Execution

hip and knee - Isometric hold of the  bilateral hip flexors, sinster knee flexor and dextor knee extensor.
Hip flexor muscles used in isometric hold are Iliacus, Psoas major and minor, Rectus femoris, Sartorius, Pectineus, and the Tensor fasciae latae.

Knee joint - Knee flexors used in isometric hold are the Sartorius, Semitendinosus, Semimembranosus,  and the Biceps femoris.
Knee joint - Knee extensors used in isometric hold are the Rectus femoris.

Shoulder Girdle - Isometric hold in abduction (protraction) position of the pectroalis major uper fibers,  Deltoid anterior fibers, Deltoid middle fiers, Deltoid posterior fibers and the supraspinatus.  Isometric hold of the levator scapulae, serratus anterior, upper and middle, and rhomboids in the elevated upward rotation.   Isometric hold of the pectoralis major upper fibers, deltoid anterior, middle  and posterior fiibers and the supraspinatus in abduction(protraction) position.

Shoulder joint -  Isometric hold of your shoulder flexors and horizontal adductors for at least 10 seconds.
Shoulder flexors held in isometric hold are Anterior deltoid, and Upper pectoralis major.
Shoulder adductors held in isometric hold are Pectoralis major, Anterior deltoid and Corocobrachialis.

Elbow joint  -  Even though the shoulder adducts, the elobow joint holds in extension isometrically.
Elbow extensors held in isometric hold are the Triceps bracchii long, lateral and medial head and Anconeous.