How do you do it and what is it usefull for?

How do you do it?

Measure out exect 100 meters on a straight path.
If you have the oppertunity try to do it on a flat surface AND on a uneven surface.

Try to ride the 100 meter path in walk and trot while counting you staps several times.

An other way you can try to do this is by measuring your time it takes you to ride the 100 meters

What is this usefull for:

If your know how many staps your horse makes in 100 meters you can use that when your map reading and have to know your distance until the place you have to turn right of lift.

In a higher level of TREC riding you will be using this aswell for the azimut tests