How Jess Pettrow Built the Aerobic Engine for HYROX’s Elite 15 — From 400m Speed to 20-Hour Training Weeks (#29)

Jess Pettrow is one of the fastest athletes in HYROX, combining elite track speed, strength training, and a relentless commitment to the process. In this episode, she shares how she cut eight minutes from her HYROX time by building her aerobic capacity, increasing training volume, and developing a structured program with coach James Kelly.

We break down her 18–20 hour training weeks, the alternating easy-day/quality-day structure she uses to stack consistent volume, and the key lessons she’s learned about racing — from pacing burpee broad jumps to managing energy before the decisive wall balls. Jess also explains why fueling and heart-rate monitoring are underrated, why maximal strength is often overrated for HYROX, and how a strong training environment on Australia’s Sunshine Coast has helped elevate her performance as she prepares for the World Championships.

Episode breakdown:

00:00 Intro: Jess Pettrow’s season highlights and world record

00:28 Total dedication to sport and love of the process

02:24 Why the athlete lifestyle is so rewarding

04:00 From first HYROX to cutting 8 minutes off her time

05:20 Track background: 400m, 800m, and college running

07:18 From track to strength training, CrossFit, and hybrid fitness

10:25 First HYROX race and what hooked her into the sport

11:50 Training environment with James Kelly and Joanna Wietrzyk

14:05 Weekly training structure: 18–20 hours, easy vs quality days

19:56 Building volume, aerobic capacity, and long-term progression

22:03 Future improvement and identifying performance limiters

24:28 Trusting her coach and building the athlete-coach relationship

26:59 Overrated vs underrated: sprints, long runs, gels, squats, HR monitors

31:52 How to race HYROX well: pacing, energy management, and strategy

35:08 Burpee broad jumps: pacing, EMOMs, and movement breakdown

38:57 Wall balls: fatigue, breathing, rhythm, and technique

42:19 2026 season goals and World Championship mindset

43:52 Coaching philosophy and helping athletes of all levels

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