Aerobic efficiency and the treadmill

Blog post by Marco Altini

What's aerobic efficiency again?

Aerobic efficiency relates to your ability to sustain a given workload. Good endurance athletes tend to have high aerobic endurance, meaning that they can sustain a relatively high workload (for example pace or power), at a relatively low effort (typically measured in terms of heart rate).

To determine your aerobic efficiency we compute the relation between output (pace or power) and input (heart rate). Intuitively, a lower heart rate for the same output (pace or power), when consistently shown over periods of weeks, translates into better aerobic efficiency.

Similarly, a higher power or faster pace at the same heart rate is linked to improved aerobic efficiency. By analyzing the relationship between input and output for running or cycling activities, you can easily track aerobic efficiency changes over time, as you progress with your training.

You can do so in HRV4Training Pro, under Insights / Aerobic  endurance.

How can you use this feature?

The  aerobic efficiency feature in HRV4Training Pro can help you better understand if your training is progressing well, without the need for specific testing. As you go for example from the off season to your base (or other) training phase, you should see your aerobic efficiency improve as your pace gets a bit quicker  at a given heart rate for example. 

Similarly, you could use aerobic efficiency to capture your response to environmental factors such as a training camp at altitude. During my research I have used exactly this principle for example to determine which athletes have or have not adapted to a training camp at altitude, based on their aerobic efficiency getting back to pre-camp values, or failing to do so  (you can learn more here).

Running on a treadmill

Running on a treadmill is different from running outside. Forces are reduced, ventilation is most likely poor, your stride might be a bit shorter, etc. 

Additionally, the hardware and software we use to track treadmill workouts and upload them to Strava or TrainingPeaks might estimate our pace with a certain degree of error. As a result, the relationship between heart rate and pace differs from outdoor running, to a point that it can create artifacts in our aerobic efficiency analysis.

For these reasons, we added a new control in the aerobic efficiency analysis in HRV4Training Pro, to let you filter out workouts with zero elevation gain reported, which is typical of treadmill workouts.

Giving  you more control

Below is an example of how this new filter works. First, you can configure your control panel to include mostly aerobic workouts based on duration and heart rate ranges, as well as environmental factors (temperature, altitude, etc.):

As you can see the control panel allows you also to filter out by elevation gain, which can be helpful if you run on trails from time to time, which typically provides data which is not particularly useful in the context of determining aerobic efficiency, due to the many variables involved (e.g. different terrains).

In this example, we had issues first due to an inaccurate footpod, and secondly due to either an overcorrection or simply the fact that as mentioned earlier, the relationship between heart rate and pace differs indoor:

This is something that can be now filtered out, using the "zero elevation" button:

Which gets us this:

As you can see the data now better reflects aerobic efficiency for this athlete, without artifacts created by running from time to time on a treadmill.

We  hope you'll enjoy the new feature. Use code SCIENCE for 15% off any plan at HRV4T.com