Neck Rotation — For core training, always include rotational exercises and stretches, twisting and turning. (homefitnessguru.net)
It is important to exercise your spine in all directions, and incorporating rotational exercises in your core workouts will help to keep your spine balanced. (ab-core-and-stomach-exercises.com)
Many people neglect rotational exercises in their ab workouts, but I encourage you to strengthen your spine is all directions. (ab-core-and-stomach-exercises.com)