LOWER ABDOMINAL MYTH
By Alice Lockridge MS PhysEd
Fitness instructor jargon perpetuates the misconception that “lower abdominals” is a muscle group. Because they believe the lower abdominal is a muscle, some instructors contend that "lower abs" need to be strengthened in some special way to attain a much-desired flat stomach.
The phrase "lower abdominals" implies that one of the abdominal wall muscles, the rectus abdominus, is lower than the others. This is not true. Each of the four-pairs of abdominal muscles has attachment sites on the pubic bones. No one of them is any lower than the others. And nothing lower than the pubis is part of the abdominal wall.
If the words "lower abdominals" refer to the lower half of the rectus abdominus, the implication is that the lower half of a muscle can contract without its upper half being affected. This is impossible. The structural construction of muscles won't allow contraction of only part of a fiber. When a muscle shortens - the whole fiber, along its entire length, is shortening.
Back to the Basics
To understand the abdominal muscles, it is important to understand the basics of all skeletal muscles. A muscle has at least two ends. These ends each attach directly, or by way of a tendon, to at least two separate bones. Each muscle crosses at least one joint. When the muscle contracts it either causes the joint between the two bones, to flex (bend) or extend (straighten). One end of the muscle, referred to as its origin, is usually stable and doesn't move. The other end, called the insertion, usually is the end that moves when the muscle contacts.
The meaty part of the muscle (belly) is made of fibers that stretch from the origin to the insertion. The long fibers in the rectus abdominus muscle go from the origin (on the ribs and xiphoid process of the sternum) to the insertion site (on the pubic symphysis). A concentric contraction, during a curl-up, is performed as the two ends move toward each other. The lower end, which is heavier, remains stationary, and more of the motion is noticed from the upper end (chest area) moving toward the hips. For full range-of-motion to occur on each repetition of the exercise, the muscle relaxes and allows its two ends to move apart and to regain its resting length.
THE
ALL OR NOTHING PRINCIPLE OF MUSCLE FIBER CONTRACTION
During contraction the two ends of the rectus abdominus muscle move toward each other, or one end can remain still while the other end moves toward it. They may switch duties, or they both may move toward the middle. But the entire length of the muscle fiber is always involved, regardless of which end is mobile. It's all or nothing. There's no isolation of just one half of the fiber.
The all-or-nothing principle pertains to the entire length of a muscle fiber, not to all the fibers of a muscle. One fiber may contract while a nearby fiber does not, but the fiber that is contracting is committed along its entire length. A muscle fiber cannot contract along only half its length.
Imagine a stretched rubber band representing the rectus abdominus. As the rubber band shortens to its resting length the entire band is involved in the shortening process. This is similar to the way the muscle contracts along its entire length. For one end of the muscle to move, it must be pulled upon from the anchored end at the origin site. Hence, the lower end of the abdominal muscle cannot contract without affecting the rest of the length of fiber.
SPOT REDUCING
Some believe exercises "for the lower abdominals" are those that make the bottom end of the abs move, like when the hips lift and the ribs remain stationary. This makes you "feel" the exercise below the waist where most people store some fat. Exercisers gladly try to feel the exertion near this spot because they believe that reducing will make the nearby fat be used up. This dangerous misconception perpetuates the belief you need to feel pain to gain effects.
If spot reducing is inherently linked to lower abdominal exercises then the entire concept is incorrect. Different exercises move either one or both ends of the rectus abdominus, but that movement does not denote fat above it is going to be used to fuel the movement. Nor does it mean that one particular end of the muscle is going to be strengthened or tightened more than the other.
Variety (for interest) is the only reason to switch exercises and emphasize
either end of the muscle. The variety is nice but not essential. Moving through the full range of motion is the best way to strengthen any muscle – there are only a limited number of ways to do it!.
All professional instructors need to apply these scientific principles to all of our Abdominal Wall Workouts and end erroneous "gym talk" about "lower abs".
“There’s no such thing as Lower Abdominals!” © Alice Lockridge, MS PhysEd
Alice Lockridge
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