Do Menstrual Cycles Affect Training? The Science Explained with Dr. Nicky Keay

Designing a Robust Anti-Doping Programme for Trail Running with Brett Clothier

“Without trust, the spectacle means nothing.” In this episode, I am joined by Brett Clothier, the Head of the Athletics Integrity Unit (AIU), to discuss the structural requirements for a robust anti-doping program in trail running. As our sport undergoes a phase of professionalisation, marked by six-figure athlete contracts, skyrocketing prize money, and global broadcast deals, the risks to its integrity have never been higher. Brett brings a wealth of experience from the front lines of global athletics to explain why trail running must act now to avoid the reputational crises that have historically plagued cycling and marathon running. We pull back the curtain on the "cat and mouse" game of modern anti-doping, moving beyond simple in-competition testing to the necessity of year-round, surprise out-of-competition monitoring. Brett explains the mechanics of the Athlete Biological Passport (ABP) and why the 12-hour detection window of modern microdosing has made traditional testing protocols largely obsolete. We also tackle the "fig leaf" problem; programs that provide the appearance of integrity without the substance required to actually catch sophisticated cheats. We also address the financial realities of clean sport, discussing why a robust program costs upwards of $1 million per year and how the industry can collaborate to fund it. From the "proactive investment" required to protect the sport’s future to the counter-intuitive reality that a lack of positive cases doesn't always mean a clean sport, this conversation is a sobering look at what it takes to protect the spirit of the trails. Whether you are an athlete navigating the new professional landscape, a race organiser, or a fan who wants to believe in the performances we witness, this discussion provides a masterclass in the infrastructure of integrity. Looking for coaching or guidance? Read more at https://bornonthetrail.substack.com/p/coaching [https://bornonthetrail.substack.com/p/coaching] RELATED BORN ON THE TRAIL CONTENT We Need To Talk About (Anti-)Doping: https://bornonthetrail.substack.com/p/we-need-to-talk-about-anti-doping-trail-running [https://bornonthetrail.substack.com/p/we-need-to-talk-about-anti-doping-trail-running] FOLLOW THE ATHLETICS INTEGRITY UNIT Website: https://www.athleticsintegrity.org/ [https://www.athleticsintegrity.org/] Instagram: https://www.instagram.com/aiu_athletics/ [https://www.instagram.com/aiu_athletics/] Facebook: https://www.facebook.com/aiu.athletics [https://www.facebook.com/aiu.athletics] X: https://x.com/aiu_athletics [https://x.com/aiu_athletics] Contact the AIU at media@athleticsintegrity.org [media@athleticsintegrity.org] or at https://www.athleticsintegrity.org/contact-us [https://www.athleticsintegrity.org/contact-us] To report integrity concerns: https://www.athleticsintegrity.org/aiu-integrity-line [https://www.athleticsintegrity.org/aiu-integrity-line] WATCH THIS SHOW ON OTHER PLATFORMS YouTube: https://www.youtube.com/@bornonthetrail [https://www.youtube.com/@bornonthetrail] Spotify: https://open.spotify.com/show/6o5yHthUidO0No4VA3xdVb [https://open.spotify.com/show/6o5yHthUidO0No4VA3xdVb] Apple Podcasts: https://podcasts.apple.com/us/podcast/born-on-the-trail-going-longer/id1857231629 [https://podcasts.apple.com/us/podcast/born-on-the-trail-going-longer/id1857231629] YouTube Music: https://music.youtube.com/playlist?list=PLvFOih1rUBA2F_3Bi7Ii-cAqieAQSumU_ [https://music.youtube.com/playlist?list=PLvFOih1rUBA2F_3Bi7Ii-cAqieAQSumU_] FOLLOW BORN ON THE TRAIL ON SOCIAL MEDIA Substack: https://bornonthetrail.substack.com/ [https://bornonthetrail.substack.com/] Instagram: https://www.instagram.com/bornonthetrail/ [https://www.instagram.com/bornonthetrail/] TikTok: https://www.tiktok.com/@bornonthetrail [https://www.tiktok.com/@bornonthetrail] Facebook: https://www.facebook.com/bornonthetrail/ [https://www.facebook.com/bornonthetrail/] Get full access to Born on the Trail at bornonthetrail.substack.com/subscribe [https://bornonthetrail.substack.com/subscribe?utm_medium=podcast&utm_campaign=CTA_4]

Why Runners Should Not Strength Train

We are often told that strength training is a “non-negotiable” for longevity and performance. But for the self-coached trail runner who is balancing 40+ hour work weeks with a high-volume training block, nothing is free. Every hour spent in the gym is an hour not spent on the trails, and more importantly, it is an hour of recovery you are actively spending. In this episode of the podcast, we look at the science proving, or disproving, the injury prevention and performance benefits of strength training, what determines performance in marathon and ultramarathon events, and what elite coaches tell us about performance. This episode discusses why adding a stimulus isn’t just an addition, but a replacement of time or energy, when the aerobic benefit of a run outweighs the benefits of strength training while identifying who should double down on running and who should look towards strength training. Looking for coaching or guidance? Read more at https://bornonthetrail.substack.com/p/coaching [https://bornonthetrail.substack.com/p/coaching] RELATED BORN ON THE TRAIL CONTENT Why Runners Should Not Strength Train: https://bornonthetrail.substack.com/p/why-you-should-not-strength-train?r=39kjk2 [https://bornonthetrail.substack.com/p/why-you-should-not-strength-train?r=39kjk2] A Scientific Guide to Strength Training for Endurance Athletes: https://bornonthetrail.substack.com/p/a-scientific-guide-to-strength-training-for-runners?r=39kjk2 [https://bornonthetrail.substack.com/p/a-scientific-guide-to-strength-training-for-runners?r=39kjk2] WATCH THIS SHOW ON OTHER PLATFORMS YouTube: https://www.youtube.com/@bornonthetrail [https://www.youtube.com/@bornonthetrail] Spotify: https://open.spotify.com/show/6o5yHthUidO0No4VA3xdVb [https://open.spotify.com/show/6o5yHthUidO0No4VA3xdVb] Apple Podcasts: https://podcasts.apple.com/us/podcast/born-on-the-trail-going-longer/id1857231629 [https://podcasts.apple.com/us/podcast/born-on-the-trail-going-longer/id1857231629] YouTube Music: https://music.youtube.com/playlist?list=PLvFOih1rUBA2F_3Bi7Ii-cAqieAQSumU_ [https://music.youtube.com/playlist?list=PLvFOih1rUBA2F_3Bi7Ii-cAqieAQSumU_] FOLLOW BORN ON THE TRAIL ON SOCIAL MEDIA Substack: https://bornonthetrail.substack.com/ [https://bornonthetrail.substack.com/] Instagram: https://www.instagram.com/bornonthetrail/ [https://www.instagram.com/bornonthetrail/] TikTok: https://www.tiktok.com/@bornonthetrail [https://www.tiktok.com/@bornonthetrail] Facebook: https://www.facebook.com/bornonthetrail/ [https://www.facebook.com/bornonthetrail/] Get full access to Born on the Trail at bornonthetrail.substack.com/subscribe [https://bornonthetrail.substack.com/subscribe?utm_medium=podcast&utm_campaign=CTA_4]

Rethinking Effort and Intensity for Endurance Athletes with Siren Seiler

“The physiology can be complicated, but the training doesn’t have to be.” In this episode, I am joined by Siren Seiler, a sports physiologist and endurance athlete who brings a unique perspective to the science of performance. Having transitioned from the subjective world of competitive dance to the objective, data-driven realm of endurance running, Siren explores the friction between laboratory theory and real-world application. We discuss the mechanisms of intensity, examining how we move from the three physiological zones defined by lactate thresholds to the more granular five-zone models used by practitioners. We also tackle the practical challenges of monitoring these intensities when moving from the road to the mountains. Siren shares insights into how vertical gain and technical terrain shift the physiological cost of an effort, often rendering traditional pace-based metrics obsolete, and how breathing rate can help fill that gap. We also touch on the apparent conflict between Polarised Training and Double Threshold training and why Norway are so successful in sports. Whether you are interested in the specific mechanics of lactate monitoring or looking for a more robust way to structure your season, this discussion provides the theoretical depth needed to move from simply consuming information to making informed, science-backed training decisions. USEFUL LINKS Contextualizing the Norwegian standardized intensity zone framework in an international sample of endurance practitioners: https://www.researchgate.net/publication/396131157_Contextualizing_the_Norwegian_standardized_intensity_zone_framework_in_an_international_sample_of_endurance_practitioners [https://www.researchgate.net/publication/396131157_Contextualizing_the_Norwegian_standardized_intensity_zone_framework_in_an_international_sample_of_endurance_practitioners] RELATED BORN ON THE TRAIL CONTENT How To Improve Your Performance by 44% in Just 10 Weeks*: https://bornonthetrail.substack.com/p/how-to-improve-your-performance-by [https://bornonthetrail.substack.com/p/how-to-improve-your-performance-by] Are You a Better Judge of Effort Than Technology?: https://bornonthetrail.substack.com/p/are-you-a-better-judge-of-effort-than-technology-rpe [https://bornonthetrail.substack.com/p/are-you-a-better-judge-of-effort-than-technology-rpe?r=39kjk2] Reviewing Breathing Sensors as a Tool for Workload Monitoring: https://bornonthetrail.substack.com/p/breathing-sensor-and-heart-rate-for-performance-tracking?r=39kjk2 [https://bornonthetrail.substack.com/p/breathing-sensor-and-heart-rate-for-performance-tracking?r=39kjk2] FOLLOW SIREN SEILER LinkedIn: https://linkedin.com/in/siren-amelia-seiler-viken-a07215345 [https://linkedin.com/in/siren-amelia-seiler-viken-a07215345] Research Gate: https://www.researchgate.net/profile/Siren-Amelia-Seiler-Viken [https://www.researchgate.net/profile/Siren-Amelia-Seiler-Viken] Instagram: https://www.instagram.com/sirenseiler/?hl=en [https://www.instagram.com/sirenseiler/?hl=en] Personal Website: https://sirenseilercoaching.wordpress.com/ [https://sirenseilercoaching.wordpress.com/] FastTalk Labs: https://www.fasttalklabs.com/byline/siren-seiler-viken/ [https://www.fasttalklabs.com/byline/siren-seiler-viken/] WATCH THIS SHOW ON OTHER PLATFORMS YouTube: https://www.youtube.com/@bornonthetrail [https://www.youtube.com/@bornonthetrail] Spotify: https://open.spotify.com/show/6o5yHthUidO0No4VA3xdVb [https://open.spotify.com/show/6o5yHthUidO0No4VA3xdVb] Apple Podcasts: https://podcasts.apple.com/us/podcast/born-on-the-trail-going-longer/id1857231629 [https://podcasts.apple.com/us/podcast/born-on-the-trail-going-longer/id1857231629] Youtube Music: https://music.youtube.com/playlist?list=PLvFOih1rUBA2F_3Bi7Ii-cAqieAQSumU_ [https://music.youtube.com/playlist?list=PLvFOih1rUBA2F_3Bi7Ii-cAqieAQSumU_] FOLLOW BORN ON THE TRAIL ON SOCIAL MEDIA Substack: https://bornonthetrail.substack.com/ [https://bornonthetrail.substack.com/] Instagram: https://www.instagram.com/bornonthetrail/ [https://www.instagram.com/bornonthetrail/] TikTok: https://www.tiktok.com/@bornonthetrail [https://www.tiktok.com/@bornonthetrail] Facebook: https://www.facebook.com/bornonthetrail/ [https://www.facebook.com/bornonthetrail/] Get full access to Born on the Trail at bornonthetrail.substack.com/subscribe [https://bornonthetrail.substack.com/subscribe?utm_medium=podcast&utm_campaign=CTA_4]

Do Menstrual Cycles Affect Training? The Science Explained with Dr. Nicky Keay

In this episode, I speak with Dr. Nicky Keay about the role hormones play in endurance training, performance, and long-term athlete health. The discussion focuses on how menstrual cycles function as an important physiological signal and why they should be considered a key health marker for female athletes. Dr. Keay explains how hormones influence training adaptation, recovery, and bone health, and why disruptions to the menstrual cycle can indicate deeper problems with energy availability. The conversation also explores Relative Energy Deficiency in Sport (RED-S) and how chronic under-fueling can affect hormones, performance, and long-term health outcomes. The episode examines common misconceptions around menstrual cycles and training, what the current scientific evidence actually shows, and how athletes and coaches can interpret hormonal signals more effectively. Particular attention is given to practical implications for endurance athletes and how coaches, especially male coaches, can better support female athletes when navigating cycle-related considerations. This conversation aims to provide a clear, evidence-based perspective on female physiology in endurance sport and help athletes and coaches make more informed decisions about training, fuelling, and recovery. USEFUL LINKS Dr. Keay's Energy Availability Questionnaire: https://mypeaq.streamlit.app/#what-is-energy-availability [https://mypeaq.streamlit.app/#what-is-energy-availability] RELATED BORN ON THE TRAIL CONTENT https://bornonthetrail.substack.com/p/should-training-follow-the-menstrual-cycle?r=39kjk2 [https://bornonthetrail.substack.com/p/should-training-follow-the-menstrual-cycle?r=39kjk2] FOLLOW NICKY Contact Dr. Keay at https://nickykeayfitness.com/contact-2/ [https://nickykeayfitness.com/contact-2/] Book an appointment with Dr. Keay at https://nickykeayfitness.com/appointments/ [https://nickykeayfitness.com/appointments/] Interested in reading her books? Find more information at https://nickykeayfitness.com/new-book/ [https://nickykeayfitness.com/new-book/] Dr. Keay on Instagram https://www.instagram.com/drnickykeay/ [https://www.instagram.com/drnickykeay/] WATCH THIS SHOW ON OTHER PLATFORMS Substack: https://bornonthetrail.substack.com/podcast [https://bornonthetrail.substack.com/podcast] YouTube: https://www.youtube.com/playlist?list=PLvFOih1rUBA2F_3Bi7Ii-cAqieAQSumU_ [https://www.youtube.com/playlist?list=PLvFOih1rUBA2F_3Bi7Ii-cAqieAQSumU_] Spotify: https://open.spotify.com/show/6o5yHthUidO0No4VA3xdVb?si=nWhg4BjyQNa8F8lcsmXkJw [https://open.spotify.com/show/6o5yHthUidO0No4VA3xdVb?si=nWhg4BjyQNa8F8lcsmXkJw] Apple Podcasts: https://podcasts.apple.com/us/podcast/born-on-the-trail-going-longer/id1857231629 [https://podcasts.apple.com/us/podcast/born-on-the-trail-going-longer/id1857231629] YouTube Music: https://music.youtube.com/playlist?list=PLvFOih1rUBA2F_3Bi7Ii-cAqieAQSumU_ [https://music.youtube.com/playlist?list=PLvFOih1rUBA2F_3Bi7Ii-cAqieAQSumU_] BORN ON THE TRAIL ON SOCIAL MEDIA Substack: https://bornonthetrail.substack.com/ [https://bornonthetrail.substack.com/] Instagram: https://www.instagram.com/bornonthetrail/ [https://www.instagram.com/bornonthetrail/] TikTok: https://www.tiktok.com/@bornonthetrail [https://www.tiktok.com/@bornonthetrail] Facebook: https://www.facebook.com/bornonthetrail/ [https://www.facebook.com/bornonthetrail/] Get full access to Born on the Trail at bornonthetrail.substack.com/subscribe [https://bornonthetrail.substack.com/subscribe?utm_medium=podcast&utm_campaign=CTA_4]

Improving Ultra Marathon Performance through Metabolic Flexibility with Marco Altini

While everybody has spent 2025 increasing their carbohydrate intake, Marco spent his year improving his metabolic flexibility and fat oxidation through periodised nutrition. Although he agrees that carbohydrate availability is essential for performance and recovery, his approach challenges the assumption that simply increasing carbohydrate intake is always the primary lever for improvement. In this episode, I speak to Marco Altini about what metabolic flexibility actually is, what it is not, his metabolic flexibility and fat oxidation journey, along with practical tips and suggestions on how athletes should approach the topic of metabolic flexibility. Marco has a wealth of knowledge and I am very happy that he has decided to share some of it with my audience. Looking for coaching or guidance? Learn more at https://bornonthetrail.substack.com/p/coaching [https://bornonthetrail.substack.com/p/coaching] USEFUL LINKS [TrainingTalk] Periodized Nutrition and Metabolic Flexibility for Endurance Performance: Data and Insights from a Case Study: https://marcoaltini.substack.com/p/periodized-nutrition-for-endurance [https://marcoaltini.substack.com/p/periodized-nutrition-for-endurance] [TrainingTalk] Learnings From a Year of Periodized Nutrition and Metabolic Testing: https://marcoaltini.substack.com/p/trainingtalk-learnings-from-a-year [https://marcoaltini.substack.com/p/trainingtalk-learnings-from-a-year] [CoachCorner] When Metabolic Flexibility and Performance Move Together: Matteo’s Case Study: https://marcoaltini.substack.com/p/coachcorner-when-metabolic-flexibility [https://marcoaltini.substack.com/p/coachcorner-when-metabolic-flexibility] [CoachCorner] Should We Test?: https://marcoaltini.substack.com/p/coachcorner-should-we-test [https://marcoaltini.substack.com/p/coachcorner-should-we-test] RELATED BORN ON THE TRAIL CONTENT Do You Really Need 120g of Carbohydrates per Hour?: https://bornonthetrail.substack.com/p/do-you-really-need-120g-of-carbohydrates [https://bornonthetrail.substack.com/p/do-you-really-need-120g-of-carbohydrates] FOLLOW MARCO Do you want to be coached by Marco?: https://marcoaltini.substack.com/p/coachcorner-my-training-philosophy [https://marcoaltini.substack.com/p/coachcorner-my-training-philosophy] Substack: https://marcoaltini.substack.com/ [https://marcoaltini.substack.com/] Instagram: https://www.instagram.com/altini_marco/ [https://www.instagram.com/altini_marco/] WATCH THIS SHOW ON OTHER PLATFORMS Substack: https://bornonthetrail.substack.com/podcast [https://bornonthetrail.substack.com/podcast] YouTube: https://www.youtube.com/playlist?list=PLvFOih1rUBA2F_3Bi7Ii-cAqieAQSumU_ [https://www.youtube.com/playlist?list=PLvFOih1rUBA2F_3Bi7Ii-cAqieAQSumU_] Spotify: https://open.spotify.com/show/6o5yHthUidO0No4VA3xdVb?si=nWhg4BjyQNa8F8lcsmXkJw [https://open.spotify.com/show/6o5yHthUidO0No4VA3xdVb?si=nWhg4BjyQNa8F8lcsmXkJw] Apple Podcasts: https://podcasts.apple.com/us/podcast/born-on-the-trail-going-longer/id1857231629 [https://podcasts.apple.com/us/podcast/born-on-the-trail-going-longer/id1857231629] YouTube Music: https://music.youtube.com/playlist?list=PLvFOih1rUBA2F_3Bi7Ii-cAqieAQSumU_ [https://music.youtube.com/playlist?list=PLvFOih1rUBA2F_3Bi7Ii-cAqieAQSumU_] BORN ON THE TRAIL ON SOCIAL MEDIA Substack: https://bornonthetrail.substack.com/ [https://bornonthetrail.substack.com/] Instagram: https://www.instagram.com/bornonthetrail/ [https://www.instagram.com/bornonthetrail/] TikTok: https://www.tiktok.com/@bornonthetrail [https://www.tiktok.com/@bornonthetrail] Facebook: https://www.facebook.com/bornonthetrail/ [https://www.facebook.com/bornonthetrail/] Get full access to Born on the Trail at bornonthetrail.substack.com/subscribe [https://bornonthetrail.substack.com/subscribe?utm_medium=podcast&utm_campaign=CTA_4]