|Abdominal muscles contracting to produce reciprocal inhibition of the erector spinae.|
I used to quote the writer, Emily Dickenson, as saying, “See the world in a grain of sand…” Then a friend of mine explained that, actually, the quote was by William Blake. So much for this surfer dude acting cultured . . .
Anyway, the point is that many of the things we learn in one pose can be applied to another. Similar muscles work in Paschimottanasana as in Uttanasana (with variations). Physiological principles, such as reciprocal inhibition between agonist and antagonist muscles, also apply across the board for other skeletal muscles. I find that when we approach learning in this way, it makes what appears to be a daunting subject like anatomy more manageable.
For example, let’s look at using the abdominals in Uttanasana. The abs are composed of four muscles. Moving from the surface inward, we have the rectus abdominis in the front and the external obliques on each side. Deep to these are the internal obliques, with the deepest layer being the transversus abdominis. Contracting these muscles flexes the trunk forward and increases intra-abdominal pressure (by squeezing the abdominal organs). Bending forward from the trunk stretches the erector spinae of the posterior kinetic chain. The erector spinae comprise three columns of muscles that lie parallel to the spine. From medial to lateral, these are the spinalis, longissimus, and iliocostalis.
The erector spinae and abdominal muscles are an antagonist/agonist group, i.e. when one contracts the other stretches. As I explained for the quadriceps and hamstrings in the first blog post for this thread, the nervous system signals the antagonist muscle to relax when the agonist contracts. This physiological Ying/Yang is called reciprocal inhibition.
Engaging the abs thus has two effects. It has the biomechanical effect of flexing the trunk and deepening the pose and the physiological effect of inhibiting the back muscles from contracting, relaxing them into the stretch.
Take a look at the image above. This illustrates an excitatory signal being sent to the abdominals, causing them to activate, and an inhibitory signal to the erector spinae, aiding them to release. When you consciously engage the abs, the reciprocal inhibition happens automatically (unconsciously).
Gently contract the abdominals in forward bends like Uttanasana and feel the effect. A cue for isolating the transversus abdominis is to draw the navel towards the lumbar spine. Feel how this cue gives an added support to the low back. Combine these actions with firming the thighs to release the hamstrings, as described in our first post.
Thanks for checking in. We look forward to seeing you for the next post when we’ll illustrate how tight hamstrings affect the lumbar spine (and some tips on how to use physiology to release them).