The Progress Theory

What adaptations allow humans to freedive to extraordinary depths, and what might this reveal about our evolutionary past?

In this episode of The Progress Theory, I’m joined by Professor Erika Schagatay, a biologist and environmental physiologist who’s published over 100 papers on freediving. We explore not only the remarkable feats of breath-hold diving, but also the physiological and evolutionary mechanisms that make them possible.

We discuss how freedivers are able to go beyond what textbooks used to describe as human limits, the unique features of populations who depend on diving for survival, and Erika’s research suggesting that humans may have developed aquatic adaptations before becoming distance runners. We get into the details of bone density, spleen size and blood redistribution, plus the risks and thresholds involved in pushing human records today. Whether you’re interested in human evolution, the physiology of performance, or practical implications for training in other extreme environments, this conversation offers plenty to think about.

00:00 – Introduction and why understanding freediving matters

01:54 – Erika’s background: from Arctic Sweden to the Bajau divers

05:05 – Evolutionary theories: were we “divers before runners”?

08:43 – Human physiological changes enabling breath-hold diving

10:36 – The role of bone density and buoyancy in foraging depth

13:26 – The diving response: oxygen prioritisation and vasoconstriction

15:21 – Freediving world records: what are the current limits?

17:23 – Popularity of freediving and predicting human potential

20:07 – Categories of freediving and why “No Limits” isn’t a sport

24:43 – What No Limits diving reveals about physiology (and dangers)

29:48 – The challenge of marginal gains at the elite level

31:41 – Nitrogen narcosis: what is it and its effects at depth

34:05 – Differences between seals and humans in lung compression

36:13 – Training for lung flexibility, blood shift and mouthfill techniques

41:29 – Overlap between freediving adaptations and altitude performance

45:00 – Possibilities for cross-training: can breath-hold training help mountaineers?

46:32 – Research funding and the future of mechanistic studies

48:23 – Where to find Erika’s research and how to get in touch

• Evolution and aquatic adaptations: Erika Schagatay argues that our ancestors may have developed diving abilities and shallow-water foraging adaptations—such as increased bone density and oxygen-conserving reflexes—before becoming efficient terrestrial endurance runners. This challenges traditional views of human evolution.
• Limits of human freediving: Physiological features like the diving reflex (vasoconstriction and prioritising blood flow to the brain), spleen contraction and skeletal structure play central roles in freediving performance. Modern freedivers approach predicted human depth and time records not through sudden breakthroughs, but through tiny, hard-won gains and extraordinary specialisation.
• Freediving and hypoxic training for other sports: The same adaptations that benefit freedivers—such as spleen enlargement and enhanced blood oxygenation—may also be advantageous at high altitude. Breath-hold or apnea training could potentially support mountaineers and endurance athletes, but more research is needed to quantify these effects.

• The Progress Theory: @theprogresstheory
• Dr Phil Price: @drphilprice

For publications by Professor Erika Schagatay, see the resources below.

• Erika Schagatay: List of publications at Mid Sweden University
• Latest paper on evolution and freediving
• Summary article on the Max Planck Society website: “Endurance running or endurance diving – which came first?”
• Netflix documentaries on freediving

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

What actually happens to your body on a high-altitude expedition, and how much do genetics, experience, or fitness matter when the summit is in the “death zone”? In this episode of The Progress Theory, I’m joined by Dr Monica Piris, a medical doctor and veteran of dozens of Himalayan expeditions, to understand the physiological and practical challenges of climbing above 5,000 metres.

We explore how the body adapts (or fails to adapt) to extreme altitude, why altitude illnesses can escalate rapidly, and what individual, genetic and cultural differences mean for mountaineers. Monica describes the day-to-day realities of her role as an expedition doctor, from remote preparation through managing clients at base camp, and offers clear advice for anyone considering a serious mountain challenge. Along the way, we discuss why technical difficulty and fitness interact with altitude risk, the realities of using supplemental oxygen, and what motivates climbers to keep pushing despite the hazards.

Whether you’re preparing for an expedition or fascinated by how humans cope in extreme environments, Monica’s experience and practical insights will help you understand the real trade-offs behind altitude performance.

00:00 – The risks of extreme altitude and Monica’s background as an expedition doctor

03:28 – Common illnesses on expeditions and the realities of “glamorous” mountain medicine

04:46 – How Monica works with clients before and during expeditions

07:17 – Why doctors stay at base camp and the impact of altitude on decision-making

08:39 – What altitude does to the body: definitions and oxygen availability

10:26 – Adaptation limits above 6,000 metres and the variability in acclimatisation

12:16 – Genetics, cultural adaptation, and why some populations perform better at altitude

14:10 – Recognising and responding to high-altitude illnesses (AMS, HACE, HAPE)

18:28 – How quickly altitude illnesses can progress and the importance of self-awareness

20:14 – Managing motivation, communication and decision-making on expeditions

23:35 – Why Monica rarely faces dramatic resistance from clients

24:29 – Differences between commercial clients and professional athletes

28:22 – The distinction between elite performance and guided expedition support

30:24 – Using and not using supplemental oxygen: safety, ethics, and challenges

33:58 – Is Everest technical, or just high? What makes mountains dangerous

36:45 – How technical difficulty, fitness, and exertion affect risk at altitude

39:53 – Preparing physically and practically for mountaineering challenges

41:35 – The rise of extreme challenges and social media influence

42:11 – FKTs and what elite athletes actually need from doctors

44:29 – The reality of appetite, nutrition and fuelling at serious altitude

49:51 – Monica’s personal altitude symptoms and inter-individual differences

52:30 – Why even professionals sometimes turn around on major climbs

53:38 – Variability in individual response and the role of trip factors

55:51 – Why concurrent illness increases risk at altitude

57:07 – How to contact Monica and find out more about safe expeditions

• Altitude adaptation and risk are highly individual and context-dependent: Monica explains that physiological responses to altitude differ greatly due to genetics, previous exposure and training, and even the presence of minor illnesses or fatigue.
• Recognising and acting on altitude illness early is crucial: Symptoms such as headache, nausea, reduced exercise capacity and cough may seem minor at first but can escalate rapidly. Education and honest self-monitoring are key to safety on expeditions above 5,000 metres.
• Preparation goes beyond fitness — practical mountain experience matters: Monica emphasises that good preparation includes time spent moving in mountainous terrain, carrying loads, dealing with cold and logistical discomforts, and not just aerobic fitness. Those with practical exposure are much less likely to be overwhelmed when conditions become extreme.

• The Progress Theory: @theprogresstheory
• Dr Phil Price: @drphilprice

• Monica on Instagram: ​​https://www.instagram.com/monica_piris/
• Alpenglow Expeditions: alpenglowexpeditions.com

Explore more episodes 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:

Progress Theory Newsletter

Do you want the latest information on how to optimise human physical and mental performance sent straight to your email? Subscribe to the free Progress Theory newsletter on Substack where you will receive the latest research and recommendations on how to optimise your performance each week.

Substack

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

How do you prepare for the world’s toughest mountain challenges, especially as more people attempt rapid ascents, high-altitude marathons, or unique endurance feats at elevation? Whether you’re a seasoned climber or planning your first trek, getting acclimatisation right can be the difference between a successful adventure and a dangerous one.

I’m joined by James Barber, altitude specialist and Lead Performance Specialist at the Altitude Centre in London. We explore the science and practical application of altitude preparation: why acclimatising for 6,000 to 6,500 metres is the priority, how training protocols are adapted for increasingly ambitious or unconventional events, and why you do not need to be an elite athlete to benefit from targeted altitude exposure. We discuss the physiological adaptations that support performance and recovery at altitude, such as changes in blood oxygen saturation and breathing patterns, and look at how these approaches change for rapid ascents, ultra-endurance, and high-altitude marathons.

If you’re interested in the real details of altitude training, from basecamp to summit and everything in between, this episode will help you understand the key methods and decisions involved.

00:00 – Is the appetite for extreme altitude challenges growing?

02:00 – James’s background and the Altitude Centre’s story

05:31 – Who trains at the Altitude Centre? From elite teams to first-time mountaineers

06:44 – Testing, training, and tailoring protocols for different ambitions

09:11 – Typical progression towards Everest and multi-year preparation

11:05 – Simulating altitude: equipment capabilities and limitations

13:19 – Why acclimatising for "summit" altitudes isn’t always the goal

16:12 – Measuring and interpreting physiological adaptation at altitude

17:29 – Red blood cells, sleep tents, and when additional adaptation is needed

18:57 – Rapid ascents (flash expeditions) and when the approach must change

21:07 – Recent and emerging extreme events: Everest in 7 days, high-altitude base jumps, world’s highest marathons

24:40 – Preparing for endurance races and marathons at high elevation

26:32 – Key differences between trekking and racing at altitude

28:24 – Designing and progressing altitude training plans

30:58 – Climbing with or without supplemental oxygen: does the strategy change?

32:49 – How soon to begin: timelines and customising pre-acclimatisation

34:13 – How to connect with James and the Altitude Centre

• Pre-acclimatisation is for everyone, not just elites: As James Barber explains, most Altitude Centre clients are ordinary people preparing for challenging treks or endurance events. Careful testing and personalised plans can help anyone maximise both safety and enjoyment.
• The goal is sufficient altitude adaptation, not just maximum exposure: Acclimatisation typically aims to help people feel comfortable at 6,000 to 6,500 metres, focusing on basecamp levels rather than preparing for long periods at the highest altitudes. This approach helps make the final ascent safer and more manageable.
• Training protocols adjust to the challenge: Rapid ascents and extreme events require a higher standard of pre-acclimatisation. In these cases, combinations of active hypoxic sessions and sleep tents may be necessary, while standard protocols are usually suitable for slower treks.

• The Progress Theory: @theprogresstheory
• Dr Phil Price: @drphilprice
• The Altitude Centre: altitudecentre.com

• The Altitude Centre (altitudecentre.com)
• Everest Marathon (event page)
• Young Lives vs Cancer (charity supported by a trainee: younglivesvscancer.org.uk)

For more episodes, visit: 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

Progress Theory Newsletter

Do you want the latest information on how to optimise human physical and mental performance sent straight to your email? Subscribe to the free Progress Theory newsletter on Substack where you will receive the latest research and recommendations on how to optimise your performance each week.

Substack

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.

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

• Not 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.

The Progress Theory: @theprogresstheory

Dr Phil Price: @drphilprice

Evan Peikon: https://www.evanpeikon.com/

• Paradigm Shift by Evan Peikon
• NIRS (Near-Infrared Spectroscopy) tech and muscle oxygen sensors
• Evan Peikon Substack
• Training 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.

Book

Welcome to another episode of The Progress Theory, where we explore the latest scientific principles to help you optimise your performance. In this episode, Dr Phil Price sits down with Jem Arnold—a physiologist, physiotherapist, and PhD candidate at the University of British Columbia with a fascinating dual focus on high-performance sport and clinical research.

Jem’s work dives deep into individual responses to training and the use of Near Infrared Spectroscopy (NIRS), a cutting-edge wearable technology that measures muscle oxygenation both in the lab and out in the real world.

In this episode, Jem breaks down what NIRS is, how it works, and why its ability to capture local muscle oxygenation is so useful for endurance athletes, hybrid competitors, and anyone interested in interpreting the body’s signals during exercise. Drawing from both his research and personal experience with vascular conditions affecting elite cyclists, Jem shares insights on programming, individual variability, and how blending subjective feedback with objective tech can revolutionise our approach to training.

Whether you’re curious about the next frontier of monitoring tools, want to understand performance plateaus, or just love to geek out on physiology, you’ll find plenty to stimulate your thinking in this conversation. As always, don’t forget to follow The Progress Theory for more episodes and resources. Let’s dive in!

In this episode, we discuss:

• 00:00 Introduction
• 05:17 Iliac Artery Compression in Athletes
• 09:03 From Clinic to Laboratory Journey
• 11:28 Cyclists' Arterial Strain Issue
• 13:58 Rare Condition in Endurance Cyclists
• 18:28 Quadricep Oxygenation and Flow Limitation
• 22:04 Compensation and Performance in Athletes
• 27:01 Understanding Metabolic Demands in Exercise
• 30:33 Metabolic Limitations in Athletic Performance
• 33:10 Steep Deoxygenation: Overexertion Warning
• 37:05 Device-Specific Trends in Oxygen Measurement
• 40:04 Assessing Athletes' Functional Oxygen Range
• 44:04 From Data to Actionable Insight
• 49:04 "Assessing Power and SMO2 Balance"
• 52:53 Selective Use of Training Gadgets
• 56:04 Incremental Training Feedback Process
• 58:06 Inconsistent Data Interpretation Challenges
• 01:00:48 Blogs: Informal Idea Sharing

NIRS for Real-World Monitoring: Wearable NIRS devices provide invaluable real-time insight into local muscle oxygenation, allowing coaches and athletes to better understand individual physiological responses during both training and competition.

Individual Variability is Key: Jem emphasised that group-level sports science research doesn’t always translate directly to individual athletes. NIRS can help tailor interventions and programming by capturing each athlete’s unique response, especially when combined with subjective reports.

Practical Application Requires Context: Having all the gadgets is great, but Jem highlighted the importance of integrating NIRS data with athlete sensations, performance metrics, and expert guidance. It’s about turning data into tailored, actionable information—don’t let the numbers overwhelm the athlete or the process!

• @theprogresstheory
• @drphilprice
• @jem arnold
• Spare cycles blog
• MoxyTrain RedArtinis

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:

Progress Theory Newsletter

The Progress Theory newsletter. If you want the latest information and recommendations on how to optimise your physical and mental performance, then subscribe to the free Progress Theory newsletter on Substack today.

Substack

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.

Book

Hello, and welcome to The Progress Theory where we discuss scientific principles for optimising human performance.

In this episode, we are joined by former GB fencer and now mindset and performance coach, Claire Bennett. Now mindset is such an important part of the elite performer.

We're so focused on achieving a particular goal that we often lose sight of what's important, which can lead to resentment and sometimes poor performance. In this episode, Claire talks about her experience at the top level of fencing and how she's utilised all of that experience to start her mindset and performance coach business, Perform, be happy. 

In this episode, we discuss:

• 0:50 - Introduction
• 02:48 - Transitioning from a full time athlete career
• 09:20 -  Athlete self-care and self-appreciation 
• 12:02 - Negative perfectionism and practise
• 15:41 - Overcoming negative perfectionism
• 17:20 - Growth Mindset and Getting outside your comfort zone
• 24:12 - Anxiety in different professions
• 28:18 - Insecurity
• 32:28 - Practical recommendations from a performance coach

🔹 Purposeful Practice Over Perfection: It's not about doing more, it's about doing it right. Focus on quality, not quantity. Perfect practice, rather than just practice, leads to top performance.

🔹 Growth Mindset is Key: In any high-performing environment, whether you're an athlete or a musician, adopting a growth mindset can turn fear and self-doubt into opportunities for growth.

🔹 Embrace Challenges as Opportunities: Reframe fears and pressures by seeing them as chances to learn and grow. Shift from "I have to" to "I get to" and watch how it transforms your outlook.

• @theprogresstheory
• @drphilprice
• @performbehappy
• Singing Challenge

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:

Progress Theory Newsletter

The Progress Theory newsletter. If you want the latest information and recommendations on how to optimise your physical and mental performance, then subscribe to the free Progress Theory newsletter on Substack today.

Substack

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.

Book

Hello and welcome to the Progress Theory where we discuss scientific principles for optimising human performance. In this episode, we're joined by plyometric expert Matt McInnis-Watson. Now I don't know if you've noticed, but you quite often hear of a new world record being broken in a number of different sports, say, weightlifting or quite often in running. I'm always hearing of a new world record in, say, 5k, 10k, etcetera, etcetera. But you rarely hear of a world record being broken in a jump event such as the long jump or triple jump or high jump. I mean, Jonathan Edwards' world record in the triple jump has been going since 1995.

So what needs to happen in jump training and the culture within jump training to see an improvement in jump sports? That's why I contacted Matt. And if you have any interest in improving jump performance, this episode is for you.

In this episode, we discuss:

• 1:02 - Introduction
• 3:35 - The importance of Plyometrics in today’s society and longevity
• 8:35 -  Issues with plyometric research
• 13:44 - People get the plyometric definition wrong - still
• 16:12 - different types of plyometrics 
• 20:27 - Why are jump world records rare?
• 25:57 - Strength specificity
• 30:25 - What needs to change?
• 35:10 - Which jump sports will see the biggest changes over the next few years?
• 39:08 - Power athlete vs speed athlete
• 44:13 - The importance of supramaximal
• 50:37 - Plyometric recommendations

🔹 Plyometrics for Health Longevity: Plyometrics aren't just for athletes. They play a crucial role in maintaining reactive strength, which is vital for reducing injury risks, especially as we age. Matt highlighted how integrating plyometrics can aid in preserving dynamic capacity, thus enhancing long-term health.

🔹 The Science and Research of Plyometrics: It was fascinating to hear about Matt's critique of current plyometric research. He underscored the need for clearer definitions and proper visual documentation in studies to better understand plyometric movements and their implications for training.

🔹 Training for Future Success: A pivotal point was the shifting focus towards speed training in events like high jump and triple jump. By restructuring training to incorporate more dynamic and reflexive elements rather than solely focusing on strength, we can push the boundaries of human performance in these fields.

• @theprogresstheory
• @drphilprice
• Plus Plyos: Change the way you move
• Matt McInnes Watson | The Plyo Guy (@mcinneswatson) - Instagram

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.

Book

Progress Theory Newsletter

The Progress Theory newsletter. If you want the latest information and recommendations on how to optimise your physical and mental performance, then subscribe to the free Progress Theory newsletter on Substack today.

Substack

In this episode of The Progress Theory, host Dr Phil Price chats with hybrid athlete and S&C coach Ollie Russell about his incredible journey from being part of the Leicester Tigers rugby academy to becoming one of the top hybrid athletes in the country.

Ollie shares his passion for participating in various physical challenges, including High Rocks and Ironmans, and how these experiences have shaped his perspectives on hybrid training. They dive into Ollie's background in sports, his approach to training, and the importance of mindset in achieving peak performance.

This episode is perfect for anyone keen on understanding the balance between strength and endurance in hybrid training, as well as the value of a supportive community in reaching athletic goals. Tune in to discover Ollie's unique insights and the lessons he's learned along the way!

In this episode, we discuss:

• 00:00 Introduction
• 04:23 Transition from Rugby to Personal Trainer
• 07:47 Hybrid Training vs. Traditional Methods
• 12:33 Training for Highland Ultra in Scotland
• 15:37 Rugby Training: Longevity and Balance
• 17:44 Hybrid Approach to Specialisation
• 20:08 Raising Versatile Hybrid Athletes
• 23:55 "Building a Supportive Hybrid Fitness Community"
• 29:27 Embracing Fear to Unlock Potential
• 32:55 Mindset Boosts Physical Performance
• 37:06 Multisport Challenge and Endurance Events
• 39:11 "Chasing Success in Men's Pro"
• 41:52 Chasing Sub-Hour Race Achievement
• 44:38 Join a Supportive Community Network

• Experience Shapes Opinion: Ollie's diverse athletic background, from rugby to Ironmans and High Rocks, shows the power of varied experiences in shaping our approach to training and life.
• Mindset Matters: Ollie highlights the importance of mindset in training and performance, focusing on overcoming mental barriers to push physical limits. He reminds us that performance is not just about physical capability but mental resilience too. 🧠💪
• Community is Key: Building a supportive environment is essential. Ollie has cultivated a community where individuals, regardless of their skill level, can train together, push each other, and achieve their best.

• @theprogresstheory
• @drphilprice
• Ollie Russell (@russellperformancetraining) - Instagram
• Ollie Russel website
• Leicester Tigers rugby academy
• Hyrox
• Ironman
• Rich Froning documentary on Netflix
• Highland Ultra
• Military mindset
• Great North Swim
• Oscar Montgomery Environmental Foundation (OMF charity)
• Yorkshire Beast Challenge
• Decka Ironman

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.

Book

Progress Theory Newsletter

The Progress Theory newsletter. If you want the latest information and recommendations on how to optimise your physical and mental performance, then subscribe to the free Progress Theory newsletter on Substack today.

Substack

In this episode of The Progress Theory, host Dr Phil Price invites physiologist and researcher Dr Tom Jones from Northumbria University to discuss the intricacies of concurrent training. They delve into the concept of the interference effect—a phenomenon where endurance training can attenuate strength gains—and explore how various training modalities, intensities, and volumes can be manipulated to minimize this effect.

Dr Jones shares insights from his varied research experience across different sports, including his work with the Newcastle United Academy and the Swedish Winter Sports Research Center. The conversation touches on the real-world application of concurrent training principles, crucial mistakes to avoid, and the latest scientific understanding of acute molecular signalling.

Whether you're a coach, athlete, or fitness enthusiast, this episode offers valuable knowledge on optimising concurrent training for peak performance. Join us for a deep dive into the science of training with Dr Tom Jones on The Progress Theory!

In this episode, we discuss:

• 00:00 Introduction
• 03:51 Sports Research Journey Across Nations
• 08:46 "Concurrent Training Challenge in Football"
• 10:49 Concurrent Training: "It Depends" Dilemma
• 13:00 Aerobic Volume Limits Strength Gains
• 16:12 Interference Effect in Concurrent Training
• 19:56 mTOR and AMPK in Concurrent Training
• 25:53 Diet Control and Cycling Research
• 28:23 Aerobic Training's Interference on Strength
• 33:04 Managing Fatigue in Training Sessions
• 35:58 Understanding Technical Training Challenges
• 38:51 Concurrent Training Strategy Overview

🔹 Volume Matters: The greater the volume of aerobic training, the more likely it is to interfere with strength development. Understanding and managing training volumes are crucial for avoiding this interference effect.

🔹 Fatigue Management: Concurrent training requires careful programming. Avoiding residual fatigue from aerobic workouts can help optimise strength and power training sessions.

🔹 Effective Communication: A lack of appreciation for the physical demands of technical skills sessions can lead to common programming mistakes. Ensuring technical coaches understand these demands is vital for coherent training weeks aligned with specific mesocycle goals.

• @theprogresstheory
• @drphilprice
• @Thomas_W_Jones
• Tom Jones on ResearchGate
• Northumbria University
• Newcastle United Academy
• Aspire Academy
• Swedish Winter Sports Research Center

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:

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.

Book

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

Progress Theory Newsletter

The Progress Theory newsletter. If you want the latest information and recommendations on how to optimise your physical and mental performance, then subscribe to the free Progress Theory newsletter on Substack today.

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Hello, and welcome to The Progress Theory, where we discuss scientific principles for optimising human performance. In this episode, we are joined by a physiologist from Newcastle University, Dr. Callum Brownstein. Now managing and recovering from fatigue is so important for the success of a training programme and sporting performance. So if it's that important, we really should understand the mechanisms behind fatigue. And on top of that, we need to understand how different sports, different training modalities, different training intensities, and different training volumes all influence the type of mechanisms behind fatigue.

In this episode, we discuss:

• 0:53 - Introduction
• 8:34 - The difference between central and peripheral fatigue
• 12:15 - Determining the type of fatigue
• 16:42 - Fatigue differences between running and cycling
• 21:29 - Recoverability from different fatigue
• 23:42 - Training session order based on fatigue 
• 26:13 - Intensity and volume on fatigue
• 30:47 - Practical recommendations for training
• 33:41 - Organising a training week
• 35:32 - Pre-fatigue training

• Understanding Fatigue: Central vs. Peripheral – Dr. Brownstein explains the vital differences between central fatigue (nervous system-related) and peripheral fatigue (muscle-related) and how these mechanisms influence exercise performance.
• Exercise Modality Matters: Discover how cycling and running affect fatigue differently. While both sports show similar levels of muscle fatigue, cycling often results in more peripheral fatigue, whereas running tends to cause more central fatigue.
• Training Intensity: Keep Easy Days Easy – Emphasising the importance of staying disciplined with your exercise intensity, Dr. Brownstein highlights that crossing certain intensity thresholds can significantly compound fatigue, urging the importance of proper recovery.

• @theprogresstheory
• @drphilprice
• Callum G Brownstein (@CGBrownstein) / X
• @CGBrownstein
• Newcastle University
• ‪David Bishop‬ - ‪Google Scholar‬

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:

Progress Theory Newsletter

The Progress Theory newsletter. If you want the latest information and recommendations on how to optimise your physical and mental performance, then subscribe to the free Progress Theory newsletter on Substack today.

Substack

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.

Book