For most people, specific-training ab routines include a variety of spinal flexion movements designed to emphasize the rectus abdominis, the vertical muscles on the front of the core (rectus = erect). In the weightroom, these include familiar exercises such as crunches, reverse crunches, sit-ups and Roman chair leg lifts (although the chief emphasis ends up going to the hip flexors in such leg lift exercises more often than not). In the yoga or Pilates studio, they include a variety of V-sit exercises. While all of these may, if performed properly, leave your core stiff and sore the following days, if these make up your entire abs routine, there is an important abs muscle that you are neglecting — transverse abdominis.
The transverse abdominis runs horizontally, in the transverse plane of the body (trans = across). A simple way to think of it is that it acts like a belt, drawing your entire core in more tightly to your vertical midline. And that’s exactly what you want in order to give your waist a narrow appearance. The exercises for this ab are different from the ones mentioned for the other abs. They may not sound like much and certainly won’t look as dramatic as, say, your big bench or monster squat. But if you’ve been doggedly crunching away and still don’t want anyone seeing your exposed belly until you’re good and ready, training the TA may be exactly what your program needs.
Most people have some innate sense of how this muscle works, and proof that it’s the key to a great midsection is right there. Think about the old phrase “sucking in your gut“. When people who have no idea how to work out want their tummies to look good, they instinctively try to draw in their abs like the Frank Zane vacuum pose. This movement bears no resemblance to a crunch-type movement. They do not bend over. Their hip flexors remain neutral. The only bodypart they try to affect is the TA. And crude as it may look, bodybuilders take notice: they’ve got something there.
The TA is a deep layer of horizontal muscle fibers that does not appear to be directly involved in joint movement. This muscle can indirectly add to spinal support by providing belt-like opposition to intra-abdominal pressure, which creates a column of support for the spine as well as the trunk area (NASM, 106). In order to work the TA, then, concentrate not on challenging spinal flexion but rather spinal stabilization in neutral alignment.
Begin by becoming aware of this muscle. Sit upright on a bench. Have a partner face you, place both of his hands on your shoulders, and gently push you backward (gently!). Your goal is to maintain your upright position, not allowing your spine to extend/your back to arch. Your TA will kick in to achieve your goal.
Here’s a visualization to help you zero in on this muscle: imagine you are pulling your belly button into your spine. Place your hand on your belly button and try it, and you’ll realize what a dramatic difference actuating this muscle makes. Strengthen it, and you’ll have just that much enhancement to the appearance of your midsection.
Here’s something you can do while you’re driving. Whenever you hit the brake, contract your TA. The momentum of moving forward will provide tangible, manageable resistance. This is a great way to get in some TA work in daily life.
Keep the exercises distinct from your other ab and core exercises. You may perform them in the same workout, and indeed you should keep your TA tight throughout most of your exercises as a rule. But set aside a few specific moves to devote to training your TA alone. Train your belt on the inside, and you’ll be tightening up the one on the outside.
Exercise 1: The Cross
Stand upright with your arms straight out to your sides. Bend slightly at the knees. Position your spine in optimal neutral alignment. Now contract your TA in reps, using the visualization above. Push your belly button into your spine. No kidding, this alone can be very taxing, with proper form and energy.
Exercise 2: Cable pulldown
Attach a rope handle to an overhead cable pulley. Select weight, face away from the machine, and pull the handle down so the rope is resting comfortably over your traps. Kneel on the floor, holding the rope tightly in place. Maintain an erect posture from the knee up. Now are you are ready to begin the movement. Pull in your belly button as before, and allow that contraction to pull your torso down slightly and your navel up slightly. The key is slightly! Your hips should not flex at all. This is a very small movement, but done properly, it engages the entire abs group, and is a real smoker.
Exercise 3: Hanging TA
Suspend your body, using elbow slings or simply gripping neutrally positioned pull-up handles. This is similar to the cable pulldown; maintain a neutral posture, keep hip flexors relaxed, and contract the TA first, pulling the rectus abdominis with it.
Exercise 4: Ball Toss
This is a very advanced exercise. Be sure that your TA is adequately strengthened through the above exercises before attempting it. Use a decline bench. Anchor your feet under the rollers. Sit upright. Align your spine in a strong neutral position, activate the TA, hold the contraction and have a partner gently toss a lightweight (three to five pound) medicine ball to you, aiming at your stomach. Catch and toss it back to her. Repeat. Resistance can be increased by leaning back at the hip and by your partner aiming higher. Use your partner to monitor your posture. It is far too easy to relax the spine into spinal flexion, exaggerate the natural curves in the spine, and flex the hip joints in order to accomplish the ball handling. But to catch and return the ball is not your main goal; your goal is to maintain a neutral spine and keep your TA contracted constantly while handling the ball. Do it right, and it’s a killer.
National Academy of Sports Medicine Personal Training Certification Manual, 1999.