The term “core stability” has now become an everyday expression for most people working with low back rehabilitation. A large number of scientific publications exist in this field, particularly measurement and descriptive studies. However, there is a lack of clinical outcome studies demonstrating high methodological quality. Even today, there is little consensus about what “core stability” really is. Some perceive it as the deep stability provided by muscles close to the joints, while others claim that total activation of deep and superficial muscles is required to achieve sufficient intra-abdominal pressure to provide stability (25).