When you calculate your future hiking stages or want to know the number of kilometres we covered during our last walk we tend to simply calculate the distance between the starting point and the ending point.
Mistake!
When hiking, not all kilometres are created equal.
Far from there.
Five kilometres of walking on a flat towpath, near a canal, does not require the same effort as the same distance climbing in the mountains.
However, in both cases, you will have made 5 terminals.
This is where this new unit of measurement comes in, which makes it possible to compare the incomparable: the kilometre effort!
What is it exactly?
The kilometre effort comes to us originally from the mountain/trail raid, but finally adapts to a large number of outdoor activities… including walking!
The concept is simple: it is a unit of measurement that takes into account the distance travelled, but also the elevation.
It is also abbreviated to km/effort, km-effort or even km-e.
What is the drop?
The difference in altitude is the difference in altitude between two given points.
We talk about positive elevation when it goes up… and negative elevation, when it goes down.
Let’s take a concrete example:
On this course, we have:
- On the first stage, we have an elevation gain of +50m; i.e. an altitude difference of 50m between the low point (the bottom of the valley) and the high point (the top of the valley)
- On the last stage, conversely, we have a negative elevation of -35m.
On a complete hike, we generally calculate the cumulative elevations (i.e. added to each other):
- 50 + 5 + 50 = +105m of cumulative elevation gain (D+)
- 30 + 30 + 35 = -95m of cumulative negative elevation (D-)
There is also the notion of “global drop” which is the difference in altitude between the starting point and the end point of your hike… but I find that it is of no real interest as far as we are concerned, because it is quite possible to spend your day climbing and descending, and finally have an overall drop close to zero.
Ok… and what does this have to do with the kilometre effort?
Climbing a hill or descending a steep slope requires additional physical effort compared to walking on the flat.
It is therefore not logical to compare a walk of 10 kilometres on the flat or 10 kilometres in a hilly landscape.
Hence the kilometre-effort which is, as a reminder, a unit of measurement distinct from the kilometre, since in addition to taking into account the distance, it also takes into account the difference in altitude.
In other words :
- 10 kilometres on the flat are worth more or less 10 kilometres-effort,
- But!… 10 kilometres in a hilly landscape, and a fortiori in the mountains, correspond to many more kilometres-effort!
How to calculate a kilometer effort?
To do this, you will have to take out your calculator… but I assure you, the formula is simple!
Here are the three rules to add:
- One kilometer = 1 kilometer-effort
- 100m of cumulative elevation gain (ascent) = 1 kilometer-effort
- 300m of cumulative negative elevation (descent) = 1 kilometer-effort
Note: Some do not calculate the negative elevation… others do. I am one of those who calculate it, because a very steep descent sometimes requires more effort than a hill… especially at the end of the day!
Example N°1: 15km hike
Let’s take the first example: a 15.05km hike in the Vercors National Park (in other words… the mountains!).
This hike is a round trip and offers 1182m of positive cumulative elevation gain and therefore 1182m of negative cumulative elevation gain.
According to our calculation method, this will give us:
- 15.05 kilometers = 15.05 kilometer-effort
- 1182m of cumulative elevation gain (ascent) = 11.82 kilometer-effort
- 1182m of cumulative negative elevation (descent) = 3.94 kilometer-effort
Total: 30.81 kilometres.
This hike is given as very difficult and its duration is estimated at 7h40.
Example N°2: 15km hike
“Another 15km?!…”
Well yes, you see me coming…
This time, we will take the example of a hike around the Island of Houat (in Brittany… in other words, flat flat flat!).
This hike is a 15.08km loop, the high point is 25m and the low point is 0m. The cumulative positive elevation is 55m and the cumulative negative elevation is also 55m.
Let’s calculate:
- 15.08 kilometers = 15.08 kilometer-effort
- 55m of cumulative elevation gain (ascent) = 0.55 kilometer-effort
- 55m of cumulative negative elevation (descent) = 0.18 kilometer-effort
Total: 15.81 kilometres.
This hike is considered easy and can be done in 4.5 hours.
In conclusion?
We can never repeat it enough… Not all kilometres are created equal.
I mentioned here the impact of the difference in altitude on the difficulty of the hike, and therefore the impact that it will have on your fatigue and on the number of kilometres you can walk per day but we should also talk about many other factors:
- The weather/season/temperature: walking in the dodger or in the rain will require more effort.
- The quality of the path: a beautiful well-marked path or crossing in the moors will not require the same effort here too.
- Etc.
Also, I could have told you about my own invention which is the “kilometre-fatigue”…
The idea? Every kilometre after the 25th counts double and counts triple after the 30th!
