Knowing What Muscles To Engage

One of my friends recently posted that

Knowing what muscles to engage is what heals.

(He’s exposed to a lot of yogi’s who focus on stretching).

It inspired me to look at my own yoga practice (and what I teach and do)  in order to use my body more effectively.

It is also inspiring me to go back to the very basics, which includes looking at the possibilities for activating muscle and relaxing it.

Muscle Basics

When activated muscle tissue:

  • can shorten,
  • remain the same length or
  • lengthen.

It depends on the relative force that it is working against:

  • If working against a lesser force then it will shorten,
  • working against an equal force then it will remain the same length,
  • working against a greater force then it will lengthen.

An example of the middle case is holding a half squat with thighs level, the leg muscles work against each other and gravity to remain the same length.

An example of the latter case is slowly lowering into a squat. The quads and/or glute max, for example,will be slowly lengthening even though they are active.

When relaxed muscle tissue will tend to return to some resting length (which assumes that there is some connective tissue within the muscle that has some elastic properties, or that some fibers within the muscle are responsible for returning it to some resting length.)

While relaxed a muscle can be lengthened so that it is stretched. Or the distance it spans can be shortened so that the muscle can relax further, perhaps sinking downwards due to its own weight.

The former case, lengthening a relaxed muscle, is the basis for “relaxed stretching.”
Meanwhile the case where muscle is lengthened while active can one form of active stretching.

Feeling Tension (and Slackness)

To me one of the interesting things about muscle tissue is that with practice we can learn to feel the difference between when a muscle is relax and when it is active. We can also feel when it is being stretched while relaxed or active.

And for muscles that are too thin or too small, or too few in number to be sensible, what we can learn to feel (and control) is connective tissue tension and/or the relationship between bones which that muscle helps to control.

So what’s more important, being able to relax or contract muscle? I’d suggest that both are important. More important is being able to feel and control whether muscles are relaxed or contracted so that we can choose which we want to do.

Posture Affects Tension
(And Vice Versa)

This brings up a problem in that the ability to control a muscle depends on posture while posture or body positioning can also depend on muscle activity.

If you have trouble activating a particular muscle it may be because you need to adjust your posture (which in turn is being caused by another muscle contracting or failing to contract)

If you have trouble with achieving a particular posture (or balancing left and right, it may be because a muscle is activated or because a particular muscle is not activating.

Feel and Control

Rather than saying that muscle activation is better, or that relaxation is better, I’d suggest that the most benefit comes from being able to feel and control the body and respond depending on the circumstances and what the over all goal is.

For myself the qualities that I try to be aware of are tension and bone positioning. (Tension in connective tissue or tension due to muscle activation.) These are qualities that I can control or vary and both can be affected by muscle activation and/or muscle relaxation.

My most recent example is that my shoulders have been imbalanced. It’s felt like my right pectoralis minor tends to habitually contract.

I eventually realized that my ribcage tends to be positioned slightly rightwards relative to my pelvis and this in turn may have been the result of one or the other of my psoas muscles not activating when required. So I focused on aligning ribcage and pelvis, and also on activating the psoas on both sides.

From there I then worked on balancing the shoulders.

(Part of balancing my shoulders included activating the latissimus dorsai on the right side. Whether it was not activating because my ribcage was displaced or my ribcage was in part displaced because it was not activating, I’m not quite sure.)

The things that guided my adjustments where being able to feel or sense my ribcage in relaxation to my pelvis, the pull of the psoas on my lumbar vertebrae, and then tension in the muscles that act between shoulder blade and ribcage, and between shoulder blade and upper arm bone (humerus).


To sum up, the quality that is perhaps most important when learning to feel the body and control it is tension.

Tension enables me to feel the relationship between my bones (for example: between ribcage and pelvis) and it also allows me to feel when my latissimus dorsai or psoas (or any other muscle) is activated (or relaxed).