Most people think of crunches, planks or sit ups when they’re looking to strengthen their core. The reality is that isolated abdominal training has little carryover to functional movements and sports, and thus play a small role in injury prevention and performance. If your goal is to train for stability, then you need to enhance motor patterns that incorporate many muscles, rather than just targeting a few.
ANATOMY OF THE CORE
Panjabi et al (1992) wrote an article about all the components that play a role in providing spinal stability:
- Lumbo-Pelvic structure
- Neural activation or motor control*
- Active stability from muscular forces: local musculature (inner core) and global musculature (bigger muscles)
As you can see, stability of the spine is affected by several components of our bodies not just the “strength of your core”.
*What the hell is “motor control”?
Motor control has to do with the constantly changing distribution of intrinsic and extrinsic muscles, and ongoing central nervous system mediation. It refers to the ability of the brain to turn muscles on and off depending on the demands of the task, in order to achieve stability, or coordinated movement*
Isolated core exercises have their time and place. They are a great tool to gain initial activation and control of the inner unit. But what happens once we’ve already mastered that? There must be a line of progression to standing and dynamic movements where you are using a combination of the inner unit (your deep core stabilizers) and the outer unit or prime movers (like your glutes, hamstrings, quads etc). Even if we increased the strength of the inner unit, if we don’t make the connection between the two and correct erratic movement patterns, strengthening the core can only take us so far. Because of this, we need to think about it in terms of integration and how we actually create movement.
Maximal muscle activity in the core musculature is observed during single-plane activities, but when performing functional tasks that demand multiple muscle groups to be activated at the same time, their activation is significantly diminished. This leads us to believe that isolated core exercises may not help us improve stability, stiffness and control in “functional multiplanar” tasks.
The purpose of this article is to introduce the concept of the Anatomical Slings and what their role is in stability and performance.
The anatomy slings are groups of muscles that work in an integrated fashion or in synergy to produce movement and create stability around joints. The concept of core stability can further be enhanced by increasing strength and motor control of these slings in parallel to activating the inner core.
The human body is a complex system made up of “slings” or “chains”. These slings are combinations of local/inner unit (transverse abdominis, diaphragm, pelvic floor, and multifidus) and outer/global unit that work in synergy to produce functional movements, and when trained appropriately can improve strength, speed and power output. These slings are commonly under looked as we tend to get stuck in the smaller picture when we experience injuries or weakness, and often focus only on specific muscles.
The slings are composed of a combination of local and global stabilizers. Local stabilizers are mainly concerned with providing joint stiffness and segmental stability, while most of the strength and power is coming from the big global muscles. Together they form a very powerful muscle synergy. In order to maximize trunk stability, we can’t just target the local unit, as this will not significantly help improve core function if the body is not taught how to effectively use these slings.
- Anterior Oblique System: External and internal oblique with the opposing leg’s adductors and intervening anterior abdominal fascia.
- Posterior Oblique System: The lat and opposing glute maximus and thoracolumbar fascia
- Deep Longitudinal System: Erectors, the innervating fascia and biceps femoris.
- Lateral System: Glute medius and minimus and the opposing adductors of the thigh
PART II of this article will cover common injuries related to these slings and my favorite exercises to strengthen each sling!
Stefanie Cohen, SPT