Abdominal Stability and Mobility

Abdominal exercises are ubiquitous in fitness literature. The anterior torso gets a lot of attention in fitness settings and may be the most problematic from an aesthetic perspective. We put on weight easily in this area and take it off with difficulty. Never mind that we cannot “spot reduce” body fat, exercises for the abdominal muscles are a central part of every fitness program, exercise magazine and book. Brooks writes: “How do you get washboard abs? Lose subcutaneous body fat by expending more calories than you take in, hope the fat is used from the abdominal area and choose your parents well.” Readers will notice that there’s nothing in Brooks’ quotation about abdominal exercises, but his book includes 12 exercises for trunk flexion. He also offers many strengthening exercises (extension movements) for the back and the hip joint, perhaps assuming that the back is inherently weak or that core stability means strengthening front, sides and back of the trunk. Perhaps we need a more functional look at the core muscles and an alternative exercise process.

Core stability is a watchword that focuses on anterior and posterior trunk weakness and instability. Core stability by itself is a limited concept. The human torso is designed for a combination of stability and mobility. Our bones and muscles facilitate a large amount of flexion, extension and rotational movements while fascia connects, stabilizes and maintains bony relationships. A healthy core is not just stable – it is mobile. And yet the majority of exercise regimens focus only on stabilization.

One reason for this emphasis may be the perception that a mover’s inability to extend the back from any position is due to weakness of those muscles. More likely, such weakness is due to tightness. Chronically shortened (tight) muscles neither lengthen nor shorten effectively and are thus limited in their ability to do the work of stabilizing or mobilizing. If both functions are valued, a balance of muscle function is needed.

In the western world, we are fond of simple solutions and like to think of the body as a collection of isolated muscles that can be treated without reference to one another. Dr. Vladimir Janda felt this was the wrong approach. “The motor system functions as an entity and it is, in principle, a wrong approach to try to understand disturbances of [various] parts of the motor system separately, without understanding the function of the motor system as a whole.” It’s a big order to understand how the body functions (is designed to move), but if we think beyond isolated muscle action and look at the relationships, we can make a good start – as well as work toward those washboard abs.

This article offers a new spin on abdominal strengthening. It describes a process and a sequence for dealing with the core muscles, front and back. It adds to the knowledge about abdominal strengthening and demonstrates ways to achieve more from abdominal exercises. As an end product, I will show how to increase abdominal muscle strength and achieve core stability/mobility by balancing the posterior and anterior muscle groups. The process is one of understanding anatomy in a relational way, clarifying the exercise sequence and attending to the movement and movement quality. The mantra is “stretch first, then crunch.”

Anatomy

The combined effect of the motion segments of the spine allows it to flex (forward bend) the torso in varying degrees at lumbar, thoracic and cervical levels. It is this flexion that allows for the ribs-toward-pelvis action in an abdominal curl and for raising the scapulae off the floor, both criteria for a good exercise. However, we have to remember that our bones are passive, not active members of a movement process. It is the soft tissues (muscles and fascia) that determine the location, degree and ease of movement possible in an otherwise healthy spine. Muscles play multiple roles in the body relative to gravity and the movement challenges of a bipedal creature – they cannot be considered equal or isolated actors. For the purpose of this article, I will focus on the postural muscles of the back and the phasic muscles of the soft anterior abdominal wall.

The Back Muscles

The quadratus lumborum, erector spinae group, rotatores and multifidi are the postural muscles of the back. Considered together, they range from the sacrum and pelvis to the base of the skull. The erector spinae group is the longest and the rotators are the shortest. As postural muscles, they oppose gravity and tend to be strong and tight. These muscles are always on call and active in standing, sitting up tall and bending forward, but they depend on movement through the full range of motion to function adequately. Tight muscles lack proper movement, reducing function both concentrically and eccentrically.

The Abdominal Muscles

Abdominal muscles that function as flexors of the trunk are the rectus abdominis and the internal and external obliques – the latter when used bilaterally. Along with a large amount of fasciae and aponeuroses, they form the soft anterior wall of the abdomen. These are phasic muscles that tend toward weakness and inhibition. They tend to sag in reaction to gravity, a pattern that is obvious in a large part of the population. They also tend to be obscured by overlying adipose tissue.

The rectus abdominis is the long, straight muscle that extends from the xiphoid process of the sternum and costal cartilages of ribs 5-7 to the pubic crest and symphysis. It lies on either side of the linea alba and has three transverse tendons. “This muscle acts during lumbar and lower thoracic flexion.” The internal obliques form an inverted V-shape and are angled diagonally from below upward originating on the thoracolumbar fascia, the iliac crest and inguinal ligament to insert on the inside of the lower ribs, the linea alba and the abdominal aponeurosis. Unilaterally, they rotate the trunk to the same side, and they flex the trunk bilaterally. The most superficial and the strongest of the diagonal muscles are the external obliques. They form a V-shape and are angled diagonally from above downward originating on the outside of the last eight ribs. They insert on the iliac crest, the abdominal aponeurosis and the linea alba. Used unilaterally, they rotate the trunk to the opposite side and, bilaterally, they flex the trunk. None of the abdominal muscles cross the hip joint; however, they may contract isometrically to help stabilize the torso in certain movements such as leg raises. The transversus muscle is not a trunk flexor but a compressor of the abdominal contents.

Hip Flexors/Extensors

The muscles crossing the anterior hip joint, specifically the iliopsoas group, the rectus femoris and the tensor fasciae latae, all serve to stabilize the hip joint in the hook-lying (flexed) position. They are not prime movers for the abdominal curl. A person with tight hip flexors may show an excessive lumbar lordosis, but this cannot be improved by a pelvic tilt or by abdominal strengthening on its own. Posteriorly, the gluteals do not act on the back muscles but are extensors of the hip against gravity. We should not expect that exercising these muscles would improve either core stability or mobility.

Relationship Between Back Tightness and the Abdominal Curl

Back tightness is problematic for an abdominal curl because it inhibits the contraction of the weaker abdominal muscles. As the mover with a tight back attempts an abdominal curl, the unstretched posterior muscles resist lengthening (eccentric action). This leads to incomplete shortening (concentric action) of the anterior abdominal wall muscles. The client tries to overcome these limitations by using excessive tension in the anterior neck and chest muscles or by using the hip flexors to raise the trunk. Abdominal curls become a tug of war instead of a smooth and effective recruitment of the abdominal muscles.

We get muscle definition from movement, especially resisted movement. Muscle fibers must shorten (do work) to increase in size. Without proper, resisted movement, there will be no strength gained and weakness may increase. To facilitate the action of the abdominals and improve the quality and the effectiveness of the curl, stretch the long back muscles to a normal resting length before attempting abdominal strengthening (stretch first, then crunch).

Balancing the Anterior and Posterior Muscle Groups

I strongly recommend testing the back muscles for tightness to learn if there is a front-to-back imbalance. The following two-person test is simple, reliable and useful in the training setting. The trainer instructs and observes while the client does the movement.

• The client sits tall and well back on a bench with the thighs fully supported. This position eliminates hamstring involvement that could invalidate the test.
• Ask your client to bring her forehead toward the mid-point of her thighs with no further hip flexion (i.e., pelvis remains upright).
• The client holds the position while the trainer observes her back in profile looking at the curve of the back from the waist (L5/S1) through the neck and head. The lumbar and cervical segments should lose their normal lordosis and flex somewhat. The thoracic segments should flex also to create a continuous curve in the lower rib and interscapular areas.
• If there is a perfect, continuous curve, the ROM of the postural back muscles is probably normal.
• If there is tightness in any area, the curve will be interrupted by flattened portions in any area (lumbar, lumbo-dorsal, lower thoracic, interscapular or cervical). The flat areas indicate muscular tightness. The degree of curve will vary among clients but the optimum shape does not.
• Observe not just the end result of the test movement, but the ease with which the client does the test. If the movement is stiff, halting or incomplete, even if it ends with a smooth curve, the muscles are not uniformly lengthened and should be stretched.

Stretching the Tight Back

If the above test shows back tightness, the trainer should teach a stretch that will lengthen those muscles. There are few effective back stretches in literature. A truly useful stretch targets specific fibers with body position, anchors one end of those fibers and draws the other end away with appropriate timing.

I have developed a three-dimensional back stretch that targets all of the postural muscles listed above (quadratus lumborum, erector spinae group, rotatores and multifidi) in one stretching exercise. Called 3-D Back Stretch, it has four stages. Each stage relates to the previous stage, creating a cumulative effect. It is due to this accumulation that the stretch of this large and powerful group of muscles is achieved. We should remember that the muscles listed also act unilaterally producing lateral flexion and rotation of the spine to one side or the other. Any stretch that acts on several muscles will be complex but the pay-off is excellent, so take your time and practice with a partner. The “trainer” reads the instructions which are written for the client and coaches the “client” through the positions.

3-D Back Stretch

Starting Position	Stage 1

• Starting Position: Sit cross-legged on the floor or sit on a bench with your feet well grounded. Sit up tall and rest your hands on the floor out to each side.
• Stage 1: Inhale and exhale. Contract the abdominals lightly and laterally flex torso and head to the right side. Raise left arm overhead with the shoulder relaxed and the left hip on the floor. This will target the left QL and erector spinae fibers. Keep your head and torso in the frontal plane with face to the front. Push against the floor with your right hand to help keep left hip down. Inhale and exhale again.

Stage 2	Stage 2 (Side View)

• Stage 2:Inhale. Maintaining the lateral flexion of Stage 1, exhale as you flex upper torso, neck and head with no rotation in shoulders. See side view of Stage 2 below. Think of softening in the sternum as you exhale. Take your raised arm with you into the flexion. Inhale and exhale again. The flexion occurs from the lumbar to the occipital base. The muscles targeted include the erector spinae group, multifidi and rotatores.

Stage 3	Stage 4

• Stage 3: Inhale. Maintaining the two previous positions, exhale as you rotate the left shoulder toward the right knee. Allow the left arm to relax diagonally downward in front of the knee. Inhale and exhale again. This stretch targets the deep rotator muscles. Your left hip must remain on the floor; this helps anchor the lower portions of the long back muscles.
• Stage 4:Inhale. Exhale and bring your torso to your midline and your arms to your sides, maintaining the flexion of cervical, thoracic and lumbar spines. Inhale. Exhale as you extend your back into an upright posture returning to the starting position. Repeat the stretch to the left, and again to the right and left sides. Each side with the breathing should take 40-60 seconds.

If you are doing this stretch on a bench, sit well back and arrange for the feet to be on the ground or supported on a stool. It is equally effective when done on a bench as on the floor (see photos). 3-D Back Stretch may be done by oneself, assisted by the trainer using a contract/relax (PNF) process, or coached using verbal and tactile cueing. Take care to be precise about the positions and the timing/breathing so that the back’s lateral flexors, extensors and rotators each have their turn at lengthening.

I recommend doing this stretch in a pre- and post-test format to appreciate its effect.

• Pre-test: Do a routine abdominal curl about 10 times.
• Stretch: Perform 3-D Back Stretch four times alternating sides.
• Post-test: Repeat the abdominal curls and the test for back muscle length.

Typically, clients will feel and the trainer will see the difference between the pre- and post-tests. What does the trainer look for?

In the curl:

• Increased ROM in trunk flexion
• Increased smoothness of movement, both concentric and eccentric
• Greater endurance
• Less anterior chest/neck tension
• Less strain in arms, chest, neck and chin

In the test:

• Improved shape of the back curve from lumbar to skull with reduction of the flattened areas previously observed
• Increased ROM; client can flex the trunk further toward the thighs
• Increased ease going into the test, i.e. getting there is easier

The personal trainers to whom I have taught this test and stretch find them a valuable addition to their programs. The two techniques resolve numerous frustrations many clients experience in working with the core muscles. 3-D Back Stretch is used by the Pilates instructors I teach to facilitate all of the roll down as well as roll-up exercises. For many clients of Pilates work, tight backs make these exercises very difficult and sometimes impossible to perform correctly. When they learn 3-D Back Stretch, they can move on to more advanced work and enjoyment of the process.

References:

1. Brooks, D (2001). Effective strength training. Champaign, IL: Human Kinetics.
2. Janda, V (1982). Muscles as a pathogenic factor in back pain. Proc. of IV IFMOT Conference, Christ Church, New Zealand.
3. Janda, V (1983). Muscle function testing. London: Butterworths.
4. Lewis, G (1988). Notes from tutorial sessions with author.
5. Woodruff, DL (2002).  Postural and phasic muscles: application to exercise protocols. PTontheNet.com, December.