What does it actually take to become a faster HYROX athlete?

Dr Charlie Davids joins us to explore the physiological demands of HYROX, combining his research in muscle physiology and strength training with his own experience competing in the sport.

The conversation examines why aerobic capacity provides the foundation for HYROX performance, how lactate threshold and critical speed influence race pacing, and why muscular endurance may become more important than maximal strength once athletes reach a sufficient strength level.

Charlie also shares findings from his research linking running speed at the second lactate threshold to HYROX performance, alongside practical approaches to periodization, station technique, and training under fatigue.

The episode also explores blood flow restriction training and its potential to improve muscular endurance and aerobic adaptations, while highlighting where more research is still needed to establish meaningful performance benefits.

Interested in learning more about the latest developments in endurance performance and sports science? Subscribe to the HIIT Science email list for updates on new research, courses, and educational opportunities. And for access to our adaptive HYROX training plans check out athletica.ai.

Prof Paul Laursen https://www.paullaursen.com/
Dr Charlie Davids https://scholars.latrobe.edu.au/cdavids
https://www.instagram.com/drcharliedavids/
https://www.trainrox.com/athletes/charlie-davids

Developing a footballer is about more than preparing them for the next match. It means understanding what that individual player needs to keep training, developing, and ultimately reach their potential.

Mattia Modonutti joins us to share his approach to player development and performance within elite football. Rather than treating performance as a collection of separate disciplines and datasets, Mattia explains why the real value comes from getting coaches, strength and conditioning staff, nutritionists, medical teams, and mental performance practitioners around the same table to build a richer
understanding of the athlete.

The conversation explores training continuity, individualizing load within a team environment, balancing match demands with long term physical development, and the difference between simply using a physical capacity during football and actually training it. Mattia also shares how his thinking has evolved as he moved from hands on coaching into performance leadership and why being evidence informed means combining research with experience, practitioner expertise, and athlete feedback.

Interested in learning more about the latest developments in endurance performance and sports science? Subscribe to the HIIT Science email list for updates on new research, courses, and educational opportunities.

Speaker:

Mattia Modonutti: https://www.linkedin.com/in/mattiamodonutti/

For decades, VO2 max, movement economy, and fractional utilization of VO2max have been widely presented as three key determinants of endurance performance. But how strong is the evidence for that third piece?

Yannick Sondermann and Dr Lars Schwalm join us this week to challenge some long standing assumptions around fractional utilization and explore whether it truly deserves the weight it has been given in traditional endurance performance models.

Drawing on their recently published work, they unpack what fractional utilization actually represents, whether it changes meaningfully with training, and why improvements in the metric may not always mean what we think they do. They also explore VO2max, movement economy, durability, strength training, and what coaches should actually focus on when trying to improve performance.

The conversation ultimately comes back to a simple question: are we focusing on the variables we can actually change?

Interested in learning more about the latest developments in endurance performance and sports science? Subscribe to the HIIT Science email list for updates on new research, courses, and educational opportunities.

Today's Speakers:

Prof Paul Laursen https://www.paullaursen.com/

Yannick Sondermann: https://www.linkedin.com/in/yannick-sondermann/

Dr. Lars Schwalm: https://www.linkedin.com/in/dr-lars-schwalm-223ab2420/

Resources:

https://journals.humankinetics.com/view/journals/ijspp/aop/article-10.1123-ijspp.2026-0039/article-10.1123-ijspp.2026-0039.xml