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Abdominal Training

Abdominal Training For Bodybuilders

Regardless of whether you are on stage or at the beach, few things catch the eye quicker than a tightly packed midsection. History it appears would have us believe that ‘carved from stone’ abdominals were a trademark feature of warriors and gods long since past. Artists portray such characters as being muscular with chiselled midsections: Romans and Spartans come to mind. In modern times, bodybuilders are stepping on stage at up to 130 kilos, displaying thick ridges with deep grooves, completing their abdominal development. Aside from their aesthetic charm, the abdominals have an extremely functional role in providing stability to the core. Furthermore, they also play an important part in facilitating respiration. You already know that in order to see the abs clearly, the less body fat the better. As a rule of thumb, they generally become evident when a body fat level of about 10 percent has been reached. When you hit around the six percent mark, the obliques become apparent and grooves surface. Below six percent and you’re well on your way. As has been detailed many times before, this is one muscle that although they can be conditioned with the correct training stimulus, you will never see them if they are hidden underneath an insulating layer of subcutaneous body fat.

Basic Anatomy & Physiology of the Abs

The abdominals consist of four muscles: the rectus abdominis, internal and external obliques and the transverse abdominis. The rectus abdominis is located at the top of the pelvis and extends up to the lower ribs. It is responsible for bending the spine forwards and sideways, whilst also tilting the pelvis backwards. It is the rectus abdominis that provides the quintessential six or eight pack that everybody strives for. The second muscle is the internal obliques. This muscle is located beneath the external oblique and its fibres run at right angles, starting at the pelvis and running up to the lower three ribs. They are responsible for bending the spine forwards and sideways, and spinal rotation. The third muscle is the external oblique. This muscle lies above the internal obliques and its fibres run parallel, extending from the pelvis up to the lower eight ribs. They are responsible for the same muscle actions as the internal obliques. It is the obliques that when body fat levels are low enough, provide those parallel grooves above the outside of the hips. The fourth muscle is the transverse abdominis. This muscle is the deepest of the abdominals and extends across the abdomen in a horizontal direction. It starts at the front of the pelvis and the lower six ribs, whilst traversing around to the rear of the pelvis. It assists the spine in bending forwards and is one of the target muscles activated isometrically (tension without movement) in core stability training.

Advanced Anatomy & Physiology of the Abs

The abdominals consists of four muscles, which are as follows: Rectus Abdominis (rectus = straight & abdom = abdomen) - The rectus abdominis originates on the pubic crest and symphysis. It inserts onto the xiphoid process and costal cartilages of the 5th and 6th ribs. It is responsible for the following muscle actions:

  • Spinal joint flexion,
  • Spinal joint lateral flexion, and
  • Pelvic girdle backward tilt.

Internal Oblique (internal = inside & oblique = running at an angle) – the internal oblique originates on the iliac crest and inguinal ligament. It inserts onto the linear alba and lower three ribs. It is responsible for the following muscle actions:

  • Spinal joint flexion,
  • Spinal joint lateral flexion, and
  • Spinal joint rotation (same side)

External Oblique (external = outside) – the external oblique originates on the lower eight ribs and inserts anteriorly via the abdominal aponeurosis onto the linea alba. Additionally, some fibres insert onto both the iliac and pubic crest. It has the same muscle actions as the internal oblique. Transverse Abdominis (transverse = running straight across) – the transverse abdominis originates on the inguinal ligament, iliac crest and the costal cartilages of the lower six ribs. It inserts via the abdominal aponeurosis and linea alba. It is responsible for helping in spinal joint flexion.

Exercises For Abdominal Training

The following table identifies exercises for the rectus abdominis and the percent (out of 100) EMG activity:



Weighted incline crunch


Bench crunch


Weighted crunch


Ab roller


Nautilus crunch


Pulley crunch



The aforementioned exercises are but six of a wide variety available. We were unable to locate MRI data for abdominal exercises and consequently, are unable to provide further direction as to the best exercises to choose. However, a plethora of information that details findings of controlled studies that have utilised variations of EMG is available. The most prevalent findings seem to indicate that in addition to those abdominal exercises already listed, the following exercises, in order, initiate the highest mean percentage of EMG activity for the rectus abdominis:

  1. Bicycle manoeuvre (248%) – in the supine position bringing the opposite elbow to opposite knee.
  2. Hip flexor machine (212%) – although the primary muscle action here is hip flexion, which is initiated by the psoas muscle, the recruitment is still particularly high.
  3. Fit ball crunch (139%) – raising the torso to no more than 45 degrees.
  4. Vertical leg crunch (129%) – supine position, hands cradling the head for support, legs fully extended in the air, lifting the torso towards the knees.
  5. Reverse crunch (109%) – supine position, hips and knees flexed at 90 degrees. Cross the feet over, press the lower back into the floor and your hips will rotate slightly, your legs will reach toward the ceiling.

In contrast, the best exercises for the obliques based on current literature would suggest the following:

  1. hip flexor machine (310%).
  2. bicycle manoeuvre (290%).
  3. reverse crunch (240%).
  4. vertical leg crunch (216%).
  5. fit ball crunch (147%).

It is worth noting that the aforementioned figures are listed as a percentage of the activity of a traditional crunch, which yields an EMG score of 100%. For example, the bicycle manoeuvre for the rectus abdominis yields a 148% greater activity than the traditional crunch. Contrary to popular belief, it is not possible to isolate the upper or lower portions of the muscle. The rectus abdominis is one continuous sheath; therefore, the entire muscle is activated, although in varying degrees, by all abdominal exercises, irrespective of whether the muscle action is spinal joint flexion or hip flexion.

The Final Word on Ab Training

The rectus abdominis has predominately fast twitch muscle fibres, meaning it responds favourably to high intensity and high speed movements. In addition to those exercises already listed, cable woodchoppers and explosive plyometric medicine ball exercises are highly recommended. If you’re still doing 500 sit ups a day and wondering why you’re not getting anywhere, you might want to re-evaluate your methods. Furthermore, ensure your body fat levels are low enough so you can showcase your hard work.

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