Creating external rotation on a hinge movement can help recruit the deep 6 rotators and glute max as an external rotator to kick in and help produce more power in the sagittal plane.
Not only this, but creating more hip external rotation opens up the hip joint as it moves into hip flexion. Hip flexion with internal rotation is the closing down position of the hip, and is often the aggravating movement for any type of femoroacetabular impingement. Learning to create external rotation in this population should decrease the chances of anterior hip pinching on hinging movements.
Keeping the foot straight and creating rotational torque through the hips.
Think 'knees out'.
Then without resistance, but still with the rotation intention.