Coachcast Title Card

How to Utilize Running Power Metrics with Dr. Will O’Connor

BY TrainingPeaks CoachCast Host Dirk Friel

Dr. Will O’Connor takes us through the nuances of using running power in training. Will and Dirk get into the scientific side of power meters, discuss the accuracy and data consistency from devices like Stryd and other wearables, and learn how to use critical power zones to break down the metabolic costs of running variable terrain. Will also touches on some of the lessons in his Fundamentals of Running Power TrainingPeaks University course.

Will is a running scientist and former triathlete based in New Zealand. He drew on his background in organic chemistry to complete a Ph.D. in Sport & Exercise Science from Massey University, where his research investigated metabolic flexibility and ketogenic diets in ultra-endurance performance. Will competes at the elite level in ultrarunning events — he’s used a run power meter since day one — and is a coach and host of the “Running with Dr Will” podcast.

Standout Quotes

“That is what running power is, regardless, we just forget about how they’re measuring it or, you know, the nuances of the number, whether it’s metabolic or mechanical. It is for once giving us that objective number to say, like, this is really insightful as to why you were unable to maintain a pace, you know, or achieve the finishing time that you otherwise thought possible.”

“My hierarchy system of using [data], we have these three metrics. We have the triangle, you know, of heart rate, pace [and] power. How do we use them, and how do we use them together, based [on] the knowledge that we have to ensure that we always have a metric that we can rely on?”

Dr. Will O’Connor On Leveraging Power Data Analysis
Utilizing Running Power Analysis infographic

“With cycling, we’re very much concentrated on the mechanical work. We have the mechanics to measure the strain, the force and the energy going through the system, which is the bike. Whereas in running, it’s still kind of a little hazy as to whether we’re trying to determine metabolic power or mechanical power. Metabolic power being, how much energy is it taking you to run the 7:30 mile. Because there’s, yes, there’s the mechanical work.

When cycling, we take the mechanical work and we interpret it as like, I guess, a proxy for metabolic work. Your mechanical threshold, the amount of power you can…the 300 watts you can do for 20 minutes or whatever, we know that 95% of that’s probably going to be around your anaerobic threshold…Whereas, in running, there are some reports that it’s how much metabolic work are you doing, as opposed to how much mechanical work you’re doing. And at the fundamental level, it doesn’t really matter because the way we’re using this number that’s being reported as running power is merely just a means to control our energy across a distance or duration.”

Hr Pace Power Analytic Approach infographic

“The variability [in running output] is nowhere near as large as cycling. So what typically happens is whenever there’s, say, an overpass or a bridge or just that small hill on your way…you know, it’s a few hundred feet or something small. Right? Like, nothing. I’ll see these big spikes in power to maintain pace because it’s so small. It’s half a mile long, you can just “push up it.”

And when we’re thinking about a marathon effort — we’re dealing with really aerobically fit individuals and heart rate, as I said, is the dial-up of metrics, the heart rate might not drift out of Zone 2 or Zone 3, whatever you’re using over the course of three minutes. And you could be pushing into Zone 4 or, say, 100-105% of your power threshold. Pace looks fine, the heart rate’s drifting up, but not until right near the end of the climb. And then you’ve got the descent, so the heart rate starts to come back down. You’re back in control of pace.

[Afterward] I can see these big spikes, and I say, “Hey if we take a look at this 30-minute effort, these three minutes, these four, five minutes in Zone 4 [power] and you’re wondering why your heart rate was at 190 at the end of the second 30-minute effort?” When we’re looking at these power efforts, regardless of how fit or efficient you are and your heart rate being very stable, never exiting Zone 3, running a hill at Zone 4+ power is costing [you] anaerobic work.”

Running Efficiency Elite Amateur infographic

Will O’Connor Online

TrainingPeaks University Courses

A Coach Using Trainingpeaks On Her Laptop In Her Home Office

Start Your 7-Day Free Trial

Explore all TrainingPeaks features and more with a free 7-day trial for coaches. Tools built by coaches to make coaching easier.

Coachcast Host Dirk Friel
About TrainingPeaks CoachCast Host Dirk Friel

Dirk Friel is the host of the TrainingPeaks CoachCast and Co-Founder of TrainingPeaks. He is a lifelong athlete with a passion for cycling and ski mountaineering and firmly believes in goal setting, dedicated deliberate training and coaching for all. Learn more about his work at TrainingPeaks and follow his adventures on Instagram @dirkfriel.

Visit TrainingPeaks CoachCast Host Dirk Friel's Coach Profile