We showed you the Y exercise for lower trapezius activation on a Swiss ball before. Once you have mastered this exercise, our favorite progression involves performing the Y exercise on the Roman Chair for the following two reasons:
1: Its a low back pain exercise. Isometrically holding this position on a back strong is the absolute best way to activate your deep spinal stabilizers, the Multifidus muscles. Recent research has demonstrated an extremely strong correlation between multifidus muscle dysfunction (weakness, delayed inactivation) and low back pain. So strengthen those multifid to help with you back pain!
2: Amazing activation of the posterior chain. Isometric hamstring and glut activation is necessary to maintain this position as well.
3: It saves time! Simultaneous work on shoulder stability (lower trap), back stability (multifidus), and posterior chain activation!