It is important to stretch your left hand when playing the mandolin to avoid injuries. Learn tips on how to do this technique correctly from a mandoliAn player in this free video clip.
This next exercise keeps your middle finger planted and you move up the neck. You are going to start on the fourth fret and it is similar to the first exercise. So that is the whole exercise, keeping your middle finger planted and it is trying to move just the finger that is moving so trying to keep that pinky from flailing around, any extra movement not necessary.