What is training intensity distribution (TID)?

For many years, the topic of whether a polarized or pyramidal training intensity distribution is more effective for endurance athletes has been hotly debated. Arturo Casado, PhD, is one of the foremost researchers in this area (and former European Champion in the 1500 metres). Today, Arturo dissects what the science really says in 2026: whether there is a winner, and if not, what are the athlete-specific, event-specific, and other variables that impact which training distribution will bring the best results. We also discuss specific training models from Canova to Norwegian from both scientific and practical perspectives, and bring it all together with practical advice relevant for amateur triathletes and runners. 

HIGHLIGHTS AND KEY TOPICS: 

• The science and practice of training intensity distributions. Who should use polarized versus pyramidal TIDs and when? 
• How do factors such as athlete level, age and sex, sport or modality, distance or event, periodization and more impact the choice of training intensity distribution?
• The science and practise of different training models in distance running, including Lydiard, Kenyan, Canova, Norwegian, Coe and more
• How do best practices differ between amateur athletes and elite runners and triathletes?  
• Practical tips and takeaways

DETAILED EPISODE SHOWNOTES: 

• We have detailed shownotes for all of our episodes. The shownotes are basically the podcast episode in written form, that you can read in 5-10 minutes. They are not transcriptions, but they are also not just surface-level overviews. They provide detailed insights and timestamps for each episode, and are great especially for later review, after you've already listened to an episode. 
• The shownotes for today's episode can be found at https://scientifictriathlon.com/tts695/

LINKS AND RESOURCES: 

• Arturo’s ResearchGate, Instagram and World Athletics profiles 
• Effects of polarized, pyramidal, and combined training periodisations with Luca Filipas, PhD | EP#328 - study mentioned in the interview
• Michele Zanini (part 2) | EP#394 - the Renato Canova training method
• Training Periodization, Methods, Intensity Distribution, and Volume in Highly Trained and Elite Distance Runners: A Systematic Review Casado et al. 2022
• World-Class Long-Distance Running Performances Are Best Predicted by Volume of Easy Runs and Deliberate Practice of Short-Interval and Tempo Runs - Casado et al. 2021
• Does Lactate-Guided Threshold Interval Training within a High-Volume Low-Intensity Approach Represent the “Next Step” in the Evolution of Distance Running Training?- Casado et al. 2023
• Pacing strategies in men's and women's world- record marathon performances and Olympic Games and World Championship's winning performances - Casado et al. 2024
• Training Intensity Distribution, Volume, Periodization, and Performance in Elite Rowers: A Systematic Review - Zhong et al. 2025
• Which Training Intensity Distribution Intervention will Produce the Greatest Improvements in Maximal Oxygen Uptake and Time-Trial Performance in Endurance Athletes? A Systematic Review and Network Meta-analysis of Individual Participant Data - Rosenblat et al. 2025

WHAT SHOULD I LISTEN TO NEXT?

If you enjoyed this episode, I think you'll love the following related episodes:

• John Davis – Coaching, physiology, and running calculators | EP#464
• [Triathlon Science] Durability decoded – a 2025 perspective with Michele Zanini, PhD
• Gabriele Gallo, PhD – The Science of Cycling Performance | EP#441

You can find our full episode archives here, where you can filter for categories such as Training, Racing, Science & Physiology, Swimming, Cycling, Running etc.

You can also find separate archives for specific series of episodes I've done, specifically Q&A episodes, TTS Thursday episodes, and Beginner Tips episodes. 

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