Contacting the ball at the top of arms reach
If I did not contact the ball at the top of arms reach I would loose acceleration because the force is greater when the arm is at full reach. By contacting the ball at full arms reach you are creating a longer leaver and increasing the moment of inertia by increasing the force upon which you can accelerate the arm forward to serve the ball. If the ball contacted beyond the top of arms reach the height of release is lower and it won’t make it over the net. If I do not have my arm stretched out to full length prior to contacting the ball I won’t be able to generate as much momentum and therefore transfer of momentum to the ball is not at its highest.
Stand with feet shoulder width apart
This is important as it ensures you are balanced. If not applied your base of support would be smaller and you would be unbalanced. Being unstable impacts the angle at which you can throw the ball and the angle at which the ball is contacted. An angle of release which is too low might result in there not being enough height for the ball to get over the net. A wider base of support would also allow the athlete to apply greater force. The greater the force applied the greater the acceleration and therefore the more effective the serve.
When moving to hit the ball, transfer your weight fully to your front leg. This is important because it will result in transfer of momentum. When the ball is hit momentum of the body and the ball is conserved. Some of the momentum generated by the body is transferred to the ball. Stepping forward allows for a more effective transfer of momentum. Transferring your weight fully onto your front foot by stepping forward also allows greater force to be applied through the principle of force summation. By using the large muscles first we can maximise the muscular force that each muscle group associated with...