A Practical Guide on How to Train With a Running Power Meter
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There is no denying that trends in training fluctuate over time while major tenets in training remain stable. Pace, distance, and heart rate are relatively consistent metrics that most runners are familiar with. The technology to interpret these values has evolved over time and the metrics associated with these training tenets allow runners to reach higher performance levels once they adapt to using these tools.
As technology continues to increase, new concepts emerge with much promise. Some technology requires users to invest a bit of time and effort into learning how to use interfaces and technological setup with the payoff in improvement after they adapt to their new-found gadget. Simplicity in presentation and promise of improvement is what every brand would like to offer athletes keen on setting new PRs and making that next leap in performance level. One of these newer technological concepts, specifically in long-distance running is power.
Power is displayed as a standardized metric called Watts. Most running power meters come in the form of a foot pod that clips onto some part of the shoe with the shoelaces being the primary spot secure the foot pod. Measuring from the foot allows for the capture of the entire running gait and improves distance and pace accuracy. My goal of this post is to simplify the practicality of training with a running power meter and why adding in a simple tool can improve the planning, racing, and analysis of your running.
The Basics of Training with a Running Power Meter
You might have questions about what is actually being recorded during your run, and how you can track these different metrics. Here goes the list:
- Power - Power is displayed in Watts (per second). I personally like to compare Watts per kilogram in case of weight changes while training.
- Form Power - When you run not all power is dedicated to moving forward. As much as we would like to think that we are perfectly efficient, individual form and inefficiencies impact how much power is being expended aside from forward motion. Form power is that number that is not being used to move forward.
- Form Power Ratio - Is the metric to look at when analyzing form power. The idea is that you want your Form Power to either remain the same or go down as your overall Power increases. The trend is the important thing to look at.
- Cadence - This is a relatively simply explained metric. The number of times the same foot hits the ground. Some people like RPM (rotations per minute, or that one foot being tracked) or SPM (total steps per minute). Cadence can be reported via accelerometers in a watch but foot tracking is always more accurate.
- Ground Contact Time - The time in milliseconds or ms that the foot is spending on the ground. This is a metric that goes along with cadence and some of the other biomechanical metrics. My suggestion is to feel out your own personal ground contact time in the post run analysis and see if you are on the low end. If so, adding in specific plyometrics can help with efficiency.
- Vertical Oscillation - This is the measure in centimeters or cm that the center of mass of the body moves up and down. Typical ranges are 5-9cm. Vertical oscillation will decrease when running uphill.
- Leg Spring Stiffness - This is probably my favorite unique metric to track. Leg spring stiffness is the measure of the elastic forces in the lower leg, such as the Achilles and other tendons and ligaments/fascia. LSS divided by weight in kg allows for comparison across runners. The change in LSS over a run can be a signal for fatigue. The better a runner is, generally the more resistant they are to fatigue and their LSS/kg drops less during a race.
How to Incorporating Power into a Running Training Plan
Let’s say you are in the possession of a running power meter. Now how do you actually use it? I will assume the device is paired with a watch and you can see power live during your run and that you have a setup to review data after the run as well.
My first suggestion is to run like normal for 1-2 weeks to start to build up a base of data to look at. There isn’t much use in watching a number on your watch screen the first week except to see how your power changes on different surfaces or as you run up and down hills.
Determining Running Zones with your Power Meter
Once you have a few runs the next step is to get familiar with power zones. There are a few different methods behind this:
- The easiest is to run a race wearing a power meter, typically a 5k or 10k. You’ll get your power average for the race and your time and input it into a calculator. You’ll then get what is called a power duration curve based on the estimate from your race.
- The second method is a little bit more strenuous but very valuable. A Critical Power Test can be used to add another data point to your power duration curve and give a better idea of how you perform at longer versus shorter distances. The most optimal test procedure is to run a 2400m time trial, walk/jog 20 to 30 minutes, then run a 1200m time trial. These efforts (with their time and power) are input into a calculator and fit along your curve to give a more accurate depiction of your running performance.
- For platforms like Stryd, Critical Power can be calculated automatically and is updated whenever a change in your fitness is detected based on the data you import.
The most important number to look at once you’ve established this curve is your Functional Threshold Power or FTP. Stryd refers to this as “Critical Power” so I will refer to it as CP. This is the power you can sustain for 1 hour and is fundamental to establishing other ranges. Zones vary, and your coach might have a preference for a specific zone breakdown they would like you to use. So now you have all the numbers and math behind you. How do you put it to use to help your running?
Using a Power Meter on an Easy Run
The goal of an easy or recovery run is to maintain fitness and not overcook yourself for the next quality workout or next run coming up. Pace does not matter and should not matter when it comes to an easy run. You can run varying terrain at the same exact pace but exhaust yourself for an important workout because you were glued to hitting an arbitrary time it takes to complete a set 1k or 1mi distance.
If a recovery effort for a runner is usually 8:00-mile pace on flat terrain, but they go run a rolling course with 500ft elevation gain at an 8:00-mile pace, this is obviously more stressful than a flat run. When you focus on running a specific recovery power you gain the ability to monitor recovery with a better understanding of the stress put on your body. Running easy runs or recovery runs at 65-80% of your CP ensures you are recovering and ready to go for the next planned workout or run.
Examples of How to Structure a Run Workout with you Power Meter
Let’s look at some workouts now and give some examples of how to structure sessions to be consistent, maintainable, and specific to current fitness and running goals. Here is an example workout for a runner looking to target a mile race at the end of the season, but also working on their Threshold at the beginning of the season. They just did a CP test so they know their CP is 300 watts, and their goal for the mile race is 350 watts:
- 15 minutes warm-up at 65-75% of CP - 195 to 225 watts
- 20 minutes at 98-102% of CP - 294 to 306 watts
- 5 minutes at 50-65% of CP - 150 to 195 watts
- 4 x 1 minute at goal mile power - 350w
This workout lets them get some extremely specific running at the end goal mile power, while still training an extremely specific threshold power based on their current fitness. They can then build off of this based on their training plan and not worry about guessing if they are actually in a certain type of shape or not.
How to use a Power Meter on a Long Run
Our example runner is now training for their road racing season during the summer. They set out to do a 15-mile run with the first seven as a warmup, six miles as a progression from Marathon wattage down to CP wattage, then two miles cool down.
Their structure looks specifically like this:
- 7 miles at 65-75% of CP - 195 to 225 watts
- 6 miles starting from 90% of CP to 100% of CP - 270 to 300 watts
- 2 miles at 65-75% of CP - 195 to 225 watts
The course that our runner ran on had a very large uphill in the third mile and the pace drops 20 seconds for that mile. The wattage, however, remained consistent and they were able to finish exactly with the effort intended instead of burning themselves up too early in the run. On race they won’t worry about maintaining a harder effort at the same pace up a large hill, they’ll pace themselves with an even steady effort and make sure all their hard work is realized when they cross the finish line.
How to use your Power Meter for Pacing on Race Day
The half marathon is here and based on a recent CP test the runner thinks they can now run at 305w over the course of the half marathon. They set their watch to a 10-second watt average and set alerts when they go above 310w and when they go below 295w. They end up pacing perfectly based on effort and finish with a 1 minute PR and have averaged 307w!
How to Analyze your Power Meter Data after your Race
Our runner wants to learn a little bit more about their race and see where they might’ve been able to improve even more. The power looks extremely consistent with their lowest mile average being 298w and highest being 312w. They notice that their cadence dropped a few steps per minute in the middle of the race and their vertical oscillation increased a few tenths of a centimeter. Their form-power ratio dropped slightly during this section as well. They were over-striding in the middle and they might have been a little less efficient than they could have been. Now they know to keep it in mind for the next tempo run or longer race.
So that's what I have for a brief introduction to the practicality of training with a running power meter. Is it for everyone? No. Is it for people wanting to improve? Sure. I think the potential to improve your running with a power meter is immense and the technology is only improving day to day.