Human Engineering: Static Stability/Posture

Human Engineering: Static Stability/Posture

(see part 1 of this series here)

by Sanjeev Joseph

You made it through my first module on the basic concepts and structures that are part of the human movement system. Let’s dive a little deeper into these areas, and see how they interact to create static stability, also referred to as posture.

The Core

The core consists of the transverse abdominus and the lower rectus abdominus. Yes, there are other muscles of the core, but these are the main ones that control the lumbar spine, which is the central point of your body. Specifically, the center point of your body is usually the L4-L5 and L5-S1 vertebral segment (located at most people’s waistline). Normal human movement leads to shear, torsion, compression and wedging because of physical forces like gravity, mass of the individual, strength of the muscles/bones/soft tissues.

So it’s very important to figure out how to manage getting the forces that travel through here move without disrupting the delicate structures that transmit the forces. Like many things in nature, there is a delicate balance that has to be maintained in order for things to work just right. Any disruption can lead to immediate or long term problems. This is managed by increasing awareness and training your systems in the right way to achieve and maintain this delicate balance.

How Does the Core Work, Exactly?

Think of a water hose and a wall. Imagine that you open a tap at full force and you put your hands out. The water would hit your hands and disperse in all directions. It would look something like this

Now imagine the same thing being done by the core.

  • For starters, you should be lying on your back with your hips and knees bent, feet resting flat and your body relaxed (this is called hooklying). You should be breathe through your nose and out through you mouth to gain the most relaxation. This is so that the deep muscles of the core can work without any interference from other muscles. Contract The Core by tightening up the muscles just behind the front of your waistline and press your lower back (L4–5 and L5-S1) into the surface you are lying on. When the Transverse Abdominis and Lower Rectus Abdominus contract together, they can drive the forces of the contract backward toward the L4–5 and L5-S1 segments.

This force, upon contact with these structures, will lead to a dispersion along the soft structures. Another way to call this phenomenon is spinal DECOMPRESSION. These soft structures are the discs present between the bones. So if COMPRESSION leads to damage, then DECOMPRESSION will result in reversal of the damage. The key to executing this is to direct the forces to the disc that is having the most compression/damage and not anywhere else. Think of it like hitting the bullseye of a target. If you miss, the result will also be missed.

  • Progress to sitting: Do the same activity on a chair with a hard backrest. This helps the core engage and decompression against gravity, also moving you toward other more complex activities that require you to be upright.
  • Progress to standing: Then do the same set of exercises in standing. First standing with your back against a wall for support. Eventually, you will be able to contract it while free standing.

The Axial Structures

Next, we have the rest of the spinal column, consisting of 32 vertebra, a sacrum, skull and ribcage. All of these structures have soft padding called discs in between them and are interconnected by myofascia, muscles, ligaments and controlled by the nervous system. Sensors are distributed in large quantities around these areas, and are most sensitive to pain stimuli.

To engage these areas, you must have good voluntary control of the paraspinals muscles, intercostal muscles, abdominal wall (obliques, upper rectus abdominis) and muscles of the chest wall. In the same hooklying position, you would engage these muscles by pressing the entire spine into the surface you are lying on. The resistance provided by the hard surface on which you are lying on helps the muscles to produce and closed loop of resistance to embody the spinal structures and keep it stable.

A good example of full axial stability is the mountain pose. It can be practiced against a wall, the progress to free standing poses. To accomplish the pose, stand with your core pulled in, then stand as tall as possible with the arms to the side and pointing the crown of your head to the sky, like the summit of a mountain. The goal is to make yourself as tall as possible while contracting the core.

Scapular Stability

You shoulder blades are called the scapulae. The scapular area is another critical location. It’s between the shoulder blades and the spine. They work with the back, trunk muscles to create stability for the arms. They also work with the upper arms to create automated and coordinated movements of the upper extremities.

An easy way engage these muscles is to squeeze the shoulder blades together toward the spine while contracting all the core and axial stabilizer muscles that you have learned in the previous segment. Collectively, this results in good trunk, shoulder and neck posture. In addition, it is a great platform to create efficient and smooth motions of the arms.

Remember is to keep the ribs lower to prevent the back from being overextended and resulting in problems in the neck, shoulders, back and lumbar spine.

Hip and Pelvic Stability

Much like the scapular areas, the hip and pelvis are held together by muscles coordinating with the spine and lower extremities. These muscles include the Gluteals (Maximus, Medium, Minimus), Piriforms (Notoriously injured and problematic), Tensor Fascia Lata, hip flexors, Iliotibial Band (ITB), Hamstring and even the Quadriceps Femoris.

When they work together, the keep the pelvis properly balanced and aligned with the spine at the somewhat rigid Sacro-Iliac Joint (SIJ) and the pelvis with the Femur (long bone of the thigh) through the hip joint (articulation of the acetabulum of the pelvis and head of the femur). The best way to engage these muscles is by standing and getting into the mountain pose, while squeezing your cheeks (buttocks), tucking in the sit bone and moving your hips forward.


By adopting these techniques, you not only become more aware of the muscle that control your posture, but you also set the canvas for great movement. You will be more efficient in your activities, and have less injuries and more energy throughout the day. You will be able to do more and for a longer time. It takes time, repetition and discipline to really master these skills, so get started now!

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