I’ve never been very flexible, even as a child.
However, now as an adult who has just turned 60, I find myself in some/many ways more fluid than other women my age.
I’ve talked here before about Rolfing, and what a tremendous difference it has made in my life. Not just physically either. When your body becomes more aligned and intergrated, your brain works better too. Also certain types of yoga, such as yin yoga, is very helpful in discovering your body.
What I have learned over the years is that forcing your body into positions it’s not ready for can bring about not only injury, but frustration.
In order for fascia to stretch you need to take a position to just where you feel a stretch, then back off about 10%.....then wait. After 2 to 5 or so minutes, you should feel a release. It will feel so delicious you’ll now want to stay there for more time.
If your fascia is all bound up though, you’ll experience much less success.
So yeah, you can make huge changes, if you give your body the room and time.
Don’t know about doing splits though, not every body is built to do that, and I personally don’t think it’s necessary to devise such an arbitrary goal.
It would be much much more useful to have your entire body working together rather than just proving to yourself you can force yourself into a position that really serves no purpose.