The starter phase of a fitness program is important because it

⇒ aids  the performer in preparing  physiologically for exercise reducing the chance of joint and muscle injury.
⇒ prepared the body for exercising the blood flow to the muscles allowing them to loosen up which can raise the flow of oxygen to muscle cells.

Not sure exactly what kind of answer you are looking for so i hope this able to be a effective listener and also being  a good conversationalist. and most of all just being there when someone needs you.i hope this .