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Why 90% of People FAIL the LOWER ABDOMINAL Test

Written by: Nick Jack
Category: 2014
on 21 October 2020
Hits: 2186

If you have read any of my previous articles about core training you would know that I am not a big fan of isolated abdominal exercises. I have often stated most core training exercises and programs are highly over-rated and create more problems than they solve. However, the question that often comes up is why do I use the lower abdominal test as part of our assessment? And why do I often prescribe it as an exercise to do at home with most beginners? It seems like a complete contradiction that I often rate isolated abdominal training very poorly, yet I still use an exercise like the lower abdominal leg test. There are several reasons for this as I will explain in great detail today. But the most interesting fact with this exercise is that 90% of all clients I test in our assessment fail! And it is the reasons they fail that find this exercise very useful.

Why Do People Use Lower Abdominal Exercises

There are two main reasons people see a need to exercise the lower abdominal. The first one is to have the flat washboard abs that we see on magazine covers. The second is to improve core stability for prevention of injury.

The damaging effects of the COVID lock-downs are now starting to fully show in many people who have not been eating well or exercising and now the dreaded "muffin top" is sticking out over the top of the pants! We have been convinced that to fix this problem all we need to do is isolate the abdominal muscles with specific exercises to make it stronger and more toned.

Anyone with even the slightest knowledge in strength training will know it is impossible to spot reduce, yet this information seems to be ignored by the masses who still pound out hundreds of reps of abdominal exercises in the belief it will make their abs look better.

The other reason we regularly see exercises like this used is to treat back pain or used as an injury prevention method in the belief that stronger abs prevent back pain. Unfortunately, the strength of the abdominal muscles is not important and this approach is very rarely successful. The reason for that is it WILL NOT change the faulty movement that is causing your injury, which with most back injuries is to do with bending. The body will instantly sacrifice any strength it has if it only knows how to move with the same dysfunctional movement it has always used.

The secret to all injury and rehabilitation programs is to identify and change the faulty movement patterns causing instability and pain to joints. You can read more about this in the article – Why having a strong core will not prevent back pain

Now that we know why people love to train their lower abdominal muscles let’s take a closer look at the exercise I use as a test to see how it works and why so many people fail.

How to Do the Lower Abdominal Test

  1. Lying on your back with a blood pressure cuff or your hand place underneath your low back at belly button level.
  2. Bend your knees to 45° raise both legs in the air keeping the knees bent. Pump the cuff up to 40mm/hg draw your belly button inwards and slightly rotate your pelvis backwards which will flatten your low back into the cuff rotate your pelvis to the point where the pressure in the cuff raises to 70mm/hg. (If you do not have a cuff rotate your pelvis until you feel a light pressure on your hand).
  3. Lower both legs back to the floor maintaining the pressure on the cuff. The pressure on the cuff should not vary greater than +/- 5mm/hg throughout the exercises.
  4. Failure to do this means you fail the test!

I like to use this exercise as a test with people on the first day for it tells me several things about how they move. I tend not to think of it as just a simple strength test, but more as a way of assessing how they choose to provide stability to their pelvis and spine.

The things this one test can tell me are:

  • If they know how to breathe correctly to create intra-abdominal pressure
  • If their hips are more dominant than their abdominal stabilizers
  • How much their posture is affected by the way they stabilize
  • If they have good coordination and body awareness
  • If compensation is likely with other more functional movement

Often this test will become their first homework exercise and I will explain to them why they failed and show them what they need to do to become better at it. Far too many people focus on planks and sit-ups to improve abdominal strength which only seek to further weaken the lower abdominal. This brings me to the point that is always brought up when I mention lower abs.

Do The Upper & Lower Abs Even Exist?

There is a lot of controversy surrounding upper and lower abdominal muscles. There is one school of thought that believes you cannot activate only a part of the rectus abdominous, whereas others believe that you can, pointing out that the upper part is more dominant over the lower part.

In Dr Stuart McGill's book "Low Back Disorders" this is something that they spent considerable time researching in the lab with EMG devices across many movements to see if only one part of the abdominal muscle activated. What they found is that a distinct difference between an upper and lower rectus abdominous does not exist in most people.

Once force is required the rectus abdominous appears to act as a cable with active tension upon its entire length. This means that in theory you could train this muscle with one single exercise. As opposed to the obliques that are involved in multiple angles and positions.

See the article - To Strengthen The Obliques You Must Understand Their Purpose

However, their research did show that the level of activation within the rectus varied considerably depending on the movement being used and that certain part of the trunk were more prone to stiffness and shortening than others. The way the rectus interacted with its various partners during movement plays a massive role in it performing its function of providing stability to the pelvis and the spine.

What this means is that while the rectus is one single muscle the strength of the muscle and influence on various movements can vary greatly depending on its use.

Before going further we need to explain what these muscle partners are and this is where you need to understand the core is made up of both the inner unit and the outer unit.

The Inner Unit & the Outer Unit

What people fail to understand is that your abs are unable to move you, other than making you wiggle or flop around like a fish out of water. You need your arms and legs to move you for your abdominal muscles are not capable of doing much. Basically the abdominal muscles have very little influence over how you move, for this is not their true purpose. This is very important to understand and will explain why I believe many core exercises are incorrectly implemented.

The CORE is really a combination of both small stabilizing muscles known as the Inner Unit, combined with large prime mover muscles that operate like a series of complex chains and systems to provide stiffness on a greater scale. This known as the Outer Unit. True core strength requires the use of both.

The inner unit is incorporated in almost every movement of the human body. These muscles can act as an isometric or dynamic stabilizer for movement, transfer force from one extremity to another, or initiate movement itself. The role of the inner unit is to stabilize the spine. That’s it.

The deep abdominal stabilizers (inner unit) are actually quite small and unable to generate much force in comparison to the larger exterior muscles. The stabilizers are mainly concerned with providing joint stiffness and segmental stability. Their work is what you would classify as low level activity needed for long periods of time. It would be bad if your stabilizers only lasted 30 seconds.

They are also known as "feed-forward" muscles in that they react quicker than any other muscle group, to prepare the body for movement. The only way they can work effectively and influence the integrity of movement is to fire first. The ability of the inner unit muscles to contract prior to force production of the larger prime mover muscles (geared toward movement) is more important than their strength. Research shows that in people with no history of low back pain, the TVA fires 30 milliseconds before arm movements and 110 milliseconds before leg movements.


These muscles cannot provide movement and they are definitely not strong enough to provide gross stiffness for heavy or more powerful speeds. They need the assistance of the outer unit muscles to do this. Meaning that in order for them to be used correctly with correct timing and the way they are intended to, they must be trained in conjunction with the outer unit!

This is much more difficult to explain and really involves all of the large prime mover muscles. The outer unit or large prime mover global muscles are more designed to move the body, and what you would classify as high level activity needed in short bursts. However, they are unique in that they are also designed in a way to move but at the same time provide stability via use of what is called the myofascial slings, that help to co-ordinate the correct sequence of movements. This is very important to understand as it gives you some clues as to how the body prefers to move, and more specifically how it moves most efficiently!

Read the article - Improve Core strength by using the slings to see specific examples of the outer unit.

Why Do People Fail?

As you would expect it is not just one reason for a person failing this test as there are many things to consider, but without a doubt the most dominant factor is to do with the HIPS.

1. Muscle Inhibition

This is the classic case of compensation causing muscle imbalance and eventually muscle inhibition. We see this all the time with people who have chronic back pain or hip pain.

This is where the hips have learned to become stabilizers of the pelvis, instead of providing movement and in turn have disabled the abdominal muscles from firing first. There is no way you can maintain a neutral pelvis and lumbar spine if you are using your hip muscles to do all the work.

The HIPS are practically stealing work from the abdominal muscles!

This is a massive problem because the hips are primarily concerned with providing the exact opposite role to stability which is MOBILITY. The hips are a joint designed to be very mobile, having to withstand both direct loading stresses and large rotational forces with weight-bearing activities. Their role is to move into positions that maintain neutral spinal alignment and prevent excessive flexing and extending. Unfortunately they are prone to developing stiffness from inactivity, sitting for long periods, and poor training techniques.

The lower abdominal exercise becomes much harder when hip stiffness is present and compensation is inevitable. Instead of providing mobility for the legs to lower to the floor they do the exact opposite, they contract and stiffen. Every time the hips try to fire up to create the stiffness in the spine they move the pelvis into anterior tilt and as a result of this you lose your lumbar spine stability.

This is seen very easily when the spine lifts off the blood pressure cuff. Below is a screenshot from a video I did years ago with Women's Health & Fitness magazine where I worked with one of their models who could not do this exercise. You will see very clearly her compensation as she lowers her legs.


Click here to watch the full video. Fast forward to the 2:34 mark to see this.

The harder people try the worse they make it if they are relying on their hips for stability. Over time through constant repetition this is permanently encoded into the nervous system as the way to provide stability the pelvis and lumbar spine.

Apart from inactivity and sitting for long periods causing this, undoubtedly the biggest factor is faulty training methods. One way to combat this is to weaken the hips via stretching or foam rolling prior to completing the lower abdominal exercise. This weakens the neural connection for the hips to steal the abdominal muscles work. I used to think this was all you needed to do, however over time I realized there was much more to it than that.

3. Faulty Training Methods

Have you ever wondered why you can do so many more sit-ups if someone holds your feet? The reason is not that you have now found a way to engage the hips into the movement of trunk flexion. Once you have done enough repetitions of this you have now taught the body that this is the preferred way to stabilize the lumbar spine!

This is also when we begin to see TRUNK GRIPPING and use of the posterior tilt in almost every exercise. This is also why you will often see much more strength in the UPPER-RECTUS ABDOMINOUS segments compared to the lower.

Below is a quick video where I look at four common exercises where we show you poor form due to poor over-use of rectus abdominous and a poor understanding of how to create true stability. I also explain why you should NEVER do sit-ups on the floor!

When people adopt a trunk gripping strategy they are over-activating the external obliques that will create a posterior tilt of the pelvis. While this may give them the flat abs they were looking for, it will now cause a series of muscle imbalance chain reactions that will eventually lead to pain.

Additionally, with chronic over-gripping of the posterior hip, the individual will tend to over-compress their hip joint during simple resting positions such as sitting. Over-compression of the hip joint makes it very difficult for people to release their hip muscles when they need to bend, squat, lunge in everyday life.

With the lower abdominal exercise itself it is important NOT TO FULLY POSTERIOR TILT. This is taught in Pilates and is called "imprint" and is a recipe for disaster. This is a terrible position for the lumbar spine and is where we see bulging discs begin to appear. While you may in fact pass our test, you have actually become too good and any benefit you would have had is now negated by the fact you have moved too far into flexion.

"The safest position for the spine is in neutral" - Dr Stuart McGill

Trunk gripping will lead to rigidity and actually more back pain! Ironic considering it is a strategy adopted by the body to prevent pain. In particular is the danger in creating a DISC BULGE as the lumbar spine is forced into flexion as they constantly tuck their pelvis under. In addition to this you will begin to see flaring of the rib cage (see picture below) that will now result in a change of breathing.

Over-activity of the outer unit muscles leads to weakening of the inner unit, and over time you will see stiffness and rigidity creep into the thoracic spine. Now you are likely to develop neck pain!

This brings me to the next point which is do you know how to breathe correctly?

4. Poor Breathing Mechanics

This is an interesting factor to consider and it can be very difficult to change if you are in fact adopting poor breathing strategies. In the book "The Psoas Solution" by Dr Evan Osar he discusses in great detail the damage of excessive belly breathing and how it can create problems with the lower abdominal muscles.

He states,

"Individuals who have over-focused on belly breathing tend to create a learned inhibition of the abdominal wall, likely because there has been such chronic overstretching of these muscles and their investing fascia. This along with the loss of proper thoracic involvement in the respiratory process results in a migration of the organs inferiorly."

What this means is that the gastrointestinal organs sink into the lower abdomen giving the appearance of distended abdominal area. Your first instincts would be to conclude that this is "weak" but it is the exact opposite as the muscles will be in constant tension and stiffness. Dr Linda Joy refers to this dysfunction as "pressure belly".

Now you definitely do not want to be a chest breather either, as this also causes massive problems throughout the body. What you need to do is learn how to breathe normally when at rest, but also how to create stability and stiffness when you need it during exercise and lifting.

During the lower abdominal exercise the faulty stabilization most people use is to push their abs out, instead of using a bracing strategy.

You must be careful not to pull in too much which is something I used to teach years ago. I began to change my mind on this and use McGill's bracing strategy instead which uses a combination of the inner and outer unit. It stiffens the entire abdominal wall and encourages the rib cage to lock onto the pelvis to prevent any buckling of the spine.

The main benefit of using this strategy is it easy to adopt it later on in the more advanced and much more difficult exercises that demand higher thresholds of stability. You can see a video below of how I teach this breathing strategy to create stability in multiple movements.

Breathing is a very complex topic to go into so I suggest to read our detailed article about this here - Do you know how to breathe correctly when you exercise?

When I Would NEVER Use This Exercise!

There is no doubting the lower abdominal exercise is a great way to develop core control but there are certain people I will NEVER use this with. These are the people who are stuck in a flat back posture and their pelvis is permanently locked into posterior tilt.

This exercise is very risky for this person as it encourages them to become even more locked into posterior tilt and will increase their chances of developing a hip problem or worse a bulging disc injury to the lower back!

You will also find this person is very good at this exercise anyway as their back is constantly pushing into the ground. Their problem is not weak abs, but tight abs and they need to learn how to release the stiffness and develop more anterior pelvic tilt and lumbar extension with the back extensors.

Below is a picture of what a flat back posture looks like in comparison to other postural types. The flat back posture is the highest risk when it comes to back pain and the relationship with abdominal exercises cannot be over-stated.

Now that you are familiar with why people fail this test and how to breathe correctly to create stability how do you make it easier if you cannot do it and harder if you have mastered it.


To make this exercise easier there is several things you can do. If we call the bent leg position with both feet in the air level 4 you can work back to level one by doing a few things.

  1. Start with both feet in the air and lower only one leg at a time (level 3)
  2. Start with both feet on the ground and lift only one leg at a time (level 2)
  3. Keep both feet on the ground and simply practice bracing (level 1)

Once you have mastered each stage you begin to progress to the next level until you eventually you master level four and that brings you to other progressions.

The video below shows you in great detail how to use several regressions to allow you time to develop the necessary skills to complete this test correctly. This also shows you a few progressions to use, and the one I really like is the standing lower abdominal test. 


There are many great exercises you could use to encourage further strengthening of the lower abdominals and by far the best ones are movements that use the legs like squats, lunges and deadlifts. But if I was to look for a slightly harder abdominal focused movement I would look at the PRONE JACKKNIFE and the SIDE PLANK.

Firstly the prone jack-knife is a very tough exercise to get right and this is an exercise the flat back person will struggle with as it demands a certain degree of hip and back extensor strength. You also need a great understanding of how to maintain anterior pelvic tilt.

The reason it hits the lower abdominal so well is that you cannot flex your upper rectus abdominous to do this, all the work must come from the lower end as you are moving your legs and not your trunk into flexion. Add on top of this the added challenge of upper body strength you now have a very challenging exercise.

The other exercise that is a great progression for strengthening the lower abdominal muscle is the side plank. Most of you would be pretty surprised to think that the lower abdominal works hard in this as you would assume it is mainly being driven by the oblique muscles. And while it is true the obliques are working very hard, the lower abdominal must fire up to maintain a neutral position of the spine due to the incredible shearing forces of gravity trying to flex it laterally.

McGill found during his testing of all movements that this exercise had the highest EMG reading with the lower abdominal muscles! There are several ways this can be performed but my preferred choice is to start with the kneeling position as shown in the video below.

Last but not least we cannot ignore the impact poor nutrition can have on the function of the abdominal muscles.

Do Not Ignore Nutrition

In the book “How To Eat, Move & Be Healthy” by Paul Chek he explains how pain or inflammation of the digestive organs will reflex to the abdominal muscles, leaving the stabilizer muscles weak or disabled, and your back exposed to injury!

He says,

“Internal organs borrow pain sensitive nerve fibres from the muscular system".

This means that when an organ is in pain, the brain cannot determine if it is the muscle or the organ that hurts. The brain only knows what segment of the spine the pain came from. The brain then tells all the tissues and organs on the nerve channel to behave as if they are in pain. Since pain weakens muscles, the abdominal muscles lose tone and strength, and simply don’t respond to exercise very well at all. It completes the like a muscle that doesn't think it is in pain!

This is where a person is trying to get their abs to be flat with all types of crazy ab exercises when the real problem is the food they are eating! Food intolerances causing bloating, and lack of hydration causing constipation can create a large belly that has nothing to do with strengthening. And both of these nutritional problems cause serious problems for the pelvis and lumbar spine in terms of stability as the abdominal muscles are basically shut-down!

You can read more about the link between nutrition and abdominal function by clicking here.

Do You Need More Help?

For all the information you need to know about core training and abdominal exercises you will find the two reports featured below have everything you need. The Little Black Book is suitable for those without injury and looking to get into great shape and tone up the abdominals. The back pain secrets programs is more suited to the person who recognizes they need to improve their core stability to get out of pain. The way in which abdominal training is used will vary depending on the person's needs. 

Click on the image below of the program you need to get your instant copy.



I must apologize for writing another epic of a newsletter. I must admit I thought this was going to be a quick one but once I begin to dissect all the information it seems to turn into a bigger article than I first thought. I hope this exercise shows you how to identify poor stability strategies that your body may be using and the various things you may need to explore to correct it.

The lower abdominals are often the target of excessive training and this can be much to the detriment of your body. By having a more intelligent approach to this part of the body you will achieve the result you are looking for. To summarize the main reasons for people failing this test it would be hip dominance over abdominals, poor breathing mechanics and bracing strategies, faulty training techniques and possibly nutritional deficiency.

This is a great exercises if used wisely but if it is abused you will pay a price for your ignorance.

For more ideas and information on specific topics I may not have covered in detail be sure to check out our INDEX PAGE on the website that has over 200 of our best articles. These are all sorted into categories for quick reference so you can find what you are after more easily.

If you do need specific help with your exercise program please feel free to reach out to me for help and we can set you up with your individualised program.

About The Author

Nick Jack is owner of No Regrets Personal Training and has over 15 years’ experience as a qualified Personal Trainer, Level 2 Rehabilitation trainer, CHEK practitioner, and Level 2 Sports conditioning Coach. Based in Melbourne Australia he specialises in providing solutions to injury and health problems for people of all ages using the latest methods of assessing movement and corrective exercise.


  • Functional Anatomy of the Pelvis and the Sacroiliac Joint - By John Gibbons
  • The Vital Glutes - By John Gibbons
  • Movement - By Gray Cook
  • Corrective Exercise Solutions - by Evan Osar
  • Back Pain Mechanic - by Dr Stuart McGill
  • Diagnosis & Treatment Of Movement Impairment Syndromes - By Shirley Sahrman
  • Low Back Disorders - by Dr Stuart McGill
  • Ultimate Back Fitness & Performance - by Dr Stuart McGill
  • Core Stability - by Peak Performance
  • Athletic Body in Balance - by Gray Cook
  • Anatomy Trains - by Thomas Meyers
  • Motor Learning and Performance - By Richard A Schmidt and Timothy D Lee
  • Assessment & Treatment Of Muscle Imbalance - By Vladimir Janda
  • How To Eat, Move & Be Healthy by Paul Chek
  • Scientific Core Conditioning Correspondence Course - By Paul Chek
  • Advanced Program Design - By Paul Chek
  • Twist Conditioning Sports Strength - By Peter Twist
  • Twist Conditioning Sports Movement - By Peter Twist