usually when I have to poo.
Y’all missing the point. OP isn’t asking when to stretch. The question is what kicks off the feeling. Pretty certain it has to do with blood flow, as that’s the point of stretching.
I thought the point of stretching was to gain flexibility.
That’s a pre-exercise thing. I think OP’s talking about stretching in your chair or bed.
I find I’m far more flexible after exercise. Not supposed to stretch cold.
When your muscles feel tight or tense, or a bit achy, you’ll automatically feel like stretching them.
Every day. When I don’t, the odds of injury goes way up. The push notification is pulling a muscle.
If my joints feel a little stiff, or if I bend a certain way and it’s not real comfortable, then I focus on that and give it an extended focused stretch.
Also, it’s a good idea to stretch before any physical activity.
You don’t normally, until you get old and realize you’ve lost a ton of mobility. It’s something you need to actively notice.