This is the 12620th most frequent Spanish word.
mueven
"Move" (third-person plural form of "mover").
In this sentence, 'mueven' is used as a reflexive verb indicating physical movement of oneself.
Ellos se mueven para ejercitarse.
They move to exercise.
Here, 'mueven' is used to describe the lack of mobility or action of an object.
Las ruedas del auto no se mueven.
The car wheels do not move.
In this context, 'mueven' refers to the action of moving a part of one's body deliberately.