Some of the ERs can be stretched with the piriformis stretch... puts the hip in external rotation (makes the muscle shorter), but then pulling it into flexion allows the muscle to lengthen and stretch.
You can get the same result of ER stretch with the picture in the OP and piriforimis stretch variations in the post above mine.
Generally, IRs don't get too tight in the hip unlike the shoulder. ERs tend to get tighter because normally we sleep with the feet in slight ER + many of us walk with slight ER + do our lifts with some ER.
Last edited by Steven Low; 06-21-2009 at 11:07 PM.