A bass run is a sequence of bass notes which occur between two chords. Many bass runs begin on the root note of the first chord and lead to the root note of the second chord. In the following fingerpicking example, a bass run is used to connect the chords C to F and back again. The first bass run uses the bass notes C - D - E and F to ascend from the C chord to the F chord. These notes are then reversed to descend from the F chord to the C chord.
Bass runs are also commonly used when playing pick style accompaniments, as shown here. This example could also be played using right hand fingers for the upper notes and thumb for the bass notes and runs.
The next example uses bass runs between the G, C and D7 chords. This time the bass run is played as the picking pattern is continued with the right hand.
This example makes use of both bass runs and arpeggios. It can be played either with a pick or fingerstyle. Hold down the chord shapes indicated as much as possible except when playing notes which are not in the chords.