This is a great exercise to work all four fingers, as well as develop coordination between the strumming and fretting hand. As you ascend, try to keep your fingers down. For example, if you move from the 5th to the 6th, keep your first finger down on the 5th fret. 5th fret is played with first finger (pointer) 6th fret- 2nd finger (middle) 7th fret- 3rd finger (ring) 8th fret- 4th finger (pinky)
A disgusting fingering and string-skipping exercise. I do this about every 3 days and it helped a lot.