Let's embark on the truth about abs, and the illusion some create...
Do you remember straight leg lifts? Remember how they arched and stressed the low back? Remember how you felt the pull or burn in the front top part of your legs? The reason is because everyone started at end range. (The legs straight out in front) Why do you think people put their hands under the lower back while performing leg lifts? It is because the abdomen region is now working as a stabilizer to protect the lower back. What muscles are the prime movers in a leg lift? If you answered the hip flexor group, rectus femoris, psoas and iliacus you are correct. What no spot reduction, no lower abs? There are no lower abs in the human body -- that is geography not anatomy. However you can research a gentleman named Kendell who coined the term "lower abdomen region" which is different from training the upper and lower abdomen. Many articles can be found on Kendells research such as "Pelvic Floor Stability and Trunk Muscle Co-activation." We need to understand the safe range, what activates, and how to correct poor exercise techniques. If you are one of those who is currently doing leg lifts, please understand this fact; it will develop tight hip flexors, stresses the lumbar region (hence the hands under the back to protect) and will lead to many muscular imbalances. I almost forgot... I ask you... what's the goal? I bet some say stomach lower abs.
Another explanation would be: The legs are just extensions off our core, a moment arm. When you throw them out and away from the pelvis, it creates a pull on the pelvis. Moreover the rectus abdominis acts like a stabilizer to maintain congruence with the entire lumbo pelvic hip complex (hip region). Moreover it is now a stress and strain on the lower back and pelvic area, and a host of microscopic tears being created. We all must understand how to decrease specific disproportionate forces that trickle through the system and create muscular stress, strain and imbalances.
Heres another truth about the famous king's chair, queen's chair, or what you may know as the Bosu ball ab chair. You get up onto your elbows, and start lifting your legs up. This has nothing to do with abs. The truth is it was designed to sell health club memberships. People "feel" a strain as they lift their legs. This is predominantly the hip flexor group.
Think about the body's position while in an abs chair. There is no difference between the body's position in the chair or to the position of lying leg lifts (on the floor). However the risk elevates higher in the chair. Question: Why would you load your entire body weight on your shoulder joints, to stress your low back, and train your hip flexors?
Think about this... The rectus a long flat superficial muscle (six-pack abs muscle) originates on the pubic symphysis and the pubic crest, and it inserts (finishes) on the xiphoid process of the sternum and the 5th-7th costal cartilages. Its actions are to compress the abdominal contents to stabilize the spine, and flex the spine (pull it forward like in crunches). (Don't do crunches tell you later.)
The rectus, like the external oblique is a phasic muscle. All this means is that its primary role is to move the spine, and its secondary role is to stabilize the spine. The rectus provides most of the strength for bending motions in the spine. The rectus is the muscle that gives you the six-pack abs look. (When body fat decreases.) The rectus has white tendinous intersections -- inscriptions that divide the muscle into sections. Think of sitting bare butt in a strapped lawn chair. The abs only get their six-pack look from the thickness of the fascial tissue. I have clients who have 8 percent body fat with no "six-pack" no blocks because of their predisposition to thinner connective fascial tissue. Since the rectus is only anchored to bone at its ends, it does not have great leverage without the tendinous intersections. I ask again... after knowing the attachments and the actions, how can hanging strap leg lifts, or being in the chair lifting your legs concentrically and eccentrically contract the "six-pack"? This is another form of perception, sensation, marketing, and the ability to "feel" tension in a region. Is it wrong? No but it is super high risk, creates a host of muscular imbalances over time, activates the lats, and demands stabilization from the glenohumeral joint (shoulder). What was the goal? I think to train the abs? We can think of more beneficial anatomically correct movements for the goal of spinal flexion (abs). Do we need to flex the spine to get definition/ripped/shredded? No that happens in the kitchen! When we hang from straps, or lift our legs in a chair we are wasting our most precious commodity Time!
Let's keep going! Isolated rotations seem to be one of the most popular exercises in the gym. What are people thinking of when they are doing isolated rotations? They are all thinking spot reduction.
This is what the manufacturers of the products or machine companies want you to think. Then we go ahead and mimic the movement by doing rotations with a broomstick, or side bends with a dumbbell or 25-pound plate. Now that the medicine ball has been re-introduced in the fitness industry we have clients doing seated "disk grinder" rotations. How many degrees of rotation does the lumbar spine have in a "fixed" position? Moreover to make matters worse a trainer takes the client over to the decline ab bench connects their feet, as they grind and twist side to side. This is just another form of "perception" a new cool move to sell a medicine ball, or to alleviate boredom in a routine. Unfortunately it is a great way to add a host of orthopedic concerns over time. Remember there is no such thing as spot reduction. You cannot reduce inches or burn fat in any area by working that area. Think of this when you're shaving your legs, or face. When you cut yourself do you say, "Oh, man chin blood," or "leg blood"? Fat is like blood; it is systemic. When you move the body in specific ways it does not justify a reduction in girth, or inches. Stick twists, side bends with weights are in what we call a "tension under time block" 30-90 seconds... that is the goal of maximum hypertrophy (muscle building).
I ask you this, think about this intuitively: Who wants to build a blocky waist?
As a personal trainer did any client walk into a gym and ask to build his or her obliques? On a scientific level, when we talk about the microanatomy of muscle, and all the specific finite functions, 92 percent of the people in America have a deranged disk. Under safe micro-progressions it will strengthen, but you better not do a rotation, a side bend, or a medicine ball "Russian twist."
Dave Parise
CPT MES FPTA