Sidebend is a great upper body strengthener through the shoulder joint and shoulder-to-ribs muscle call serratus anterior (to support the shoulder joint). Once that is stable, use the movement to sidebend your spine, engaging the smaller muscles closest to the spine that initiate a sidebend, as well as obliques, inner thighs, and quadratus lumborus. EVEN more than that, use this exercise to expand the ribs to facilitate breathing: whole body movement for expansive breath. 3 reps each side.
