(This is a little factoid that I shared on my yoga FB page, and I thought I'd also share it here on my blog because it's a pretty important concept for yoga teachers to understand. It's not a full blog post like my usual ones, but I have some more of those coming soon. :) )
SUPER COOL ANATOMY FACT #53: You probably know that your muscles move you around, but did you know that your connective tissue plays an important role in moving you around too? It's harder to picture because we know that our connective tissue doesn't actively contract like our muscles do. But our connective tissue actually stores what's called *potential energy* when it lengthens.
Think about this frog here. When this frog decides to jump, it first moves into a crouch, which stretches its tendons & other connective tissues, loading them with potential energy. When the frog releases this position, it certainly uses its *muscles* to propel itself forward, but its jump is hugely enhanced by the stored potential energy that was loaded into its connective tissues. It would never jump as impressively far if it didn't have its spring-like connective tissue to propel it much further than its brute muscle force alone could.
We humans rely on properties like this when we move too. It's therefore important to keep our connective tissue healthy for optimal energy storage and force transmission. One great way to cultivate healthy connective tissue is to integrate active stretching into your yoga/movement practice. When we strength-train our tissues at all ranges, we signal our connective tissue to grow stronger and stiffer ("stiff" being a good thing when we're talking about connective tissue!) We don't create healthy, efficient tissues by pulling on them and trying to make them longer - we create strength and resiliency in our tissues by making them stronger at all ranges.
Try thinking less about "length" and more about strength and efficiency in your yoga/movement practice and see if your flexibility magically improves anyway! My new hamstrings-focused online yoga practice is a great place to start if these ideas are newer to you. :)