This stretch expands the chest muscles while lengthening the latissimus dorsi and serratus anterior muscles, according to Gallagher. Sit upright with feet firmly planted on the ground. Keep the spine neutral and place hands interlocked behind the head. Hold and allow the chest to open for three breaths, while the elbows open to the side. Exhale; laterally flex the spine on the left side – imagine the left side of the rib cage moving closer to the hip bone. Hold for five deep breaths, return to center and repeat on the opposite side.