Graphs showing results of the 3 movements, flexion–extension, lateral bending and rotation. Means shown with standard deviations. Range of motion was increased when inducing a defect in AF and decreased when closing the defect, p < 0.0003. Neutral zone was also increased when applying the defect and decreased when closing it, but not significantly. Neutral zone stiffness also an indicator of stability in the motion segment showed deterioration when the AF was injured, but regained when the injury was closed.