What does watts/kg mean at threshold?
The threshold, also called functional threshold power (FTP ), describes the highest power output that can be sustained over a period of approximately one hour without fatigue setting in. Watts/kg relates this power output to body weight and provides a number that allows different athletes to compare.
Example:
Two cyclists have an FTP of 300 watts.
-
- Athlete A weighs 60 kg → 300 ÷ 60 = 5 watts/kg
- Athlete B weighs 75 kg → 300 ÷ 75 = 4 watts/kg
Despite the same absolute power, athlete A is more efficient because he produces more power per kilogram of body weight.
Why is watt/kg so important?
- Comparability between athletes
Watt/kg makes it possible to compare athletes regardless of size or weight. This figure is often crucial, especially in weight-bearing sports like road cycling.
- Performance indicator in specific disciplines
- Flatland: Absolute wattage is more important than watts/kg, as air resistance dominates.
- Uphill: Here, watts/kg determine how quickly you can manage the climb.
- Training control
Understanding your own watt/kg values helps you to precisely define training zones and work specifically on weaknesses.
How do you measure watts/kg at threshold?
- FTP test on the indoor trainer or outdoor
A 20-minute test is a common method. The average power over these 20 minutes is multiplied by 0.95 to determine FTP.
- Determine body weight
Weight should be measured under realistic competition conditions, e.g., without unnecessary clothing.
- Invoice:
FTP value ÷ body weight = watts/kg.
How do you interpret the values?
| Watt/kg at threshold |
Level (cyclists) |
| < 2.5 |
beginner |
| 2.5–3.5 |
recreational athlete |
| 3.5–4.5 |
Ambitious amateur |
| 4.5–5.5 |
Semi-professional |
| > 5.5 |
elite |
This table varies depending on the sport, gender and age, but provides a rough guide.
How can you improve watts/kg?
- Increase in absolute performance
- Training in the threshold performance range (e.g. interval training with 90–105% FTP).
- Improve aerobic capacity through longer, moderate sessions.
- Optimize body weight
- Reduce fat mass: A healthy diet combined with aerobic training helps you achieve an optimal competition weight.
- Maintain muscle mass: Strength training ensures the necessary performance.
- Combined approach
- For most athletes, the key is the combination of performance improvement and weight management.
Watt/kg: Not everything, but a lot
Although watts/kg is a key metric in endurance sports, it shouldn't be viewed in isolation. Factors such as mental strength, technique, and race tactics are equally crucial to success. Nevertheless, the number provides a clear guide to assessing your own performance level and making targeted progress.
Invest in your training, maintain a balanced diet, and monitor how your watts/kg develop over time – progress is the best motivation!
