New study out on muscle oxygen saturation (SmO₂) breakpoints using NIRS 🎉 First authored by @igfjarillo.bsky.social - I contributed via the statistical analyses. While we present the findings elsewhere, here I focus on what’s new about our approach and why it matters ⬇️🧵 1/8

Science & Cycling 2026: great talks, inspired, back to work. Thank you @inefcat.bsky.social for the opportunity.

Trabajando para generar una versión en castellano del magnífico libro de @lakens.bsky.social A falta de corregir la numeración de los párrafos, ya he revisado el capítulo 2: control de errores. @samuelpleon.bsky.social @frangfr.bsky.social @mavadillo.bsky.social juangff85.github.io/inferencias-...

Garmin & Whoop are betting on muscle oxygen monitoring. Before you trust a muscle battery score: SmO₂ varies ~6% day to day. That's more noise than you'd want. Check out the first post of my new blog series "Science Translated"👇

Science Translated: How reliable is your muscle oxygen saturation monitor? – PS²

Measuring muscle oxygen saturation is coming to Garmin and Whoop. Before you trust them, here’s what the reliability data says.

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This video explains how Pogačar is beating Vingegaard lately: @teamemiratesuae.bsky.social sets a hard pace early on the climbs, draining Vingo’s W′. Then Pogi attacks, using his superior W′ to finish him off. m.youtube.com/watch?v=bgF1...

Pogacar revienta a Vingegaard en 2´30" | Juan Flecha

YouTube video by Comouna Flecha

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I find it interesting to compare Hautacam times in TDF22 and TDF25. Pogačar, that day climbed in 37:38 (VAM 1696 m/h), today in 34:56 (1828 m/h). Improvement of 132 m/h. Vingegaard, that day 36:34 (1747 m/h). Today, 37:06 (1720 m/h). Worse by 27 m/h... Itzulia 2024 comes to my mind... #TDF2025

Do you remember Alberto Contador climbing style? youtu.be/c7EYFjkXpYc

Is Seated Climbing Faster? Pogačar’s 2025 Tactic Decoded

YouTube video by Global Cycling Network

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Muy importante, en verano si vais a la playa:

Wonderful podcast. If Ginés Viscor is speaking, you listen. 🙏🏻 Amazing work from Fissac as always — making physiology accessible to everyone. www.linkedin.com/posts/ignaci...

Wonderful podcast. | Ignacio Fernandez Jarillo

Wonderful podcast. If Ginés Viscor is speaking, you listen. 🙏🏻 Amazing work from Fissac - Fisiología, salud y actividad física as always — making physiology accessible to everyone.

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An ongoing case study: I love working alongside dedicated athletes. Here are some insights into Xavi Estivill’s progress over the past 18 months.

Can’t be prouder of this guy! He crushed it with a 4h32 at Vitoria 70.3. We’ve been working together for over 1.5 years now. The last 7 months we’ve finally had uninterrupted training, after a challenging first 10 months marked by bike accidents and health issues.

Last week, I had the opportunity to teach one of the sessions of the Triathlon course for Sports Science students at INEFC Barcelona. We explored physiological assessment in endurance sports from an integrative perspective.

Open water project, brutal weekend, mega team. The learning never stops.

Open Water Project, data collection day 1. Brutal day 🤝 @inefcat.bsky.social

It doesn’t matter if I’m in the middle of a base phase or a specific training block—I’m always loyal to the once-a-week LT1 session. No need to be complicated: ≈35 minutes of total work, broken into intervals. I aim for a Borg RPE of around 11–12. This is always an internal load driven session.

The process continues: Pilot testing #OpenWaterProject ✅ Spent the morning at @canalolimpic testing the MOXY and heart rate sensors. Exciting times ahead as we move closer to the official start of this project! Grateful to be part of this journey—big thanks to everyone involved.

And finally, this is a fantastic video about the last meeting of the RED Synchro Project II. It is a great pleasure for me to participate in a project like this, dedicated to improving the health and performance of artistic swimmers. m.youtube.com/watch?v=gbKB...

RED Synchroproject 2 - Video Jornada

YouTube video by Recerca_Esport

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Two weeks ago, I had the opportunity to delve into the topic of hypoxia as part of my Integrative Physiology master’s program. It was a privilege to learn from esteemed experts such as Jean-Paul Richalet, Ginés Viscor, José Antonio Calbet, and Anna Carceller.

Training is progressing well in the pursuit of a sub-33-minute 10K. Yesterday’s session was a strong step forward, accumulating 30 minutes at LT2 with 5 x 6’ @ 3:45/km. Today’s focus: RMT, heat training, and isometric work. Learning while exercising ✌🏼

Is the maximal lactate accumulation rate (VLamax) a reliable indicator of maximal glycolytic power? Our latest systematic review explored this question. A little article but happy for what represents and for being the first one. Read the full article: recyt.fecyt.es/index.php/re...

So... No, HIIT is not a replacement for low-intensity work. In fact, I would argue that the more high intensity work that you have in your program, the more low-intensity work you must do to healthily balance it out. /endRant

Quiet, please! The remarkable power of silence – for our bodies and our minds

Quiet, please! The remarkable power of silence – for our bodies and our minds

Our increasingly noisy world has been linked to cardiovascular disease, anxiety and depression, as well as hearing loss. But that’s not the only reason we need more peace and quiet in our lives No dogs barking. No lawnmowers. No revving engines. No…

theguardian.com

And now, I’m learning to code in Python while studying for my second master’s in Physiology, preparing my first lessons as a teacher, writing my first scientific articles… and trying to break 33 minutes for 10K. Busy times! 😂 Hope this few "tweets" serve as a presentation ❤️

Then, in December: Our communication titled “Can muscle oxygen saturation provide real-time insights into the glycolytic contribution during intervals in the severe intensity domain?” was accepted for presentation at the Young Researchers in Sports Sciences Conference, organized by UAB.

Also in november I was part of a research summit that took place in the CAR of Sant Cugat were I did a presentation highlighting the potential of NIRS technology in the context of artistic swimming. Link: surl.li/gjecsr

Some updates: Last Nov, my master’s thesis titled “Exploring the Relationship Between Muscle Oxygenation Breakpoints and Ventilatory Thresholds in Triathletes” was awarded the prize for the Best Master’s Thesis in the field of sports performance at the ANECAFYDE congress. Link: surl.li/toprpd

Ignacio Fernández Jarillo guanya el premi al millor TFM de rendiment esportiu al  Congrés ANECAFYDE

L’Ignacio Fernández-Jarillo, col·laborador del GRCEIB,  ha estat el guanyador del premi al millor Treball Final de Màster (TFM) de la branca de rendiment esportiu al   I Congreso Nacional de Estudi…

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Since my Twitter account got hacked, I’ve been missing some of the connections I had there—especially those related to research, mNIRS, and endurance performance. I considered resetting Twitter, but I feel this platform is the better option.