Get a strong, lean back by doing a single arm row with a resistance tube. This back strengthening exercise works each side of the back equally with the same number of repetitions on both the right and left sides.
Assume start position as shown by placing resistance tube firmly under your left foot. Make sure to keep your back straight and bring your right leg behind you.
Hold handle with left hand and bend elbow up toward ceiling by squeezing your shoulder blade toward your spine.
Repeat with right arm (make sure to switch your legs as well).