Analyzing a running session is difficult. Indeed, multiple factors can distort the analysis, first of all the quality of the data.
The accuracy of GPS is at best 1%, or 10 meters per kilometer, or 2 to 4 seconds per kilometer for runners. This is in the best of cases, sometimes the accuracy is even worse, especially in the city with the reflection of buildings or in the forest.
In addition, heart rate, especially measured on the wrist with an optical sensor, is often not very accurate, even on high-end watches.
Beyond these measurement-related factors, there may be disturbances external to performance, in particular:
- The weather
- The night
- The surrounding environment: am I stopped at an intersection or by other users?
Factors intrinsic to the runner can of course also alter performance:
- The level of fatigue
- The level of stress in his personal or professional life
- Biomechanical problems in case of injury
We can have access to the weather, the time of day or other factors but it remains very complicated to give an analysis of a session without taking into account these different factors.
What is taken into account today
Science has shown the effectiveness of taking into account the feeling of effort of the runner, this is what we ask after the association of activities to the planned session. The feedback on the session is therefore based on this feeling, by comparing the feeling of effort expected and the one entered by the runner. This blog post goes into detail about what effort feedback is.
The overall data also allows us to calculate the training load, which we take into account over several weeks to establish your program.
In addition, training paces are primarily based on your past times and your target time. The competition is often more reliable to analyze because the factors mentioned above are often optimized on the day of the race: unhindered course, optimal level of fitness, excitement of the race…