In Episode 23 of The Indoor Rower Podcast, Tony breaks down Zone 3 rowing training in a five-zone heart-rate model — also known as UT1 (Utilisation 1) in rowing, Zone 2 in a three-zone model, and Sweet Spot training in endurance sport.

This episode explains why UT1 training is one of the most effective — and most misunderstood — intensities for rowing performance, particularly for indoor rowers, masters rowers, and endurance athletes.

Using exercise physiology research alongside over 40 years of rowing experience, Tony explains how training at lactate levels between 2–4 mmol/L improves aerobic power, raises anaerobic threshold, enhances muscle fibre efficiency, and increases the ability to push harder for longer.

You’ll also learn how UT1 should be used in moderation, why it must sit between UT2 aerobic base training and VO₂ max high-intensity work, and how misusing this zone can limit long-term progress.

What You’ll Learn in This Episode

• What Zone 3 / UT1 / Sweet Spot training really is
• How lactate works and why 2–4 mmol/L improves endurance performance
• Key physiological adaptations from UT1 rowing training
• How UT1 influences muscle fibre recruitment and aerobic development
• Heart-rate drift and controlled exposure to higher intensities
• How to structure UT1 alongside UT2 and VO₂ max sessions
• Practical lessons from four decades of competitive rowing and coaching

Episode Timeline

• 0:00 – Introduction to Zone 3 and UT1 rowing training
• 2:10 – Understanding different training zone models
• 4:05 – Lactate explained for rowers
• 6:07 – Physiological adaptations from consistent UT1 training
• 7:39 – Muscle fibre adaptations and aerobic development
• 8:44 – Heart-rate drift during UT1 rowing sessions
• 9:38 – Combining UT1 with UT2 and VO₂ max training
• 11:21 – Tony’s experience using UT1 across his rowing career
• 12:05 – Key takeaways and performance summary

Related Resources

📘 Read the full article on Zone 3 / UT1 rowing training:
👉 https://tonylarkman.com/zone-3-rowing-training-ut1-performance/

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