The purpose of the Running Efficiency score is to compare your measured VO2 Max of your most recent run to your 90-day average VO2 Max measurement. Efficiency represents the performance of a singular run, rather than being a measurement of your overall fitness. This score will have a much higher correlation to how fast (pace) your most recent run was, compared to your average run speed (pace). You can also think of this as an equation (Today's VO2 Max/90-day avg. VO2 Max = Running Efficiency), this is a short-term, acute, measurement.
Here is some important information to keep in mind when it comes to the Running Efficiency score.
- It is necessary to have 2 minutes+ of constant or steady running data throughout your run, these 2-minute intervals will be counted as one data point. For example, a 1 min interval and 1.5 rest will not be counted as a valid data point.
- There is an "invalid data" filter designed to ensure the accuracy of the Efficiency score. This filter measures over the course of one minute to make sure the change of heart is not greater than +/- 10 beats, and the change of pace does not exceed 1.08km/h (0.671 mph). Data with greater variance than mentioned above is difficult to measure accurately and for that reason, we have chosen to exclude it.
- Only runs with a significant amount of time spent in the 70-90% maximum heart rate range will be counted as valid data. Heart rate values higher or lower than this range create a much higher error margin when estimating Efficiency (and related) metrics.
- The Running Efficiency algorithm only counts running data from the first 10-40 minutes of a run. The reason for this is that, in the later phases of a run (40+ minutes), there are many more factors that affect performance and estimation abilities. We would like to eliminate these uncertainties which is why only the first 10-40 minutes are assessed.
For more information on related topics, visit: Running Efficiency Explained