With the arrival of affordable running power meters like Stryd, power has become an important metric in running over the past years. Now it’s time to unlock the power of your running power meter. Previously, power was only a number expressing your output. Today INSCYD links this running power to your individual physiology. The result: a human performance lab on your foot. You can now gain access to your aerobic- and anaerobic energy contribution, your fat- and carb combustion, your lactate production- and recovery rate and many more important metrics.. based on running power. Read how you can connect running power data with metabolic lab data – with or even without using a lab – and watch the recording of our webinar with Stryd.
BY LOEK VOSSEN
Benefits of using running power
This is probably not the first time you hear about running with power. I assume you’ve heard about some of the advantages, like:
- Power enables you to quantify exercise intensity and use it in training, racing and when creating a training plan.
- Power is a better measure for intensity than speed, because speed depends on incline, wind, terrain etc.
- Power is a better measure for intensity than heart rate, because your heart rate can differ per day. Heart rate data is not comparable with the heart rate of your friend and doesn’t respond quickly to changes in intensity.
Learn more about the benefits of using running power. Watch the recording of our webinar with Stryd
Even though these advantages help athletes to train and race more effectively, not all coaches and runners are convinced yet. Moreover, those who already use running power can experience a lack of connection between their power number and the actual physiological processes in their body.
In other words: currently, power is only a number expressing your output. You can link it to your threshold power (or citicial power, or run FTP) or you can track your maximum power over different durations, but that’s basically where it ends. There is no connection between your individual physiology and these running power metrics. But that changes from now on.
Here’s how INSCYD adds physiological meaning to running power, and makes it a must-have for every runner, triathlete and coach.
Adding physiological meaning to running power
With INSCYD you can add a whole metabolic lab to your power meter. Here are some examples.
Add substrate utilization to running power
What if you did not only have a power number, but also the carbohydrate- and fat combustion rate at that intensity. With INSCYD, that’s possible.
Here’s an example of an athlete who now knows exactly how much carbs and fat he/she burns, at any given running power:
Are you into (ultra) trail running? Then now you can use this information to determine how much carbohydrates you need to refuel at any given power intensity, to survive your ultra run.
Say your goal is to run at an intensity of 220 watts. In INSCYD, you can now hover over the graph and see that you’ll burn 100 grams of carbohydrates per hour at this intensity.
You could also turn it around and start with the substrate utilization. Maybe you want to know the running power that corresponds to the intensity at which you burn the most fat. The graph shows that this occurs at 195 watts (top of the green fat cumbustion line).
Another way to display substrate utilization based on running power is by looking at the substrate contribution, percentage wise:
As you can see, the percentage of fat combustion goes down to zero towards threshold power.
Are all these graphs a bit overwhelming? Why not start with adding substrate utilization to your standard (Stryd) power zones. Here’s an example of a runner with a critical power of 295 watts. The image shows the standard Stryd power zones (left) and the corresponding substrate utilization (right):
It goes without saying that these numbers are highly individual.
Learn more about carbohydrate combustion in relation to fueling (nutrition) and pacing via this article that includes a white paper. Or watch our webinar together with Stryd, to learn more:
Add energy contribution to running power
Here’s another “lab metric” that you can now add to your power numbers.
Let’s assume you ran a 5 km race. During the race you’ve produced 320 watts, while your threshold power equals 300 watts. Where did those 320 watts come from? Which energy system contributed to that power number?
Just because the running intensity is above threshold does not mean all energy came from the anaerobic energy system.
By adding (%) energy contribution to your running power (zones), you know the source of the power. This makes it easier to understand which energy system you rely on during a race.
Here’s an example of how that would look like for our example athlete in a 5 km race:
The image shows that when our example athlete runs a 5 km race at 320 watts, 287 watts (89%) are produced by the aerobic energy system and 34 watts (11%) are produced by the anaerobic energy system.
Similar to the fat and carbohydrates graph, you can also use the INSCYD software to get this information straight out of a graph. For steady state conditions:
As you would expect, the percentage of anaerobic energy contribution increases when running power increases.
Let’s assume “you get better at what you train for”. Then knowing where the power comes from helps you to understand which energy system you’re using – and therefore improving – during a training session.
For coaches, this is precious information when comparing athletes, because two athletes can run at the same power number, while not having similar energy contributions. This can be true, even if their threshold power is exactly the same.
Learn more about the possibilities during our webinar together with Stryd:
Add lactate values to running power
Although it goes beyond the scope of this article to talk about all the INSCYD physiological data that you can add to running power, let’s have a look at one more example: blood lactate concentrations.
Especially endurance coaches like to base training intensities on lactate concentration. But how do you assess the lactate concentration of your athlete when all you have is running power? With INSCYD you can do that, without needing to actually measure lactate during training.
If we look at the standard Stryd power zones in the image below (left) we can simply add lactate concentrations (right). In this case it’s the lactate concentration after 10 minutes of running on the target power. As you would expect, the lactate concentration at an intensity (way) above threshold (zone 5) results in an unrealistically high lactate concentration. In other words: this athlete is not able to run in this training zone for 10 minutes in a row.
Now you know what the lactate concentration of your athlete will be when he/she is running at a certain power. (These lactate numbers – like all other metrics mentioned before – are based on an INSCYD test. More about that in the last paragraph.)
As always, you can also turn things around. Want to know what running power would result in a lactate concentration of 4 mmol/l after 10 minutes? Here you go:
Now you might be wondering: how can I start adding more physiological meaning to my power numbers, as shown in the examples above?
How to get started
In the past, you used to either have running power data without a strong physiological backbone, or metabolic lab data that was not actionable for those who have a running power meter.
With INSCYD we combine these two worlds.
It all starts with an INSCYD test. You can perform this test in the field, using:
- A lactate analyzer and a running power meter like Stryd, or;
- A lactate analyzer and a (GPS) speed sensor, or;
- A (GPS) speed sensor only – which enables testing remotely.
You can also perform the test in a lab, using:
- A lactate analyzer and optionally: a VO2 analyzer and/or a running power meter.
Learn more about the INSCYD test, INSCYD software and practical benefits of using a power meter in racing and training. Watch the recording of our webinar together with Stryd.
Human Movement Scientist at INSCYD