Pace is a relative notion in running. Many parameters can influence the pace of your run, in particular the gradient of the terrain and also the surface: track, road, grass, trail, etc… Weather conditions also play a role in the performance and speed of a runner. The Grade Adjusted Pace takes into account the most important parameter: the steepness of the terrain.
What is Grade Adjusted Pace?
Speed represents the ratio of distance traveled to time elapsed. It’s often measured in miles or kilometers per hour, but runners typically express pace as minutes per mile or kilometer.
During a consistent effort going from flat to uphill, the pace decreases, however if one goes from flat to downhill, the pace increases.
It is therefore possible to adjust this real pace to take into account the change in gradient. It is the pace equivalent to running on a completely flat course.
How to calculate Grade Adjusted Pace?
The formula is:
Flat equivalent pace = Virtual distance / time
Flat equivalent pace = (Distance + k1 * positive elevation gain – k2 * negative elevation gain) / time
With k1 and k2 correcting coefficients. If you go uphill, it’s as if the flat distance was greater than the actual distance, and if you go downhill, it’s the opposite, it’s as if the flat distance was less than the actual distance.
k1 and k2 depend on the slope and are not equal, since we do not make up for the lost time uphill.
How does RunMotion Coach calculate this parameter?
From the activities we receive from Strava, or from your GPS watch, we have access to the gradient of the terrain and the distance. So for each lap or kilometer (or mile) we can calculate this flat grade adjusted pace with the formula above. Our research gave us coefficients k1 and k2 which best describes the influence of the slope.
The only limit to our calculations lies in the technicality of the course. The applied coefficients were validated in road races, that is to say on a hard surface and without any sharp turns.
On technical roads, or if the ground is muddy, the efficiency isn’t as good. It would therefore be necessary to add another corrective term to the virtual distance. It is possible that the grade adjusted pace is underestimated during trail running or cross country. The heart rate is therefore sometimes a more accurate indicator of the effort made on this type of terrain.