It’s a common sight around the world, with athletes and gym-goers attempting to build their “Abs,” but are they actually doing so? Recently, I came across a video featuring the famous athlete Virat Kohli, where the focus, as evident in the first 12 seconds, was to work on the Rectus Abdominis, commonly referred to as the “Abs workout.” Let’s dive into the science behind this particular exercise and break down what’s happening to the athlete’s body in this form of exercise. It’s not about the athlete, who is a legend and one of my favorites, but rather to better understand how every action we take with our body can have repercussions that don’t necessarily indicate the true picture of what’s happening inside.
To better illustrate this concept, I have searched through my collection of images and selected one that closely depicts the muscular activity that occurs during this exercise. While the exact positioning of Virat’s back may differ, the muscle usage in the image is quite similar. Let’s start by examining the position of the back and the muscles involved:
1) The Scapular stabilizers or what we commonly refer to as the upper back muscles.
2) The erector spinae muscles group – the muscles that run essentially vertically on either side of the spine
This particular exercise form is highly effective in working out the aforementioned muscle groups, as can be seen in the image. Additionally, maintaining this posture requires a significant amount of energy expenditure.
Let’s now examine how this exercise form affects the Rectus Abdominis muscle, also known as the Abs. To demonstrate this, I’ll share a picture of myself doing the same exercise form, but in an inverted position. This perspective allows for a clear view of the Abs muscle while the erector spinae muscles are contracting, just like in Virat’s exercise form.
In the image on the left, you can see the erector spinae muscles group engaged in extending the spine to maintain a straight back. However, in the image on the right, the Abs muscle is elongated and at rest. This is precisely what occurs when the spine is extended. So, how does this “work” the Abs, and what benefits does it provide to this muscle group? In reality, it does very little. Again not against it but doing it for abs is scientifically incorrect in my opinion.
Let’s imagine that we take a screenshot of Virat’s exercise and turn it upside down. You’ll see the same straight back and elongated Abs muscles. The movement you see in the Abs in the video is primarily due to the PSOAS muscle, responsible for pulling the legs up. This muscle is located right under the Abs muscle and is connected to the leg. So, when you do this back extension exercise and lift your legs, it creates the illusion that your Abs are getting a workout. However, your Abs muscles are not the primary mover here, and the major muscle involved in the movement is the PSOAS.
The rule for muscles is that they only work on the joint they cross. Let’s take a closer look at the two muscles involved – the PSOAS and the Rectus Abdominis, shown in the figures beside. As you can see, one muscle (the PSOAS) is attached to the leg, while the other (Rectus Abdominis) is not. So, if your focus is on leg movement, how can the latter have any role to play? And even if the Abs muscles were working slightly, considering the placement of the PSOAS muscle behind the Abs, is it really worth the effort after observing what it does to your upper back?
Muscle rule: muscles only work on the joint they cross.
Here’s a simple test to determine the effectiveness of this exercise for your Abs. Try doing ab crunches on the floor and pay attention to your Abs muscle, then have someone touch it to feel how much it contracts. Next, hang from a pole and lift your legs, similar to the video. Pay attention to your Abs muscle again and have someone touch it to feel how much it contracts. You’ll likely realize that you’re not really using your Abs muscles at all.
In layman terms, you can see clearly see one muscle (the PSOAS) is attached to the leg whereas the other (Rectus Abdominis) is not. So how would the latter have any role to play if your focus is on the leg movement? And even if it was working your Abs just a little, by the sheer placement of the PSOAS muscle being behind the Abs, is it really worth the effort after observing what it is doing to your upper back?
In addition to fatiguing your scapular stabilizers (upper back), engaging in this exercise form may also overwork your PSOAS muscle, especially if you participate in field sports like cricket, hockey, or baseball, where the PSOAS is constantly active throughout the game and even during sleep. Therefore, it does not require any further contraction.
To activate our abs, we need to flex them, even if it’s just a little bit of flexion, as shown in the running picture on the left. The rectus abdominis muscle performs various other functions while running, but it is essential to demonstrate how it comes into action.
If you choose to pursue this exercise form, it would be better to rest your arms on the sides of a regular gym machine, and even then, you would have to make an effort to slightly flex/bend forward from the top and rotate the pelvis while pulling the ribs and pelvis together. However, even then, it is the PSOAS muscle that is the primary mover, not the abs muscles.
Regarding the ab exercises demonstrated in the video above, there are two questions that I am interested in knowing the answers to in the strength and conditioning field:
Is the back being flexed in this exercise? If not, how does it become an exercise for the abs/rectus abdominis?
Can we consider this exercise as working the scapular stabilizers, erector spinae group, PSOAS, and structural muscles like the transverse abdominis or QL?
If anyone reading this has any other explanations or insights, I would be interested in learning more.
Umesh Chhikara
Movement Specialist I S&C trainer I Relaxation therapist
Umesh Chhikara 