You only need one simple tool to increase your arms mobility and flexibility of your thoracic spine: the foam roller. In this video, Point Performance’s Adam Gershowitz, DPT, illustrates how to use a foam roller to stretch your thoracic spine which increases your ability to bend backwards.
Start with the foam roller perpendicular to your spine. It is important to remember not to foam roll your spine beneath the rib cage.
Keeping your butt on the ground, begin to engage your abdominals. Place your hands behind your head and lean back until you feel pressure or stretching in the thoracic spine.
Hold the position while you take a nice deep breath and increase the stretch on the exhale. To attain the proper form, make sure not to let your ribs flair upward.
Repeat this four or five times alone your upper spine, you might need to hug yourself when stretching your upper spine to get your shoulder blades out of the way.