Try doing this in a loop starting out slow and building up speed. It gives my left hand a major work out since it's on the
lower strings and lower on the fretboard.
|---------------------------------|------------------------------------|
*|---------------------------------|------------------------------------|
*|---------------------------------|------------------------------------|
*|----------------------5-9-5-7-9-*|7-9-7-5-*--------------------------|
*|------3-7-3-5-7-5-7-9-*---------|---------9-7-5-7-3-5-7-5-3-*------|
*|3-5-7-*---------------------------|-----------------------------7-5-3-*|
*Rinse and repeat...*