PCS Coaching

Efficiency Factor: A Guide to Tracking Progress and Moving Forward

4-minute read

Introduction

As a coach, I’m constantly analysing data to ensure my athletes are progressing towards their goals. One of the metrics I use daily in TrainingPeaks is Efficiency Factor (EF). It’s a simple yet powerful way to measure how efficiently an athlete’s body is working, and it plays a key role in monitoring aerobic development over time.

Whether I’m reviewing a long endurance ride, sweet spot intervals, or steady Zone 2 sessions, EF gives me an insight into how well an athlete is adapting to their training. This blog will dive into what EF is, how I use it to guide training decisions, and how athletes can use it to gauge when they’re ready to move to the next phase of their training. Let’s unpack this valuable tool and see how it can help you maximise your performance.

What Is Efficiency Factor?

Efficiency Factor (EF) measures your aerobic efficiency during a workout. It is calculated by dividing your Normalised Power (NP) by your Heart Rate (HR):

Essentially, EF reflects the power you produce per beat of your heart. Improvements in EF signify enhanced aerobic efficiency, meaning you can generate more power with the same or lower heart rate.

What Do EF Values Indicate?

EF values generally range from 1.10 to 3.0, depending on fitness, workout type, and effort zones:

  • 1.10–1.30:
    Typical for beginners or recovery rides. A low power-to-heart-rate ratio suggests an underdeveloped aerobic system or very low intensity.
  • 1.30–1.50:
    Moderate fitness level, often seen during base training phases as aerobic adaptations are building.
  • 1.50–2.0:
    Well-trained athletes during steady-state aerobic efforts (e.g., Zone 2 or sweet spot rides). Indicates efficient cardiovascular and muscular systems.
  • 2.0–3.0 and Beyond:
    Rare and found in highly trained athletes during high-intensity intervals or time trials. Reflects exceptional aerobic and anaerobic efficiency.
TrainingPeaks shows your EF in the Analysis tab if you use both HR & Power when training.

Training to Improve EF

To enhance EF, focus on structured training that promotes aerobic adaptations, muscular endurance, and cardiac efficiency.

1. Base Training Phase

Build a strong aerobic foundation with low-intensity, high-volume Zone 2 rides. These efforts maximise mitochondrial density and fat metabolism, critical for improving EF.

2. Sweet Spot Training

Sweet spot training (88–94% of FTP) is a balance between intensity and sustainability, ideal for improving aerobic efficiency.

3. Long, Steady Rides

Include long rides at moderate intensity to build durability and improve fat metabolism. These adaptations contribute to higher EF values over time.

4. High-Intensity Intervals

Once your aerobic base is solid, introduce VO2 max and threshold intervals. These sessions improve your capacity to sustain high power and clear lactate efficiently.

Tracking and Interpreting EF Trends

Monitoring EF helps gauge the effectiveness of your training over time. Compare similar workouts (e.g., steady Zone 2 rides) to track progress. Key insights include:

  • Positive Trends:
    A rising EF reflects improved efficiency. For example, an increase from 1.30 to 1.50 during steady-state rides suggests training is effective.
  • Plateaus:
    Stable EF values over several weeks may indicate that aerobic efficiency has reached its peak. A new training stimulus, such as sweet spot intervals, may be required.
  • Declines:
    A drop in EF could signal fatigue, insufficient recovery, or overtraining. Prioritise rest and reassess your plan before continuing.

When to Move to the Next Phase

Progression depends on EF trends and overall goals:

  • Stable or Increasing EF:
    When EF improves consistently and you feel strong, it’s time to introduce higher-intensity work or shift to race-specific preparations.
  • EF Plateau:
    A plateau suggests it’s time to adjust training stimulus—incorporate intervals or tempo efforts to target new adaptations.
  • Declining EF:
    If EF drops, prioritise recovery and evaluate your training load before advancing.

Considerations for Using EF

While EF is a valuable metric, it’s best analysed alongside other data like Training Stress Score (TSS), Intensity Factor (IF), and perceived effort. Factors such as hydration, temperature, and heart rate variability can influence EF on any given day. Focus on trends over time rather than isolated values.

Additionally, EF is most reliable during steady-state efforts (e.g., Zone 2 rides) and less so at very high or low intensities due to heart rate lag or variability.

Conclusion

Efficiency Factor provides an insightful measure of aerobic efficiency, helping athletes and coaches track progress and make informed training decisions. By starting with a solid aerobic foundation, progressing to sweet spot and interval work, and monitoring trends, you can optimise performance and know when to advance your training.

Remember, improvement takes time and consistency. Use EF as a guide and remember that EF is just one of MANY metrics so it’s important to listen to your body! If you need help with your training, reach out and get in touch with me! https://pcscoaching.com.au/coaching/book-a-breakthrough-session/ Happy training!

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High Performance Mountain Bike Coach

Donna Dall

My speciality is helping serious and recreational mountain bikers break through plateaus to attain higher levels of performance so that they can get fitter, faster, stronger and win more races!

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