Nearly everyone is familiar with the “six pack” portion of our abdominals, i.e., the rectus abdominus; but, right next door in the shadow of the six pack are external and internal (abdominal) obliques and the transverse abdominals (tranversalis) on the sides of the waist and wrapping horizontally around the torso from front to back and near vertically from the ribs down to the pelvis. The muscles need to be attended by appropriate exercises too because they collectively work as a natural weight belt, responsible for assuring a stable core by increase intra-abdominal pressure necessary for the support of the vertebral column. They also compress organs and make possible forceful inhalation and expiration.
Aside from engaging these core muscles during big lifts – like deadlifts – one can train them directly through exercise for certain articulations of the spine.
Flexion is the term bending the spinal joints resulting in a decrease of angle so that the upper torso necessarily moves toward the pelvis.
Exercises for flexion of the spine include sit-ups, crunches, knee raises, and leg raises. Normal executions of these movements utilize primarily the rectus abdominis with secondary employment of the obliques. However, emphasis can be shifted to the obliques and tranversalis adding a twist into their performance.
Alternate twisting knee raises turn a familiar crunch into an oblique-oriented exercise. For this, place your cupped hands against your ears. As you squeeze your stomach muscles to crunch, simultaneously draw one knee up toward the opposite elbow, breaking one foot’s contact with the floor. Relax and repeat with the alternate knee and elbow.
Spine Lateral Flexion (Abduction) and Spine Reduction (Adduction)
Lateral flexion (abduction) is lateral movement away from the midline of the body; moving the spine to the side (left or right); the upper torso moves to the side toward the pelvis. Reduction (adduction) is a return to the start from lateral movement.
Exercises for lateral flexion and reduction of the spine include side bends (dumbbell or cable) and side crunches.
Dumbbell side bends, for example, are pretty straightforward. Simply stand with dumbbells in hand hanging at your sides. Bend laterally, allowing the dumbbell to move down the side of your leg, as far as comfortably possible to one side, pausing briefly, then returning to an upright position and repeating to motion to the other side.
Side crunches, with or without a Swiss ball, require lying on your side and driving the high shoulder (the one further from the floor) away from the floor, working the obliques. Switch to the other side and repeat.
Rotation is rotary movement around the longitudinal axis of the spine thereby rotating the torso to one side or the other.
Exercises for rotation of the spine include the various versions of trunk twists.
Cable trunk twists start with you seated or standing at an adjustable cable station. Using a one-hand grip attachment for the cable, you can either use both cables and alternate twisting from side to side against resistance or use one cable at a time performing multiple repetitions to the same side before switching.
Lying trunk twists can be performed lying on a Swiss ball with a medicine ball, dumbbell, or other source of resistance held over your chest. While keeping your lower body in place, twist your upper body to one side (with whatever might be held in your hands moving to the side too), and then twist to the other side.
By performing exercises for these articulations, you will effectively target both the oblique and transverse abdominals.