flexors

Does that mean if they aren't touching, your hip flexors relax?

Measurements included motor unit number, size and activation and voluntary strength of the elbow flexors and knee extensors.

Or the piece of plastic makes your molars and canines touch which causes your hip flexors to relax?

Lastly, exercise your supporting muscles, like hip flexors and stabilizers in your core and lower legs.

If you sit all day the couch stretch [1] helps a lot to undo the shortening in your hip flexors.

My self-diagnosis was some kind of muscle and/or tendon strain in my psoas / hip flexors.

You probably have lumbar lordosis, weak hip flexors, weak abs or all of the above.

It tends to shorten the hip flexors which ultimately can affect your lower back 3.

The anterior tilt is typically caused by short hip flexors and weak glutes/hamstrings to pull the pelvis back into a level position.

Lots of people who sit for most of the day have lumbar lordosis or weak hip flexors (I did).

Because of the nature of the subtle movements, your hip flexors are engaged often (as long as you don't completely slouch on them).

I also added more core-strength exercises, including some for the hip flexors, which might be helping support as well.