Can Intentionally Cramp Muscles

Hello folks, my mother and I are both suspected of having EDS and hope to go get tested. It would solve a huge medical mystery on that side of the family tree.

However, I'm curious if any of you can intentionally cause muscle cramps? I'm very inflexible and despite stretching and I have this weird thing where I can flex my muscles and they cramp in about 20 seconds. Not just my feet but my calves, upper legs, back, arms, neck, etc. I've slowly learned what positions cause muscle cramps and how to undo it. It's not all my muscles but a decent amount. A lot of "normal" stretching can cause it as well.

I have no mineral deficiencies and I'm very hydrated. I've been able to do this since I was a child. However, it's just very weird I was wondering if any folks here had similar issues?

Edit: Omg thanks for all the responses!!! I remember questioning all my friends over the past month and them thinking I was crazy for being able to do that. I got to hypothesizing that maybe the joint hypermobility was forcing the muscle to contract more intensely or in ways that it was not supposed to and that's why it would be seen with hypermobile folks.

However, I'm glad the community is so welcoming. I never even considered EDS as me and my mom are the most "inflexible people on earth". A couple weeks ago, my hypermobile friend clarified the difference to me and I scored quite high on the beighton scale. I did a bit more research and hachi machi, not only did a lot of symptoms match me but my mother and that side of the family (seriously, there were some very oddly specific ones). Even if we don't have EDS there's a high possibility for some connective tissue disorder and am reaching out to my cousin who does research (not saying what specifically b/c it'd be easy to find him, but it's got to do with genetics).