Polestar + MP: Outer unit/Slings

What are the four outer units?

Anterior and posterior oblique slings, deep longitudinal system and lateral system.

Briefly describe the difference between the inner unit, outer unit, and abdominals.

Inner unit: deep stability. Outer unit: larger movement and force transmission. Abdominals: connect the inner and outer units and provide both stability and movement.

What do the inner unit, outer unit, and abdominals do together?

Together they create lumbopelvic stability and efficient movement. It is important to note that the abdominals are not a fully separate system; for example, the obliques are included in the outer unit.

The outer unit consists of four systems that work together to integrate and coordinate movement between which five body parts?

Shoulder girdle, thorax, spine, pelvis, and femurs.

What is the main function of the deep longitudinal system, and in which plane does it integrate and work?

It works in sagittal plane integration and especially helps with extension. It forms two columns of support along the back of the legs and the sides of the spine. It ties together the back of the body from the top of the head to the back of the heels.

What does bilateral and unilateral activation of the deep longitudinal system produce?

Bilateral activation produces extension. Unilateral activation produces rotation and lateral flexion.

How does the deep longitudinal system work together with the posterior and anterior oblique slings?

It works with the posterior oblique sling to create extension and counterbalances the anterior oblique sling to support flexion.

Which six muscles or structures are included in the deep longitudinal system?

Erector spinae, quadratus lumborum (QL), sacrotuberous ligament, hamstrings (especially biceps femoris), gastrocnemius, and plantar fascia.

In what plane does the anterior oblique sling (AOS) system work?

Transverse plane integration.

What is the main function of the anterior oblique sling system?

Its main function is to coordinate rotation and lumbopelvic control, and it does this together with the posterior oblique sling.

What type of movement results from bilateral and unilateral activation of the anterior oblique sling system?

Bilateral activation produces flexion. Unilateral activation produces rotation between the rib cage and the pelvis. The rib cage can rotate over a still pelvis, or the pelvis can rotate under a still rib cage.

What muscles are included in the anterior oblique sling?

Serratus anterior, external oblique, contralateral internal oblique, and contralateral adductors.

If you are rotating to the left, which anterior oblique sling is active, and which side of each muscle is activated?

The right anterior oblique sling is active: right serratus anterior for control and stabilization, right external oblique for rotation to the left, left internal oblique for rotation to the left, and left adductors for control and stabilization.

If you are rotating to the right, which anterior oblique sling is active, and which side of each muscle is active?

The left anterior oblique sling is active: left serratus anterior, left external oblique, right internal oblique, and right adductors.

How do you know which side is called the right anterior oblique sling and which is called the left anterior oblique sling?

The sling is named from the side it starts on. For example, the right serratus anterior means it is the right anterior oblique sling.

Which plane does the posterior oblique sling (POS) work in, and what is its main function?

It works in transverse plane integration. It is a myofascial system of structures that works together with the anterior oblique sling to create rotation and lumbopelvic control.

How would you describe the movement of the posterior oblique sling using bilateral and unilateral activation?

Bilateral activation creates extension. Unilateral activation creates rotation between the rib cage and the pelvis. Either the rib cage or the pelvis can be still while the other rotates.

Which parts of the body does the posterior oblique sling system include?

Latissimus dorsi, thoracolumbar fascia, and contralateral gluteus maximus.

What is an activity that is a good example of how the posterior oblique sling is used?

Walking and running. The posterior oblique sling connects the upper body with the opposite leg and hip, creating a natural cross-body system that allows force transfer and pelvic stability.

If you are rotating to the left, which posterior oblique sling is active and which muscles or structures are active on each side?

The right posterior oblique sling is active: right latissimus dorsi contributes to posterior trunk and shoulder girdle control; the thoracolumbar fascia transfers force across the body; and the left gluteus maximus contributes to pelvic and hip control and stability.

Which plane does the lateral system work in, and what is important to note about its movement?

It works primarily in the frontal plane, but its movement is not limited to the frontal plane. It is also very active in sagittal plane exercises such as squats, lunges, and heel lifts, because the sling helps keep the hips/pelvis level.

What is the main function of the lateral system?

It keeps the pelvis level over the femurs and provides lumbopelvic stability. It also helps with hip abduction and adduction and pelvic upslip and downslip. For example, when standing on one leg, the lateral system keeps the pelvis stable.

Which four muscles are included in the lateral system?

Quadratus lumborum (QL), gluteus medius, gluteus minimus, and contralateral adductor.

What is the location and main function of the quadratus lumborum (QL)? And which systems is it part of?

It is a deep lateral lower-back muscle between the lower rib and iliac crest. Its main function is lateral flexion and stability. It is part of both the Deep Longitudinal System (DLS) and the Lateral System.

What is the location and main function of the adductor? And which system is it part of?

It is a medial inner upper-thigh muscle. Its main function is to adduct the hip and thigh and stabilize the pelvis. It is part of the Lateral System & the AOS.

You are practicing single-leg weight bearing. You are standing on the right leg and lifting the left leg. Which lateral system is active, and which side of the four muscles are active?

The right lateral system is active. Right QL, right gluteus medius, right gluteus minimus, and left adductors.