To target the sides of the torso, try this effective stretch.
- Sit on the ball with your feet slightly wider than hips-width distance apart.
- Place your right hand on the ball beside your right thigh. Keeping your hips pressing equally into the ball, raise your left arm into the air. Lean your torso to the right, gazing underneath your left arm, stretching through the left side of the torso. If it's easy, bend the right elbow slightly to deepen the stretch.
- Hold for a few breaths, lift the torso up, and then switch sides.