Lock from itself.

As lie on spine, uner waist applied rolled towel, legs are bended in knees under straight cover, feet are on floor, under head is stand of books, hands stretched up, wrists crossed till lock, do not opening fingers,turning a palms od crossed wrists from itself up, as here happening a hands turning in pre shoulders and elbow joints and good stretching in elbow joint, as here exercise is benefit in such diagnosis, as epicondylitis, as here are three variants for training.
Isometric as keeping palms turning from itself for 30 sec, after returning back theirs, repeat for three times.

Dynamic as turning palms from itself, keeping pose for three sec, turning wrists in initial pose,repeat exercise for 15 times.
Variant of this exercise,when you are hands stretching as for maximally behind head, as your shoulders joints allowing.