This exercise is intended to open up the front of the pelvis. The foam roller adds additional height to the pelvis to increase the stretch and provides a secure surface on which to place the pelvis.
To do this exercise you will need a mat and a foam roller. Start by lying on your back with the foam roller underneath your pelvis. The foam roller should be perpendicular to your spine. Hug one knee towards your chest and reach the other knee out long. Keep your heel connected to the ground. Continue breathing as you reach your leg long away for you. Continue breathing as you do a few ankle circles in each direction. Then switch legs to stretch the other side.
Things to think about
It is important to keep hollowing out the abdominals as you stretch so that your spine remains neutral as opposed to extending. Every time you exhale imagine rocking your pelvis away from your leg to add opposing forces.