Why 80/20 Doesn’t Work for Every Runner with Jonah Rosner

You have likely seen the term 80-20 running: a training approach where 80% of runs are easy, and 20% are hard. But is this an infallible rule as people present it on social media, or are there times when you may run more hard workouts - or more easy runs? We discuss the nuance of training intensity distribution with sport scientist Jonah Rosner. Thank you to our sponsors: ✨ Amazfit : User-friendly simple running watches with advanced features, at an affordable price point. Use link http://bit.ly/4nai73H for 10% off your purchase. ✨ FlipBelt: Sleek storage options, including no-bounce running belts and shorts. Use code TLF20 at flipbelt.com for 20% off your purchase. ✨ Previnex : Previnex creates clinically effective, third-party tested supplements made with high-quality ingredients, including Muscle Health Plus (creatine). Use the code treadlightly for 15% off your first order at previnex.com ✨Join us on Patreon.com/treadlightlyrunning or subscribe on Apple Podcasts starting in December, when we’ll be releasing special subscriber-only content! In this episode, you will learn: ✅ What is 80-20 running? ✅ What does 20% of your training hard actually look like? ✅ Polarized vs pyramidal training ✅ Why so much of your training is easy running ✅ How to approach training intensity in a marathon build ✅ The load differences of different training paces Who should and should not use 80-20 training About our guest: Jonah Rosner is a sport scientist, strength coach, and running performance coach based in Brooklyn. He spent the past decade working with athletes across every major American pro sport, including serving as the Applied Sport Science Coordinator for the Houston Texans in the NFL, one of the youngest sport scientists in league history. Jonah now focuses on helping everyday runners train with the same clarity and structure used in elite environments. He partnered with Nike to run the Nike Running Performance Lab NYC, where he used advanced testing and technology to build individualized strength and marathon training programs. Today, Jonah creates some of the most widely shared science-backed running content online. His free weekly newsletter, Marathon Science , breaks down training, strength, fueling, and performance into simple takeaways runners can use immediately. Subscribers get free tools like his daily nutrition guides, carb-loading cheatsheet, and strength-for-runners resources. You can join the newsletter at: https://marathonscience.beehiiv.com/ — it’s packed with practical insights grounded in real sport science. If you enjoyed this episode, you may also like: 🎧 Running for Health vs Performance (14 Nov 2025) 🎧 Is it Bad to Run in Zone 3? (12 Jan 2024) 🎧 Understanding Different Marathon Training Plans and Methodologies (24 Jan 2025) Let’s stay connected: ➡️ Tread Lightly Running Podcast on Instagram: https://www.instagram.com/treadlightlyrunning/ ➡️ Laura Norris Running on Instagram: https://www.instagram.com/lauranorrisrunning/ ➡️ Subscribe for weekly evidence-based newsletters, straight to your inbox, on https://lauranorrisrunning.substack.com/ ➡️ Run to the Finish on Instagram: https://www.instagram.com/runtothefinish/?hl=en ➡️ Thousands of running gear reviews and training guides: https://runtothefinish.com/