Episode 23: Zone 3 Training, UT1 & Sweet Spot: How to Improve Rowing Performance Artwork

The Indoor Rower

A podcast dedicated to indoor rowing. Aimed at improving your performance and knowledge of the indoor rower whether you use a Concept2, Waterrower or the latest Hydrow.Training, nutrition, periodisation, health and fitness, strength, speed, technique and tips from Tony, rowing coaches, athletes and former champions competing at the top of their game.Whether you're starting a health and fitness journey, are a seasoned indoor rower, rowing on the water, looking for tips to improve your 2k or simply interested in the new fitness trend to hit the gyms in 2022, The Indoor Rower will provide useful information to get the most out of the sport.

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Episode 23: Zone 3 Training, UT1 & Sweet Spot: How to Improve Rowing Performance

December 23, 2025 • Tony Larkman • Season 1 • Episode 23

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/

🌐 Website: https://tonylarkman.com

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✉️ Email: tony@tonylarkman.com