Deadbug Anti-Extension Progression: Moment Arms & Torque Production

Deadbug Anti-Extension Progression:
Moment Arms & Torque Production

Core stability is a hot topic in the world of physical therapy and S&C for good reason. Today’s video blog provides you with an example anti-extension progression, beginning with a basic, day 1 pelvic control drill (1️⃣), & progressing towards weighted, higher level versions (4️⃣/5️⃣). Check out the video below and then tune in for a follow-up message below!

It’s important to understand the underlying concept that allows this progression to be so effective: TORQUE PRODUCTION & MOMENT ARMS!

Revisiting physics, we know that TORQUE is a product of the FORCE APPLIED and the distance from the point of force application and the axis of rotation, or the MOMENT ARM. Think of a wrench! A wrench with a longer handle allows you to create more torque with the same amount of force!

We can apply this to single-leg lowers & deadbugs by understanding that our leg is the moment arm upon which gravity acts.  This produces torque applied at the hip which is transmitted up the chain. In response, our musculature must produce an equal amount of force in order to maintain lumbopelvic position.

  • When we straighten our knee or lower our leg further, we’re effectively increasing the moment arm, and our trunk musculature must contract harder & produce more force to maintain the same position.

We can take this further by including our arms or lowering both legs at the same time!.

  • Our arms add another point at which gravity act to create more extension force. The arms are a part of our upper quarter shifting the focus more towards controlling rib cage, rather than pelvic, positioning.

Lowering both legs at once increase the mass and eliminates the rotational component created when performing the unilateral Deadbug!

This is an important concept to understand and some critical thinking can help you apply it to ALL therapeutic exercise. It’s this kind of knowledge that allows you to adjust for the trainee in front of you, find success with a wider range of individuals, and enhance your abilities as a provider!