Running with Power: Bringing Wattage to the Run Leg

If you've been coaching on the bike side for any length of time, power is already part of how you think. You know what it looks like when an athlete holds 78% of FTP through five hours at Ironman. You can pull up a power file and read the whole story, where things fell apart, where they left time on the table, whether the training block actually did what you wanted it to do.

The run has always been harder. Heart rate lags, gets thrown off by heat and fatigue and that third cup of coffee. Pace falls apart the second you hit a real hill. RPE is honest but it's still just a feeling. There's always been a measurement gap on the run leg, and running power is what's starting to close it.

Running power uses the same conceptual foundation as cycling power. It gives you a real time, effort-independent measure of the mechanical work your athlete is putting out. The metrics will look familiar fast: Functional Threshold Power is still the highest sustainable effort for roughly 35min to an hour (depending on aerobic conditioning and fatigue resistance). Pmax is still peak short-duration output. Functional Reserve Capacity still tells you how much capacity you have above threshold before things start falling apart.

The training zone logic carries over too. Polarized or pyramidal distribution, time in zone, 90-day power curves, it all slots into whatever analytical workflow you've already built for bike files in WKO5 or TrainingPeaks. That's not a coincidence. Running power isn't trying to reinvent anything. It's extending a framework you already trust into a discipline that's historically been harder to measure.

The place running power pays off quickest is terrain. On a flat course, pace is a decent gauge for effort. But once your athlete hits a long climb, pace becomes almost useless, they slow down, the number looks bad, and they either overcook it trying to hold pace or back off so much the split suffers.

Power helps normalizes all of that. Consistent watts on an uphill means controlled, prescribed intensity, regardless of what pace says. For athletes prepping for hilly courses or running off a hard bike leg, this changes how precisely you can guide execution. That's a real shift.

Running power also gives you a more complete mechanical picture. Paired with ground contact time, vertical oscillation, and stride rate, data that Stryd, Garmin's running dynamics accessories, and to a lesser extent Apple Watch all capture, you can start connecting power output to movement efficiency. An athlete producing solid watts with poor economy is a different problem than one who moves well but lacks fitness. Power helps you tell which is which.

Three main options are worth knowing. Stryd is the most complete — it's a small foot pod that captures the fullest data set and gives you the most detailed power file for post-session analysis. If an athlete is serious about their data and willing to add one more piece of kit, Stryd is the current standard for depth.

Garmin's running power is built into their GPS watches and running dynamics accessories. A lot of your athletes probably already have access to it without realizing it. A little less data than Stryd, but no extra device is required, and minimum setup. Apple Watch generates a running power estimate too, though with fewer supporting metrics and less depth for coaching analysis.

Simple take: Stryd for athletes who want to go deep, Garmin for athletes who want to try it with hardware they already own (helpful for coaches learning to use power as they can begin gathering it for analysis immediately), and Apple Watch as a useful awareness tool even if it's not your primary instrument.

Here's where running power differs from cycling power in a way that actually matters for how you use it,  and it's worth being clear on thi

On the bike, a power meter measures real mechanical force. A strain gauge physically detects what's applied to the pedals or crank and converts it to watts. The number is a direct measurement. That's why a 250-watt FTP means the same thing across power meter brands, and why you can meaningfully compare cycling data across athletes and devices.

Running power is estimated. There's no pedal force sensor equivalent. Instead, it's derived from motion data, acceleration, ground contact time, vertical movement — and processed through proprietary algorithms to produce a wattage figure. What you're seeing is a model output, not a direct measurement.

What this means in practice: a 300-watt threshold on Stryd and a 300-watt threshold on Garmin are not the same thing. The algorithms differ, the inputs are weighted differently, and the numbers live in separate reference frames. Benchmarking athletes against each other, or comparing one athlete's Stryd data to another's Garmin data, won't work. The numbers don't hold up.

But that's not really how you should be using it anyway. The value is the same as cycling power in that you want to track one athlete's trends over time on the same device relative to themselves. Is their FTP moving block to block? Is their power distribution shifting the way you'd expect in a base phase? Are they producing more watts at the same heart rate, suggesting improved economy? Those questions are all answerable. And they're the right questions.

Think of running power as a reliable internal compass for each athlete, not a universal gauge you hold up against the field. Used that way, on a consistent device, within a consistent analysis environment, it's genuinely useful.

Running power isn't as mature as cycling power yet. The measurement methodology is fundamentally different, and the ecosystem is still developing. But for coaches who already speak the language of watts on the bike, the lift to apply it on the run is small. The frameworks are the same. The analysis workflows are compatible. And the gap it fills of being an objective, terrain-neutral intensity measure is a big step forward for coaching.

The key thing to understand is that you're working with a self-referential metric. Establish an athlete's baseline on a single device. Build their zones from it. Track trends across blocks. And resist comparing watts across devices, platforms, or athletes, as that's not what the number is designed to do.

Done right, running power gives you what cycling power gave coaches decades ago: an intensity window that isn't fooled by terrain, weather, or fatigue. For triathletes who've always had a clearer picture of their bike leg than their run leg, that's a real step forward. And for the coaches guiding them, it's a tool worth understanding well.