How Your Downward Dog Promotes Graceful Aging

As a dog lover, I’m not alone in believing these creatures have important knowledge to pass along to us humans. With this in mind, I want to discuss how aging affects your body and bring to your attention some recent evidence from the scientific literature on how stretching–and Downward Dog Pose–can help.

Downward Dog Pose and Reciprocal Inhibition  

Reciprocal inhibition is a biomechanical and physiological process whereby when we contract a muscle on one side of a joint, the muscle on the other side is inhibited from contracting. This takes place to varying degrees throughout the range of motion of a joint and enables us to do things like walking.

For example, when you contract your tibialis anterior to dorsiflex your foot while walking, you automatically inhibit the calf muscles. This helps to prevent catching your toes.

Reciprocal inhibition is controlled and regulated at the level of the spinal cord and also the brain. Of course, as we reach the ends of range of motion of a joint, a process known as co-contraction kicks in to stabilize the articulation, thus modulating the inhibitory effect of the contracting muscle on its antagonist. In other words, we are not Gumby.

Figure 1 illustrates the agonist/antagonist pairs for the forward bend Paschimottanasana (Seated Forward Bend) and the backbend Setu Bandhasana (Bridge Pose).

(Figure 1: Agonist/Antagonist pairs in Paschimottanasana and active Setu Bandhasana.)

Reciprocal Inhibition and Aging

Scientific studies have demonstrated that reciprocal inhibition diminishes as we age (and also in certain disease processes). This is particularly important for activities such as walking. For example, if the tibialis anterior does not efficiently inhibit the gastrocnemius/soleus muscles of the calf, the person tends to catch their toes, stumble and fall.

If that weren’t bad enough, our bones also weaken with age, so falls can lead to fractures–especially of the hip. This puts the person in a hospital under the care of an orthopedic surgeon and so on…(a story I know all too well). So, methods or techniques that improve reciprocal inhibition could potentially benefit us as we age.

How Stretching Can Help

Recent scientific evidence has shown that stretching can increase reciprocal inhibition between antagonist muscles. For this study, the authors investigated the effect of stretching on reciprocal inhibition between the tibialis anterior and the gastrocnemius/soleus complex. They stated:

“In conclusion, we have found that three weeks of twice-daily, static plantar flexor stretching resulted in a significant increase in reciprocal inhibition, measured in soleus and gastrocnemius during voluntary, tonic dorsiflexion contractions.” (The full article is listed below in the references)

These are some of the same muscles we work with in Adho Mukha Svanasana (Downward Facing Dog Pose). Thus, regular practice of this yoga pose may help maintain reciprocal inhibition between the tibialis anterior and the calf muscles. 

(Figure 2: The tibialis anterior as agonist and gastroc soleus as antagonist in Down Dog pose.)
 

Active Stretching

In active stretching, one improves muscle flexibility by contracting the opposing muscle group while stretching the target muscle. In the case of the hamstrings, this means engaging the quadriceps during the stretch.

Shirley Sahrmann, PhD (Professor of Physiotherapy at Washington University School of Medicine) and others have advocated active stretching as a means of increasing muscle flexibility. It improves flexibility of the muscles on one side of the joint while improving strength and function of the muscles on the other side.

A recent article from the medical literature compared active vs. passive stretching of the hamstring muscles. The authors stated:

“Such an active technique is based on reciprocal inhibition between agonistic and antagonistic muscles.”

And concluded:

“Active stretching produced the greater gain in the AKER (active knee extension range of motion) test, and the gain was almost completely maintained four weeks after the end of the training, which was not seen with the passive stretching group. Active stretching was more time efficient compared with the static stretching and needed a lower compliance to produce effects on flexibility.” 

This makes sense to me from a yoga perspective as well–keeping in mind that there are many different ways to climb the mountain. Improving muscle flexibility is only one of the functions of asana practice. Active stretching, among other benefits, improves your mind/body connection, alignment of your joints and your mental focus. Improved focus in turn helps to identify and correct imbalances.

(Figure 3: An agonist/antagonist pair in Warrior I (gluteus maximus and iliopsoas).)

Figure 4 shows a couple of page spreads from our Yoga Mat Companion book series, illustrating a step-wise approach to working with muscle engagement in the poses.

(An excerpt from “Yoga Mat Companion 1 – Vinyasa Flow and Standing Poses”.)

(An excerpt from “Yoga Mat Companion 2 – Hip Openers and Forward Bends”.)

NB: Evidence based medicine ranks publications and studies according to “levels of evidence”. Level I studies are considered to be more reliable, and are based on randomized controlled trials. Level VII evidence, on the other hand, is essentially an opinion, with variable reliability depending on the source and their actual expertise.

The study on active vs. passive stretching I referenced above was a randomized controlled trial (RCT), and is thus Level I(b) evidence.

Reprinted with permission of thedailybandha.com

3d Graphic Designer / Illustrator Chris Macivor has been involved in the field of digital content creation for well over ten years. He is a graduate of Etobicoke School of the Arts, Sheridan College and Seneca College. Chris considers himself to be equally artistic and technical in nature. As such his work has spanned many genres from film and television to videogames and underwater imagery.