Running Power
Running power is a measure of the mechanical work rate produced during running, expressed in watts (W) or normalized to body weight as watts per kilogram (W/kg). Like cycling power, running power provides an instant, direct measure of training intensity that is unaffected by terrain changes, wind, cardiac drift, or the 30–60 second heart rate lag — making it an increasingly popular tool for pacing, training zone prescription, and performance tracking in distance running.
Deeper Explanation
Running power is calculated by measuring the forces produced by the runner's body and the rate at which those forces are applied — specifically the combination of horizontal propulsive power (overcoming air resistance and changing velocity) and vertical power (combating gravity and spring-mass oscillation). Modern running power meters integrate accelerometer, gyroscope, and barometric pressure data to estimate total mechanical power output in real time.
How running power differs from cycling power: Cycling power is measured directly as the torque applied to the pedals multiplied by angular velocity — a purely mechanical measurement with high accuracy and strong scientific consensus. Running power involves more complex biomechanics and is currently estimated through algorithms rather than direct measurement, which introduces device-to-device variation. Running power values are not directly comparable between different brands of running power meters.
Key running power concepts:
Critical Power (CP) / Running FTP: The running equivalent of cycling FTP is often called critical power — the power output that can be sustained for approximately 60 minutes. Some tools refer to this as running FTP. It defines the boundary between sustainable steady-state running and power outputs that cannot be maintained indefinitely. Running power zones are set as percentages of critical power, mirroring the Coggan zone system used in cycling.
Power-based running zones (approximately):
- Zone 1 (Recovery): Below 80% of Critical Power
- Zone 2 (Endurance): 80–89% of Critical Power
- Zone 3 (Tempo): 90–95% of Critical Power
- Zone 4 (Threshold): 96–105% of Critical Power
- Zone 5 (VO2 max): 106–120% of Critical Power
Gradient-adjusted pacing: A major advantage of running power over pace is that power automatically accounts for gradient. Running uphill at 150W is the same physiological effort as running on flat ground at 150W — pace will be different, but power reflects actual workload. This makes power the ideal pacing tool for trail running, cross-country, and hilly road courses where pace-based targets break down completely.
Form Power: Some running power systems (notably Stryd) also report "Form Power" — the power wasted on vertical oscillation (bouncing) rather than forward propulsion. Lower Form Power relative to total power indicates better running economy. Improving running form typically reduces Form Power, allowing the same total power to produce higher running speed.
Typical running power values by performance level:
| Level | Typical Running Power (W/kg at 5K race pace) | |-------|----------------------------------------------| | Beginner (35+ min 5K) | 3.0–4.5 W/kg | | Recreational (25–35 min 5K) | 4.5–5.5 W/kg | | Trained (20–25 min 5K) | 5.5–6.5 W/kg | | Competitive (17–20 min 5K) | 6.5–7.5 W/kg | | Elite (sub-13 min 5K) | 8.0–10.0 W/kg |
Note: Running power W/kg values are not comparable to cycling W/kg values — running involves different mechanical efficiencies and the absolute numbers are higher for equivalent performance levels.
How Running Power Relates to Training
Instant feedback on effort: Unlike heart rate, running power responds instantly to changes in effort. A runner hitting a hill at 150W of effort will see power spike immediately, whereas heart rate may not fully reflect the increased effort for 30–60 seconds. This makes power valuable for even-effort pacing on variable terrain.
TSS calculation for runners: Running power enables TSS (Training Stress Score) calculation for runs — the same metric used for cycling — enabling unified cross-sport training load tracking. Running TSS is calculated identically to cycling TSS, with Critical Power substituting for FTP.
Training zone prescription: Critical power testing (a 20-minute maximal run effort, with power × 0.95 as the CP estimate) provides a personalized threshold from which all running power zones are derived. This mirrors FTP testing for cyclists.
Running economy tracking: Long-term tracking of power-to-pace ratio at standard intensities reveals running economy improvements. If an athlete produces 250W at 5:00/km pace and later produces the same 250W at 4:50/km pace, running economy has improved — the same mechanical output now produces faster speed, reflecting better biomechanical efficiency or reduced energy cost of running.
How Fitiv Uses Running Power
Fitiv Pulse supports running power data from Stryd (the most popular running power meter) and compatible Bluetooth running power sources. When a running power meter is paired, Fitiv displays:
During workouts:
- Real-time running power in watts
- Running power zones displayed alongside heart rate zones
- Pace and power simultaneously for complete intensity context
- Lap power averages for interval tracking
After workouts:
- Average and normalized running power for the session
- Power zone distribution (time in each zone)
- TSS calculated from running power, enabling unified training load tracking alongside cycling TSS
- Power-to-pace efficiency ratio
Training load integration: Running TSS from power-based workouts feeds into the same CTL/ATL/TSB model as cycling TSS and TRIMP, giving multi-sport athletes a single unified view of training stress regardless of sport. For runners who do not have a running power meter, Fitiv continues to calculate TRIMP from heart rate data for equivalent training load tracking.
Frequently Asked Questions
Q: Do I need a running power meter to use power-based training? A: A dedicated running power meter (such as the Stryd foot pod) or a compatible GPS watch with built-in running power estimation (some Garmin models) is required. Stryd is the most widely used and validated running power meter, attaching to the shoe lace and transmitting via Bluetooth. It is compatible with Fitiv and enables all power-based features including TSS calculation and power zone tracking.
Q: Are running power values comparable between different athletes or devices? A: Running power values from different device manufacturers use different algorithms and are not directly comparable. A Stryd reading of 300W does not equal a Garmin running power reading of 300W — each is calibrated to its own algorithm. Within a single device, the values are internally consistent and perfectly useful for training purposes. This differs from cycling power, which is a direct physical measurement and is directly comparable across certified power meter brands.
Q: Is running power better than pace for training? A: Running power is better than pace for pacing on varied terrain (trails, hilly roads) because it accounts for gradient automatically. On flat, consistent surfaces, pace and power are closely correlated and both work well. Running power also responds faster than heart rate to effort changes, making it more useful for interval work. Many athletes use all three simultaneously — power for real-time effort control, pace for performance context, and heart rate for physiological state monitoring.