Plasticity occurs when a part of the body deforms irreversibly. Think of what would happen if you slowly stretched a plastic bag, the bag would lose its shape and, in that process, it would lose its ability to ‘bounce back’. The same thing happens in the body, where, as the result of sustained stress, the body stretches, irreversibly, into a new position.
This is very different from elasticity, although the two are often confused. Elastic tissue deforms but within a range that allows it to reform afterwards, just like when an elastic band is stretched and then released. If, on the other hand, the elastic band was stretched so far that it lost its ability to release, that would be an example of plasticity.
Fascial plasticity shapes the body and gives us access to more long-lasting flexibility. It can also assist with tissue rejuvenation. That said, a word of caution; fascia wears out if it is repetitively stretched or over-stretched over a long period of time. When fascia wears out in this way it loses its springiness and with that, also its kinesthetic intelligence and elastic recoil capacity. When our fascia wears out we need to focus, not on stretching further, but on practices that help it rehydrate and reinvigorate its sensory awareness.
If our desire is to train plasticity, it is helpful to lean towards relaxed poses (think yin practice) that are held for several minutes at a time. Movements that have a reinvigorating effect are also helpful, for example, gentle dynamic movements that gently engage the muscles and fascia that have just been released.
Did you know that fascia is responsible for the 'felt sense' of the body? Learn more about the quality of kinaesthesia here.