Stability Ball Back Extension

The stability ball back extension trains the spinal erectors, the glutes and the hamstrings by hinging over a ball and raising the torso back to a straight line. Using a ball rather than a fixed bench has a specific advantage: the curved surface supports the hips while leaving the spine free to move through a fuller range than a flat pad allows, and the instability adds a small continuous demand on the deeper stabilisers. It is a valuable counterweight to abdominal work, since training only the front of the trunk creates an imbalance the lower back eventually pays for. Stop at a straight line rather than arching beyond it, because extra range at the top loads the lumbar joints without adding muscular work. Add weight sparingly and only once the unloaded version is comfortable.