The Answer

To begin it is necessary to define the sequence of movements necessary for an optimal execution of the forward pass skill. (For the description of the skill the below explanation is for a right handed athlete)

• The Athlete begins by positioning themselves side on, with their non-throwing arm facing their target.
• The athlete ensures that they have both their hands on the ball at or just below chest level. The right foot is planted and supports the weight of the body whilst the left foot is non-weight bearing ‘and underneath or slightly in front of the left hip depending on individual technique’. (Heppe, 1992)
• The throwing arm draws back behind the body with the elbow joint at a 90 degree angle.
• The leading leg strides forward and the hip abducts thus rotating the pelvis.
• The back foot pushes and the shoulders and trunk rotate towards the target.
• The rotation of the shoulders ‘initiates rapid elbow extension and the external rotation of the throwing arm reaches its maximal position’ this then needs to be followed immediately by an internal rotation of the throwing arm to bring the ball towards the target.
• The athlete continues the rotation of the body whilst sequentially extending the muscles from the shoulder joint all the way to the tips of the fingers towards the target. 
• The follow through allows full wrist flexion and rotation so that the hand finishes its range of motion with the palm facing the ground and fingers pointing at the target.  As a result rotational energy is applied to the ball which forces  the ball to spin, exhibiting the marker for successful skill execution the ‘spiral’