Starting position

Starting position-  You want to have your knees bent slightly with the bar hanging from around knee level.
Shoulder Girdle- Scapulothoracis retraction (adduction) by trapezius middle and lower fibers, the Rhombiods.  Depression by the lower Trapezius, pectoralis minor and Subclavious.
Shoulder Joint- Ecentrically contracting your shoulder extensors by the posterior fibers of the deltoid, lower fibers of the Pectoralis Major, Latissimus Dorsi, Teres Major.
The Elbow and Radioulnar joint-  The elbow is stabilizing while the radioulnar joints are rotating 180 degrees from anatmical position by the pronator teres muscle.
Hip Joint- Is isometrically contracting by the Iliopsoas, rectus femoris, sartorius, pectineus, gracilis, semitendinosus, semimembranosus, biceps femoris, gluteus maximus, medias.
Knee joint- Is being isometrically contracted by the vastus lateralis, vastus medias and vastus intermedialis.