Measuring the power running, in watts, is already possible with standing sensors and with some watches. As in cycling, power is used to train areas. This article is only for running with potentiometer. HR zones and power in general are in zones by HR and power.
Rapid response: The power zones in running are calculated as a percentage of your critical power (CP), an estimate of the maximum power you can hold for quite some time. Stryd, the most used sensor, proposes 5 zones: soft (65 to 80% of the CP), moderate (80 to 90%), threshold (90 to 100%), intervals (100 to 115 %) and repetitions (115 to 130 %).
What is the power in running
Power is mechanical work per unit of time. A sensor in the shoe estimates it from speed, slope and movement. Unlike the pace, the power changes instantly with the slopes or wind; unlike the HR, there is no delay. One study found that the Stryd sensor was validly measuring several race parameters at submaximal speeds (Imbach et al., 2020).
Critical Power (CP)
Stryd defines critical power as the threshold from which the dominant type of fatigue changes, and estimates it as your maximum metabolic effort for about 40 minutes (Stryd). It can be calculated with a test, with recent races or automatically from your workouts.
The 5 power zones of Stryd
| Zone | % COP | Typical use |
|---|---|---|
| 1. Soft | 65-80 % | Rolling, long throw, base |
| 2. Moderate | 80-90 % | Marathon simulation, tempo |
| 3. Threshold | 90-100 % | Long series, specific 10K work |
| 4. Ranges | 100-115 % | Series, 5K specific work |
| 5. Repeats | 115-130 % | Short series, track speed |
Example: with a CP of 250 W, zone 1 ranges from about 163 to 200 W (65-80%) and zone 3 from 225 to 250 W.
Power, pace, or heart rate
| Metric | Advantage | Limitation |
|---|---|---|
| Power | Instant; useful on slopes and with wind | Depends on the sensor; values are not comparable between brands |
| Pace | Simple and known | Cheat on slopes, wind and technical terrain |
| Heart rate | Reflects internal response | He is late and changes with heat, tiredness or stress |
The ideal is to combine them. If you train with HR, calculate your areas with the HR area calculator Or look. methods to calculate your HR zones.
Practical Tips
- Always use the same sensor: Watts of different brands are not comparable. Stryd warns that the values of other potentiometers or wrists do not reflect the CP of your system well.
- Check the COP every few months or when your shape changes.
- Don't chase the number in the soft shoots: sensations rule.
Plan your areas in TrainingForever
In TrainingForever your coach plans running sessions and sees how they go, with sessions synchronized with Garmin Connect. With TrainingForever, your coach has all the features free up to 5 athletes; from there, 0.99 € per active athlete per month, with a maximum of 49 €/month. For the athlete it's always free.
What a Coach Says
«The power I like in trail and with wind, where the pace deceives. But I always combine it with sensations." — Marc Bañuls, coach with more than 15 years of experience
Frequently Asked Questions
How do I calculate my power zones in running?
From your critical power (CP): for example, with the 5 areas of Stryd, zone 1 ranges from 65 to 80 % of your CP.
What is critical power?
An estimate of the maximum power you can hold for quite a while; Stryd places it around your maximum effort of about 40 minutes.
Can I compare my watts to those of another runner?
Only if you use the same system and express it per kilo of weight. Between brands, values are not comparable.
Power or heart rate?
Better both: the power responds instantly and the HR reflects how your body responds.
Sources
- Stryd Help Center. Critical Power Definition.
- Stryd Help Center. Power Zones.
- Stryd. Running with Power: Stryd manual (area table in % of critical power).
- Imbach F, Candau R, Chailan R, Perrey S. Validity of the Stryd power meter in measuring running parameters at submaximal speeds. Sports. 2020;8(7):103.
