Difficulty relaxing is strongly associated with emotional and psychological stress.

“I think there's a very clear association between an individual that um if you just look at them from a movement and exercise perspective has a very difficult time uh relaxing and uh and relaxing sounds like such a silly word but I mean that in a sort of a clinical sense right like if they can't let their rib cage down if they can't properly generate intraabdominal pressure if they can't go through a sequence of movements that generates some amount of motor control and compensatory relaxation contraction”