm.nih.gov/39405022/

https://journals.physiology.org/doi/full/10.1152/japplphysiol.00692.2025?rfr_dat=cr_pub++0pubmed&url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org

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Today’s speakers:

Prof Paul Laursen https://www.paullaursen.com/

Prof Guillaume Millet https://www.linkedin.com/in/kinesiologui/

Episode 200 marks a major milestone for us, and we celebrate it with someone who played a foundational role in our journey. Professor Ken Nosaka joins us to reflect on how eccentric training research shaped modern training practice and brought our paths together.

We revisit the early ECU years, then dive deep into what Ken’s research has taught us about muscle soreness, muscle damage, the repeated bout effect, and how adaptation really works. This episode blends history, science, and real world coaching insights that still shape how we train today.

In this episode, we sit down with Dr Andrew Koutnik to unpack one of the most discussed sports science reviews in recent years. Drawing on more than 100 years of research and a series of tightly controlled trials, we examine evidence that challenges the long-held belief that more carbohydrates automatically lead to better performance.

We explore why muscle glycogen and carbohydrate oxidation do not consistently predict performance, how athletes can sustain high-intensity and endurance output with much lower carbohydrate intake, and why protecting brain energy may be a key limiter during exercise.

The conversation also examines why some highly trained athletes still show markers of poor metabolic health, what this means for current fueling guidelines, and why context matters when translating science into real-world practice.

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References:
https://academic.oup.com/edrv/advance-article/doi/10.1210/endrev/bnaf038/8432248?login=false

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Today’s speakers:

Prof Paul Laursen https://www.paullaursen.com/

Dr Andrew Koutnik https://www.instagram.com/andrewkoutnikphd/

In this episode, we sit down with François Fourhet to trace a career that has moved from hands on clinical practice to global performance environments, research leadership, and now consulting and teaching.

François shares the three major chapters of his journey: early years as a sports physio in Reims, nearly a decade in Doha within Aspire and Aspetar, then his Swiss chapter at Hôpital de la Tour where he helped build a research driven physiotherapy department and later led it. Along the way, they unpack what it really takes to make interdisciplinary performance support work, how François shifted into research without losing the practical thread, and why dissemination matters as much as publishing.

The conversation also gets tactical: ankle return to play, why isokinetic testing is misunderstood, how curve based analysis changes decision making, and the story behind Ankle Go, the free tool designed to help clinicians make smarter calls after ankle injury. If you work in rehab, performance, or team leadership, this episode is packed with ideas you can use immediately.

Today’s speakers:

Dr Martin Buchheit https://martin-buchheit.net/

François Fourhet https://www.linkedin.com/in/fran%C3%A7ois-fourchet-43b7b868/

In this episode, we sit down with Professor Arne Güllich to unpack one of the most talked about sports science papers in years, recently published in Science. Drawing from data on more than 30,000 high performers across sport, music, chess, and science, the conversation challenges the belief that early dominance and early specialization are the keys to elite success.

Arne breaks down the now viral performance trajectory figure, explores why most world class adults were not standout juniors, and explains what truly separates those who peak at the highest level from those who plateau. The discussion moves from theory to practice as Paul reflects on his role as a parent of a 15 year old swimmer, asking the questions many parents and coaches are quietly wrestling with.

This episode is essential listening for anyone involved in youth sport, talent development, or long term athlete health and performance.

References:
https://www.science.org/doi/10.1126/science.adt7790

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Today’s speakers:

Prof Paul Laursen https://www.paullaursen.com/

Prof Arne Güllich: https://www.linkedin.com/in/arne-g%C3%BCllich-4438a7376/

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In this episode, Dr. Martin Buchheit is joined by Dr. Scott Frey, a neuroscientist and founder of Cerebral Performance, to explore how brain science can improve athletic performance. The conversation focuses on central fatigue and why cognitive load can meaningfully reduce physical output, decision making quality, and error recovery in sport.

Scott explains why athletes often taper the body but rarely taper the brain, and shares practical ways to reduce mental load in the lead up to competition. They also discuss how cognitive testing, mood and motivation ratings, and HRV can be combined to monitor central fatigue, plus how cognitive training can be integrated into gym work or interval sessions to build fatigue resistance when it matters most.

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Today’s speakers:

Dr Martin Buchheit https://martin-buchheit.net/

Dr. Scott Frey https://cerebralperformance.com/

In this episode of the Training Science Podcast, Prof Paul Laursen is joined by Stephan Nüsser, performance physiologist and founder of a performance diagnostics lab in Germany, for a deep and practical discussion on lactate testing and endurance performance. Drawing from decades of applied work with cyclists, endurance athletes, and motocross professionals, Stephan explains how lactate can be used to individualize training, define true Zone 2 intensity, and guide long-term athlete development.

The conversation explores why lactate is often misunderstood, how production and clearance reflect underlying metabolism, and why longer step protocols can provide clearer insight than fixed threshold formulas. They also discuss carb-optimized nutrition, metabolic flexibility, and why training and fueling should be viewed as a single integrated system rather than separate decisions.

References:
https://sndc.de/

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Today’s speakers:

Prof Paul Laursen https://www.paullaursen.com/

Stephan Nüsser: https://www.instagram.com/sndcde/

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