Starting Position: Lie on your side on a mat with your legs and feet stacked. Both knees are bent to about 90 degrees and the knees are tucked up toward the hips. Your hips and shoulders are stacked and vertical to the floor. The spine and head are in a straight line. Reach your lower arm out along the mat at chest level. Wrap your upper arm around your trunk holding your ribcage. Engage your abdominal muscles to stabilize your spine. Pull the shoulder blades down toward your hips without moving your trunk. Try to hold these engagements throughout the exercise.
Gently exhale and begin to rotate your trunk by pulling the ribcage around with your upper arm. Try to keep the hips still. If your upper thigh slides backwards your hips are moving. Continue to rotate your trunk until you feel a comfortable stretch. Do not bounce or push. You should not feel pain. A deeper bend at the hips along with abdominal engagement will help prevent arching in your low back during the stretch. Grasping under your ribcage facilitates the rotation and stretch of the trunk and reduces stress in the shoulder joint.
Hold this position for 15 - 30 seconds then relax and return to your starting position. Perform 2 - 4 repetitions then repeat to the opposite side.
Progression 1: Straighten the bottom leg and rest the inside of the top knee on a small riser. In this variation, the top leg may rotate with your trunk. You will see and feel the top leg sliding backward during the rotation. Try to stabilize your hips while allowing rotation to occur only in the trunk.
Progression 2: Remove the riser place the top knee firmly on the floor. In this variation, the top thigh may lift off the floor and rotate with your trunk. Try to facilitate stabilizing the hips by pressing the knee into the floor and only allowing rotation to occur in the trunk.
Progression 3: Repeat the same exercise, but begin with both arms reaching out in front of your body at chest level. As you begin to rotate, bend the upper elbow, sliding it towards your trunk, then unfold the arm in the opposite direction at chest level as you continue your rotation and open your chest toward the ceiling. Rotate until you feel a comfortable stretch in the trunk and shoulder. Avoid arching your back or rotating your hips. This will increase the stretch in the shoulder and chest, in addition to your trunk.
To maximize the benefits of this stretch and reduce the potential for injury, it is important to follow the instructions provided carefully.