The purpose of this article is to bring awareness that a six-pack rectus abdominus requires recruitment of the transverse abdominis to sustain abdominal strength in order to prevent separation of the linea alba.
The rectus abdominus development is a great show highlight, but be careful in equating that development to core strength. Why? Because for the most part in developing the rectus abdominus one may be off-setting development of the transverse abdominis (TVA) sheath of muscle beneath. The TVA acts as a corset that supports the lumbar spine.
Without equal attention to the TVA, the linea alba will (see picture below) soon begin to weaken causing the medial line of the left and right rectus abdominis to separate, causing pain and sometimes protrusion of tissue between the muscle walls.
What is Diastasis Recti?
This condition known as a gap between the left and right rectus abdominis muscles is called Diastasis Recti (DR). [1,2] (The condition, however has no associated morbidity or mortality and should be differentiated from an epigastric hernia or incision hernia, which can be ruled out using ultrasound.)
“The distance between the right and left rectus abdominis muscles is created by the stretching of the linea alba, a connective collagen sheath created by the aponeurosis insertions of the transverse abdominis, internal oblique, and external oblique.” 
Who’s at Risk for Diastasis Recti?
It’s common for babies to be born with DR, especially premature babies. Usually no intervention is required and the gap will close gradually as the baby grows.
Later in life the risk of developing DR increases for adults who:
- Are overweight in the abdominal area;
- Lift heavy weights incorrectly;
- Perform excessive and inappropriate abdominal muscle exercises;
- Are pregnant.
“Women are more susceptible to DR when over the age of 35, high birth weight of child, multiple birth pregnancy, and multiple pregnancies. Additional causes can be attributed to excessive abdominal exercises after the first trimester of pregnancy.”
The separation known as DR usually runs from the xiphoid process to the umbilicus resulting in a ridge running down the midline of the abdomen. It becomes more prominent with straining and may disappear when the abdominal muscles are relaxed. The medial borders of the right and left halves of the rectus abdominis muscle can be palpated during contraction.
Prevention and Correction of Diastasis Recti
DR is a symptom of excessive and unsupported intra abdominal pressure, the same state that creates other pelvic and abdominal problems including hernia and prolapse. Intra-abdominal pressure increases when performing exercises such as squats, dead lifts, crunches, and the like. In fact any resistance exercise when the Valsalva maneuver (forcibly exhaling while keeping the mouth and nose closed) occurs (which keeps the chest and shoulders firm and rigid, bringing greater support to the arms) will cause unnecessary intra-abdominal pressure.
Correct breathing has to be a conscious effort in weight lifting sports. If breathing is not performed correctly during weight training it will lead to potential serious problems such as a dangerous spikes in one’s blood pressure. Improper breathing such as the Valsalva maneuver will lead to core weakness and improper musculature contractions; and as previously mentioned will lead to stretching/tearing of the linea alba.
When DR happens to weight lifters there should be an integrated program designed to re-align, re-connect and then strengthen the entire core musculature, rather than be addressed in isolation (and rather than focussing only on ‘closing the gap).
The following is not to be done when DR occurs:
- Any exercise that causes the abdominal wall to bulge out.
- Certain yoga poses that stretch the abdominals, e.g. the cow pose, all back bends and belly breathing.
- Pilates movements such as spinal flexion, head float, double leg extension.
- Movements where the upper body twists, causing one hand to touch the foot while the other hand extends upward.
- Using an exercise ball to lie backwards.
- Flexing the upper spine off the floor against gravity.
- Abdominal crunches.
To help build abdominal strength, (which may or may not help reduce the size of DR) the following is suggested 
- Core contraction – In a seated position, place both hands on abdominal muscles. Take small controlled breaths. Slowly contract the deep abdominal muscles by pulling them straight back towards the spine. Hold the contraction for 30 seconds, while maintaining the controlled breathing. Complete 10 repetitions.
- Seated squeeze – Again in a seated position, place one hand above the belly button, and the other below the belly button. With controlled breaths, with a mid-way starting point, pull the abdominals back toward the spine, hold for 2 seconds and return to the mid-way point. Complete 100 repetitions.
- Head lift – In a lying down position, knees bent at 90° angle, feet flat, slowly lift the head, chin toward your chest, (concentrate on isolation of the abdominals to prevent hip-flexors from being engaged), slowly contract abdominals toward floor, hold for two seconds, lower head to starting position for 2 seconds. Complete 10 repetitions.
- Upright push-up – A standup pushup against the wall, with feet together arms-length away from wall, place hands flat against the wall, contract abdominal muscles toward spine, lean body towards wall, with elbows bent downward close to body, pull abdominal muscles in further, with controlled breathing. Release muscles as you push back to starting position. Complete 20 repetitions.
- Squat against the wall – Also known as a seated squat, stand with back against the wall, feet out in front of body, slowly lower body to a seated position so knees are bent at a 90° angle, contracting abs toward spine as you raise body back to standing position. Optionally, this exercise can also be done using an exercise ball placed against the wall and your lower back. Complete 20 Repetitions.
- Squat with squeeze – A variation to the “Squat against the wall” is to place a small resistance ball between the knees, and squeeze the ball as you lower your body to the seated position. Complete 20 repetitions.”
All corrective exercises should be approached by pulling in the abdominal muscles rather than a pushing of them outwards. A favorite exercise among strength trainers to correct DR is:
- Lie on your back, knees pulled in allowing feet to be flat on the floor
- Grab the left rectus abdominis with the right hand and the right rectus abdominis with the left hand.
- Perform a posterior pelvic tilt
- While the lower back is flexed to touch the floor, perform a crunch without lifting the shoulders off the floor and pull both sides of the rectus abdominis together while breathing out.
- Relax and breathe in, releasing the spine
- Repeat the crunch, again focusing on pulling both halves of the rectus abdominis together.
*Consultation of a professional physiotherapist is recommended for correct exercise routines.
In effect, the strengthening must come from the inside out; i.e. the TVA, the inner, deepest abdominal muscle. The typical crunches, sit-ups, bicycle crunches do not effectively engage your TVA.
Pushing the abdominal cavity outward will not develop the TVA. Rather, in addition to pushing your abdominal cavity outward which focuses only on the rectus abdominus there also needs to be a pulling the abdomen inward toward the spine which will develop the TVA muscle sheath, preventing the separation of the linea alba, i.e. DR.
1 Benjamin, D.R.; Van de Water, A.T.M; Peiris, C.L. (March 2014). Effects of exercise on
diastasis of the rectus abdominis muscle in the antenatal and postnatal periods: a
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2 Norton, Jeffrey A. (2003). Essential practice of surgery: basic science and
3 Brauman, Daniel (November 2008). “Diastasis Recti: Clinical Anatomy”. Plastic
and Reconstructive Surgery 122 (5).
4 Harms, M.D., Roger W. ”.Why do abdominal muscles sometimes separate during
5 Liao, Sharon (February 2012). “15 minutes and you’re done: crunch-free abs”. Real Simple (Time Inc.) 13 (2).
6 Engelhardt, Laura (1988). “Comparison of two abdominal exercises on the reduction of
the diastasis recti abdominis of postpartum women”. ProQuest Dissertations and Theses.
UMI Dissertations Publishing. Retrieved 10 June 2013.