The ”hop and block” exercises are the most important concerning the preparation of the throw. The blocking of the left leg is the technical way to transfer the forces built during the run up (25% approximatively of the forces produced and transferred to the implements) . The ”hop” is the technical way to prepare for the block and also allows the thrower to prepare for the throw by getting in the most favourable posture.  There are many variations among the throwers on how to do this hop (With more or less impulse and suspension) and this block (Passive , active , full block , left foot orientation etc…) . It depends on the individual morphology and characteristics of the thrower. BUT , in all cases , the critical point of this phase concerns the right foot action at the landing of the hop and going into the block , it is really a turning point of the throw which connects the approach run up with the throw itself. For the coach it is an observation key phases which will tell him how technically good the thrower really is !