SuppVersity EMG Series - Rectus Abdominis, Obliques and Erector Spinae: The Very Best Exercises For Sixpack Abs and a Powerful Midsection
|Image 1: There is more to a strong core |
than just the m. rectus abdominis aka
'the abs' (red); its imperative to train your
obliques (blue) and the muscle strands
of the erector spinae muscles which
stabilize your spine (violette)
- the m. rectus abdominis (image 1, red), which consists of two parallel muscle strands that run vertically on each side of the anterior wall of the human abdomenis and are often simply referred to as 'the abs'
- the external and internal oblique muscles (image 1, blue), which pull the chest downwards and compress the abdominal cavity (external) also have a limited action in both flexion and rotation of the vertebral column (both) and cover the transverse abdominis muscles, which are located beneath the obliques and help to compress the ribs and viscera, thus providing thoracic and pelvic stability
- the muscles of the erector spinae (image 1, violette), which are of paramount importance to your life, because they stabilize and protect your spine
|Navigate the SuppVersity EMG Series - Click on the desired body part to see the optimal exercises.|
I. Training the m. rectus abdominis (aka 'the abs') & the oblique muscles
Six or eight packs - genetics or training? It is an urban or, I should say a 'gym myth' that you "progress from a six- to an eightpack" by training your abs until they hurt. The way your 'abs' look, which includes the number of packs, is determined by genetics and body fat level. The latter, by the way, is the reason why so many trainees believe they would just have to keep training until - almost magically - the 7th and 8th pack would pop up. While this does work for many people, it is not because of training-induced hypertrophy, but rather due to atrophy - adipocyte-atrophy, or fat loss to be precise. Especially the lowest of the six or eight packs tend to be covered by a very stubborn layer of stress-fat, that's why many peple begin to see them, when their training advances and their body fat levels drop.The EMG data from Boeckh-Behrens & Buskies also goes to show that even in the case of the rectus abdominis and the external and internal oblique muscles, true isolation is impossible. Everytime you engage in any type of core exercise both the central, as well as the lateral stabilizers or, in other words, the abs and the obliques will be working.
|Table 1: Top 12 ab- and oblique exercises; ranking according to Boeckh-Behrens & Buskies, 2000|
Perfect form counts, especially on the advanced movements
|Image 2: Trainees tend to (ab-)use the psoas major and thus decrease the activation of the 'abs', when doing leg raises, sit-ups etc. (image by Beth ohara @ Wikipedia)|
A perfect example of improper form compromising exercise efficiacy is the hanging leg raise, where, in the case of the upper part of the m. rectus abdominis, you can see that the exercise must have produced an extraordinarily high EMG activity in some, and a rather mediocre muscular activation in other subjects. Otherwise the ranking according to mean EMG for the exercise over all subjects (rank 2) and the mean exercise rank for the individual (rank 3) would be identical. Those of you who know how to do the exercise properly will know that even under professional supervision many trainees fail to actually flex their abs and thus train their psoas major (cf. image 2) instead of their abs, when they hang like a flabby sack from the bar and swing their legs up and down. A similar shift away from the m. rectus abdominis and towards the psoas, occurs in all ab-exercises where your legs are held in a fixed position, the most dreaded example being the classic sit-up, from which generations of trainees developed a hollow back (hyperlordosis); a pathology that cannot only entail lower back pain, but will also make your abdomen stick out even further, the result of which would be an untrained pair of abs that "sticks out" not in the intended metaphorical, but in the unwanted literal sense. Don't get me wrong, I am not generally against doing sit-ups, let alone leg raises (they are in fact among my favorite core exercises), I just want you to make sure, you are doing them right, so that you...
- do not get hurt,
- do not develop muscular imbalances, where despite or rather due to improper ab training your m. rectus abdominis becomes the weakest link and thus
- do not put yourself at danger of developing a (painful) hollow back and an untrained pair of abs on a portruding abdomen
Exercise tip #1 - the road to correct hanging leg raise: Done properly, hanging leg raises are the king of all ab-exercises, which does yet require practice and a core that is already pretty strong. Therefore I would suggest beginners start out with the lying leg raises with their hands or one of those pillows under their lower back for lumbar support. By trying to press their hands / the pillow into the floor in the course of the movement, they will develop the core stability that is necessary to progressI suppose, some of you may be disappointed, that exercises like the cable crunch or your favorite abdominal trainer have not made it to the list. While I think that many of the ab-machines share the same problematic psoas major activity as improperly executed hanging less raises or sit-ups, I count the cable crunch among the most effective ab exercises one can do.
- from the supported to the unsupported lying leg raises
- from leg raises on the floor to leg raises on a decline
- from decline leg raises to hanging leg raises
|Image 3: Exercise variation is key, especially for advanced trainees, who do not want to hit a plateau. Therefore, even self-proclaimed 'pros' should not back off from stability exercises like the side plank, which is the 2nd most effective exercise for the oblique muscles in the top 12 (image from www.everkinetic.com)|
Exercise tip #2 - Exercise intensity and the myth of high-rep-training for abs: In that it is important to accept that they may be no limit to the number of 1.25 pounds of weight you want to try to add to the bar every week, there certainly is one to adding another rep to the number of crunches, leg raises or side-bends you perform. In the case of the crunch, for example, the beginner would first have to practice doing the basic crunch right, to feel his abs working, to be able to stop half-way up or down and deliberately contract his muscles and to "peak-contract" his m. rectus abdominis until it hurts. The advanced trainee, on the other hand, will have to refrain from increasing the number of reps beyond a max of 20 reps. Instead, they should focus on increasing torque by eitherIf you are doing the right exercises and increase reps and then weights, incorporate advanced exercises and still do not see progress, I can tell, without even even knowing what you had for breakfast that it ruined your efforts in the gym. Having great abs is 75% diet and 20% whole body training and 5% ab training, remember that whenever you get the idea that doing another 100 sit ups or training your abs every day (every other day = max) would magically melt the fat away... you better save the time for some serious squatting, deadlifting or high intensity interval training if you want your abs to shine in their full glory. II. Training the erector spinae (focus on lumbar part) Contrary to having "great abs", which is probably the #1 on the wish-list of trainees in gyms all around the world, impressive erector spinae muscles appear to be way less popular in a world where the divide between morbidly obese exercise dyslectics and ripped exercise freaks is ever increasing. And while the former simply ignore that a strong lower back may save them from a whole host of minor ailments of will experience on top of heart disease, diabetes and Alzheimer's in their later life, the latter keep looking at their sixpacks and simply take for granted that the literal flipside of what they consider the epitome of a fit and healthy body (their sixpack) would look alike. Sometimes this may be the case, more often than not, those are however the same guys and girls who neither squat or deadlift, because they falsely assume that this would make them bulky. The EMG data by Boeckh-Behrens & Buskies goes to show that, due to this commonly held misconception many trainees miss out on the two most effective (hard-)core exercises.
- varying the position of his arms - beginner: hands support lower back; intermediate: hands on the chest / at the sides of your head; advanced: arms extended behind the head
- adding light weights - e.g. holding a light dumbbell in your hands when you do the crunch with your arms extended behind your head, on the leg raises you could use some of those weight straps for the ankles, etc.
- switching to more advanced exercises - properly executed hanging leg raises, for example, activate the upper part of the abs almost as effectively as crunches; they are the #1 exercise for the lower abs and #3 for the obliques; but they are difficult to do and require an already fortified core (cf. exercise tip #1)
|Image 4: Variations of the deadlift (here the romanian deadlift) are still the most basic lower back movements|
- Leg raises on the lying leg curl machine*
- Classic squat
- Hackquat machine
- Deadlift (100% body weight)
- Romanian deadlift (50% body weight)
- Partial Deadlift (50% body weight)
|Figure 3: EMG activity of erector spinae (lumbar part) during six selected core exercises with standard equipment relative to the "king of all exercises", the squat (data adapted from Boeckh-Behrens & Buskies. 2000)|
- the deadlift is the most taxing and at the same time most stimulating exercise for the muscles of the erector spinae, and
- the partial romanian deadlift (legs straight) is probably even more taxing and thus more stimulating than the "classic" deadlift (the EMG data seems to confirm that, as the subjects lifted 2-times the amount of weight on the classic deadlift, yet the muscular activation increased by only 76%)
|Image 5: The flutter kick with endcontractions & the pelvic lift, which is similar to the lying hip extension with the exception that you bend the free leg (100°) turn to be slightly more effective than the good old reverse extensions|
- Flutter kicks, prone position, with peak contractions
- Pelvic lift, knee angle 100°
- Hyper-/reverse extensions
- Bird (plank position, no arm activity)
- Sitting upright arms spread like an eagle
|Figure 4: EMG activity of erector spinae (lumbar part) during five selected body-weight exercises relative to the well-known hyper-/reverse extensions (data adapted from Boeckh-Behrens & Buskies. 2000|
III. Conclusion: 3 basic moves for a fortified core!
I suppose, there were not too many big surprises in this issue of the SuppVersity EMG Series, or at least I would hope so... you did not believe all those exotic contortions Men's Idiocy & co invent each spring to attract new readers would be worth doing. Did you? Some sort of crunch, some leg raises and one of the core (this refers to both your core as well as the core of your workout) exercises, i.e. deadlifting or squatting max 2-3 times a week is all it takes to fortify the center of your body. If you want the additional bonus of a shiny six (or eight-)pack, do at least as many squats and deadlifts as you do crunches, add in some HIIT (high intensity interval training) and stick to your diet.
|Image 6: You asked for it, here is the |
info - the ab-roll-out probably is probably
among the most effective ab-exercises, as well.
An EMG-optimized routine
There is of course a myriad of ways of combining the individual exercises, my personal recommendation for overall core development (based on EMG measures) would yet be as follows*:
- Crunches < 20 reps; vary arm / hand position or add weight + peak contractions to build intensity without going past max. 25 reps
- Leg raises < 15 reps; vary according to exercise tip #1; do at least one of your sets with your legs / torso rotating sideways, alternate left and right
- Deadlift variety 10-12 controlled reps; select the deadlift variety you feel isolates your lower back best
- Kneeling cable crunch < 15 reps; add weight whenever possible
- Side bends < 15 reps; add weight if necessary, be cautious not to bend over or go into hyperlordosis
- Hyperextensions** < 12 reps, with proper form + peak contraction; add weight if necessary