Stance

Stance - The quarterback stands behind the center and waits for the ball come into his hands, knees slightly bent and seeing what formation the defenders are lining up in.
Shoulder Girdle - Abduction with the Pectoralis minor and the Serratus anterior.
Shoulder Joint - Flex shoulder approximataly 45 degrees isometrically with slight adduction while waiting for the ball.
Elbow Joint - Both the elbow joints are in extension and muscles being used are anconeus, triceps brachii medial, lateral and long head.  Both the forearms are being pronated while waiting for the ball.
Hip/Pelvic Girdle - With the knees slightly flexed, the hip/pelvic girdle has slight external rotation on both sides working the pectineus, biceos femoris, gluteus maximus, piriformis, gemellus superior and inferior, obturator intermus and extermus and the quadratus femoris.  With this movement, the main plane of motion is the Transverse plane.
Knee Joint - Both knees are in slightly flexed approximately 20 degrees as well as externally rotated 30-40 degrees.  The muscles used for this motion to occur are biceps femoris, popliteus, semi-membranosus and the semi-tendinosus.