Mechanics of Stretching

There is something about stretching that I love. It may have something to do with the release of the “feel good” endorphins, as a strong physiological response. In studying and doing research for this YTT, I found myself very interested in understanding the mechanics behind stretching. It is pretty insane how our body works. Gaining a strong knowledge base behind the mechanics of stretching I believe will be key to not only to enhancing my personal practice but also the practice of others.

The muscle spindle stretch receptor is located in the belly of a muscle and is responsible for detecting changes in the length and tension of a muscle. When a muscle stretches, these receptors send signals to the spinal cord to contract and counter the stretch. This protects the muscle from being overstretched or tearing. When we hold postures for a longer period of time or when we back part way from the stretch, the firing rate of these receptors is lessened and we are able to go deeper into a stretch.

In connection to this mechanic is Reciprocal inhibition. When an agonist muscle contracts the antagonist extends in a yin yang manner. This spinal cord reflex assures that when a prime muscle contracts, its opposing one relaxes in order to accommodate the contraction. We are consciously able to work with this mechanism to improve and deepen our Asanas. When we hold poses and are told to engage a certain muscle group (ie the hip flexors) the opposing muscles relax in a reciprocated manner and we can melt deeper into the stretch.

Finally we have the Golgi Tendon Organ that is located at the joining point of a muscle and tendon. It detects changes in tension. When tension increases it signals our muscles to relax in order to prevent injury (contrary to the muscle spindle receptor which signals muscles to contract). Proprioceptive Neuromuscular Facilitation is a phenomenon based around this organ to really help with ones stretching. In PNF we intentionally contract one muscle in order to stimulate the Golgi tendon organ to send signals to relax the muscle. This creates a “slack” which we can take full advantage of to deepen a stretch. As teachers we may use this technique carefully with students to wean away from the use of blocks and go further into each stretch. This deepening instills in students a sense of confidence and progression, which may act as a motivator to be consistent in their dedication in practice.

As a yoga practitioner I am aware of the significance in stretching and am often learning ways in which to improve the alignment and depth of my stretches. As a teacher I want to know how and why stretching works. Understanding this will allow me to adopt techniques to facilitate stretching in a very safe but effective manner. It will shine light on how and why my students are moving the way they do and where I can work with their mechanics to improve their practice.

Laura McCone